Effect of finish rolling process on precipitation hardening of TiC in a titanium microalloyed steel

doi:10.13251/j.issn.0254-6051.2025.02.031

Abstract

Abstract: Nucleation parameters of TiC precipitation in austenite (γ) in a Ti microalloyed high-strength steel were calculated according to the solid solution precipitation theory and classical nucleation growth dynamics theory of binary precipitates. Then the TiC precipitation-time-temperature (PTT) curve and TiC nucleation rate-temperature (NrT) curve were drawn. The effects of finish rolling on the TiC nucleation rate, TiC precipitation rate, strength, and hardness were also studied. The results show that the temperature of the maximum nucleation rate of deformation-induced TiC precipitation is 740 ℃, the fastest precipitation temperature is 820 ℃, and the corresponding finish rolling temperature for the maximum hardness is 880 ℃. When the finish rolling temperature is 780-830 ℃, the rate of deformation-induced TiC precipitation is not significantly affected by temperature and has almost no effect on the hardness. As the finish rolling temperature increases from 830 ℃ to 880 ℃, the rate and precipitation amount of deformation-induced TiC precipitation decrease, promoting an increase in the amount of fine TiC precipitation during coiling, an increase in precipitation hardening effect, and an increase in hardness. When the finish rolling temperature is higher than 880 ℃, the hardness decreases due to the increase in grain size.

Key words: Ti microalloyed steel, TiC precipitation, PTT curve, NrT curve, finish rolling temperature

CLC Number:

TG142.1

Wang Rui, Cui Yan, Peng Xiying, Feng Yunli, Sun Xinjun, Yong Qilong. Effect of finish rolling process on precipitation hardening of TiC in a titanium microalloyed steel[J]. Heat Treatment of Metals, 2025, 50(2): 200-205.

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