Heat Treatment – Ammonia is widely supplied for furnace atmospheres used in the heat treating of a broad range of metal components.
Dissociated ammonia (DA) is typically produced by the end user by thermal cracking of anhydrous ammonia to generate a reducing gas atmosphere that is 75% hydrogen and 25% nitrogen. This atmosphere protects metal surfaces from oxidizing while exposed to high temperatures. Disassociated ammonia can be the most economical means of supplying such an atmosphere to batch or continuous heat treat operations. Commonly supplied heat treat processes include annealing, sintering and brazing of low carbon steel, stainless steel and copper-based alloys.
Raw ammonia (non-dissociated) is used by certain heat treating processes that require the delivery of nitrogen directly into the surface of certain steel alloys at high temperatures such as nitriding and carbonitriding.