Numerical Prediction of Fracture Behavior for Austenitic and Martensitic Stainless Steels

Two types of stainless steels are compared in this paper, austenitic X15CrNiSi25-20 and martensitic X20Cr13, based on their numerically predicted fracture behavior. There are engineering applications where both of the steels can be considered for use and where these materials can be exposed to crack occurrence and growth, so proper distinction between them is desirable. Comparison is made on the basis of J-integral values that are numerically determined using finite element (FE) stress analysis results. FE analysis is performed on compact tensile (CT) and single-edge notched bend (SENB) type specimens that are usually used in standardized J-integral experimental procedures. Calculated J-integral values are plotted versus crack growth lengths for mentioned specimens. Results show somewhat higher values of J-integral for steel X20Cr13 than X15CrNiSi25-20. Further, when comparing J-integral values obtained through FE model of CT and SENB specimen, it is noticed that CT specimens give somewhat conservative results. Results obtained by this analysis can be used in predicting fracture toughness assessment during design process.