Fig 52 stress and strain development in wire and rod

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Unformatted text preview: eduction of area. Mechanics of Drawing Area reduction in drawing r = Ao - A f Ao ; Draft d = Do - D f No friction and true strain = ln A = Y f = Y f ln o The ideal stress Af Ao 1 = ln Af 1- r Ao = Y 1 + ln Taking into account friction and die angle, d f tan Af Do - D f Do + D f D Lc = where = 0.88 + 0.12 L, D = 2 , 2 sin c Ao ln The drawing force F = A f d = A f Y f 1 + Af tan Maximum Reduction Assume perfectly plastic material (n=0), no friction, no redundant work, Ao Ao 1 d = Y f ln = Y ln = Y ln =Y Af Af 1- r Then ln Ao A f = ln 1 1 - r = 1 Ao A f = 1 1 - r = e max = 1.0 The maximum possible area ratio Ao A f = e = 2.7183 The maximum possible reduction rmax = e - 1 e = 0.632...
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This document was uploaded on 03/14/2014.

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