Chapter 3 - Rolling of metals

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Example: Determine the maximum possible reduction for coldrolling a 300 mm-thick slab when µµµµ = 0.08 and the roll diameter is 600 mm. What is the maximum reduction on the same mill for hot rolling when µµµµ = 0.5? 2 From Eq.7, ( ∆h) = µ R For cold-rolling max 2 ( ∆h) = ( 0. 08) ( 300) = 1. 92mm For hot-rolling ( ∆h) = ( 0. 5) ( 300) = 75mm max max Alternatively, we can use the relationship below L p sinα = R = ∆h = 1. 92mm Suranaree University of Technology Tapany Udomphol Jan-Mar 2007 2 R∆h , α = R tan ( ) − 1 µ
Simplified analysis of rolling load The main variables in rolling are: • The roll diameter. • The deformation resistance of the metal as influenced by metallurgy, temperature and strain rate. • The friction between the rolls and the workpiece. • The presence of the front tension and/or back tension in the plane of the sheet. We consider in three conditions: 1) No friction condition 2) Normal friction condition 3) Sticky friction condition Suranaree University of Technology Tapany Udomphol Jan-Mar 2007
Page 1 and 2: Rolling of metals Subjects of inter
Page 3 and 4: www.world-aluminium.org Introductio
Page 5 and 6: Sheet rolling machines Rolled strip
Page 7 and 8: Rolls Mill rolls Mill rolls Suranar
Page 9 and 10: Typical arrangement of rollers for
Page 11 and 12: Typical arrangement of rollers for
Page 13 and 14: Different types of rolling processe
Page 15 and 16: Transverse rolling • Using circul
Page 17 and 18: Shaped rolling or section rolling A
Page 19 and 20: Simulation of ring rolling Simulati
Page 21 and 22: Powder rolling Metal powder is intr
Page 23 and 24: Thread rolling Cut thread and rolle
Page 25 and 26: Example for hot strip mill process
Page 27 and 28: Cold-rolling Cold rolling www.willi
Page 29 and 30: Cold-rolling Cold rolling • Cold
Page 31 and 32: h o Forces and geometrical relation
Page 33 and 34: • At only one point along the sur
Page 35 and 36: h o v o p A R N B h f Friction hill
Page 37 and 38: Therefore Free engagement will occu
Page 39: Problem with roll flattening When h
Page 43 and 44: 2) Normal friction situation In the
Page 45 and 46: • Frictional force is needed to p
Page 47 and 48: 3) Sticky friction situation What w
Page 49 and 50: Relationship of µµµµ, rolling l
Page 51 and 52: Problems and defects in rolled prod
Page 53 and 54: Uniform thickness • Under high ro
Page 55 and 56: Flatness • The roll gap must be p
Page 57 and 58: • Hot mill can be provided with f
Page 59 and 60: Possible effects when rolls are ove
Page 61 and 62: • Edging can also be caused by in
Page 63 and 64: Rolling mill control • Modern con
Page 65 and 66: Rolling load P3 P2 P1 Situation whe
Page 67 and 68: Thickness measurement in continuous
Page 69 and 70: The stresses acting on an element o
Page 71 and 72: The forces acting in the vertical d
Page 73 and 74: The rolling load or total force P i
Page 75 and 76: Torque and power Torque is the meas
Page 77 and 78: The torque M T is equal to the tota
Page 79: References • Dieter, G.E., Mechan

Chapter 3 - Rolling of metals

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