Laser cutting primarily involves melting or vaporizing the material to create a cut, and the subsequent cooling process does not significantly affect the hardness of mild steel. So laser cutting mild steel does not typically result in hardening of the material.
Hardening of steel occurs through processes such as heat treatment, which involve controlled heating and cooling cycles to alter the material’s microstructure and increase its hardness. Laser cutting, on the other hand, involves localized heating of the material during the cutting process but does not involve the controlled heat treatment necessary for significant changes in hardness.
However, it’s important to note that the heat generated during laser cutting can introduce a small heat-affected zone (HAZ) in the vicinity of the cut. The HAZ refers to the area where the material’s microstructure and properties may be slightly altered due to the localized heating and subsequent cooling. In the HAZ, there might be a minor change in hardness, but it is typically limited to a shallow depth and does not result in significant hardening of the overall material.
If intentional hardening of mild steel is desired, separate heat treatment processes, such as quenching and tempering, are typically employed after laser cutting to achieve the desired hardness levels.
It’s worth mentioning that laser cutting parameters, such as laser power, cutting speed, and assist gases, can influence the extent of the HAZ and potential material changes. Proper optimization of laser cutting parameters can help minimize any undesired effects on the material, including changes in hardness.