Open AccessThe influence of the heating rate of cemented constructional steels on the growth of austenitic grain in the process of high-temperature holding
Author(s) -
В. А. Кукареко,
A. L. Valko,
А. Н. Чичин
Publication year - 2019
Publication title -
vescì nacyânalʹnaj akadèmìì navuk belarusì. seryâ fìzìka-tèhnìčnyh navuk
Language(s) - English
Resource type - Journals
eISSN - 2524-244X
pISSN - 1561-8358
DOI - 10.29235/1561-8358-2018-63-4-399-406
Subject(s) - materials science , isothermal process , austenite , metallurgy , impurity , grain boundary , grain growth , phase (matter) , thermal , grain size , microstructure , thermodynamics , physics , chemistry , organic chemistry
The influence of the heating mode of samples of constructional cemented steels 20ХН3А, 20ХГНР and 15ХГН2ТА on the value of austenite grain after high-temperature isothermal aging at 1000 °С is studied. It is shown that the heating of steels at a rate of 1.2–3.0 °C / min in the phase-transformation interval stabilizes the grain structure of the steels and leads to a slowing down of the kinetics of the growth of austenite grains during prolonged high-temperature aging, which makes it possible to increase the temperature of the chemical-thermal treatment of steels. It is concluded that the stabilization of the grain structure of steels is associated with the formation of segregation of impurity atoms and particles at grain boundaries with high-angle disorientation during slow heating, which prevents migration of grain boundaries in the process of prolonged high-temperature aging. A high-temperature chemical-thermal treatment of a batch of billets from steel 20ХН3А under experimental conditions with stepwise heating in the phase-transformation interval provided a qualitative fine-grained structure of the cemented layer.