FEM estimation of mechanical parameters involved in crack initiation on Alloy A182 using tapered specimens (44)

Abstract

Alloy A182 is widely used in the nuclear industry as a weld filler alloy in the first pressure barrier of the PWR reactor. Operational experience has detected cracking problems in service conditions, commonly named PWSCC (Primary Water Stress Corrosion Cracking). The CERT test (Constant Extension Rate Test) carried out with tapered specimens, allows to have a range of strain rates in the same test.

The objective of this work is to find pure mechanical threshold criteria for crack initiation in the material. For this, FEM simulations have been carried out with the true stress-strain curve of an A182 alloy belonging to the European MEACTOS project as the only input. From these simulations, the influence of strain rate, plastic strain, and triaxiality parameters on the stress threshold value can be estimated. These results are consistent with the experimental data obtained on testing with high temperature simulated primary water.