Substantiation of the narrow-jet plasma technology for finishing cutting of steel sheets

Abstract

The paper presents a study of the effect of the PMVR-5.2 plasma torch inclination angle on the cut surface profile, the structure and hardness of the material of the edge on 10 mm thick 09G2S steel plates. The plasma torch implements the narrow-jet technology. The heat-affected zones prove to have a gradient structure. When cutting is performed at an angle of 30°, there appear ∼500 μm thick edges with a 15 to 30 μm thick surface zone of structureless martensite having a microhardness of 900 HV 0.025 and a zone of fine-lamellar pearlite with a hardness of 350 HV 1. This requires mechanical removal of a 40 μm thick layer from the cut surface before subsequent welding. When the plasma torch is inclined at an angle of 90°, the quality of the edge material requires no mechanical removal of the heat-affected zone for subsequent welding. © 2019 IOP Publishing Ltd.