|The combined effect of chemical composition and cooling rate on transformation temperatures of hypoeutectoid steels|
SCHINDLER, I. NĚMEC, J., KAWULOK, P., KAWULOK, R., ŠEVČÁK, V., OPĚLA, P., RUSZ, S.
vol. 56 (2018), no. 3, pp. 163 - 170
The transformation temperatures Ar3 and Ar1 of four unalloyed hypoeutectoid steels with a carbon content of 0.029–0.73 % were determined using dilatometric tests. Unusually high cooling rates of 2 and 8 °C s–1 were used intentionally, corresponding to the conditions in the wire rod rolling mills. The developed regression models are phenomenological and allow a simple prediction of transformation temperatures, depending only on the cooling rate and the chemical composition of the steel represented by the carbon equivalent (in the case of Ar1), respectively by the Ac3 temperature (for Ar3). When calculating the Ac3 temperature, it was worth considering its non-linear dependence on carbon content. It has been verified that the derived equations are applicable even at relatively low cooling rates when the austenite decomposes exclusively on ferrite and pearlite.
hypoeutectoid steel, carbon equivalent, dilatometer test, cooling rate, decomposition of austenite, transformation temperature
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