Which discontinuity is not typically associated with austenitic stainless steels?

Hydrogen cracking is not typically associated with austenitic stainless steels due to their unique microstructural and compositional properties. Austenitic stainless steels are more resistant to hydrogen embrittlement compared to other steel types, particularly ferritic or martensitic steels. This resistance is primarily due to their face-centered cubic (FCC) crystal structure, which allows better accommodation of hydrogen without leading to cracking.

In contrast, other discontinuities such as porosity, underbead cracking, and thermal stress cracking can occur in austenitic stainless steels. Porosity can arise from trapped gases during welding, underbead cracking can result from issues in the heat-affected zone under high thermal stresses, and thermal stress cracking can occur due to rapid cooling and temperature variations during the welding process. The inherent characteristics of austenitic stainless steels help mitigate the risk of hydrogen cracking, making it less of a concern when working with these materials.