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GATE 2018 ME (ME1) – Question 45

Casting, Forming and Joining Processes · Bulk forming and sheet forming, estimation of load · 2 marks · Multiple choice

Maximum cross-sectional reduction per cold wire-drawing pass is $R=1-e^{-(n+1)}$, where n is the strain-hardening exponent. For a perfectly plastic material, R is ______.

  1. 0.865
  2. 0.826
  3. 0.777
  4. 0.632

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Correct answer: (D) 0.632

Explanation

Perfect plasticity has n = 0. Substitute into the supplied relation: $R=1-e^{-1}=0.63212$ (D).