Heat treatment of large-scale forgings at the Ural Heavy Machinery Factory

Abstract

ion scheme dictate special features of the treatment of heavy-duty forgings, which are uncharacteristic for heat treatment of small articles. These factors, and also the presence of micro- and macroliquation, and the development of high compressive stresses in the center of heavy-duty forgings during the cooling process, which affect the phase transformations, make it impossible to compare the results of laboratory experiments, and result in the need to conduct more research on full-scale components. To develop a rational production process for heat treatment, there must be data on the metallurgical quality of the forgings, the temperature distribution within the volume of the component, the kinetics of the transformation of austenite over a broad range of cooling rates and temperatures, and the level of mechanical properties across the section of a component after this heat treatment. In developing a heat-treatment technology for heavy-duty forgings, it is necessary to utilize one's own practical experience, and domestic and foreign data in the area of metallurgy, metal science, and heat treatment. Considering the special technological features of the heat treatment of forgings, it is necessary to note separately the characteristic features of preliminary and final heat treatment. Preliminary, or primary heat treatment (PHT), is an imprescriptible part of the technological process of forging production. The traditional purpose of PHT is the formation of the required structural state prior to final heat treatment, including the aging of the superheated forging structure and provision for machinabillty. The basic problem involving