PROTECTIVE PAINTS FOR HEAT TREATMENT: New developments in regards to requirements of health and safety as well as environmental regulations

摘要

If steel components are carburized, carbonitrided or nitrided, ionitrided or vacuum carburized according to one of the many different technologies which are meanwhile used for steel hardening, it is in many cases required to leave some areas of the workpiece unhardened for later machining, turning, drilling, broaching, coldforming, laser or electronic beam welding. Since more than 50 years, protective paints have been successfully used to protect heat treated steel parts locally from carbon and nitrogen pickup by providing a gas light layer on the surface of the workpiece. This paper describes the most commonly used protective paints for all kinds of carburizing and nitriding processes with particular emphasis on newly developed water base products considering and redeeming present requirements in regards to health and safety as well as environmental regulations. This report will give some information on the major industries where protective paints are used successfully, and state-of-the-art automatic/semi-automatic equipment is shown to achieve this in a safe and economic way.