A steel wire is drawn from an initial diameter (di) of 10 mm to a final diameter (d_f) of 7.5 mm. The half cone angle (α) of the die is 5° and the coefficient of friction (μ) between the die and the wire is 0.1. The average of the initial and final yield stress [(σ_y )_avg] is 350 MPa. The equation for drawing stress σf. (in MPa) is given as:
The drawing stress (in MPa) required to carry out this operation is (correct to two decimal places).