The Valve Springs Carbo-Nitrided at a High Temperature for High Speed Engines

A new heat resistant steel wire was developed for automotive valve springs. The purpose of the development is to apply a high temperature carbo-nitriding process to the springs to have a longer fatigue life. The valve spring processed at an optimal temperature was found to have a fatigue life about five times as long as the conventional Si-Cr oil-tempered wire springs processed at a conventional low temperature.