A high-strength steel bar must be cold-reduced from a diameter of 1.00 in. to 0.65 in. A number of schedules have been proposed. Which of the schedules below would you choose to avoid drawing failure and minimize the likelihood of centerline bursts? Explain. Assume that η = 0.50.
A. A single reduction in a die having a die angle of 8?.
B. Two passes (1.00 to 0.81 in. and 0.81 to 0.65 in.) using dies with angles of α = 8?.
C. Three passes (1.00 to 0.87 in., 0.87 to 0.75 in., and 0.75 to 0.65 in.) using dies with angles of 8?.
D. E, and F. Same schedules as A, B, and C, except using dies with α = 15?.