CORROSION RESISTANCE OF LARGE COMPONENTS PRODUCED FROM AF932N* HIGH NITROGEN STAINLESS STEEL INGOTS

摘要

The availability of large components with high corrosion resistance and mechanical strength combined with high toughness is becoming an increasing need in oil and gas industry as well as for power and petrochemical applications. Duplex and super-duplex stainless steels provide a good combination of such properties but they are limited in thickness because of strong toughness reduction and possible presence of sigma phase on large sections. Because of the well-known beneficial effect of nitrogen on austenite stabilization, corrosion resistance, strength and toughness, high nitrogen austenitic stainless steels containing nitrogen above 0.5 % can provide an excellent alternative to duplex and super-duplex stainless steels, especially for a product thickness as large as 350 mm and greater. In this context, a high nitrogen steel designated as AF932N has been manufactured in large section sizes. Details of manufacturing process and characterization of AF932N alloy in terms of mechanical properties, microstructure and corrosion resistance, especially in regards to hydrogen embrittlement are presented and discussed in this paper.