Fracture Mechanism of 09g2s Low-Alloy Steel Welded Sample Subjected to Heat Treatment and Equal Channel Angular Pressing During Impact Bending

Abstract

The aim of the work: the investigation of a fracture mechanism in 09G2S low-alloy steel welded sample with K-shaped grooving on a thermal impact area (TIA) after equal channel angular pressing (ECAP) and tempering + ECAP. 
 There are carried out impact bending tests of 09G2S steel welded samples in which Menage incision is carried in the TIA. Micro-fractograms are presented and the analysis of a fracture mechanism in Menage samples of 09G2S steel with welded joints subjected to impact bending at the temperature of 233ºK is carried out. It is shown that the fracture of welded samples subjected to tempering and the ECAP in the TIA is ductile and characterized with the presence of a dimple micro-relief as well as basic metal fracture. In its turn, 09G2S welded steel strengthened by means of the ECAP as a result of impact bending at the temperature of 233ºK is fractured quasi-brittle in the TIA. At the same time there are observed facets of quasi-microchip, micro-cracks and micro-dimples. A mixed fracture is also characteristic expressed in the interchange of brittle and ductile areas.