Chapter 3 - Rolling of metals

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P r sineαααα P r Roll bite condition For the workpiece to enter the throat of the roll, the component of the friction force must be equal to or α F α Fcosαααα α The angle of bite or the angle of contact F is a tangential friction force Pr is radial force greater than the horizontal component of the normal force. α sinα P F ≥ cos r sinα ≥ cosα tanα Suranaree University of Technology Tapany Udomphol Jan-Mar 2007 F Pr But we know Therefore ≥ F = µ Pr µ = tanα …Eq.5 • If tan αααα > µµµµ, the workpiece cannot be drawn. • If µµµµ = 0, rolling cannot occur.
Therefore Free engagement will occur when µµµµ > tan αααα Increase the effective values of µµµµ , for example grooving the rolls parallel to the roll axis. α 1 + α1 >α >α 2 Using big rolls to reduce tan αααα or if the roll diameter is fixed, reduce the h o Suranaree University of Technology Tapany Udomphol Jan-Mar 2007 α 2
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: h o v o p A R N B h f Friction hill
Page 39 and 40: Problem with roll flattening When h
Page 41 and 42: Simplified analysis of rolling load
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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