A cold heading operation is performed to produce the head on a steel nail. The strength coefficient for this steel is 600 MPa, and the strain-hardening exponent is 0.22. Coefficient of friction at the die–work interface is 0.14. The wire stock out of which the nail is made is 5.00 mm in diameter. The head is to have a diameter of 9.5 mm and a thickness of 1.6 mm. The final length of the nail is 120 mm.

 

(a) What length of stock must project out of the die in order to provide sufficient volume of material for this upsetting operation?

(b) Compute the maximum force that the punch must apply to form the head in this open-die operation.