The effects of ion-nitriding on friction and wear behavior of low carbon steel (SM20C, KS) were investigated. Three kinds of specimens were prepared, the first one was furnace cooled after ion-nitriding, the second one was water cooled after ion-nitriding while the third one was hydrogen-treated after ion-nitriding.
The results showed that the wear resistance increased more for the water cooled specimen than for the furnace cooled specimen. For hydrogen treated specimens, there was little increase in wear resistence when compared with the specimens of non-nitriding.
The wear volume increased rapidly when the wear depth passed the compound layer of the specimens. Therefore, it is concluded that the existance of the compound layer is beneficial to wear resistance for the carbon steel used here.
At the initial stage of wear, the friction coefficient of all three kinds of nitrided specimens is larger than that of non-nitrided specimens, which is caused by the rough surface due to the nitriding. However, as the wear progresses the friction coefficient depends strongly on the difference of hardness between the pin and the disk.