Lager transformation hardening of a medium carbon steel

The results of laser transformation hardening trials on a medium carbon steel are described. A 2kW fast axial flow laser was used, producing a defocused beam with a conventional plano-convex lens and also an annular beam with an Axicon lens. Assessment of the hardened zones was made by examining the morphology and microstructure. Trends in the morphology of the hardened regions were predictable, but a variation in microstructure was observed that could not be related to the laser process parameters.