Effect of Prestrain on Brittle Fracture Initiation Charcteristics

Abstract

As one of factors which have great influence on the brittle fracture initiation characteristics of steels, the prestrain can be touted.
Previously, the effect of prestrain on the notch toughness of steels has been investigated by using V notch Charpy impact test specimens, but quantitative analysis on the effect of prestrain has not been made.
In this paper, in order to evaluate quantitatively the effect of prestrain on the brittle fracture initiation characteristics of steels, mild steel, 60, 80 and 100 kg/mm² high strength steels and 9% Ni steel which had been prestrained by 2-8% at room temperature were investigated by using the deep notch test.
It can be concluded that the effect of prestrain is relatively great for mild steel and 100 kg/mm² high strength steel, but small for 60 and 80 kg/mm² high strength steels and 9% Ni steel.