Effect of quench-tempering conditions prior to nitriding on microstructure and fretting wear mechanism of gas nitrided X210CrW12 steel

In this research the effect of quench-tempering conditions prior to industrial gas nitriding on the microstructure, fretting wear behavior and mechanism of nitrided X210CrW12 steel was investigated. The results reveal that higher tempering temperature can increase the thickness of the compound layer and the diffusion layer, and the amount of nitride precipitates also increases. The specimen tempered at the lower temperature has a thinner compound layer but a higher nitrided layer hardness. In addition, decarburization occurs during the nitriding process. The wear mechanism is also explained by the FEA wear model. The thickness of compound layer and the hardness of diffusion layer are the main factors that influence the wear behavior of the nitrided specimens. Increasing the wear resistance of counter material leads to the transition of wear mechanism from slight adhesion to severe abrasion. When the counter material is GCr15, all nitrided specimens present the similar wear rate values, while the wear rate of the specimen with the higher diffusion layer hardness and thinner compound layer tempered at the lower temperature of 550 degrees C is lowest when the counter material is SiC.