STRUCTURE AND FRACTURE-TOUGHNESS OF HIGH-STRENGTH PERLITE-CEMENTITE CAST-IRON AFTER PLASMA TREATMENT

Treatment of cast iron is a promising application of surface strengthe ning by highly concentrated energy sources. As a structural material, cast iron in widely used in many branches of industry. The conventiona l methods of bulk heat treatment and surface strengthening (for exampl e, by high-frequency currents) do not make it possible to realize comp letely the potentially high operating properties of cast iron. At pres ent considerable experience has been accumulated in plasma and laser s trengthening of various grades of cast iron. However, the literature c ontains little data on the interrelation of the structure, phase compo sition. hardness, and wear resistance with the crack resistance of cas t irons. At the same time, analysis of operational damage in cast iron parts shows that brittle fracture and breaking are an important cause of failure in such parts. The present work is devoted to investigatio n of the structure, the nature of disruption, and the criteria of shor t-term crack resistance of cast irons in surface strengthening by a hi ghly concentrated plasma jet.