Liquid Nitriding of Steels^[1]

The liquid nitriding process has several proprietary modifications and is applied to a wide variety of carbon steels, low-alloy steels, tool steels, stainless steels, and cast irons. This article discusses the applications, subclassifications, operating procedures, and maintenance procedures, as well as the equipment used (salt bath furnaces) and safety precautions to be undertaken during the liquid nitriding process. It describes the different types of liquid nitriding process, namely, liquid pressure nitriding, aerated bath nitriding, and liquid nitrocarburizing. Environmental considerations and the increased cost of detoxification of cyanide-containing effluents have led to the development of low-cyanide salt bath nitrocarburizing treatments. The article reviews the wear and antiscuffing characteristics of the compound zone produced in salt baths with the help of Falex scuff test.