metalcasting industry research - springer · property improvements with sand cores in aluminum...

AFS Funded & Monitored ResearchFourteen active projects are currently being funded through the allocation of

a portion of the AFS Corporate Member Dues in FY2015–2016 and FY2016–2017.

Helium-Enhanced Semipermanent Mold

Aluminum Casting (12-13#05)

Coordinator: Prof. Paul Sanders, Michigan Tech University;Prof. Kyle Metzloff, UW-Platteville and AFS Aluminum Per-manent Mold Committee (2E)

Significance to Metalcasting Industry

Previous studies on helium-enhanced cooling were conductedfor aluminum sand and permanent mold casting (see refer-ences). One study (Doutre, 2000) mentions semipermanentmolding as promising, but does not document the process orproperty improvements with sand cores in aluminum casting.The objective of this work is to optimize and document theprocess parameters for helium-assisted semipermanent moldcasting of aluminum and characterize the resulting structureand properties compared to a baseline casting cooled withouthelium injection. Pilot-scale trials provide a cost–benefitanalysis that can be used by industry to help determine whe-ther productivity improvements can be realized with helium-assisted cooling in semipermanent mold (SPM) casting.

Abstract

Helium as a highly conductive gas may provide a method toincrease heat transfer into the sand cores used in

semipermanent mold casting. Silica sand has high heatcapacitance but when used as a permeable core has lowconductivity when compared to the ferrous mold materialmost commonly used in permanent molds. Semipermanentmold casting is an excellent application for helium-enhancedcooling, as the sand core(s) provide an ideal location forhelium injection and improved heat transfer in the slowestcooling part of the mold. The process, microstructure, prop-erties and cycle time improvements using helium-enhancedcooling have been measured and documented. Casting cycletime improvements of 7–11 % have been measured withhelium-enhanced cooling.

Keywords. semipermanent mold (SPM), casting, helium,cooling rate

Background

The effect of helium injection in aluminum permanent moldcasting has been investigated by Doutre (2000), Wan andPehlke (2004), and Metzloff (2009). Filling the air gap thatforms between the solidifying metal and permanent mold withhelium increases the heat transfer coefficient and castingcooling rate. Higher cooling rates decrease the time to ejectionresulting in throughput improvements. Doutre measured theeffect of helium on the cooling rate of several aluminum alloys

Metalcasting Industry Research

Support of research is critical for North America to maintain astrong, vibrant, healthy and continually advancing metalcastingindustry. Part of the AFS mission is to promote these activitiesfor the betterment of our membership, our industry and oursociety.

AFS directly funds research projects from allocation of aportion of the annual dues paid by AFS Corporate Member-ship. The current AFS Funded Research Projects are describedbelow. The other projects are funded through research part-nerships, government funding and industry contributions. AFSparticipates in these projects by securing industry partners andproviding technical management and oversight. Currentresearch funding partnerships include: the Advanced CastingResearch Center (ACRC) is part of the Metal ProcessingInstitute (MPI) at Worcester Polytechnic Institute (WPI), theUS Department of Defense (DOD), Defense Logistics Agency

(DLA), Castings Solutions for Readiness (CSR) Program fun-ded through the American Metalcasting Consortium (AMC),the National Network for Manufacturing Innovation and thethree current consortium: (America Makes—National AdditiveManufacturing Innovation Institute, Lightweight InnovationsFor Tomorrow—LIFT which was formerly called Lightweightand Modern Metals Manufacturing Innovation—LM3I andDigital Manufacturing and Design Innovation—DMDI), theNational Institute of Standards and Technology (NIST)AMTech award for advanced manufacturing technology plan-ning grant ‘‘The Pathway to Improved Metalcasting Manufac-turing Technology and Processes—Taking Metal CastingBeyond 2020’’ and the New Generation Sand Casting Con-sortium (NewGen), which is a partnership between AFS andthe National Industrial Sand Association (NISA) investing inmetalcasting research relating to improving and advancing sandcasting.

International Journal of Metalcasting/Volume 10, Issue 3, 2016 355

using cylindrical and plate molds and found a 30–50 %reduction in time to ejection temperature. Doutre found thathelium-enhanced cooling improved commercial semiperma-nent mold intake manifold casting productivity by 29 %, butthe details of the helium injection process (injection time,location related to cores, etc.) and the resulting microstructureand mechanical properties were not discussed.

Wan and Pehlke performed both modeling and experimentson helium injection on permanent molds. They found thatinjection of helium (as compared to air) improved coolingtimes to 400 �C by 37 % with conductive mold coatings and48 % with insulating coatings. Metzloff examined the effectsof helium-enhanced cooling in a production environment withconductive and insulating mold coatings and the effect ofexternal mold cooling. The helium injection was most bene-ficial with a standard insulating coating and external cooling,yielding a 33 % reduction in cycle time over the baselineproduction practice and a 10 % reduction over an optimizedcycle without helium injection. The permanent mold in thisstudy had a large internal metal core through which heliumwas injected. The benefit of helium was likely minimized as thecasting shrunk onto the metal core, decreasing the air gap inthe core area. It was thought that the helium injection wouldhave a greater effect if the air gap was larger, especially insemipermanent mold castings that have poor thermal con-ductivity in the sand core regions.

Saleem (2012) studied the effect of helium on the cooling rateand resulting properties of sand castings. This study found a43–100 % increase in cooling rate with a correspondingdecrease in secondary dendrite arm spacing (SDAS) leading toa 34 % increase in yield strength and a 22 % increase inultimate strength with no significant loss in ductility or increasein cost. Argyropoulos (2008) found that helium injection into arefractory mold made the gap develop up to 34 % fastercompared to air injection, but the heat transfer rate was higherby up to 48 %.

The objective of the study was to develop and document aprocess and the resulting microstructure, properties and pro-ductivity for He-enhanced semipermanent mold casting ofaluminum. In the case of this study, the helium was injecteddirectly into core which is expected to be in contact with theslowest cooling part of the casting.

Conclusions

A process for injecting helium into the core of a semiper-manent mold casting was documented, and the effects onmicrostructure, mechanical properties and productivity weremeasured and analyzed. The following can be concluded fromthis work:

• No significant effect on SDAS or mechanical propertiesdue to high PM heat transfer during solidification

• Injecting He into a SPM core decreases the total cycletime by 7–11 %

• MAGMA optimization was used to ‘‘estimate’’ thermalconductivity in the core with He injection

Status Update: The project is now complete and the finalreport has being written and will be distributed first to the AFSDivision 2 members and then made available for AFS mem-bers. Planning is now underway for utilizing the toolingdeveloped for this project to study the influence of sand corevariables in semipermanent mold dimensions. Updates aregiven at AFS Division 2 Aluminum 2E committee meetings,with the next meeting being June 2016–2017 at WPI. The finalresults will be published as an IJMC paper and will be pre-sented at the 2017 AFS Casting Congress. Those wishingmore information about the project should contact theSteering Committee chair Brian Began at [email protected] or Prof. Paul Sanders at [email protected].

High-Strength Cast Iron Castings Produced

by Engineered Cooling (14-15#03) Phase 2

Coordinator: Dr. Simon Lekakh and AFS Ductile Iron, CGIron & Gray Iron Research Committee (5R)

Significance to Metalcasting Industry

The possibility of the development of high-strength ductileiron in the as-cast conditions by applying engineered cooling(EC) to castings from temperatures above eutectoid reactionswas investigated. The application of EC was theoretically andexperimentally investigated for three metalcasting processes:cast into massive sand molds, cast into thin shell molds andfor continuously cast bars. The special EC method utilizedcontrolled impulse cooling parameters that were relevant forcastings with a variety of wall thicknesses. The developedstructure could be customized to achieve an attractive com-bination of strength, ductility and hardness.

Abstract

The possibility of development of high-strength ductile ironcastings in the as-cast condition by applying an engineeredcooling was investigated for three processes: cast into massivesand molds, cast into thin shell molds and continuously castbars. A bench-scale cooling device that included fine spraywide angle nozzles that are operated by computer-controlledsolenoid valves was used. The temperature of the casting wasmonitored by an infrared pyrometer. Engineered cooling wasapplied to castings shaken out early from a sand mold,through a thin shell mold without shakeout, and directly onthe surface of continuously cast bars. The computational fluiddynamic (CFD) simulation models were developed for thesecases, and the process parameters were experimentallyinvestigated for different casting geometries: plates, bars, box-type castings with internal cores and turbochargers. Theresults of several experimental heats with cooling parametervariations are illustrated by microstructures and tensile testsperformed on samples taken from the experimental castings.The possible strengthening level and process limitations arediscussed.

Keywords: ductile iron, solidification, structure, engineeredcooling

356 International Journal of Metalcasting/Volume 10, Issue 3, 2016

Background of High-Strength Cast Iron Processes

The structure of cast iron castings consists of eutectic graphiteof different shapes (from lamella to nodules) and a metalmatrix formed during eutectoid reaction at a slow cooling rate,because castings are still in the sand molds. In industrialpractice, the mechanical properties of cast iron produced insand molds are altered by controlling melt treatment(spheroidization and inoculation) and alloy chemistry (carbonequivalent, alloying). Because there are no special processesapplied after casting solidification, these methods could bereferred to as indirect control of metal matrix (Figure 1).

Indirect control of metal matrix. The kinetics of a eutectoidreaction depends on a carbon diffusion flux from austenite tothe graphite phase. If conditions allow carbon to escape fromaustenite to the nearest graphite phase, low carbon ferriteforms; however, when obstacles delay austenite de-carburiza-tion, it transforms to a ferrite/cementite mixture, termedpearlite. A pearlite/ferrite ratio is mainly a function of:

– nearest neighboring distance (NND) between graphiteprecipitates, which presents a scale of carbon diffusiondistance;

– Si and Mn segregation, which control carbon activityand diffusivity. Si and Mn have a strong tendency tomicrosegregation in a eutectic cell at the solidificationtemperature. Si has a negative segregation and concen-trates in the shell near graphite nodules, while Mnpositively segregates into intercellular regions;

– transformation time, which is related to casting wallthickness if the casting cooled in the mold duringeutectoid reaction (Figure 2).

Figure 3 illustrates theoretically predicted partitioning of ele-ments in a solidified spherical eutectic cell consisting of gra-phite nodules and austenite (FACTSAGE software, Scheilmodel with suppressed diffusion in solid). These segregationpatterns survive during cooling after solidification because ofthe slow diffusivity of substitutional elements (Si, Mn, Cu).However, high diffusion mobility of interstitial carbon pro-motes quick homogenization. Because the driving force of thishomogenization is a carbon activity, higher C and Mn ininterdendritic regions could be equilibrated with less C andhigher Si in the shell near graphite modules, as schematicallyshown in the insert on Figure 3.

Several three-dimensional models were suggested to predictthe particular rate of eutectoid reaction, controlled by carbondiffusion from the simple one-dimensional model, and thepearlite index (P) will be inversely related to completion ofcarbon diffusion (Fick’s law, Eqn. 1), which is governed by thesquare of the nearest neighboring distance (NND) betweengraphite nodules and the reaction time (s) that relates to wallthickness S taken in power n (Chvorinov’s rule):

s / NNDð Þ2=D Eqn: 1

P / NND2=Sn Eqn: 2

Because wall thickness also influences on NND, castinggeometry has a complex effect on the pearlite index (P) (Fig-ure 4): (i) in a 2- to 3-mm step, partially suppressed graphitenucleation during solidification (high NND) and intensivecooling during eutectoid transformation (low s), both promotepearlite formation; (ii) in a 5- to 7-mm step, a large nucleationrate of graphite decreases NND and promotes the completion

Figure 1. Indirect and direct methods for control ofmetal matrix in cast irons.

Figure 2. Factors controlling carbon diffusion duringthe eutectoid reaction in cast iron castings.

Figure 3. Simulated (Scheil model, FACTSAGE soft-ware) segregation of alloying elements in a eutectic cellat the end of solidification. The inserts illustrates Mn, Siand C partitioning in austenite before the eutectoidreaction


of C diffusion resulting in a ferritic matrix; (iii) increasing thewall thickness to 8–10 mm promotes pearlite formationbecause of a lower nodule count and an equally short reactiontime; and (iv) in a heavy section, slow cooling favors forming aferritic matrix even at a large NND. These results indicate thatindirect methods are not as effective for control of metalmatrix structure in castings.

Direct control of metal matrix in cast iron. Methods of directcontrol of strengthening the metal matrix (Figure 1) can bespecified as alloying, different types of heat treatments, and, aswill be discussed in this article, an engineered cooling process.Both the alloying and engineered cooling methods could beseamlessly incorporated into a metalcasting process, while heattreatment needs additional facilities. Engineered cooling couldalso be done for a lean cast iron composition.

A variety of strengthening mechanisms, effective in high-strength steels and non-ferrous alloys, could be exploited indirect methods for strengthening multi-phase cast irons(Figure 5):

– Solid solution strengthening. There are two possibledirections: one approach is to promote a fully pearliticstructure by alloying with Cu, Sn or Sb. It is believedthat Cu promotes pearlite formation by developing abarrier for C diffusion around graphite precipitates.Boron plays a controversial role in strengthening. Itannihilates the Cu effect in pearlitic ductile iron, whichcould be related to B absorption into the Cu haloaround graphite nodules and makes it ‘‘permeable’’ forcarbon diffusion. The second approach is solid solutionstrengthening of soft ferrite by Si, Ni, N and otherelements. The solute atoms generate compressive ortensile stresses in the Fe-bcc lattice, depending onsolute size, and act as barriers for dislocationmovement.

– Nanoscale precipitations of carbo-nitrides of transi-tional metals (Ti, Nb, V) at optimal sizes (5–30 nm)could be more effective barriers for a dislocation

movement when compared to individual solute atoms.A combination of low alloying with controlled coolingcan facilitate precipitation hardening.

– Work hardening by twinning-induced plasticity (TWIP)or transformation hardening by transformation-in-duced plasticity (TRIP). These strengthening mecha-nisms are observed in high-strength iron–carbon alloyswith metastable austenite.

Engineered cooling. Several different ideas, involving in-lineintegrated controlled cooling into the metalcasting process,have been discussed during the last few decades in the met-alcasting community in order to increase casting strengthwithout requiring an additional heat treatment. Recently,authors studied a process for direct development of high-strength ductile iron with an ausferrite structure in the as-castcondition. The process involved a combination of alloying by3–5 % Ni, early shakeout, air cooling and holding castings inlow thermal conductivity media to develop the bainiticstructure. The authors of this article developed a concept of‘‘Engineered Cooling’’ (EC) for the production of high-strength ductile iron without the necessity of expensivealloying or an additional heat treatment.

A detailed description of this process referred to as ‘‘Engi-neered Cooling’’ (EC) is given in references in the final report.Sand (green and no-bake) mold processes have a limited abilityto control the cooling rate during the eutectoid reaction due torestricted heat flux from the casting into the low thermalconductivity mold. The green dashed line on the continuouscooling transformation diagram (Figure 6a) schematicallyrepresents a cooling pass that produces the ferrite/pearlitestructure in sand mold castings. Alloying moves the trans-formation curves further to the right allowing a fully pearliticstructure to be formed at the lower cooling rate. Employing

Figure 4. Calculated pearlite index (P) versus castingwall thickness.

Figure 5. Possible phase strengthening mechanisms fordirect control of cast iron structure.


early shakeout and a specially designed EC schedule duringsolid-state transformations can control the structure withoutneeding to alter the alloy chemistry (red shaded area in Fig-ure 6a). The possible structures, achievable by EC, are shownin an experimental cooling diagram of unalloyed ductile iron(Figure 6b). The combination of high carbon concentration inaustenite and the suppression of carbon diffusion by a highcooling rate stabilizes the undercooled austenite. Under theseconditions, carbon is the transformation controlling element.

Computational fluid dynamic (CFD) simulations and experi-mental tests were used to study the EC process, and threecritical parameters were formulated. They include:

– cooling rate[2 �C/s, to develop the desired structureof metal matrix,

– limited temperature gradient in the casting wall(\100–1500 �C) to avoid excessive stress anddistortion,

– restricted final surface temperature above Ms([260–3000 �C), to avoid martensite formation.

In Phase I of this project, the concept of an EC process wasexperimentally verified for a 1’’ wall thickness plate casting. Asdescribed in this article (Phase II), the possibility of thedevelopment of high-strength ductile iron castings in as-castconditions by applying an EC was investigated for threeprocesses: cast into massive sand molds, cast into thin shellmolds and continuously cast bars. The results of severalexperimental heats with EC parameter variations are nowdiscussed.

The majority of industrially produced cast iron castings have amicrostructure consisting of graphite phase in ferrite/pearlitemetal matrix which were developed directly in metalcastingprocessing (as-cast) without needing an additional heat treat-ment. The ‘‘as-cast’’ cast iron structure was formed during:(i) solidification (prime structure) and (ii) eutectoid reaction

(final structure). The current state-of-the-art cast iron indus-trial processes mainly control the mechanical and thermo-physical properties through the prime solidification structureby:

• carbon equivalent variation for controlling primeaustenite/graphite eutectic ratio

• inoculation treatment for graphite nucleation anddecreasing chill tendency

• magnesium treatment for controlling graphite shape(flake in gray iron, vermicular in CGI and spherical inductile SGI)

• melt refining from dissolved impurities (S, O, N) and• melt filtration for improving casting cleanliness.

Practically speaking, only one method—an additional alloyingby Cu, Mo, Ni and other elements, is used for direct control ofthe structure of metal matrix formed during eutectoid reac-tion. The all described above methods could be called‘‘chemical’’ methods because they control the microstructurethrough changes in the cast iron composition. However,‘‘chemical’’ methods have some serious limitations: (i) high costof alloying additions, (ii) limited increase strength in as-castcondition, and (iii) need an additional austempering heattreatment for achieving a higher-strength of cast iron castings.

Analysis of the performance of standard cast irons with dif-ferent graphite shape and targeted properties is included in thisproject. The mechanical property data are represented by, socalled quality index, which is a strength/hardness ratio. Forexample, standard SGI is significantly stronger than CGI;however, SGI has lower thermal conductivity which is a lim-iting factor for application for cast components of intensivelythermo/mechanically loaded heavy-duty engines. The targetedproperties for CGI produced by a novel process in ‘‘as-cast’’are shown in Figure 1. The targeted strength of GI will benear the level of current CGI, and targeted strength of SGI in

Figure 6. (a) Illustration of phase transformations in castings from plain (black bold curves) and alloyed (black thincurves) ductile irons: green line—cooling in sand mold, red shaded area—EC process, and blue line—austemperedheat treatment; (b) structures achievable by applying continuous cooling to room temperature and to isothermalholding temperature (3800 �C) at different cooling rates.


‘‘as-cast’’ condition will be matched to the strength of heat-treated castings.

The objective of this project was to develop a novel metal-casting process for production of high-strength cast ironcastings in ‘‘as-cast’’ condition applying engineered cooling.The goals include:

• increase ‘‘quality index’’ (UTS/HB ratio)• increase strength without sacrificing toughness• decrease casting cost by eliminating alloying elements• decrease energy consumption for heat treatment

Conclusions

The possibility of the development of high-strength ductileiron in the as-cast conditions by applying engineered cooling(EC) to castings from temperatures above eutectoid reactionswas examined. The application of EC was theoretically andexperimentally investigated for three metalcasting processes:cast into massive sand molds, cast into thin shell molds andfor continuously cast bars. The special EC method utilizedcontrolled impulse cooling parameters that were relevant forcastings with a variety of wall thicknesses. The developedstructure could be customized to achieve an attractive com-bination of strength, ductility and hardness.

The EC process was applied to specific castings and resultedin the following outcomes:

– sand mold casting: high-strength structures of unal-loyed ductile iron were developed in castings with0.7–1.5 in. wall thicknesses;

– shell mold castings: process is not effective whencooling was applied through the low conductivity shell;

– continuous castings: direct controlled cooling of con-tinuously cast products could modify the structure inbars up to 8 in. in diameter in-line.

It is important to note that the developed simulation tools andimpulse method provide a large variation of cooling efficiencyand could be used for particular process set up. The possiblestrengthening level and process limitations have been the focusof this study.

Status Update: The project is now complete, and the finalreport has being written and will be distributed first to the AFSDivision 5 members and then made available for AFS mem-bers The project is being monitored by the AFS Ductile Iron,CG Iron & Gray Iron Research Committee (5R). Thosewishing more information about the project or how to par-ticipate as a sponsor should contact the PI Dr. Simon Lekakhat [email protected].

Development of Ultra-High-Strength

Lightweight Al–Si Alloys (13-14#01)

Coordinator: Dr. M. Shamsuzzoha and AFS AluminumDivision (2)

This proposal deals with the development of shape castingsthat produce high-strength hypo- and hypereutectic aluminum(Al)–silicon (Si) alloys with silicon content in the range of6–9 % and that possess nano-sized fibrous silicon morphol-ogy in the microstructure. In an Al–Si binary system,hypoeutectic is formed with a silicon composition lower than12.7 % of silicon. In the microstructure of hypoeutectic Al–Sialloys, two major components coexist: the primary and theeutectic phase. The primary phase consists of Al containingabout 1.67 % Si as solid solution that exists in the form ofdendrites, while the eutectic structure consists of an alu-minum-rich solid solution of silicon and virtually pure siliconand that is found in between the arms of the primary Aldendrites.

Typical hypo- and hypereutectic alloys grown by impurity-modified conventional casting exhibit a microstructure com-prising of primary Si that assumes sizes on the order of10-4 m and eutectic silicon with a rather course fibrousmorphology of sizes on the order of 10-6 m. These propertiesof the microstructure have not provided ultra-high strengthand fracture toughness for such as-cast alloys. Recently, a newprocedure based upon the concept of the solubility of barium(Ba) in the silicon phase has demonstrated that a hypereutecticAl-17wt%–Si alloy can be produced without a primary Siphase being present.

This work will establish the capability of the present process ofrefinement with respect to the required Ba additions, Si con-tent and refined microstructure in hypoeutectic Al–Si alloys. Insuch pursuits using permanent mold casting techniques, thefreezing parameters for an alloy that requires the optimumamount of Ba and that reveals nano-sized microstructure willbe determined. Thus, determined freezing parameters and Bacontent will be subjected to another round of permanent moldcastings in which various commercially available lightweightAl–Si hypoeutectic alloys will be used as starting materials. Allsuch cast alloys will be subjected to T6 heat treatment con-ditions whereupon mechanical properties of the resultingtempered alloys will be determined. It is expected that acomparison of the mechanical properties of these alloys withthose known for the commercially available lightweight alloysmay reveal the scale of improvement in the mechanicalproperties of the alloys grown by the proposed method. Inestablishing this capability, some concentration will also begiven to the related freezing parameters such as undercooling(DT), growth velocity (R), and the inter-lamellar spacing (k)with the microstructure of the resulting alloys. Such determi-nation is of importance with respect to the application of thistechnology to foundry castings of Al–Si alloys of improvedmechanical properties.

Status Update: The project work of this phase is complete,waiting for final report, and the findings will be discussed atthe AFS Aluminum Division 2 meeting on June 2016–2017 atWPI. Those wishing more information about the project orhow to participate as a sponsor should contact the Steering


Committee Chair Dave Weiss at [email protected] or the PI Dr. Shamsuzzoha, at [email protected].

New Measurement for Active Clay in Green

Sand-Phase 3 (14-15#01)

Coordinator: Dr. Sam Ramrattan, Western MichiganUniversity and AFS Green Sand Molding Committee (4M)

Measurement of live clay in molding sand is critical to controlof foundry green sand. Live clay levels must be controlled todevelop and maintain proper strength levels and mechanicalproperties of the molding sand. Control of the live clay level isalso critical in monitoring of moisture and compatibilitybecause clay is the primary moisture absorber in molding sand.If clay level could be better understood, the moisture andcompatibility could be more closely controlled. Inadequatecontrol of compatibility is the leading cause of green sandcasting defects, and the associated costs of scrap, rework, laborand energy to individual foundries and the industry as wholewarrant investigations into alternative methods of control. Thefoundry industry needs a faster, more accurate and low-costalternative to properly measure active clay in green sand. Themethylene blue clay techniques employed by the foundryindustry for measuring active clay suffer poor reproducibilityand are thus incapable of maintaining accuracy. Casting defectsare consistently attributed to variations in green sand systemsand limitations of the clay control methods for green sand. Abetter clay measurement technique is necessary to improvegreen sand systems.

With research support from AFS, Western Michigan Univer-sity (WMU) has developed a new methodology based on dyeabsorption for measuring active clays in green sand. The newprocedure provides a direct instrument read that requiresminimal operator training. However, there is concern regard-ing test-to-test variability using a particular anionic type dye(orange). Any new cationic dye consumable must be envi-ronmentally friendly, of lower cost and with easier clean-upcompared to the current procedure (Phase II). The AFS 4MGreen Sand Additives and Testing Committee remains inter-ested in finding a replacement for the methylene blue clay test.The AFS 4M Committee has endorsed the Phase II approachbut ‘questioned’ the selection of an anionic type dye (orange)and felt that test-to-test variability of results was not demon-strated to the satisfaction of the Steering Committee.

The purpose of this Phase III research is to identify a cationicdye for the absorption technique developed in Phase II.Another purpose will be to refine the procedure and conductindustrial trials using clay standards. Phase III research will beconducted according to specified tasks that are reviewed bythe 4M Steering Committee.

Status Update: The cationic dye was tested against varioussand mixtures and results evaluated by the AFS Green SandMolding Committee (4M). Although the dye and test proce-dure was found to give more consistent results than conven-tional clay testing in the range of 4–6 % clay, these results

could not be extended to higher clay levels, 8–10 %. It wasdecided by the 4M committee that a final report reviewing thetest approaches, results, issues encountered and test capabilityon all the findings, but to not pursue further development atthis time. Those wishing more information about the projectshould contact Dr. Sam Ramrattan at [email protected].

Application of DSC Coupled with TGA

and MS to Assess Sand Binder Emission (14-

15#02)

Coordinator: Dr. Scott Giese, the University of NorthernIowa and the AFS 4F, 4K and 10E Committees

Emissions of hazardous air pollutants and organic volatilecomponents have been a major concern for the foundryindustry in providing a safe work environment for theiremployees. Emission studies have evolved from the emissioncompound identification work performed during the 1990s tothe correlation of emission amounts per ton of metal pouredconducted in the 2000s, most notably, the extensive emissionstudy performed by the defunct Casting Emission ReductionProgram (CERP). Data collected and presented to the foundryby CERP provided critical information for developing bindertechnologies to address emission reductions in HAPs andVOCs.

The major concern in conducting emission studies is theresearch expense to pour actual castings and measuring theemissions during the pouring, cooling and shakeout segmentsof the metalcasting process. For each casting segment, emis-sion products need to be captured for each casting segmentand analyzed. Variability in emission components is intro-duced when different casting alloys are used to simulate var-ious segment heating rates. Additionally, continuous samplingover the casting regime only provides the total emissionamount over that particular time reference and fails to illu-minate the peak production of certain emission products.From the applied research approach, it is unclear whether thecomponents of emission production are a product of complexchemical reactions occurring between the coated sand grains ina soup of VOCs, HAPs and light gases as the casting cools orare from the rapid exposure of the heated molding sand andcore binder to an oxygenated environment during the shake-out of the mold.

Research by the University of Northern Iowa Metal CastingCenter on emission modeling collected supporting data usingDSC-TGA-MS techniques. Significant findings from theresearch program identified mold atmosphere, heating rateand isothermal heating as major factors in emission genera-tion. The DSC-TGA-MS capabilities permitted the use ofdifferent atmosphere blends, simulating neutral, reducing andoxidizing conditions. Interestingly, the emission characteristicsfor a reducing and neutral environment were identical, butoxidizing conditions significantly altered the decompositionbehavior. Higher heating rates showed some early suppression


of emission products, particularly at lower temperatures, andsome evidence of higher emission generation when heated toelevated temperatures. At the conclusion of the research work,several research questions were recommended warrantingfurther investigation in developing a low-cost testing proce-dure to assess the emission generation and characteristics forgreen sand and resin-bonded cores. These research inquirieswere

• What are the kinetic rates of HAP’s and VOC’sgeneration?

• How can the DSC-TGA-MS be utilized to replicateactual emission generation?

• Do volatilized HAPs and VOCs affect the emissiongeneration by altering the mold atmosphere?

The proposed research project will greatly contribute todevelop a low-cost emission protocol to assess HAP and VOCrelease into the workplace environment. The proposedresearch approach hopes to support several research areaswhere emission analysis is critical, particularly for gas evolutionin molds and cores to reduce gas-related casting defects.

Status Update: Most recently, casting experiments to identifythe light, fixed gases that are produced during the decompo-sition of phenolic urethane have been conducted. The infor-mation collected will provide the type of atmosphere necessaryfor the DSC-TGA-MS experiments. Those wishing moreinformation about the project should contact the SteeringCommittee chair, Mitchell Patterson, at [email protected] or Dr. Scott Giese at [email protected].

Reclamation of Investment Casting Shell

Materials (14-15#04)

Coordinator: Dr. Victor Okhuysen, California StatePolytechnic University, Pomona, and the AFS 4L InvestmentCasting Research Committee

Investment casting shell materials are used once and thendisposed. This has economic, environmental and logisticalcosts. Investment casting shell materials consist largely ofstucco, flour, binder and additives. Of these, the most costlyingredients are the stucco, flour and binder. During process-ing, the binder, usually colloidal silica, undergoes an irre-versible reaction to form silica gel. Thus, it is not feasible toreclaim the binder. The stucco and flour are used as aggregateswith the binder to produce the shell. These are the materialsthat this project will focus on.

The typical materials include mullite, fused silica and zircon.The zircon is a minor ingredient by volume, but due to itshigh cost, it is of great interest. The fused silica and mulliteare used in much higher quantities, and they also constitute asignificant expense. The first step in the reclamation processwould consist of the separation of stucco and flour particlesideally to their initial size distributions from the spent shellmaterial. There are multiple mechanical methods that arecurrently used for the separation of sand and binder in sand

casting. In addition, there is a significant expertise on particlegrinding in the ceramics and mining industry. It is anticipatedthat some of these methods will be applicable to the existingproject. Once this is attained, then the possibility of sepa-rating the zircon from the mullite and/or fused silica can becontemplated. For the purposes of this project, separation isnot being considered, but this would be a likely follow upproject in the future.

Phase transformations in the ceramic can occur during thethermal cycle of the investment casting shell. Zircon and puremullite are not anticipated to have phase transformations. Onthe other hand, fused silica is known to transform to crys-talline silica in the form of cristobalite. The transformation ofamorphous phases of silica begins at around 900 �C, and asthe temperature increases, the amount and rate of transfor-mation increase. The highest rates occur between 1100 and1200 �C, and nearly complete transformation is reached by1400 �C. Lower grades of mullite (47 % alumina) reporthaving some silica, though it is not specified if crystalline oramorphous.

An additional variable in fused silica consists of the alloysproduced. In the production of steel pouring, temperatures of1600 �C are used. These are clearly beyond the formationtemperature into cristobalite. Aluminum pouring tempera-tures, though, are usually around 700 �C, below the trans-formation temperature to cristobalite. Thus, a goal of thisproject is to investigate whether fused silica can be reused forlower-temperature alloys even if it can’t be reused in high-temperature alloys.

There are regulatory trends to have foundries reduce theirsolid waste streams and spent ceramics constitute the largestwaste stream for investment casters. The reclamation wouldhelp foundries meet the regulatory targets. Lastly, if investmentcasters reclaim their ceramics, this would also simplify theirsupply chain. They would be able to better control theirinventories and depend less on the vagaries of the market andpotential supply disruptions. Work performed in Polandshowed that the use of mechanically reclaimed shell materialsused in superalloy casting can produce shells with equal orbetter green strength by the use of reclaimed flours and stucco,but for high-temperature strengths, only the shells withoutreclaimed flour matched hot strengths.

Reclamation of the ceramic materials would save in both thepurchase of new raw materials and the disposal of the spentmaterials. A survey of investment casters was conducted byAFS where 89 % of the respondents indicated interest inreclaiming ceramics. The average consumption of non-zirconceramics by these facilities was 601,000 lbs per year. Anaverage price per pound was obtained based on available dataat $0.57/lb. The average benefit for a foundry would be$342,000/year. There are 22 AFS members for whom theimpact would be $7.5 million per year. A survey of thebroader US investment casting industry yielded at least 76investment casters, and the extended benefit would be$26 million/year. This assumes 100 % reclamation of non-


zircon flours and stuccoes. Thus, even if partial reclamationwas successful, it would still be in the millions of dollars.Furthermore, once the ceramics are ground, it would bepossible to look at zircon separation and zircon-specific reusewould greatly increase the economic impact. Furthermore, thisvalue also excludes shipping and disposal savings.

The project will produce a set of instructions and guidelines asto how to approach the reclamation of ceramic shell materials.Among these instructions, there will be: recommendedequipment (based on that used in the successful results in theproject), detailed procedures and detailed notes on any chan-ges on standard procedures currently in place. The targetdissemination will include reclamation and use instructionssuch as:

• How to grind the spent shells including do’s and don’ts.• The equipment used• The amount of reclaimed material that can be added• Detailed information on what changes the facility may

experience in the production characteristics of theslurry/stucco (i.e., different viscosity, higher/lowerslurry life, pH changes, greater/less need for wettingagents, antifoams)

These materials will be the basis of any papers presented at theCasting Congress or published in journals, the materials to begenerated for CMI training and for the poster presentations.Results on milestones will be published at the earliest oppor-tunity mainly through AFS channels.

Status Update: The project and initial testing is now under-way creating prototype molds in fused silica stucco and alu-minosilicates stucco to make the MOR (modulus of rupture)testing bars, with an active steering committee determiningslurry formulations to be tested. Those wishing more infor-mation about the project should contact the Steering Com-mittee chair, Matt Cavins, at [email protected] orDr. Victor Okhuysen at [email protected].

Influence of MnS on the Properties of Cast

Iron—Phase 2 (14-15#05)

Coordinator: Richard (Rick) B. Gundlach, Element Materialsand AFS Ductile Iron, CG Iron & Gray Iron ResearchCommittee (5R)

Sulfur is generally considered a tramp element in cast iron,and its level must be controlled. When manganese is notpresent at sufficient concentrations, sulfur reacts with iron toproduce a low-melting phase that can produce hot-shortnessin iron castings. Consequently, the industry has always addedmanganese to control sulfur in cast iron. Various formulaehave been promulgated in the industry for balancing MnS incast iron. Many employ a stoichiometric relationship betweenMnS, requiring an excess Mn content to avoid FeS forma-tion. Some simply employ a MnS ratio (such as 5–7) to

assure that no FeS forms. Others advocate that the sulfurcontent must simply be at or above 0.04 %S to obtainadequate inoculation response. With the exception of a fewinvestigators, none has considered the solubility of MnS fromthermodynamic principles.

Recent research conducted for the AFS 5R Committee underResearch Contract Project 12-13#04 ‘‘Influence of MnS on theProperties of Cast Iron’’ has demonstrated that, through bal-ancing MnS according to the solubility limit of MnS inclusionsat the eutectic temperature, the strength of gray cast iron canbe optimized. Based on the literature review and the experi-mental work, it was possible to define what MnS concentra-tions might produce the best properties with regard tostrength. The experimental work focused on Class 35 iron castin sections up to 3 in. and showed that at optimum MnSlevels, the strength can be 6–10 ksi higher than in poorlybalanced chemistries.

The results of the research on MnS in gray iron raise manyquestions and, also, new ideas for future research. Several ofthose ideas were discussed at the Spring 2014 5R Committeemeeting. The one that was selected for this phase included thefollowing activity to develop a better understanding of thestrengthening effects at the optimum MnS balancing. Whilethe current study showed that maximum strength occurs atcompositions close to the solubility limit of MnS, it is not clearwhat microstructural features were optimized. The numerousmetallographic samples that are available from the previousstudy are suitable for the proposed research. The samples willbe used to determine the microhardness of the pearliticmatrix. These data will be compared with the bulk hardness ofthe samples and correlated with the tensile strength of thealloys in order to determine whether changes in the pearliticmatrix contributed to the loss in strength in alloys with poorerMnS balancing. The same metallographic samples will also beused to perform a broader characterization of the graphitestructure, since the several observations from the previousstudy strongly suggest that the variations in strength are tied tochanges in the graphite structure. Features such as cell count,mixed graphite structures (flake distribution types) and theoccurrence of spiky graphite morphology will be investigatedas a function of MnS concentrations and section size.

Status Update: The project is now complete, and the finalreport has being written and will be distributed first to the AFSDivision 5 members and then made available for AFS mem-bers The project is being monitored by the AFS Ductile Iron,CG Iron & Gray Iron Research Committee (5R). Thesefindings were presented at the 120th Metalcasting Congress,Paper 16-163. A paper based upon this report will be pub-lished in the IJMC. Those wishing more information about theproject or how to participate as a sponsor should contact theSteering Committee chair Leonard Winardi at [email protected] or Rick Gundlach at [email protected].


NDT & Microstructure Correlations to Gray

Iron Aging (14-15#06)

Coordinator: Greg Miskinis, Waupaca and AFS Ductile Iron,CG Iron & Gray Iron Research Committee (5R)

Gray iron cast components are well known to age or ‘‘cure’’after casting, resulting in strength and resonant frequency (RF)increases over time. Previous research has shown this agingeffect to be logarithmic with most of the effect (70 % or so)coming in the first 15 days after casting. There are multipletheories, however, regarding how best to account for andbenefit from this aging process. One benefit may be areduction in machining tool wear. Improved tool life has beenfound to occur in aged castings in multiple machining trialsover the years.

The literature review provides two theories regarding themechanism of gray cast iron aging, precipitation of submi-croscopic nitrides and residual stress relief. The case for nitrideprecipitation rests ultimately on limited tensile data, which,with its large variation, needs a larger study to properly vali-date. The case for stress relief relies primarily on the agingeffect found in the resonant frequency (RF) of gray cast ironand the effect of stress inducing processing (shot blasting andmachining) to the RF and tensile strength.

Ultimately, the testing protocol documented here will need tobe repeated with ductile iron. This study will attempt todetermine the optimal balance of aging, part and NVH (noise,vibration, harshness) performance, and also secondary oper-ations versus processing limitations and inventory require-ments or work in process (WIP) costs. The project objective isthe determination of the ‘‘ultimate’’ cause of the agingresponse, leading to determination of the full aging time forgray iron castings, allowing for more precise nondestructivetesting and more successful secondary operations.

Status Update: The project is now complete, and the finalreport has being written and will be distributed first to the AFSDivision 5 members and then made available for AFS mem-bers The project is being monitored by the AFS Ductile Iron,CG Iron & Gray Iron Research Committee (5R). A paper16-017 was presented at the 120th Metalcasting Congress, anda paper based upon this report will be published in the IJMC.Those wishing more information about the project or how toparticipate as a sponsor should contact the Steering Com-mittee chair Matt Meyer at [email protected] orGreg Miskinis at [email protected].

Evaluation of SDAS for Revised Aluminum

Microstructure Wall Chart (14-15#07)

Coordinator: Dr. Robin Foley, the University of Alabama atBirmingham (UAB) and AFS Aluminum Division (2)

Background and Objective: The inventory of AFS AluminumDivision Microstructure Wall Charts is depleted and needs tobe republished for availability to aluminum foundries. It is also

a key resource to the aluminum classes taught by the Instituteand many of our universities with metalcasting and metal-lography classes. The chart features grain size and modifica-tion photomicrographs with numerical rating which bothcasting buyers and casting suppliers utilize. An additionalimportant microstructural feature has emerged over the pastseveral years—secondary dendrite spacing or SDAS—whichhas a direct correlation with solidification rate and subsequentmechanical properties. Since SDAS has a proven effect onmechanical properties in hypoeutectic aluminum–silicon alloysand is strongly related to microstructure, it is very desirable toincorporate these SDAS correlations in the updated AFSMicrostructure Control in Hypoeutectic Aluminum–SiliconAlloys Chart.

The objective of this applied research is to measure SDAS as afunction of solidification rate and then establish and publishmicrostructures on a range of SDAS results which can beincorporated into the renewed and republished wall chart. Thework is being performed at the University of Alabama atBirmingham (UAB) under the direction of principal investi-gator Dr. Robin Foley.

Status Update: This project is almost complete with a pre-sentation 16-146 given at the 120th Metalcasting Congress onthe work. This will become the basis for an updated AFSAluminum Microstructure Wall Chart and a potential CastAluminum Microstructure book. Those wishing more infor-mation about the project or how to participate should contactthe Steering Committee chair David Neff at [email protected] or the PI Dr. Robin Foley at [email protected].

Investigation of Cause of Microporosity

of Various No Pb Copper-Based Alloys (14-

15#08)

Coordinator: Dr. Charlie Monroe, the University of Alabamaat Birmingham (UAB) and AFS Copper Division (3)

Copper-based alloys are an important part of the metalcastingindustry for a variety of reasons which can be attributed tohaving a great range in mechanical properties and corrosionresistance. Copper-based alloys have been used in plumbingcomponents because of these desirable properties and tradi-tionally have had lead be a component in the casting. Leadprovides improved machinability and provides pressuretightness. As lead has been linked to health concerns, the SafeDrinking Water Act was passed to limit the lead in drinkingwater. This is what caused the need for new lead-free copper-based alloys. However, microporosity has been a commonissue with some low-lead copper-based alloys. This can causeunsound pressure tightness, which leads to higher scrap levelsthat increases the price of the part. Casting simulation toolshave been implemented with varied levels of results. Castingsimulation, along with research, will be the most practical wayto prevent microporosity, so it is important to correlate thetheoretical solidification science and practical solidificationscience (experimental results) to the theoretical application


(simulation) and practical application (casting) to producequality castings.

Microporosity is a hard defect to analyze because it is noteasily seen. This defect is not normally found until the castingis tested for leaks. Proof of microporosity is generally proventhrough optical microscopy. It is also hard to pinpoint whatcauses microporosity and each individual casting whetherthere is increased air pressure, lack of feeding or other possiblecauses may have to be considered. These micropores can alsocause detriments and strength or just overall losses inmechanical property. When a part has microporosity and it isput under pressure, the microporosity can serve as a nucle-ation site for cracks. In copper alloys, where they are mainlyused for plumbing applications, this pressure tightness is amandatory factor, so microporosity must be eliminated.

This effort under the guidance of the American FoundrySociety’s Copper Division 3 is being taken to understand themechanism and possible critical values that should be avoidedin creating microporosity. The research is split into three parts:causes for microporosity in sample, analyzing the sample andsimulating the microporosity. A Bridgman furnace will be usedto study directional solidification. It can give a steady meltfront, so that the cooling rate can be mapped. The cooling rateof the furnace can be adjusted to simulate cast thicknesses of1/8’’ to 8’’ thick. The speed of the melt front can be easilyvaried as well. This furnace also will allow for temperatureranges to be recorded, as well as only needing a small samplevolume. This should allow for a procedure to be established tocreate microporosity and be able to increase/decrease itsvolume.

Status Update: This project is just starting. Those wishingmore information about the project or how to participateshould contact the Steering Committee chair Kerry Bisset [email protected] or the PI Dr. Charles A Monroe [email protected].

Veining Reduction Project (15-16#01)

Coordinator: Dr. Sam Ramrattan, Western MichiganUniversity and AFS Mold Metal Interface Committee (4-F)

Foundry engineers have long known that there is high test-to-test variability with certain precision sand specimen. A Phase Isimulation analysis was used to improve a tool design forproducing 50, 8-mm-thick polyurethane cold-box (PUCB)disk-shaped specimens. Ramrattan et al. (2014) identifieduniformity in sand binder density distribution in PUCBspecimens. A new tool was built according to recommendationfrom the simulation, and specimens were produced. Physical,mechanical and thermo-mechanical testing was conducted onthe new specimens and compared to old. The results showthat there is lower test-to-test variability with the new disk-shaped specimens. The AFS 4-F Mold–Metal InterfaceCommittee has begun a research project aimed at reducing oreliminating veining using various thermo-mechanical models.Feasibility studies that evaluated three models as veining

predictors have been completed at Western MichiganUniversity (WMU), and the results are promising.

The aim of Phase II is to evaluate a variety of PUCB disk-shaped cores using casting trial models at cast irontemperature:

i. Model #1—variable point loadii. Model #2—tension stressiii. Model #3—variable specimen thickness

The purpose is to determine whether the models can be usedfor predicting the onset of veining and penetration comple-menting thermal distortion testing (TDT) developed in PhaseI and predict the onset of veining and penetration.

Status Update: The Phase II activity is just beginning, andinitial sample test specimens are being secured. Those wishingmore information about the project or participation shouldcontact the Steering Committee chair Fritz Meyer at [email protected] or Dr. Sam Ramrattan [email protected].

Effect of Dross and Gray Iron Skin

on Ductile Iron Fatigue Properties (15-

16#02)

Coordinator: John Reesman, Caterpillar and AFS DuctileIron, CG Iron & Gray Iron Research Committee (5R)

The mechanical properties of DI, as those of most metallicmaterials, are measured on and reported (as per ASTM) onstandard machined specimens. However, most castings retainmost of the as-cast surface. This surface layer, commonlyreferred to as the casting skin, includes both surface andsubsurface and is typically incorporated in the term surfacequality. Because of the casting skin, the mechanical propertiesof the part may be significantly different from those found onthe standard ASTM specimens machined from the samecasting. It is expected that as the thickness of the castingdecreases, the relative effect of the skin on the mechanicalproperties increases. This issue has received only limitedattention.

The primary objective of the project is to quantify the impactthat endogenous dross (from liquid iron oxidized during moldfilling) has on the fatigue properties of ductile iron. The sec-ondary objective is to share, with members of the AFS, theknowledge associated with those findings in terms of theimportance of that mold filling speed might have on thefatigue resistance of the cast DI parts and characterization ofcasting defect causing the reduced fatigue strength.

The innovative aspect of this project resides primarily in thequantification of the impact of a very concrete castingparameter, the mold filling speed. Foundry men know that it isusually not well advised to rapidly fill a mold cavity. However,the impact that such a practice might have on the fatigueresistance of castings is completely unknown. Will rapidlyfilling a mold reduce the fatigue resistance of a part by 2, 25 or


50 %? Currently, no one can answer this question; there aretoo many parameters which come into play, such as skin effect(formation of a thin gray iron layer) or even the presence ofsand particles, to reliably come up with an answer.

The testing process designed for this project will be useful forfoundries which are contemplating similar work for givencustomers. However, most importantly, the informationgathered throughout this project will be an invaluable for AFSmembers, as they strive to compete on the internationalmarkets by providing high-quality products.

Status Update: This project has just started. The work is beingmonitored by the AFS Ductile Iron, CG Iron & Gray IronResearch Committee (5R). Those wishing more informationabout the project or how to participate should contact theSteering Committee chair Mark Osborne at [email protected] or John Reesman at [email protected].

Improving Dimensional Accuracy

of Castings from Silica Sand Molds (15-

16#03)

Coordinator: Sairam Ravi, the University of Northern Iowaand the AFS Cured Sand & Aggregate (4K)

The rules of thumb concerning dimensional changes frompattern to final casting are not accurate enough to predictactual casting dimensions. Metalcasters will usually require upto several trial castings and pattern revisions before they meetthe customer’s dimensional accuracy requirements. This alsocauses design engineers to add extra machine stock, whichinflates the cost of every cast part produced from silica sandmolds and cores. Typical machining for castings may cost asmuch as five to seven times what the original casting cost. Thisoften makes it more economical to produce machined partsfrom rolled alloy rather than castings. Computer simulationsthat predict final casting dimensions based on the propertiesof the molding aggregates can help in solving this issue whileproviding sustainability to silica sand molding. The NewGeneration Sand Consortium (NewGen) and AFS jointly fundthis project. The work is being conducted at both theUniversity of Northern Iowa (UNI) and University of Ala-bama at Birmingham (UAB) under the direction of UNI.

Objectives & Goals:

• Foundry validation of existing dimensional accuracycode by working with operating foundries to simulateand measure casting dimensions on production parts.

• Refine code as needed to match non-constrained coreconditions.

• Determine high-temperature retrained strength ofPUCB and PUNB cores and adjust code to compen-sate for casting solidification constraints.

• Foundry validation trials in iron for constrained castingdimensions.

• Additional material validation and process simulationcode refinements.

Status Update: This project has just started. The work isbeing monitored by the New Generation Sand Consortium(NewGen) and AFS Cured Sand & Aggregate (4K). Thosewishing more information about the project or how to par-ticipate should contact the Division 4 chair Steve Neltner [email protected] or the PI Sairam Ravi [email protected].

Prediction of Gas Evolution

from Chemically Bonded Sand Molds using

Process Simulation Software (15-16#04)

Coordinator: Sairam Ravi, the University of Northern Iowaand the AFS Cured Sand & Aggregate (4K)

Gas evolution from chemically bonded sand molds is of amajor interest to the foundry industry. It is known that con-siderable amounts of gases are evolved from sand molds andcores when molten metal is poured against them. The gasevolved, if not vented properly, may be absorbed in the metalbefore solidification, hence resulting in gas porosity in thecasting.

Several published research papers document the importanceof gas evolution from sand cores and molds and its effect onporosity. Charles E. Bates and Andrei Starobin have developedmethods for predicting local gas pressures in chemicallybonded cores and molds for iron and aluminum alloys. It hasbeen determined that gas bubbles can form when the internalcore pressure exceeds the metal-head pressure, which occursas soon as molten metal comes in contact with the core andvolatilizes the binder. Depending on the permeability of thesand and the internal core pressure, these bubbles can betrapped in the casting as solidification of the metal occurs.However, currently, the technology to predict and simulate thegas evolution from resin-bonded cores using process simula-tion software packages is still in its initial stages.

The University of Northern Iowa Metal Casting Center hasdeveloped a methodology to accurately measure gases evolvedfrom chemically bonded sand using DSC-TGA techniques.The resulting gas evolution data can be used in conjunctionwith already published research on gas bubble formation indifferent alloys to predict gas bubble formation in differentareas of the casting. Application programming interface (API)algorithms can then be developed for the major processsimulation software packages to display the gas evolutionresult in a form that will be easy to decipher for the end user.The API algorithms will use the simulation temperature dataat all points in the mold or core to calculate the formation ofgas porosity.

Status Update: This project has just started. The work isbeing monitored by AFS Cured Sand & Aggregate (4K).Those wishing more information about the project or how toparticipate should contact the Division 4 chair Steve Neltner [email protected] or the PI Sairam Ravi [email protected].


Metalcasting Industry Funded & Monitored Research

American Metalcasting Consortium/U.S. Department of Defense/

Defense Logistics Agency Funded Projects/

National Institute of Standards/AMTech Program

Castings Solutions for Readiness (CSR)

Program

AFS, as part of its efforts in the American MetalcastingConsortium (AMC), has recently secured contracts fundedthrough the US Department of Defense, Defense LogisticsAgency, Defense Supply Center Philadelphia and the DefenseLogistics Agency, Ft. Belvoir, VA. The group of projects isunder an AMC program entitled Castings Solutions forReadiness (CSR). The two new projects are continuations ofprevious AFS AMC efforts, including one project calledCast High-Integrity Alloy Mechanical Property Stan-dards (CHAMPS) and the other Casting Standards andSpecifications.

CHAMPS Project—Additional Alloy Design Data

The CHAMPS Statistical Properties Project goal is incorpo-ration of material property design data for additional castalloys, A206-T4 and T7 in a project that is just completing andjust starting investment cast stainless steel 17-4-PH and15-5PH. These will be included into MMPDS (MetallicMaterials Properties Development and Standardization)handbook, which replaced Mil-Handbook 5, so that thismaterial can be specified and used to design and manufactureflight critical components in military and civilian aircraft. Thisbuilds on the original just completed E357 effort of estab-lishing a framework to design a series of test specimens thatencompass the various section thicknesses used in theseapplications utilizing process simulation software, validate theapproach metallographically, coordinate collection of requiredsamples from a consortium of qualified foundries and submitthe data for statistical analysis and approval by MMPDS boardfor incorporation into the MMPDS standards. The benefit toDLA is that the development of statistical-based property datawill permit the use of castings across a broader range ofapplications and will provide the following benefits. TheEngineering Support Activities at the DLA will be able tomake cast alloy conversion/replacement decisions withassurance using statistical data on tensile, compressive, shearand bearing properties from the FAA recognized source,MMPDS Handbook. Also reduced lead times with castcomponents competing on an equal basis with forging andassemblies from sheet, plate and extruded mill products.

As with the E357 project, the intended outcome will be castA&B design property allowables for the alloys selected forinclusion in the MMPDS (old Mil Spec Handbook 5) to meetFAA requirements. This will allow aerospace design engineers

to specify castings without using design safety factors. AFS isworking with its own 4L (Investment Casting TechnicalCommittee) and the ICI (Investment Casting Institute) tech-nical committee to create various working groups that areactively reviewing melt practices, test casting gating and rig-ging, investing practices, heat treatment parameters and testingprotocol. A special casting test plate was designed forextracting test specimens and also attached as-cast coupons.These plates will be tested for various MMPDS properties,including tensile properties, and undergo microstructuralevaluation. The coupons will also be tested for tensile andfatigue properties. The project is now starting with the mod-eling of the gating and rigging completed and wax patternbuilt. The waxes will be supplied to participating foundries.Those wishing to participate or wanting more informationshould contact Steve Robison, AFS, at [email protected].

Casting Standards and Specifications

Accessing state-of-the-market technical, specification andtraining materials for castings is challenging. AFS is working toprovide current and qualified information in a networkfriendly form to users of castings via the Casting Standardsand Specifications project. The effort includes both archivaland recent technical information in searchable databases.Specifications and standards are summarized, and the user isguided in their application. Tutorials covering the fundamentaldesign concerns are also presented. The development of anonline material design property database will greatly enhancethe ability for the next generation of component designer tocreate the lightest weight and most efficient parts quicker andat lower cost. These tools facilitate more effective and efficientprocurement to both DoD and industry in the support ofweapon systems. Along with data from various AFS researchprojects, like the recently completed 08-09#01 & 08-09#03projects for the Development of Fatigue Properties Database,AFS has also incorporated the USAMP Light Metals MaterialsDatabase properties and recently strain life fatigue data forCGI Grade 400 and a hi-alloy Class 40 Gray Iron into the AFSCasting Alloy Data Search (CADS) onto the AFS design Website: www.metalcastingvirtuallibrary.com/cads/cads.aspx. Thiscompletes this phase of the project, and AFS is working withvarious groups, including design software providers, the designdepartments of OEMs and ASM to create Cast Alloy MaterialProperty Datasheets to be put on the ASM Material Selectorand AFS websites. This work has been compiled into anupdated DVD that is available from the AFS bookstore. This


http://www.metalcastingvirtuallibrary.com/cads/cads.aspx

is an outstanding resource for those needing validatedmechanical properties that design engineers need to make themost efficient components. The work planned under thisproject will add design properties for 4–5 additional cast metalalloys per year, while continuing to upgrade the CADS onlinedatabase. During the first 2 years, work was completed onClass 25E Gray Iron, Ductile Iron EN-GJS500-07 (lowerhardness version of 80-55-06) for 1 and 3 in. section thick-ness, HiSiMo Ductile Iron, and 1 and 2 in. section AluminumE357, with specimens coming from the previously completedCHAMPS E357 project. Work is completed for an aluminumAl4Si with samples produced in both sand and permanentmold, 535 and planned for A206. Just starting is testing for (3)cast steel grades (WCB, 4330 and 8630) with material securedfrom various sources.

For more information, contact Zayna Connor, AFS, [email protected] or AFS technical and library services,Katie Matticks at [email protected].

National Institute of Standards (NIST)

AMTech Program

Pathway to Improved Metalcasting Manufacturing

Technology & Processes–Taking Metalcasting Beyond

2020

The National Institute of Standards and Technology (NIST)awarded an advanced manufacturing technology planninggrant to a metalcasting project submitted by the AmericanFoundry Society (AFS). The Pathway to Improved Metal-casting Manufacturing Technology and Processes—TakingMetalcasting Beyond 2020 project is one of the 19 initiativesthat were awarded a total of $9 million to develop technologyroadmaps aimed at strengthening US manufacturing andinnovation performance across industries.

AFS is the lead organization in the project that will be laun-ched by the American Metalcasting Consortium, which iscomposed of four industry associations that represent 95 % ofthe nation’s 2000 foundries. The goal is to conduct anindustry-wide roadmapping effort to identify research andrelated actions aimed at achieving significant improvements inprocessing capabilities and productivity. Specific objectives areto:

• Reach industry consensus onmetalcasting capability gaps,solution priorities and investment recommendations.

• Identify potentially transformative technologies requir-ing collaborative research.

• Establish clear problem definitions and a commonframework for parallel work by multiple organizations.

• Chart a transition path to facilitate interoperability ofdeveloped solutions with existing systems.

• Build a collaborative infrastructure tailored to theroadmap’s targeted outcomes.

• Initiate development of an infrastructure that supportsan advanced US metalcasting industry.

Castings are in every sector of the economy including trans-portation, energy, mining, construction, maritime, fluid power,instrumentation, computers, defense and household products.A strong US metalcasting industry is needed to maintain globalcompetitiveness. To improve the domestic metalcastingindustry, there are significant challenges needed to improveproductivity, manufacturing practices, advanced alloy andcomponent performance, and attract employees and studentsneeded for energy efficiency, and environmental compatibility.The vast majority of metalcasters are small businesses that donot have the resources to perform the advanced research anddevelopment necessary to remain competitive and maintainsustainable enterprises

The American Metalcasting Consortium (AMC) roadmap-ping planning process identified, selected and developedtechnological alternatives to ensure a competitive US met-alcasting industry. AMC integrates the nation’s top aca-demic metalcasting researchers with the four leadingmetalcasting industry associations (American FoundrySociety, Non-Ferrous Founders’ Society, North AmericanDie Casting Association and the Steel Founders’ Society ofAmerica) and their members to identify new technologiesand processes to enhance the global competitiveness of theUS metalcasting industry. AMC developed a roadmap withan integrated, prioritized and readily executable plan ofaction based on mapping capability gaps to solution pathswith the greatest potential to meet goals of the industry.The roadmap resulting from an industry-wide set of sur-veys and an AMC Metalcasting Roadmapping Workshopheld on May 12–13, 2015, has been created and will bedistributed by the AMC association members and accessvia the AFS website.


National Network for Manufacturing Innovation

America Makes—National Additive Manufacturing

Innovation Institute

America Makes is the National Additive ManufacturingInnovation Institute. As the national accelerator for additivemanufacturing (AM) and 3D printing (3DP), America Makesis the nation’s leading and collaborative partner in AM and3DP technology research, discovery, creation and innovation.Structured as a public–private partnership with memberorganizations from industry, academia, government, non-government agencies, and workforce and economic develop-ment resources, its mission is to innovate and accelerate AMand 3DP to increase our nation’s global manufacturing com-petitiveness. AFS is partnering with Youngstown BusinessIncubator (YBI) who has been named a recipient of fundsfrom America Makes for the research project ‘‘AcceleratedAdoption of AM Technology in the American FoundryIndustry.’’ Along with YBI, Youngstown State University(YSU), ExOne, Humtown Products and the University ofNorthern Iowa (UNI), the project team for ‘‘AcceleratedAdoption of AM Technology in the American FoundryIndustry’’ will support the transition of binder jet AM to thesmall business casting industry by allowing increased access tothe use of binder jet equipment and the development of designguidelines and process specifications. The AFS and theAmerica Makes Consortium held a very successful session atthe recently completed 120th Metalcasting Congress andCastExpo 2016. It was attended by almost 200 participantsand reviewed the key aspects of the technology, latest researchand advancements, how the technology can promote andenhance design freedom and product improvement. The firstAFS ad hoc committee on Additive Manufacturing is nowactive and has held three meetings with a meeting and tour ofthe Caterpillar Mapleton facility and in-plant 3DSP system sitefor July 25–26, 2016. Planning is now underway for the firstAFS AM-4-Metal Casting Conference to be held at the NoviSheraton, Novi, MI October 3–6, 2016. The program willinclude tours of various AM printing sources (ExOne, Vox-eljet) and foundry users of AM, along with a 2 � day technicalprogram. See the announcement in the IJMC..

Lightweight Innovations For Tomorrow—LIFT

The Lightweight and Modern Metals Manufacturing Inno-vation—LM3I—has been renamed LIFT (LightweightInnovations For Tomorrow) and is headquartered in down-town Detroit. LIFT is led by Ohio-based EWI (EdisonWelding Institute), a company that develops and appliesmanufacturing technology innovation within the manufac-turing industry. AFS is part of a 60-member consortium thatwill pair leading aluminum, titanium and high-strength steelmanufacturers with universities and laboratories pioneeringnew technology development and research. ‘‘The long-termgoal of the LIFT LM3I Institute will be to expand themarket for and create new consumers of products and

systems that utilize new, lightweight, high performing metalsand alloys by removing technological barriers to their man-ufacture,’’ the White House said. The Institute will seek toachieve this through leadership in pre-competitive advancedresearch and partnerships across defense, aerospace, auto-motive, energy, and consumer product industries. The WhiteHouse noted that lightweight and modern metals are utilizedin a vast array of commercial products, from automobiles, tomachinery and equipment, to marine craft and aircraft.‘‘These ultra-light and ultra-strong materials improve theperformance, enhance the safety, and boost the energy andfuel efficiency of vehicles and machines,’’ the White Housesaid. The Institute will advance the state of processing andfabrication technologies for lightweight and modern metalsby facilitating the transition between basic/early research andfull-scale production of associated materials, components andsystems. AFS will champion the role of the metalcastingindustry as a key metals manufacturing sector in this effort,with two initial projects being started in the casting area: oneon thin-walled ferrous and the other on thin-walled non-ferrous castings. A presentation discussing the Thin WallFerrous Casting project first-year activities was presented atthe 120th Metalcasting Congress, (Presentation 16-165).

Digital Manufacturing and Design Innovation—DMDI

The idea behind the Institute is that manufacturing is beingtransformed by digital design, which replaces the draftsman’stable with the capacity to work and create in a virtual envi-ronment. AFS feels that the establishment of a Digital Man-ufacturing and Design Innovation (DMDI) Institute willincrease the successful transition of digital manufacturing andinnovative design technologies through advanced manufac-turing, create an adaptive workforce capable of meetingindustry needs, further increasing domestic competitiveness,and meet participating defense and civilian agency require-ments. This project will benefit the US manufacturing industryby providing resource, focal point and network for resolvingtechnical barriers currently limiting the application and inte-gration of digital manufacturing and innovative design tech-nologies. As it relates to the metalcasting industry, the use ofthese technologies will assist in the more rapid developmentand production of lighter weight metalcast components formilitary, energy, transportation and commercial applications.This can allow for design innovation via part consolidationand near net-shape capabilities of metalcasting, the weightreduction potential of such materials as magnesium, alu-minum, titanium and next-generation ferrous metals, and theimproved quality and productivity of advanced casting pro-cesses, this unique program can make significant stridestoward production of high-integrity, complex cast componentsand advance our manufacturing base. The Institute will also bea resource for training our workforce from manual labor tomore highly skilled and technical jobs.


AFS Information Services

Casting Process and Alloy Assistance

The AFS website offers assistance for casting design engineersin selecting the best casting process for a potential component,and also provides casting alloy design and property data onmany commonly used alloys. The website provides castingusers, design engineers and purchasers with relevant andaccurate information on casting capabilities and properties,providing easily accessible and retrievable information from asingle site. The alloy data can be quickly exported to aspreadsheet or FEA tools. The comprehensive site includesassistance for selection of alloys, casting process, alloy prop-erty data for many common alloys and a metalcaster directoryto locate potential casting sources. The Casting Alloy & Pro-cess Selector, the Casting Alloy Data Search and the Metal-caster Directory are located on the AFS Web site,http://www.afsinc.org/. Contact Katie Matticks, technical andlibrary services for assistance or more [email protected].

Technical Resource

Technical department staff and technical committee membersprovide regular contributions to MODERN CASTING andMetal Casting Design & Purchasing magazines. CastTIPand testing 1–2–3 columns are regular features and documentthe best practices for various procedures and tests used in themetalcasting industry and various casting defects, includingpotential causes and solutions. AFS technical staff associatesare available to support AFS members with technical help,casting problems and metalcasting information. Assistance isavailable through telephone, e-mail requests and CastingCon-nection discussion posts.

CastingConnection

Want to be connected to the metalcasting industry like neverbefore? Whether you are an AFS member, or thinking of

becoming one, the AFS CastingConnection private social pro-fessional network is where your experience begins. Cast-ingConnection is an environment to connect, engage and sharecritical industry information and best practices in real time.Through the Open Forum and sites devoted for our specialinterest groups, members can gather to network via a compre-hensive member directory, participate in focused discussiongroups and access and share useful and informative documentsand media in all formats. Visit https://castingconnection.afsinc.org.

Library

The AFS online library database serves the needs of themetalcasting industry for current and historic metalcastinginformation. AFS is continuing to electronically archive the fullAFS Transactions series using nondestructive scanningtechnologies. The project is nearing completion, with all AFSTransactions fully electronically archived and web searchable,from the very first edition (published in 1896) to the present.Located at www.afslibrary.com, the website houses a largecollection of metalcasting reference material. For moreinformation on the library website, contact AFS technical andlibrary services, Katie Matticks, [email protected].

AFS is launching an incredible new program that providesunlimited access to e-learning as well as our entire AFS OnlineLibrary at one set price. We are offering this exciting newindustry-specific training, information and education programat an introductory price and only to our Corporate Members.Starting July 1, 2016, the e-Learning and Library SubscriptionProgram will give subscribing organizations full access toonline modules for formal staff training or when specificneeds arise, plus unlimited access to the AFS Online Librarycontaining thousands of technical papers and articles. You canfind more information and a video showcasing the interactiveelements of the course modules at www.afsinc.org/elearning.

AFS Technology Transfer

CastExpo’16/120th Metalcasting Congress

More than 6000 metalcasters attended the recent AFSCastExpo’16 at the Minneapolis Convention Center, April16–19th. The event featured more than 460 exhibitors on theshow floor, keynote speeches, technical presentations and AFSInstitute courses. CastExpo is the largest trade show andexposition for metalcasting in the Americas and offers met-alcasters, suppliers, and casting buyers and designers theopportunity to connect and educate themselves on the latestand greatest metalcasting has to offer. The education sessionsprovided four days of practical advice, the latest technology,foundry case studies as well as opportunities for personal andprofessional development. Education targeted all job

responsibilities, from executives to plant floor personnel, andincluded keynote speakers and metalcasting courses from theAFS Institute. A new feature, the AFS Hub, offered a publicarea on the show floor for meetups, foundry in a boxdemonstrations, a photographer for professional headshots,and presentations by exhibiting AFS Corporate Membersshowcasing technology and innovations. This area also inclu-ded virtual reality and 3D printing demonstrations. For moreinformation on CastExpo, contact Metalcasting Congresscoordinator Pam Lassila at 847/824-0181 x240, or [email protected]. Next year’s 121st Metalcasting Congress isscheduled for April 25–27, 2017, at the Wisconsin Center,Milwaukee, WI.


http://www.afsinc.org/

https://castingconnection.afsinc.org

https://castingconnection.afsinc.org

http://www.afslibrary.com

http://www.afsinc.org/elearning

Conferences, Workshops and Webinars

AFS Conference on Additive Manufacturing for Metalcastingis scheduled for October 3–6, 2016, in the Detroit MI area, atthe Sheraton Detroit Novi, Novi MI. This conference willcover all areas relating to the emerging technology of 3Dprinting and additive manufacturing (AM) in the metalcastingindustry. Sessions will include component design for AM,

mold design and modeling, equipment, materials, investmentcasting and case studies of foundry applications. The confer-ence will also feature several plant tours of additive manu-facturing metalcasting facilities. For more information on AFSconferences and workshops, contact Laura Kasch, AFStechnical assistant, 847/824-0181 x246, or [email protected].

Metalcasting Industry Calendar of Events

2016

Aug 7–8 AFS Advanced Foundry Waste Seminar, Milwaukee Hilton City Center, Milwaukee, WI

Aug 9–11 AFS 28th Environmental, Health & Safety Conference, Milwaukee Hilton City Center, Milwaukee, WI

Aug 22–23 AFS Leadership Summit, Location to be determined

Sep 11–13 AFS Foundry Executive Conference, The St. Regis Deer Valley, Park City, UT

Sep 26–28 North American Die Casting Association (NADCA), Die Casting Congress and Tabletop, Greater ColumbusConvention Center, Columbus, OH

Sep 28–30 65th AFS Northwest Regional Conference, Coast Inn and Suites, Vancouver, BC

Oct 3–6 AFS Conference on Additive Manufacturing for Metalcasting, Sheraton Detroit Nova, Novi, MI

Oct 5–7 FundiExpo, Queretaro, Mexico

Oct 14–16 Non-Ferrous Founders’ Society (NFFS) 2016 Industry Executive Conference & Annual Meeting, Loews VentanaCanyon Resort, Tucson, AZ

Oct 15–18 Investment Casting Institute (ICI) 63rd Annual Technical Conference and Expo, Hyatt Regency Columbus,Columbus, OH

Oct 26–28 Ductile Iron Society (DIS), 2016 World Conference on ADI, Westin Hotel, Atlanta, GA

Nov 16–18 SME FABTECH, Las Vegas Convention Center, Las Vegas, NV

Nov 17–18 FEF College Industry Conference, Westin Hotel, Chicago, IL

Dec 7–10 Steel Founders’ Society of America (SFSA) National T&O Conference, The Drake, Chicago, IL

Dec 13–14 AFS Marketing and Selling of Castings, Westin O’Hare, Rosemont, IL

2017

Mar 14–17 2nd South African Metal Casting Conference andWFO Technical Forum 2017, Guateng, Johannesburg SouthAfrica

Apr 25–27 AFS 121st Metalcasting Congress, Wisconsin Center, Milwaukee, WI

Sep 18–20 North American Die Casting Association (NADCA) Die Casting Congress & Tabletop, Hilton Atlanta, Atlanta,GA

Oct AFS 29th Environmental, Health & Safety Conference, Hotel TBD, Birmingham, AL



2018Apr 3–5 AFS 122nd Metalcasting Congress, Convention Center, Fort Worth, TX

Oct 15–16 AFS Storm Water Seminar, Hyatt Regency Birmingham—The Wynfrey Hotel, Birmingham, AL

Oct 15–17 North American Die Casting Association (NADCA) Die Casting Congress & Exposition, Indianapolis, IN

Oct 17–18 AFS Environmental Health and Safety Conference, Hyatt Regency Birmingham—The Wynfrey Hotel,Birmingham, AL


2019Apr 27–30 CastExpo’19, Georgia World Congress Center, Atlanta, GA

Jun 25–29 GIFA, Dusseldorf, Germany

For further information on conferences and meetings, please contact the appropriate organization directly at the phone number orweb address shown below. Information is updated frequently on the AFS website: www.afsinc.org

American Foundry Society 847/824-0181

Aluminum Association Inc. 703/358-2960

American Metalcasting Consortium 843/760-3219

American Society of Mechanical Engineers (ASME) 212/705-7100

ASM International 440/338-5151

Casting Industry Suppliers Association 623/547-0920

Ductile Iron Society 440/665-3686

FEF 847/490-9200

Industrial Minerals Association—North America 202/457-0200

Investment Casting Institute 291/573-9770

Iron Casting Research Institute 614/275-4201

Institute of Indian Foundrymen www.indianfoundry.org, [email protected]

The Minerals, Metals & Materials Society (TMS) 724/776-9000

National Industrial Sand Association 202/457-0200

Non-Ferrous Founders’ Society 847/299-0950

North American Die Casting Association 847/279-0001

SME ww.sme.org and www.rapid3devent.com

Steel Founders’ Society of America 815/455-8240

World Foundry Congress www.wfc2016.jp

World Foundry Organization World Foundry Organization [email protected]


http://www.afsinc.org

http://www.indianfoundry.org

http://www.rapid3devent.com

http://www.wfc2016.jp

AFS Conference on Additive Manufacturingfor Metalcasting

We hear a lot in the news about 3-D printing technologies in manufacturing. How

does this apply to the metalcasting industry?

The American Foundry Society’s first full technical conference on additive manufacturing(AM) and 3D printing. The conference will focus on how these new emerging technologiesare being utilized in the foundry to produce cast components, and will cover all aspects of AMand 3D printing for the metalcasting industry, such as printing of sand molds, printing ofinvestment casting waxes, equipment, materials, practical case studies of foundry applicationand actual castings. The conference will include plant tours of AM facilities.

Tentative Program

• Keynote Presentations: Learn from the early adopters and hear metalcasting industry leaders discuss how they haveincorporated this new technology and made it work in the foundry.

• Component Design for AM: There is much more design freedom and few constraints for AM produced castings.Component design and engineering are very different than other casting processes.

• Mold Design and Modeling: What does a sand mold look like made without patterns or tooling? How does this affectgating and risering? This session will discuss computer modeling and the molding process specific to AM.

• Equipment: A review of available AM equipment and a preview of new technologies and coming innovations.

• Materials: Although the actual materials (sand, binders, etc.) are not substantially different than other casting processes,they must be specifically tailored to AM applications. This session will discuss sand, binders, refractory mold coatings, sandadditives and specialty and synthetic sands.

• Investment Casting: Overview of current technologies relating to use of 3-D printing in investment casting, includingcase studies from foundries, customers and early adopters.

• Foundry Application Case Studies: Case studies and actual components produced by AM technologies. Learn howpattern shops and foundries have used this new technology. Presentations will include the economics of AM and differenttypes of components that are being manufactured, and how foundries have incorporated this new technology into theirfacilities

Plant Tours

• Several plant tours are planned. Attendees will be able to see the equipment in operation, printed sand molds and cores andinvestment casting operations.

Visit the conference website at www.afsinc.org/additive or

scan the code with your mobile device. For more informa-

tion, contact:

Steve Robison, [email protected] / 847-824-0181 x 227

Laura Kasch, [email protected] / 847-824-0181 x 246


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