EFFECTS OF NITROGEN ON HYDROGEN EMBRITTLEMENT IN AISI TYPE-316, TYPE-321 AND TYPE-347 AUSTENITIC STAINLESS-STEELS

Hydrogen embrittlement of AlSl type 316, 321 and 347 stainless steels with nitrogen alloying has been studied by a tensile test through cathodic charging. The results show that addition of nitrogen improved resistance to hydrogen cracking regardless of the failure mode. Fracture surfaces of cathodically charged steels showed intergranular brittle zones on each side of the fracture surfaces. AlSl type 316 with nitrogen alloying stainless steel is more resistant to hydrogen embrittlement than AlSl type 321 with nitrogen alloying steel, whereas AlSl type 347 with nitrogen alloying steel is susceptible to hydrogen embrittlement. Nitrogen alloying of stainless steel increased the mechanical properties in hydrogen environments by increasing the stability of austenite. © 1990 Chapman and Hall Ltd.