MATERIAL SELECTION AND CONDITIONING TO AVOID BRITTLENESS CAUSED BY NITRIDING

摘要

A system for changing the temperature of a working fluid, including ammonia, includes a working fluid source and a steel tube (150', 160'). The working fluid source is configured to direct a flow of the working fluid. The working fluid from the source is at a temperature. The steel tube (150', 160') has a treated inner surface layer defining a flow passage. The surface may comprise a mill finish surface (155', 165'), an oxidizing surface (161) and/or a chromized surface (162). The tube is configured to receive the working fluid from the source and to direct the flow of the received working fluid along a path to change the temperature of the received working fluid.