P. Weymer, Ipsen, Inc., Cherry Valley, IL
Solution nitriding or the Ipsen SolNit® process is a newly developed thermo-chemical heat treating process for case-hardening stainless steels. If treated with normal nitriding or carburizing processes, stainless steels lose most of their corrosion resistance due to the formation of chromium nitrides or carbides. The Ipsen patented case hardening process is very different from the conventional nitriding process. It imparts a nitrogen rich case measuring up to 0.100” (2.5 mm) on parts made from either austenitic or martensitic stainless steels while at the same time preserves or improves the parts corrosion resistance. Attendees will learn about the background theory, microstructure, application, and results of solution nitriding in Ipsen’s high pressure gas quench furnaces.
Summary: Solution nitriding is a new case-hardening process for stainless steels. It is carried out in the austenitic state. In this state, nitrogen thermally dissociates and diffuses into the surface of stainless steels. It can result in a case depth of up to 0.100" (2.5 mm) deep by treatment at 2,000 to 2,100F (1,100 to 1,150C) in nitrogen at 0.1 to 1.3 bar pressure. Quenching yields a high-hardness martensitic case (about 0.5% nitrogen) on low-carbon martensitic steel grades, and a high-strength austenitic case (up to 0.5% nitrogen) on austenitic or duplex steel grades. In contrast to conventional carburizing, the corrosion resistance of solution nitrided stainless steel is significantly enhanced. This process makes it suitable for bearings, pumps, tools and gears.
