Analysis of the Effect of Nonmetallic Inclusions on Steel Strengthening upon Laser Treatment

Abstract

Abstract The main factors governing a mixed effect of nonmetallic inclusions as internal sources of microalloying on local strengthening of steels upon laser treatment are systematized and analyzed. The processes, which govern the nature of the microcomposite zone formation, heterogenization regarding the structure of steel matrix and inclusion–matrix phase boundaries, as well as the decrease in the sizes of inclusions and their content in the surface layer, are discussed. The effect of preliminary laser treatment on the mechanism and parameters of crack formation near inclusions upon subsequent deformation at 25–900 and 1000–1250°C is shown. The effect of the saturation zones of steel matrix on the form of crack propagation from inclusions is determined.