Investigations of material hardness and structural changes in the heat-affected zone during plasma cutting

Investigation of the heat-affected zone during plasma cutting can significantly contribute to a better understanding of mechanical, structural, and chemical properties of a material in the kerf zone. The experimental research in this paper is concerned with the intense heat impact of a plasma jet on the surface layers of stainless steel. The heat-affected zone was investigated by measurement of its approximate width, analysis of its phase content, and transformations during the material cooling process, as well as measurements of micro-hardness near the cut edge. The material structural changes were related to the micro-hardness and temperature distribution in the workpiece. This research provides useful information about the heat-affected zone, its impact on the workpiece material properties, and the need for the secondary operations. The narrow heat-affected zone and the good quality and consistency of the cut result from favourable mechanical and thermophysical properties of austenitic stainless steel.