Surface Hardening of Stainless Steels by Kolsterising

Abstract

In many applications stainless steels need a hard and wear resistant surface. The common used austenitic stainless steels have excellent corrosion properties but very poor tribological characteristics. Depending on the demand of a high corrosion resistance there are only a few technologies to meet the necessary standard. A very successful process is the diffusion of carbon into the surface by the Kolsterising process which is done at very low temperatures so that no chromium carbides are precipitated. A high carbon content, dissolved in the lattice improves surface hardness and wear resistance by maintaining corrosion resistance. A surface hardness of over 1000 HV, a considerable improvement of wear resistance, an elimination of fretting (cold welding) and corrosion resistance in many hazardous environments are the results when Kolsterising is applied on austenitic stainless steels. Results of the influence of this hardening process on different properties of austenitic and duplex stainless steels are presented. Some examples for very successful applications of this surface treatment in different fields like automotive industry, medical industry, food processing and consumer industry are shown.