Impact Toughness of Low Alloy Steels Subjected to Heat Treatment and Equal-Channel Angular Pressing at Low Temperature

摘要

The paper deals with the impact toughness and fracture mode of the low-alloy 09G2S steel in the as-delivered state and in the condition after equal-channel angular pressing (ECAP) and annealing at impact bending in the temperature range of 293-203 [K]. The results on impact toughness KCV and fracture mode of Charpy test specimens made of the 09G2S steel in the as-delivered state and in the condition after hardening are presented. There is a decrease in the steel impact toughness in the examined temperature range after annealing at 673 [K], ECAP, and ECAP with annealing compared to the corresponding value for steel in the as-delivered state. For the 09G2S steel treated with various techniques, the temperature-KCV plot drop occurs smoothly, without abrupt changes, in the examined temperature range, in contrast to the behavior of this value with the upper threshold of the fracture appearance transition temperature for the steel in the as-delivered state.