Manufacturing Technology - Rollingpresentation
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I.Rajkumar, Assistant Professor, Kalasalingam University
Transcript of Manufacturing Technology - Rollingpresentation
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ROLLINGKalasalingam university 15-01-2015i.rajkumarMechanical engineering
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WHAT IS ROLLING?? Rolling is the most widely usedforming process, which provides highproduction and close control of finalproduct. The metal is subjected to highcompressive stresses as a result ofthe friction between the rolls and the metal surfaceThe process of plastically deforming metal by passing it between rolls.kalasalinagm university *[email protected]
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TERMINOLOGYBillet is the product obtained from a further reduction by hot rolling(cross sectional area > 40x40 mm2).Bloom is the product of first breakdown of ingot(cross sectional area > 230 cm2).Slab is the hot rolled ingot(cross sectional area > 100 cm2 and with a width 2 x thickness).SEMI FINISHED PRODUCTSkalasalinagm university *[email protected]
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Continued...FURTHUR ROLLING PROCESSESMILL PRODUCTSPlate is the product with a thickness > 6 mm.Sheet is the product with a thickness < 6 mm and width > 600 mm. Strip is the product with a thickness < 6 mm and width < 600 mm.kalasalinagm university *[email protected]
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FORMSHOT ROLLINGCOLD ROLLINGkalasalinagm university *[email protected]
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HOT ROLLINGHot rolling is ametalworkingprocess that occurs above the recrystallization temperature of the material. Hot rolled metals generally have little directionality in their mechanical properties and deformation inducedresidual stresses. However, in certain instances non-metallic inclusionswill impart some directionality kalasalinagm university *[email protected]
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Also includes cooling ....Non-uniformed cooling will induce a lot of residual stresses, which usually occurs in shapes that have a non-uniform cross-section, such asI-beamsandH-beams.Hot rolling is used mainly to producesheet metalor simple cross sections, such asrail tracks.
APPLICATIONkalasalinagm university *[email protected]
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COLD ROLLINGIt also improves thesurface finishand holds tightertolerances.Cold rolling occurs with the metal below its recrystallization temperature (usually at room temperature). Commonly cold-rolled products include sheets, strips and rods; products being smaller than the same products that are hot rolled.Due to smaller size of the workpieces and their greater strength than hot rolled stock, four-high or cluster mills are used.kalasalinagm university *[email protected]
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HOW IS THIS DONE...?ARRANGEMENTS OF ROLLERS USED IN ROLLING MILLSTWO HIGH MILLTHREE HIGH MILLThe stock isreturned to theentrance forfurther reduction.Consist of upper andlower driven rolls anda middle roll, whichrotates by friction.kalasalinagm university *[email protected]
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Continued....CLUSTER OR SENDZIMIRFOUR HIGH MILLSmall-diameter rolls(less strength &rigidity) aresupported bylarger-diameterbackup rollsEach of the workrolls is supportedby two backingrolls.kalasalinagm university *[email protected]
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WHERE IT IS DONE?Rolling mill is a machine or a factory forshaping metal by passing it through rollersA rolling mill basically consists of rolls bearings a housing for containing these parts a drive (motor) for applying power to the rolls and controlling the speedkalasalinagm university *[email protected]
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TYPES OF ROLLING PROCESSESkalasalinagm university *[email protected]
CONTINOUS
TRANSVERSE
SECTION OR SHAPE
RING
CONTINOUS CASTING AND HOT ROLLING
THREAD
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CONTINOUSThe objective is to decrease the thickness of the metal with anincrease in length and with little increase in width.kalasalinagm university *[email protected]
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TRANSVERSE Using circular wedge rolls. Heated bar is cropped to length andfed in transversely between rolls. Rolls are revolved in one direction.kalasalinagm university *[email protected]
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SECTION OR SHAPE Flat slap is progressively bent into complex shapesSuitable for producing moulded sections such as irregular shaped channels and trim.kalasalinagm university *[email protected]
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RINGA specialized type of hot rolling that increases the diameter of a ringThe resulting grain structure is circumferential, which gives better mechanical propertieskalasalinagm university *[email protected]
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CONTINOUS CASTING AND HOT ROLLING
Metal is melted, cast and hot rolled continuously through a series of rolling mills within the same process.kalasalinagm university *[email protected]
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THREADRolled threads are produced in a single pass at speeds far in excess of those used to cut threads. Dies are pressed against the surface of cylindrical blank. As the blank rolls against the in-feeding die faces, the material is displaced to form the roots of the thread, and the displaced material flows radially outward to form the thread's crest.kalasalinagm university *[email protected]
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REFERENCESROLLING;browsed on 13-4-2011;16:12:45.Kalpakjian,Serope ; Steven R. Schmid;Theory of Machines.,4th Edition.Notes on Rolling from: Suranaree Institute of technology.kalasalinagm university *[email protected]
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THANK YOUI.RAJKUMARKALASALINGAM UNIVERSITY Copyright 2013 Deepak Sharma IIT MandiTemplate Downloaded from fppt.comkalasalinagm university *[email protected]
