回火加热速率对3Cr2MnNiMo钢组织及性能的影响

Effect of tempering heating rate on microstructure and properties of 3Cr2MnNiMo steel

研究了快速加热回火(300℃/s)对3Cr2MnNiMo钢碳化物形态分布和力学性能的影响,结果表明:与低速加热回火(1℃/s)对比,快速加热回火有利于获得细小、弥散分布的碳化物。提高回火加热速率,延迟了位错的回复,这种延迟作用增加了碳化物形核位置,提高碳化物的形核速率和弥散程度,随着回火保温时间的延长会弱化加热速率的影响。当回火温度为660℃、保温时间为1 s时,加热速率从1℃/s提升至300℃/s,试样硬度提升53.3 HV;回火时间延长至1 800 s、300℃/s加热速率下的试样硬度比1℃/s加热速率下的试样硬度值高9.4 HV。

The effects of rapidly tempering(300 ℃/s) on the carbides morphology and mechanical properties of 3 Cr2 MnNiMo steel were studied. The results showed that compared with low speed tempering(1 ℃/s), rapidly tempering was beneficial to obtain fine and dispersed carbides. It was considered that increasing the tempering heating rate could hinder the disappearance of dislocations in the recovery process, which increased the nucleation position of carbides, resulting in a higher nucleation rate and a finer dispersion of carbides. However, the effect of heating rate would be weakened by the prolongation of tempering time. When the tempering temperature was 660 ℃ and the holding time was 1 s, the heating rate increased from 1 ℃/s to 300 ℃/s, and the hardness of the sample increased by53.3 HV. With the tempering time extended to 1 800 s, the hardness of the sample at 300 ℃/s heating rate was 9.4 HV higher than that at 1 ℃/s heating rate.