Chapter 3 - Rolling of metals

More documents

Recommendations

Info

Example: A 300 mm-wide aluminium alloy strip is hot-rolled in thickness from 20 to 15 mm. The rolls are 1 m in diameter and operate at 100 rpm. The uniaxial flow stress for aluminium alloy can be expressed as σσσσ = 140εεεε 0.2 (MPa). Determine the rolling load and the power required for this hot reduction. From Eq.20 ' 1 P = σ ob[ R( ho − h f ) ] 2 Q p ⎛ 20 ⎞ ε1 = ln⎜ ⎟ = 0. 288 ⎝ 15 ⎠ 20 −15 r = = 0. 25 20 R 500 = = 33. 3 h f 15 σ σ o ' o = k 1 ' 1 = ε ∫ o 140 n ε dε n+ 1 kε = ε ε ( n + 1) 1 ( 0. 288) 1. 2 0. 2 b = 0.3 m, R = 0.5 m, h o = 0.02 m and h f = 0.015 m, we need to know σσσσ ’ o and Q p . 1 = 91MPa n + 1 Suranaree University of Technology Tapany Udomphol Jan-Mar 2007 ε o = n kε 2 P = ( 91)( 0. 3) 36 3 a N W = 0. 5 = 4π R∆h = = 100 / 60 = 1 [ 0. 5( 0. 020 − 0. 015) ] 2 ( 1. 5) = 2. MN 0. 5 1. 67 s 0. 5x0. 005 −1 −6 −1 ( 0. 025)( 2. 36x10 )( 1. 67) Js = 1. 24MW 1 = 0. 025m Q p can be found from graph(~1.5) when reduction r and R/h f are known.
References • Dieter, G.E., Mechanical metallurgy, 1988, SI metric edition, McGraw-Hill, ISBN 0-07-100406-8. • Edwards, L. and Endean, M., Manufacturing with materials, 1990, Butterworth Heinemann, ISBN 0-7506-2754-9. • Beddoes, J. and Bibbly M.J., Principles of metal manufacturing process, 1999, Arnold, ISBN 0-470-35241-8. • Lecture note, 2003. • Firth Rixson leavelets. • Metal forming processes, Prof Manas. • Metal forming lecture, Ass Prof. P. Srichareonchai. 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 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: The torque M T is equal to the tota
show all

Chapter 3 - Rolling of metals

Create successful ePaper yourself

Delete template?

Save as template?