snd powder metallurgy

7/26/2019 SND Powder Metallurgy

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A Seminar onAdvanced Technology in Powder Metallurgy



Advanced Technology in PowderMetallurgy

• Introduction

• Process

• Efect o density on various mechanical

properties.• Advanced Technology

• Applications

• Advantages

• Limitations

• onclusion

• !eerences



Powder MetallurgyPowder metallurgy is a "ranch ometallurgy which deals with the

production o metal and non metalpowders and su"se#uentlymanuacture o components "y

using these powders.



Flowchart of Powder Metallurgy Process.

Producing metal powders o suita"le si$e% shape and purity.

&lending and mi'ing o powders

ompacting

Presintering

Sintering



() Production o Metal Powders *Methods

(. Atomi$ation

+. !eduction

,. Electrolysis-. rushing

. Milling

/. ondensation o metal vapours



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!ange o particle si$es



Automisation



Automisation

• A high pressure steam or li#uidimpinges on the molten metal which ispassed through ori0ce causing it to

automise into 0ne particles.• Sometimes inert gas is used to get pure

powder.

• 1igh #uality powders o Aluminum%"rass% iron% stainless steel% tool steel%super alloys are produced commercially



!eduction

• The compound o metals are reduced with2 and 1+ gas in controlled atmosphere

• The reduced product is crushed and ground

to get metal powder.• e. a. Tungsten o'ide * Tungsten powder

Iron hloride * Iron powder

• Metal powders o"tained * opper% Iron% Tungsten% Moly"denum% 3ic4el.

• 5ery convenient% economical% and 6e'i"lemethod% so it is widely used.



Electrolysis

• The process is similar toelectroplating

• In this process anode and cathodeare placed in the electrolyte "ath.

• 1igh intensity current detoriatesanode and cathode is deposited "ypure copper powder.

• The cathode plates are ta4en out andscraped of to collect copper powder.



Electrolysis



ElectrolysisIron Powder opper Powder



rushing

• Totally mechanical process.

• &rittle metal or alloy can "e easilycrushed.

• It re#uires crushing machinery li4estamps% hammers% 7aw crusher etc.



rushing Process

8aw rusher 9yratory rusher !ollrusher



Milling

• This is also mechanical process.

• :sed whenever large amount o powder is to "eproduced.

• :sed or hard% sot% ductile or "rittle materials.• It re#uires "all mill% impact mill% eddy mill% orvorte' mill.

• A "all mill is widely used which is hori$ontal

"arrel shaped container holding num"er o "allswhich "eing ree to tum"le a"out as thecontainer rotates.

• Then crush or grind to get 0ne powder.



Milling

This contains cylindrical vessel rotating hori$ontally

along the a'is. Length o the cylinder is more or lesse#ual

to diameter. The vessel is charged with the grinding

media. The grinding media may "e made o hardened

steel% or tungsten car"ide% ceramics li4e agate%porcelain%

alumina% $irconia. ;uring rolling o vessel% the grinding

media < powder particles roll rom some height. This

process grinds the powder materials "y impact =collision < attrition.



Milling process &all Mill 5i"ratory &all Mill

Attrition Mill

!od Mill 1ammer MillPlanetary Mill



ondensation

• :sed or metal powder li4e >inc%admium% Magnesium.

• In this process the metal can "e"oiled and the vapours o the moltenmetals are condensed to give metalpowder.

• :sed only or small scale production.



+) &lending < mi'ing oPowders

• ;iferent powders along with lu"ricant mi'ed in a "allmill. Lu"ricants are added to reduce riction during thepressing operations. This reduces die wear and lowersthe pressure re#uired or pressing.

• Ater mi'ing the re#uired properties li4e heatresistance% riction% weight and hardness can "eo"tained.

• &lending types – ;ry method

– ?et method@ Li#uid medium li4e alcohol% acetone% "en$ene ordistilled water are in wet milling.

Advantages o wet mi'ing () !educes dust. +) Avoidse'plosion ha$ards% ,) Prevents surace o'idation.



,) ompacting

• ompacting means pressing the powdersinto their semi0nished orm o desiredshape.

• Powders are compacted "y using highpressure.

• ompacting methods

() ;ie pressing

+) !oll pressing

,) E'trusion



;ie pressing



!oll compacting



E'trusion



Presintering

• ?hen some machining is re#uiredthen presintering operation isemployed "eore sintering operation.

• Bor presintering the compacted partsare heated or a short time at atemperature considera"ly "elow the

sintering temperature.



Sintering

• Sintering is done to get re#uired strengthand hardeness in the 0nished product.

• Sintering consists o heating a compacted

parts in a urnace to a temperature "elowmelting point o the ma7or constituent in acontrolled atmosphere.

• Sintering is process o "onding solid "odies

"y atomic orces.• Sintering gives re#uired shape to the

component.



Secondary operations

• In many cases% the powderedproducts may "e used as sinteredcondition% "ut in other cases where

desired surace 0nish% tolerance% ormetal structure can "e o"tained "ycertain additional secondary

operations.(. Si$ing +. oining ,.

Machining

-. Impregnation . In0ltration /.



(. Si$ing

• Sintering process produces somedistortions and alteration in si$e.

• To ma4e it dimensionally correct%place in die and repressed.

• Si$ing improves surace 0nish also.

• A slight change in density occursater si$ing operation.



+. oining

• The sintered part is repressed in thedie to reduce the void space andimpart re#uired density.



,. Machining

• Beatures as thread% under cuts%grooves etc are not o"tained atersintering process.

• Such machining is done aterpresintered operations.

• &oring% turning% drilling% tapping etc

can "e done on the presintered partsusing tungsten car"ide tools.



-. Impregnation

• Sintered porous parts may "eimpregnated with oil% grease or wa'to give sel lu"rication properties.

• Sintered parts may "e impregnatedwith plastic also. – Improves corrosion resistance

– Improves machina"ility. – Introduce pressure tightness.



. In0lteration

• A part is 0rst pressed and sintered romiron powder which gives CC density.

• Then a replicaFin0ltrant) o copper is

placed over the part.• It is heated in urnace.

• The in0ltrant melts and enters in

porous parts gives (GG density.Advantage It increases strength% hardness

and density.



C. 1eat Treatment

• Sintered parts are heat treated to improve – ?ear resistance

– 9rain structure

– 1ardness – Strength

• 1eat treatment processess – Stress relieving% ar"urising% ar"onitriding%

3itriding% Through hardening% Inductionhardening%

Precipitation hardening.



/. Plating

• r Plating * Impart pleasing appearance

• 3i plating * Protect rom corrosion resistance.

• Sn plating * Improves rictional characteristics.

• u and Ag plating * Improves electricalconductivity.

• 3ote@ &eore plating the parts are impregnated

with plastic% so electrolyte is not entrapped inporous structure.



Efect o ;ensity on ;uctility and Toughness o Be3 P=M alloy



Efect o ;ensity on Strengtho Be3 P=M alloy




(. Improvement in or mechanical properties.

a. &y Increasing powder compressi"ility=homogeneity%dust and ha$ard reduction.

–. &etter particle si$e distri"ution.

–. Atomisation no$$le geometry

–. 1ighpressure water atomi$ation

–. 5acuum induction melting% degassing and pouringurnaces to replace the common ones.

–. To enhance the sintered steels homogeneity and toreduce dust% the traditional elemental powdermi'tures are "eing replaced% in spite o their lowestcost.

Advanced Applications or Metal



Advanced Applications or MetalPowders

Application Metals Uses

A"rasives Be% Sn% >n leaning% a"rasive wheels

Aerospace Al% &e% 3" 8et engines% heat shields

Automotive u% Be% ? 5alve inserts% "ushings% gears

Electrical=electronic Ag% Au% Mo ontacts% diode heat sin4s

1eat treating Mo% Pt% ? Burnace elements%thermocouples

8oining u% Be% Sn Solders% electrodes

Lu"rication u% Be% >n 9reases% a"rada"le seals

Magnetic o% Be% 3i !elays% magnets

Manuacturing u% Mn% ? ;ies% tools% "earings

Medical=dental Ag% Au% ? Implants% amalgams

Metallurgical Al e Si Metal recovery% alloying

3uclear &e% 3i% ? Shielding% 0lters% re6ectors

2Hce e#uipment Al% Be% Ti Electrostatic copiers% cams




". Improving the die 0lling and lu"ricationprocesses.

• A high 0lling density and uniormity over the

cross section o the die cavity is essential orgood #uality parts o"taining.

• :se o agitating eedshoes or vi"ratory eeders.

• :se organic "inder.

• A good lu"rication during compaction plays ama7or role in o"taining a high and uniormdensity.




c. Advanced compaction methods

• ?arm compaction up to (GG

allowing ahigher densi0cation at the same appliedpressure.

• 1igh velocity compaction leading to higher

density "y a hydraulically operatedhammer.




d. 1igh Temperature Sintering• 1igher densi0cation.

• &etter homogeni$ation• Batigue resistance and toughness "eing

improved.

• &ut it leads to the crystal grain growthand higher cost.




+. E'tending PM capa"ility o comple' partsprocessing.

a. Powder In7ection Molding.

• Powder In7ection Molding FPIM) com"ines the polymer in7ectiontechnology with powder metallurgy. &y in7ection o a powder"inder mi'ture Feedstoc4) in a die cavity% theoretically anyshape can "e reali$ed.

a. Selective Laser Sintering.

• In each layer and "etween two successive layers% a laser"eam% "y a computer controlled se#uential displacement incoordinates% 7oints particles upon a program to reali$e there#uired cross section o the part or that layer. The process isrepeated until the whole part is "uiltJ% layer"ylayer.

A li ti P d



Applications o PowderMetallurgy

(. Porous products * porous "earings% 0lters

+. Electrical contacts in automo"ile industry

,. ran4shat drive% camshat sproc4et

-. Piston rings% "ra4e liners% connecting rods.. ;oor mechanism.

/. Sintered gears F?ithout much manuacturing)

C. !eractory parts e.a. Tungsten in electric"ul"% 0lament in K ray tu"e% cathode%anode% control grid.

A li ti d



Applications o powdermetallurgy

D. ?ire drawing dies% wire guides% deep drawing%stamping% "lan4ing tools% roc4 drilling "its Fmadeo tungsten car"ide)

. 3on porous "earings% electric motor "rushes.

(G.Military and deense applications in roc4ets%missiles% cartridge cases% "ullets etc.

((.Atomic energy applications in various uelsystem% control rod systems and radiation

re6ectors.

(+.Parts in cloc4s% timing devices% typewriters%calculators% permanent magnets.



Powder Metallurgy@

ermet cutting tools

FeramicMetal composite)

www.kyocera-yashica.com.br

www.moldma4ingtechnology.com

www.tool"arn.com

Microstructure@ ceramic particles in metal matri'

ermettipped saw "lade or long lie

ermet cutting inserts or lathe



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Slightly porous appearance



oee.nrcan.gc.ca

P=M netshape gears are common% save machining time

Metal 0lters



Powder Metallurgy@Porous Metals

2ilimpregnated Porous &ron$e &earingsnic.sav.sk

www.hd"earing.com

www.ondrives.com



Borged on let P=M on right

Powder Metallurgy@ onnecting !ods

www.dpsperormance.com

d d l i i 9



Powdered Metal Transmission 9ear

• ?arm compaction method with (/Gton press• Teeth are molded net shape@ 3o machining• :TS N (%GGG psi• ,G cost savings over the original orged part

www.chipm.com

Powdered Metal Tur"ine "ladedis4 F"lis4J)@ ( pieceO



Powdered Metal Tur"ine "lade dis4 F "lis4 )@ ( pieceO

www.ml.arl.a.mil



onventional Borging vs. Borging o Powdered Metal "lan4 F+nd op)

;e9armo



P=M Tungsten Light"ul" Bilament@GG hrs at +GG°

?ire is creep resistant% note acets on closeup are evaporated ?.

Advantages o Powder



Advantages o PowderMetallurgy

(. Machining is not re#uired.

+. ;imensional accuracy and surace 0nish.

,. More cleaner and #uieter applications

-. 1igh production rates.

. 3o wastage.

/. omple' shape can "e produced.

C. Longer lie o components.D. E'cellent reproduci"ility.

Advantages o Powder



Advantages o PowderMetallurgy

. P=M is only method to produce porousproducts.

(G.S4illed wor4er is not re#uired.

((.Impossi"le parts li4e tungsten car"ide can"e produced "y P=M process.

(+.:se o diamond in industry is due to P.M only.

(,.3o need to study phase diagram.

Limitations o Powder



Limitations o PowderMetallurgy(. 1igh Production ost .

+. 1igh Tooling ost.,. omplicated products can not "e produced.

-. Poor Physical properties.

. Large si$ed products can not "e produced due to

re#uirement o large presses./. E'treme care should "e ta4en in handling pyrophoric

FBire E'plosive) powders li4e Mg% Th% >r

C. To'ic powders li4e :% &e% Th should "e handled

careully.D. 3ot economical or small scale production.

. an not o"tained any speci0c alloy.

(G.;ensity may vary.



onclusion

• The powder metallurgy product can"e improved – &y improving mechanical and physical

properties li4e ductility% toughness%strength% homogeneity etc.

– &y using modern manuacturingtechni#ues li4e in7ection mounding%Selective Laser Sintering etc.



ReferencesMaterial Science < Metallurgy "y 2. P.hanna

Material Science < Metallurgy "y ;r. 5. ;.odgire

;e9armo@ E.P. ;e9armo et al% Materials andProcesses in Manufacturing% ?iley% +GG,.

www.parmaco.com

www.kyocera-yashica.com.br

www.moldma4ingtechnology.com



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