Manufacturing

A round cross section extrudate is produced from a billet 150mm length and 75mm in diameter through a direct extrusion operation with extrusion ratio rx=4.0. The dic angle (half-angle) =60. The work metal has a strength coefficient =515MPa and strain hardening exponent =0.18. Use the Johnson formula with a=0.8 and b=1.5 to estimate extrusion strain. Determine the pressure applied to the end of the billet as the ram moves forward at (Show all calculations involved): i) L=150mm (6) ii) L=100mm (2) iii) L=50mm (2) 1) P a e iv) L=25mm (2) v) L=0mm. (2) Question 5: A wire drawing operation produces a wire of diameter 2.0mm through a die with entranee angle =20 and a coeffieient of friction at the work-die interface =0.07. If the wire has a starting diameter of 3.0mm and a strength coefficient K=215MPa and a strain hardening exponent n=0.25. Determine ( Show all calculations imolived): (6) i) The draw stress. (1) ii) Draw force in the operation. Question 6: A round disk of 150mm diameter is to be blanked from a strp of 3.2mm.half-hard cold-rolled steel whose shear strength = 310MPa. Determine. (4) (a) the approprate punch and die dianeters. (4) (b) blanking force