RELATION BETWEEN CYCLIC PLASTIC STRAINS AND DECREASE IN FRACTURE TOUGHNESS OF STRUCTURAL STEELS

Abstract

The purpose of this study is to present the relation between cyclic plastic strains and the decrease in the fracture toughness of structural steels. The fracture toughness of structural steels subjected to cyclic plastic strains is investigated by Charpy V-notch impact tests. It is shown which is more suitable, the plastic skeleton-strain or the equivalent plastic strain, for relating the decrease in the fracture toughness due to cyclic plastic strain to that due to monotonic plastic strain. The relationship between the decrease in the fracture toughness and the increase in the stress due to plastic strain and aging is established. A way to assess the decrease in the fracture toughness of structural steels due to cyclic plastic strains is proposed.