Behaviour of Materials of Construction during Cracking of Ammonia at 600°c

Abstract

The behaviour of different materials of construction during the cracking of ammonia at 600°c, and at an operating pressure of 100 mm of water (∼100 Nm⁻² above atmos. pressure) was studiedfor periods up to 1500 h. Carbon steel suffered decarburisation. Low chromium – molybdenum alloy suffered nitriding and decarburisation, and stainless steels such as AISI 304, 316 L, 329, 310, 321 and 347, and also SLX–254 and HV–9A, Incoloy 800, and titanium, all suffered some degree of nitriding. Data are presented on the kinetics of the nitriding attack and on weight changes. Of all the materials tested, Type AISI 347 gave the best performance up to a period of 1500 h.