A cylindrical specimen of 75 mm height and 50 mm diameter is cold forging into a final height of 36 mm. The flow curve of the material is described of the parameters K = 350 MPa and n = 0, 17 while the coefficient of friction is μ = 0.1.
(a) Calculate the piston force at start of machining, intermediate heights of 62 mm and 49 mm and the final height of 36 mm. For the calculation, use the non-homogeneous deformation approach but the coefficient of heterogeneity is given (by Groover) by the relationship Qa = 1 + 0.4 μ D / h.
(b) Calculate the forging load to the final height of 36 mm by applying it friction hill method