Plastic Deformation of Metal and the Octahedral Shearing Stress Theory (1st report)

Abstract

The experiments were carried out to study the stress-strain relation in the metal under combined stress condition. In the case concerning the 1st report, the tubular specimens of 0·4%C steel with the open ends or the closed ends were at the first time deformed up to plastic range by internal oil pressure, which was removed soon, and then the specimens were subjected to tensile force in the axial direction. Experimental results : (1) The more severely the specimens with the closed ends were strained in the pressure tests, the greater the material was strain-hardened by the tensile strain except the non-prestrained specimen. (2) In the case of the specimens with the open ends, the elastic limits became lower with increase in the amount of the prestrain, while strain-hardening by tensile strain was greater in the range of large strain.