MANISHANKAR KUMAR 09/ME/23 09148007013 ROLLING MANISHANKAR KUMAR 09/ME/23 09148007013

Introduction Rolling is a metal forming process in which metal stock is passed through a pair of rolls. Due to compressive stress exerted by rolls, the metal thickness reduces.

History of modern rolling Modern rolling practice can be attributed to the pioneering efforts of Henry Cort (England).  Used grooved rolls for rolling iron bars. Patent issued- 1783 Modern writers have called him “father of modern rolling." Grooved rolls

Hot rolling Occurs above the recrystallization temperature of the material. Poor surface finish due to oxidised metal Complex part shapes can be generated

(strengthening of a metal by plastic deformation) Cold rolling metal usually at room temperature increases  strength via  strain hardening   (strengthening of a metal by plastic deformation) improves  surface finish and holds tighter tolerances

Processes Roll bending produces a cylindrical shaped product from plate or steel metal. Flat rolling is the most basic form of rolling with the starting and ending material having a rectangular cross-section. Ring rolling is a specialized type of hot rolling that increases the diameter of a ring.

Mills A rolling mill has a common construction independent of the specific type of rolling being performed. Main components are Work rolls, Backup rolls, Rolling balance system, Roll changing devices, Mill protection devices, Roll cooling and lubrication system, Pinions, Gearing, Drive motors, Electrical controls, Coilers and uncoilers etc.

Tandem mills A tandem mill is a special type of modern rolling mill where rolling is done in one pass. In a traditional rolling mill rolling is done in several passes, but in tandem mill there are several  stands  (>=2 stands) and reductions take place successively.

Defects Undesirable Degrade surface appearance Adversely affect the strength Sheet metal defects include: Scale, Rust, Scratches, Gouges, Pits, & Cracks May be caused by impurities and inclusions Wavy edges – result of roll bending

Conclusion... Rolling is the most common metal forming process and generally used when change in cross-sectional area is required. It allows a high degree of closed-loop automation and very high speeds, and is thus capable of providing high-quality, close tolerance starting material for various secondary sheet metal working processes at a low cost .

Bibliography Manufacturing Science - Ghosh & Mallik Groover M.P., Fundamentals of Modern Manufacturing Wikipedia - Rolling (metalworking) Google images

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