Modelling creep damage in heat affected zone in 321 stainless steel. Part I: Quantitative study of intergranular damage

Abstract

During service at high temperature, stabilized stainless steels are well known to present a serious form of intergranular cracking in the Heat Affected Zones (HAZ) referred to as the reheat cracking phenomenon which is very deleterious for the structural integrity of welds made in this steel. The purpose of the present study is to present quantitative results on mechanical behaviour and the damage at high temperature of simulated HAZ which show different sensitivities to intergranular cracking. Creep laws are determined and an intergranular damage model is identified using the local approach to fracture based on mechanical tests performed at 600 °C and metallurgical observations on smooth specimens and two types of notched specimens.

Continuum damage mechanics modelling based on simulations of microstructural evolution kinetics

“…Chabaud-Reytier et al have also made a quantitative study of intergranular damage in heat affected zones in type 321 stainless steels. 14 The damage parameter in their study is defined as the percentage of the cracked grain boundary length in the total boundary length in the area of measurement. The damage parameter for the unaged material increases sharply at low creep strains and then very slowly at higher strains with increasing creep strain.…”