Temperature distribution and structure in the heat-affected zone for steel sheets after laser cutting

A calculation is performed for the temperature distribution and studies are conducted for the structure of the heat-affected (HAZ) zone in sheet steel St3 with a thickness of 6 and 10 mm after laser cutting (LC). It is shown that, with increasing LC speed, the temperature in any section of the HAZ is reduced. Increasing laser power in the studied range has almost no effect on the temperature distribution in the HAZ. The temperature fields appearing in the course of LC are compared with the location of the HAZ regions differing in structure. The area with ferrite structure under heating stays in a state of pre-transformation before a eutectoid transformation; the cause of its formation could be an enhanced diffusion mobility of interstitial atoms near the critical point A c 1 .