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Rolling Process
Rolling is a metal forming process that uses rolls to reduce the thickness and increase the length of metal workpieces. It can be done hot or cold. Hot rolling occurs above the metal's recrystallization temperature and results in a more uniform structure, while cold rolling occurs at room temperature and produces closer tolerances and a better surface finish. The document defines various products of rolling like billets, blooms, slabs, plates, sheets and strips based on their dimensions. It also describes different types of rolling processes like continuous, transverse, shape, ring and thread rolling as well as the types of mills used like two-high, three-high and four-high mills.
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Overview of the rolling process presented by Deepak Sharma at IIT Mandi on April 15, 2011.
Rolling is a forming process involving compressive stresses that plastically deforms metal between rolls.
Definitions of billets, blooms, slabs, and semi-finished products related to metal rolling.
Descriptions of products obtained from rolling, including plates, sheets, and strips based on thickness.
Introduction to different forms of rolling: hot rolling and cold rolling.
Hot rolling occurs above recrystallization temperatures, affecting mechanical properties and stress.
Hot rolling is essential for producing sheet metals and simple cross sections, with attention to cooling.
Cold rolling, done below recrystallization temperature, enhances surface finish and precision of products.
Explanation of two high and three high mill arrangements for rolling processes.
Cluster or Sendzimir four-high mills use small work rolls supported by larger backup rolls.
Key components of a rolling mill, including rolls, bearings, housing, and power drives.
Overview of various rolling processes: continuous, transverse, section, and ring rolling.
Continuous rolling decreases thickness while increasing length with minimal width change.
Transverse rolling utilizes circular wedge rolls to shape heated bars.
Flat slabs are bent into complex shapes through rolling to create custom sections.
Specialized hot rolling to increase the diameter of rings, enhancing their grain structure.
Metal is simultaneously melted, cast, and hot rolled in continuous processes.
Rolls threads in a single pass, displacing material to form threads efficiently.
Citations of sources consulted for the presentation on rolling and its theory.
Thank you note from Deepak Sharma, including copyright information and support acknowledgments.
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Rolling Process
- 1. ROLLING INDIAN INSTITUTE OFTECHNOLOGY,MANDI 15-04-2011 DEEPAK SHARMA Mechanical engineering
- 2. WHAT IS ROLLING?? •Rolling is the most widely used forming process, which provides high production and close control of final product. • The metal is subjected to high compressive stresses as a result of the friction between the rolls and the metal surface The process of plastically deforming metal by passing it between rolls.
- 3. TERMINOLOGY Billet is theproduct 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 PRODUCTS
- 4. Continued... FURTHUR ROLLING PROCESSES MILL PRODUCTS Plate is theproduct 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.
- 5.
- 6. HOT ROLLING Hot rollingis a metalworking process that occurs above the recrystallization temperature of the material. Hot rolled metals generally have little directionality in their mechanical properties and deformation induced residual stresses. However, in certain instances non- metallic inclusions will impart some directionality
- 7. 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 as I-beams and H-beams. Hot rolling is used mainly to produce sheet metal or simple cross sections, such as rail tracks. APPLICATION
- 8. COLD ROLLING It alsoimproves the surface finish and holds tighter tolerances. 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.
- 9. HOW IS THISDONE...? ARRANGEMENTS OF ROLLERS USED IN ROLLING MILLS TWO HIGH MILL THREE HIGH MILL The stock is returned to the entrance for further reduction. Consist of upper and lower driven rolls and a middle roll, which rotates by friction.
- 10. Continued.... CLUSTER OR SENDZIMIR FOURHIGH MILL Small-diameter rolls (less strength & rigidity) are supported by larger-diameter backup rolls Each of the work rolls is supported by two backing rolls.
- 11. WHERE IT IS DONE? Rolling mill isa machine or a factory for shaping metal by passing it through rollers A 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 speed
- 12. TYPES OF ROLLING PROCESSES CONTINOUS TRANSVERSE SECTIONOR SHAPE RING CONTINOUS CASTING AND HOT ROLLING THREAD
- 13. CONTINOUS The objective isto decrease the thickness of the metal with an increase in length and with little increase in width.
- 14. TRANSVERSE • Using circularwedge rolls. • Heated bar is cropped to length and fed in transversely between rolls. • Rolls are revolved in one direction.
- 15. SECTION OR SHAPE Flatslap is progressively bent into complex shapes Suitable for producing moulded sections such as irregular shaped channels and trim.
- 16. RING A specialized typeof hot rolling that increases the diameter of a ring The resulting grain structure is circumferential, which gives better mechanical properties
- 17. CONTINOUS CASTING AND HOTROLLING • Metal is melted, cast and hot rolled continuously through a series of rolling mills within the same process.
- 18. THREAD • Rolled threadsare 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.
- 19. REFERENCES •“ROLLING” <wikipedia.com/rolling>;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.”
- 20. THANK YOU Deepak Sharma IITMandi Copyright2013DeepakSharmaIITMandi TemplateDownloadedfrom fppt.com