Effect of Laser Hardening and Gas Nitriding on Wear Resistance of Steel P20: A Comparative Study

The effect of laser hardening and of gas nitriding on the microstructure and wear resistance of steel P20 (the Russian counterpart is 38KhNM) is studied. The phase composition and the microhardness of the hardened surface layers are determined and their microstructure is studied. Wear tests are performed. It is shown that both treatments raise the hardness of the steel. However, the nitrided layer has a higher resistance to plastic deformation, a higher indentation modulus, and a much higher wear resistance than the laser hardened layer. Laser hardening produces a deeper hardened layer, whereas gas nitriding provides a higher wear resistance of steel P20.