Chapter 3 - Rolling of metals

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The solution of problems in cold rolling are complicated. Some simplification to this problem has been provided by Bland and Ford. By restricting the analysis to cold rolling under conditions of low friction and for angles of contact < 6 o , then we can put sin θθθθ ~ θθθθ and cos θθθθ ~ 1. Thus Eq.14 can be written d ( σ dx h) x dθ dθ ( σ h) = ' 2 p R = 2 pr R r ( θ ± µ ) ( θ '± µ ) …Eq.16 It is also assumed that p r ~ p , so that Eq.15 can be written σ x = p r -σ ’ o . By substituting into Eq.16 and integrating, relatively simple equations of the radial pressure result. Roll entrance to neutral point: p Where r ' σ oh ⎛ σ = h ⎜ ⎜1− o ⎝ σ 1 2 ⎛ ' ⎞ ⎜ R H = 2 ⎟ ⎜ ⎟ ⎝ h f ⎠ xb ' 01 tan ⎞ ⎟ ⎟e ⎠ −1 µ ( H −H ) 1 ⎡ ⎛ ' ⎞ ⎢⎜ R ⎟ ⎢⎜ ⎟ ⎣ ⎝ h f ⎠ 1 2 ⎤ θ ⎥ ⎥ ⎦ …Eq.17 Neutral point to roll exit: ' = o h f ⎜ ⎜1 xf ' σ 02 Suranaree University of Technology Tapany Udomphol Jan-Mar 2007 p r σ h ⎛ σ − ⎝ and σσσσ xb = back tension σσσσ xf = front tension ⎞ ⎟ ⎟e ⎠ µ H …Eq.18
The rolling load or total force P is the integral of the specific roll pressure over the arc of contact. P Where b = width of sheet αααα = contact angle = R b θ = α ∫ o pdθ ' …Eq.19 The solution is replaced by the modern digital computer. Suranaree University of Technology Tapany Udomphol Jan-Mar 2007
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Rolling of metals Subjects of inter
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www.world-aluminium.org Introductio
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Sheet rolling machines Rolled strip
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Rolls Mill rolls Mill rolls Suranar
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Typical arrangement of rollers for
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Typical arrangement of rollers for
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Different types of rolling processe
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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 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: The forces acting in the vertical d
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
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Chapter 3 - Rolling of metals

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