Question

(2 marks) Calculate the forging force at the end of the stroke for a solid cylindrical workpiece made of annealed 70-30 brass that is 150 mm high and 100 mm in diameter and is to be reduced in height by 25%. Coefficient of friction is estimated to be 0.2, its flow curve is defined by a strength coefficient of 600 MPa, and a strain-hardening exponent of 0.12. Assume that a strain = 0.002. (6 marks) Wire Drawing (a). In wire drawing process, explain why you can't simply stretch the wire, rod, or bar? Fokus E Engelska (USA)

Answer 1

A Given: Material - Annealed 70-30 brass (1) Initial height , H = 150 mm (2) Initial diameter, D = 100 mm (3) final height, h = 0.75 H = 0-75x150 h = 112.5 mm - [ since height is reduced by 25%.] (4) M = 0-2 (5) Strength coefficient, k = 600 MPa (6) Strain hardening exponent, n = 0.12 (7) Strain, E = 0.002 To find: (1) forging force ,f Solution : • rolume during operation remains same. . Initial rolume = final volume : DXH = /x dxb 100%x 150 = dx 112.5 . de 115.47 mm : final radices ,v = = 57.74 mm Now flow stress, Of = ken • Of = 600 X 0.002° 12 .: S = 2 84.63 MPa 0.12

Now After forging, final cross-sectional Area, Af = d = x 1150472 .: Af = 10471.97 mm2 Actual forging force, 2 ur .; F = 284.63 X 10471.971 If 2x0.2 X 57.74 3 X 112.5 .; f = 3184 609.53 N .: F = 3184609.53 1000 kn F = 3184.61 EN