The effect of the compound layer of ion-nitrided SKT-4(JIS) steel on wear was investigated by carrying out wear tests of the two kinds of specimens; one with the compound layer as formed during the nitriding process, and the other without the compound layer. Ion-nitriding was performed in a chamber with nitrogen-hydrogen mixture at 550℃, and the specimens without the compound layer were prepared by treating them additionally with only hydrogen at 510℃ after the conventional ion-nitriding. The result of the removal of the compound layer shows that in the specimens without the compound layer, the hardness near the surface decreases by a small amount, while it increases at a distance larger than 0.1 mm-0.2 mm from the surface.
In wear test, three different sliders, made of SKH-9, SCM-4, and SKT-4 steels respectively, were prepared. In wear test with SKH-9 slider, which is harder than the specimens (with/without the compound layer), volume wear of the specimen without the compound layer is smaller than the specimen with the compound layer, however in the test with SCM-4, and SKT-4 slider, softer than the specimens(with/without the compound layer), volume wear of the specimen without the compound layer is larger than the specimen with the compound layer. A large amount of wear debris was found during wear test with SCM-4, and SKT-4 sliders, compared to that with SKH-9 slider.
