STRUCTURE AND MECHANICAL PROPERTIES OF WHITE CAST IRON AFTER PLASMA SURFACE MODIFICATION

We study the influence of surface modification with a highly concentrated plasma jet on the mechanisms of crystallization and phase transformations in welded 300Kh25N3S3 white cast iron. Depending on the modes of plasma heating, the procedure of treatment is carried out both without melting and with micro- or macromelting. It is shown that a modified zone with highly dispersed structure is formed on the surface of cast iron. This zone is commonly called a thin conglomerate of phases. We established a simultaneous increase in hardness, wear resistance, and crack-growth resistance of white cast iron after plasma modification. In this case, the procedure of treatment of cast iron without melting or with micro-melting turns out to be optimal.