Abstract: In order to improve its hardness and wear resistance, the nitriding process was studied for the 32Cr3MoVE steel workpiece. The results show that the lower nitriding temperature and the lower nitrogen potential adopted in nitriding process can effectively control the depth of bright white layer, and avoid the production of coarse alloy nitrides, but the nitriding rate is slower. By keeping the nitrogen potential maintaining always around its threshold through certain multi-stage control mode, the nitriding process can ensure the nitriding rate, control the depth of bright white layer, and inhibit the formation of brittle phases as well. Finally, the suitable gas nitriding process by nitrogen potential threshold control for 32Cr3MoVE steel is obtained through process test validation.

Key words: 32Cr3MoVE steel, gas nitriding, bright white layer, nitrogen potential threshold