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TRANSCRIPT
Basics of Rolling Mill Guide Design
ByMorgan Construction Company- A Siemens CompanyWorcester, MA 01605 USA
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Contents
IntroductionLong rolling mill guide design parametersRestbars and other ancillariesOptical alignment equipmentRod finishing mill guides
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SVAI Long Rolling (LR) Services:Spares, Guides, Upgrades & Services
Global Organization:Morgan WorcesterSiemens VAI Italy (Pomini)Morgan IndiaMorgan ShanghaiSiemens VAI UK (Ashlow – Morgan Europe)Siemens VAI Brazil (Morgan do Brazil)
and the other Siemens VAI Service locations throughout the world
With this expanded network we can be even closer to customers tosupport all activities and requirements
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SVAI Long Rolling Services
Mission:Maximize Mill Utilization
UPGRADES
RECONDITIONING
SPARES
AUDITS
MAINTENANCE
GUIDESSERVICES
TRAINING
REBUILDS
A growing global organization focused on the needs of all rolling mills
GUIDES
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Guide Equipment
It all started in 1879 with the first of many patents from Company founder Charles Hill Morgan
Together with Siemens VAI guides (Ashlow) we offer the most expansive guiding solutions of any guide supplier in the industry
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Siemens VAI guides
Main benefits:
Highest competitiveness
Quick and simple adjustment
Minimum maintenance requirements
Long operational service life
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Siemens VAI guides
Our vast guide portfolio covers the following applications and more....
Applications: including but not limited to rounds, rebars, flats, squares, hexagons and angles
Also providing:Restbars
Interstand loopers and guiding
Air/oil lubrication systems
Optical setting equipment
Water cooling headers
High-speed flaw detector guides
Leading technology in multi-slit rolling with over 40 references worldwide
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Guide Design and Rolling
The Basics of Guide Design AgendaBasic Rolling Requirements
It all starts in the Roll ShopBasics of Guide Design
Equipment design and operating parametersGeneral Guide Topics
Types of guides, considerations etc.
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Basic Rolling Requirements
Conventional Rolling StandsMill Roll Groove Pass Alignment
A program for mill roll pass groove preparation and roll tracking is requiredTogether is standard practices the rolls and stands are consistently prepared for the rolling millThe productivity of the rolling mill is directly related to the roll shop
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Basic Rolling Requirements
Conventional Rolling StandsRestbar and Saddle Alignment
The restbar elevation and position must be properly set and maintainedPremature guide failures and increased wear can be a result of poor restbar design or conditionPoor positioning results in hooked front ends, cobbles, and guide failures
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Basic Rolling Requirements
Restbar and Saddle AlignmentMechanical tools for checking alignment
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General Guide Topics
Restbars and Guide MountingsRestbar designs must be durable and provide years of accurate location of guidesMounting and clamping surfaces must be maintainedAdjusting restbars must be rebuilt and maintained for correct operationSecondary adapter plates and fine pass adjustment bases can be used for smaller guides or guides requiring more location accuracy
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Restbars & Guide Mounting Equipment
Traversing and fixed restbarsGuide mounting adapter platesFine-pass adjusting bases
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Basic Rolling Requirements
Conventional Rolling StandsStand alignment to interconnecting equipment
Proper alignment through all areas of the mill must be maintainedPremature guide failures and increased wear can be a result of poor alignmentForcing equipment out of position is not sound rolling practice
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Basic Rolling Requirements
Conventional Rolling StandsRoll Groove Cooling
Pass design, guide design, and cooling header design all must beconsidered together for proper roll coolingAdvances in materials and methods for mill roll manufacture demand increased awareness and optimization of roll cooling designsProper roll cooling reduces pass wear, increases product quality and mill utilization and decreases operating costs
Typical Static Delivery Guide With-HeaderTwist Delivery Guide With-Header
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Basic Rolling Requirements
Conventional Rolling StandsRoller guide cooling and lubrication
Review of the piping and systems for applying the roller cooling and bearing lubrication is required before and during the guide service time in the millFailure to monitor the roller cooling and bearing lubrication directly causes roller and bearing failures and cobbles
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Basic Rolling Requirements
Cantilevered Rolling StandsMill roll groove alignment
Mill roll grooves must be properly cut and inspectedMounting sleeves and tooling must be inspected and proper procedures followedSome variables can be reduced with adjustments to the guiding equipment
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Basic Rolling Requirements
Cantilevered Rolling StandsRoll housing preparation and condition
A schedule for maintenance must be createdInspection and proper procedures must be followed to maximize the equipment lifeDamaged or worn housings can result in increased guide delays and operating costs
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Basic Rolling Requirements
Cantilevered Rolling StandsBracket and saddle alignment
Mounting brackets rigidly align and hold the guides to the roll housingThe mounting surfaces and clamping equipment must be free of damage and scaleA schedule for maintenance must be created and spare parts available
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Basic Rolling Requirements
Cantilevered Rolling StandsRoll cooling and pass life
The design requirements for roll cooling increases with mill roll hardness and rolling speedRoll cooling headers need to be inspected regularly at mill roll and guide changes Worn, damaged, or poorly designed headers directly affect pass life and product quality
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Basic Rolling Requirements
Cantilevered Rolling StandsFlutter and the finishing mill
A great deal of testing of the effects of the flutter related to feed area, steel grade, and temperatures has allowed Morgan to make advances in roll pass design to reduce some of the flutter and produce the highest quality finished product tolerances at the world’s fastest finishing speedsPlease contact Morgan Rolling Services for assistance in this area
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Basics of Guide Design
Design input requirements for guides (required for all mill locations and installations)
Mill roll maximum and minimum diameterMounting restbar dovetail dimensions and locations from the center of the mill standThe distance from the stand centerline to the interconnecting equipmentThe distance between the rolling standsThe location and design of the mill roll cooling headersThe pass groove details of the incoming feed sectionThe pass groove details of the outgoing rolled section
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Basics of Guide Design
Design input requirements for guides (cont’d)The mill roll partings for each pass groove and section rolledThe key tolerance and size if the restbar has a key and keyway designThe inside dimension of the stand housing windowThe distribution of passes along the mill roll barrelThe dimension from the end of the roll barrel to the mill roll chocksThe dimension of the strand centers (for multi-strand mills only)
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Basics of Guide Design
Design input requirements for guides (cont’d)
Additional requirements for cantilevered stands only
The dimension of the roll housing to the centerline of strandThe location of the pinion bore to the guide mounting location and the dimension of the eccentric throw The design of the seal plateThe dimensions for the mounting holes and keyways for guide mounting brackets
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Basics of Guide Design
Design input requirements for guides (cont’d)The main point is that ALL input requirements must be considered when designing and installing guides to get the optimum performance and reliability
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Basics of Guide Design
What guides should be supplied?Once all the parameters are gathered a final decision is required to determine what type of guide is requiredA review of the progression of passes is required to understand the guiding requirements and options
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Basics of Guide Design
Stable pass progressionsStable progressions typically do not require secondary support from direct contact guidingSome examples of stable progressions…
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Basics of Guide Design
Stable pass progression examples…
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Basics of Guide Design
A few Un-stable pass progression examples…
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Basics of Guide Design
Review of pass progressions leads to the final decision of the type of guide to be used for the specific application
There are many reasons to choose a guide design but all factors and requirements must be reviewed for the correct choice for each rolling location
A simple but critical type of guide in the mill is the static receiving guides that deal with a wide variety of stable pass progressions
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Basics of Guide Design
Static Receiving Guides
Illustration for receiving guide discussion
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Basics of Guide Design
Static Receiving GuidesThe guide bore must be less than the full width on face of that stands work roll passThe guide bore is typically 85-90% of said pass width of faceThe length of the rifling is typically 2-3 times the guide bore for stabilityWorn static receiving guides lead to delivery guide cobbles and twist guide failures from hooked and knuckled head ends
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Basics of Guide Design
Static Delivery GuidesThe main function of delivery guides is to ensure the smooth passage of the bar from the rolling stand to the next piece of mill equipmentThere are two basic guide types: stripper and catcher
Stripper guides are used to minimize hooksCatcher guides are used to reduce change time
The chance of cobbles must be considered with the guide and mounting bracket design to protect the rolling mill stand
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Basics of Guide Design
Static Delivery GuidesIllustration for delivery guide discussion
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General Guide Topics
Roller Entry Guide DesignsTwo basic guide design types, leaf and block
Both types have design points that must be reviewed for each application and operator preference
Two and four roller guides have specific application points and must be reviewed for each application and operator preference
The back rollers of the 4 roller guide are set slightly larger than the front rollers to promote a rollerized funnel effect
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Basics of Guide Design
Roller Entry GuidesThe main function of the roller entry guide is to prevent the rolled section from rotating in the work roll pass grooveExiting product tolerance is a direct result of durability and accuracy of the guide setting and guide roller and static insertdesignThe static entry insert must minimize the impact on the guide roller and bearings but must not rub on the bar through the length of the billetThe guide roller design must be carefully reviewed to maximize roller and bearing life and product quality
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General Guide Topics
Roller Entry Guide Roller DesignProfile and V-grooves are the two main typesFor hard-metal mill rolls the profile rollers are preferred and outperform V-groove rollersBoth roller types need to be designed to utilize the full operating range of the roller entry guide assembly to provide the maximum payback for the rollers
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General Guide Topics
Roller Entry Guide Roller DesignComparison of V-groove versus profile rollers
V-groove rollers typically contact at around 65% of W.O.F.Profile rollers should have minimum contact of 75%
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Basics of Guide Design
Roller Entry GuidesRoller design
W.O.F. ContactAssembly capacityInsert clearanceRoller parameters
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Basics of Guide Design
Roller Entry GuidesInsert design with twisting entering section into guide
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Basics of Guide Design
Roller Entry Guides (cont’d)The insert clearances are 15-30% larger than the guided section based on location and speed of the guided sectionThe guide roller needs to support at least 75% of the oval pass width and can approach 100% for the smallest leader ovals for high-speed wire rodsBearing lubrication and guide roller cooling are key to guide life
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General Guide Topics
Roller Entry Guide NosepieceThe nosepiece is used to fill the space from the guide roller to the mill roll biteWith correct settings and alignment the nosepiece should never be in contact with the rolled sectionThe nosepiece width is typically equal, or nearly equal, to the dimension of the height of the preceding roller entry guide static inserts
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Basics of Guide Design
Other Roller Entry GuidesThe open top 4 roller guide with symmetrically adjusting base provides the flexibility to guide the process passes for flats, channels and angles with only adjustments for width and centering spacer shapeA top adjusting three roller guide is often used for angle and channel passes but the guide is limited to longer distances fromthe roll bite
The main requirement for this guide are for the production of sharp apex angle sections
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General Guide Topics
Roller Twist Delivery Guide DesignsFour basic guide design types: link, top adjust, outboard, and cassette.Link-style provides design and rolling flexibilityTop adjust provides ease of maintenance but limited flexibilityOutboard provides ease of maintenance and rolling flexibility but is limited in installation optionsCassette design offers strength but increased maintenance and limited installation optionsAll types have design points that must be reviewed for each application and operator preference
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Basics of Guide Design
Roller Twist Delivery GuidesThe main function of the roller twist delivery guide is to apply a force to rotate the rolled bar to the required rotational position for the next rolling standThe delivery guide insert bore must have clearance for the horizontal and twisted section to ensure no rubbing occursThe guide roller shape must consider the guide operating capacity, maximum roller diameter, and point of contact for the application of the twisting forceBearing lubrication and guide roller cooling are key to guide life
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Basics of Guide Design
Roller Twist Delivery GuidesCalculation of twist at the RE guide rollers
X = Distance from stand to standZ = Distance back from stand to RE guide rollersY = Distance from stand to Twist guide rollersT = The required twist angle
(see page 33 in guide design document for illustration)
X – Z = 90o
Y TSolve the ratio for ‘T’ where ‘T’ is
the twist angle in degrees
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Basics of Guide Design
Roller Twist Delivery GuidesLayout of guide rollers
Show rolled section at calculated twist angle TRotate rollers to near maximum guide twistConstruct tangent on rolled section at 75% W.O.F.Construct gauge diameter between two guide rollers
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Basics of Guide Design
Roller Twist Delivery GuidesDelivery inserts
Basic design is the same for a delivery guide, either stripper or catcher typeThe insert must consider the back-twist of the rolled section
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General Guide Topics
Guide Roller Bearing DesignThe proper tools must be used to install any bearings with imparting damage before the bearing is even usedTapered roller bearings for slower speeds and higher loadDeep groove ball bearings for higher speeds and longer bearing lifeBall bearing spacers must be undamaged to prevent bearing preload when installed
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General Guide Topics
Optical Alignment of Guides and MountingsBench Optics for use in the roll shopPortable Optics for use in aligning restbars and guide mounting bracketsSystem allows for guide life and product tolerances not achievable with mechanical guide setting techniques
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Universal bench optics to setup a large range of roller guides in the roll shop
Bench Optics Alignment Equipment
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Provides consistent setting of guides in the roll shop by all operatorsNo variability from operator feel and guesswork using gauge barsor cobbled sections for setup
Superior resolution for precise guide setting and increased guide life and product quality
Calibration matched to Portable Optics system
Bench Optics Alignment Equipment
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Optical Calibration
Care is taken to calibration match the bench and portable optics to ensure superior precision
Using the same mounting plates and alignment tooling the bench and portable optics are set to the exact same mechanical and optical centerline
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Portable Optics Alignment Equipment
Unsurpassed finished product tolerances
Portable optics setting in the NTM Clamped on the X-clamp mounting system
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Portable Optics Alignment Equipment
Precise positioning of the roller entry guide bracket to the centerline of the roll groove
Used as a tool for checking roll cross indicating…Worn flingers in cantilevered mill standsIncorrect pass grinding or re-cutting in the mill rollsWorn tapered sleeves on cantilevered mill standsWorn thrust bearingsIncorrect mill roll mounting or positioning
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Portable Optics Alignment Equipment
Conditions of roll cross
If crossed rolls are found then proper corrective action procedures must be in place for the operators to make a determination when the billets should be rolled
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Results: Maximum Guide Life
RE-20 guide rolling 5,5mm at 18,100ft/minute (92m/s)5,831 tons rolled
No changes to rollers or bearingsCampaign completed with no guide changes
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Specialized Guide Topics
Multi-strand Slit Rolling of RebarsThe dividing of the billet into 2,3, or 4 bars for the production of multiple finished products in a single strand rolling mill
This is done by using a forming pass design to define to areas of the individual finished strands and “slitting” the bar using slitting delivery guides or powered slitting machine
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Multi-strand slit rolling of rebars
Powered slitting machine 3-Strand Slitting guide on the Bench Optics
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Increased production for smaller finished diameters
10mm Rebar
0.0
20.0
40.0
60.0
80.0
100.0
120.0
140.0
0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
Finishing Speed (m/s)
Rolli
ng R
ate
(mt/h
)
1 x 10mm
2 x 10mm
3 x 10mm
4 x 10mm
Multi-strand Slit Rolling of Rebars
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Slit rolling pass sequence example
Multi-strand Slit Rolling of Rebars
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Slit rolling pass sequence example
Multi-strand Slit Rolling of Rebars
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Higher production of small rebar can be achieved without large capital equipment expenditures
The rolling mill can be operated to its full design capacity for the entire product mix
The product mix can be expanded to small sizes that were not cost effective to produce via conventional rolling methods
Can be easily applied to most bar mill configurations
Multi-strand Slit Rolling of Rebars
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Siemens VAI Guides
Guides for all mill types....
Recent Guiding Projects:POMINI Rod and bar mills worldwideMORGAN High speed rod mills worldwideASHLOW High speed rod mills worldwide
SMS Rod mill in Saudi ArabiaDEMAG Bar mill in Saudi ArabiaSIMAC Rod and bar mill in EgyptNKK Bar mill in EgyptDANIELI Flexi mill in Saudi ArabiaSKET Rod mill in UkraineVAI Bar mill in Kuwait
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