Affiliation:
1. Iron and Steel Institute of Z. I. Nekrasov National Academy of Sciences of Ukraine
Abstract
The purpose of the analysis is to determine the modes of heat treatment that affect the quality parameters of complex alloy steels. Steels, which contain chromium and significant amounts of other alloying elements (nickel, vanadium, molybdenum, etc.) are used for the production of the different metal products, which are working in hard operating conditions: rolling rolls, power equipment parts, piercing plug, etc. Retained austenite is always present in such steels and affects the properties of the final metal products. Should be include the following factors that increase the amount of retained austenite in complexly alloy steels: thermal stabilization of the austenite; redistribution of the carbon between the α-phase and austenite during cooling in the temperature range of the intermediate or bainitic transformation or during isothermal holding slightly above the Мp point; hardening from the intercritical temperature range; changing the cooling rate; the actual content of carbon and alloying elements; changing in the austenitization temperature, isothermal holding and heating temperature during hardening. The indicated factors should be considered during determining the final parameters of the heat treatment mode to control the amount of retained austenite in complexly alloy steels. Isothermal hardening from the γ-α-area is proposed to obtain a multiphase structure of 38HN3MFA steel. Using of the cryogenic treatment for the strengthening mode of the 38HN3MFA steel promotes the transformation of retained austenite into martensite and significantly increases the microhardness of the structural components of the steel.
Publisher
Institute of Ferrous Metallurgy Z.I. Nekrasova of the National Academy of Sciences of Ukraine
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