In this study, the effects of hydrogen and surface cracks on the tensileproperties of torsional prestrained ferritic-pearlitic low-carbon steelswere investigated. Even for a polished specimen without surface cracks,which are introduced during torsional prestraining, the tensile strengthsignificantly decreased. However, the tensile strength is recovered byremoving surface cracks via polishing. The Vickers hardness value atthe lateral surface of the torsional prestrained specimen increased withhydrogen-precharging, indicating hardening by hydrogen. A newmethod for measuring diffusion coefficient D at high prestrain value byusing hydrogen-precharged pipe-shaped specimens made fromtorsional-prestrained specimen is proposed.
展开▼
