Investigation on Crack-Extension in Stainless Steel

This paper presents briefly an experimental and theoretical research programme on crack-extension in stainless steel. This research programme is being carried out within the framework of the TNO-research programme with respect to inelastic analysis and structural integrity of components of the SNR 300. The SNR 300 is a prototype sodium cooled fast breeder reactor which is under construction at Kalkar (Western Germany). This project is sponsored by the governments of Western Germany, Belgium and the The Netherlands. The main objective of the research programme is to establish a relation between crack-extension (and initiation) and the strain-and—stress distribution near the tip of the crack for arbitrary loading programmes and in the temperature range (550°G) where the material is used in the SNR project. An important subobjective is the development and adaptation of computer programmes for fracture mechanics analysis. The behaviour of a crack in stainless steel under various circumstances is of considerable interest because of topics as: 1) the leak before break criterion; 2) the predictability of crack growth between two inspection periods. The considered material is a 304 type stainless steel in the German standards' indicated as WN 1.4948 also indicated as X6 CrNi 18 11