Examination of crater crack formation in nitrogen-containing austenitic stainless steel welds

A systematic study of the effect of nitrogen addition on the crater cracking tendency of 317L and 904L austerritic stainless steel welds was carried out. To conduct the experiment, nitrogen content of the welds was altered during welding by introducing various levels of N-2 (up to 5 vol-%) into the argon shielding gas. Crater cracking tendency was determined using FISCO test setup. The extent of solidification cracking was determined by using the hot cracking sensitivity factor,,. In the case of 317L welds, no appreciable rise in hot cracking sensitivity was noticed until 3 vol-% N2 was added to the shieldinggas. In the case of the 9041-weld, crack sensitivity initially decreased for an addition of 0.5 vol-% N-2 and then increased gradually with further N-2 addition. The explanation for this observed behavior is discussed in this paper.