Study of laser nitriding on the GCR15 steel surface

Pulse laser nitriding of GCr15 steel in the surrounding of NH3 gas was studied. The experimental results show that a high hardness, good wear resistance, compact and uniformity hard layer of iron nitride was obtained. The results of micro-hardness and wear rate testing shows that after laser nitriding, the micro-hardness of the sample increased 18 percent and wear rate of the sample decreased 50 percent, laser nitriding improves the sample's wear resistance character. The nitriding layer is about 150 μm thick and contains nitrided iron dendrites. The microstructure, phase constitution, micro-hardness, depth and wear character of the nitriding layer were determined and analyzed, and the pulsed laser nitride mechanism on the surface of GCr15 steel was discussed.