Pages: 33 Published: Jan 1965
Interlaboratory tests were conducted on 0.036-in.-thick sheet specimens of aluminum-killed steel to determine whether correlation between pressing quality and plastic strain ratio r, strain-hardening exponent n, and other tensile properties could be established. Metallurgical treatments of the specimens were varied to obtain four combinations or r and n: High r and high n, high r and low n, low r and high n, and low r and low n. The Nelson-Winlock method was used for measurement of n, and the procedure suggested by the International Deep Drawing Research Group was used for measurement of r. Good interlaboratory correlation was shown for values of r, but values of n, though adequate, did not correlate nearly as well. The specimens were subjected to three stamping operations in the production of: a panel truck door, a blower housing, and an automotive instrument panel. Press quality was evaluated by the percentage of breakage occurring during a lift. The test results demonstrate the differences in dependence on r and n of parts involving different degrees of drawing and stretching. The door panel, primarily a punch stretching operation, correlated best with r and showed little dependence on n. The blower housing correlated best with r, and the instrument panel showed a strong dependence on both r and n.
deep drawing, die drawing, metal drawing, pressing, punching, stamping, tensile properties, strain-hardening exponent, plastic-strain ratio, steels, aluminum-killed steels
Paper ID: STP48237S