Metal structure in surface zones of tubes of chromonickel steel with high-temperature thermomechanical processing

Abstract

The article discusses the impact of the structure of the surface layer of hardened steel used for the manufacture of parts experiencing high loads during operation, on the processes of crack formation. The presence of a defective layer on the surface of the car, located in the area of decarburization, determines the use of mechanical treatment to remove it, which is not economically feasible in mass production. The need for this technological scheme is also caused by constantly increasing demands on the quality of the surface of finished parts (fingers of tracks of tracked vehicles (GM), torsion bars, shafts and axles for various purposes, etc.) made of hot-rolled (hot-rolled) solid and pipe products, for highly loaded models of equipment (high static and dynamic loads). When processing bodies of revolution, depending on the diameter and length of the workpieces, machining schemes can be found in some cases that have advantages even over turning. For example, when designing new equipment for cleaning the outer surface of cylindrical billets, a suitable processing scheme may be high-temperature thermomechanical processing (HTTT) with screw compression (VO) deformation with simultaneous removal of scale during deformation.