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Microstructure evolution and mechanical properties of X12CrMoWVNbN10-1-1 steel during quenching and tempering process
Xingang Tao,Chuanwei Li,Lizhan Han,Jianfeng Gu
Keywords: Microstructure evolution, Mechanical property, X12CrMoWVNbN10-1-1 steel, Heat treatment
Abstract: The effect of heat treatments was investigated on the microstructure evolution and mechan-ical properties of X12CrMoWVNbN10-1-1 steel. The as-received steel was austenitized at1080◦C for 16 h and cooled in furnace, following tempered in two steps, i.e. at 570◦C for 18 hand then at 690◦C for 24 h. The austenitized sample had a typical lath martensite structurewith some retained austenite and no delta ferrite was observed after austenitization. Afterthe first tempering at 570◦C, there was no retained austenite remained but it resulted inthe forming of precipitates, such as Cr-rich M7C3, Cr-rich M23C6, Cr-rich M2N, Nb-rich MN,and the subgrain, as well as the reduction in dislocation density. However, microstructureobservation after secondary tempering proved the further arrangement of dislocation, sub-grain growth and the coarsening of precipitates. Hardness and impact tests were carried outfor establishing a correlation between microstructure and mechanical properties. Finally, acareful fractographic analysis of impact samples had been done using SEM and EDS.
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