Study on the Notch Toughness of Structural Steels (1st Report)

Abstract

Investigations were further performed about the effects of high temperature prestraining on the retained ductility and the notch toughness of various structural steels, and compared with the results of previous reports for a killed mild steel. Seven high tension steels, whose tensile strengths were ranging from about 50 to 85 kg/mm², were used for experiments.
It was found from the retained ductility test that the loss in retained ductility by high temperature prestraining was generally slighter for those high tension steels than the killed mild steel. At the same time it was revealed by V-notch Charpy test that the prestraining at 300°C was most harmful to the notch toughness of steels tested. But the loss in notch toughness after such treatment was fairly less compared with a marked decrease experienced in the killed mild steel.
It was suggested from the above results that the high tension steels tested might be less susceptible to the damage of thermal strain cycle during welding than mild steel.