The Effect of Bainite Type on the Evolution of Carbide Constituent During an Accelerated Aging in Cr-Mo-V Steel
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This paper aims to understand the effect of the type of bainite (i.e., the lower, the upper and the granular, developed by bainitic hardening at 550, 650 and 750 °C, respectively) on the evolution of carbide constituent due to a subsequent aging (at 700 °C for up to 500 h). The secondary carbides were identified by x-ray diffraction in the configurations of M3C, M7C3, M23C6, M2C, M6C and MC (M=Fe, Cr, Mo, Mn and V), which varied with the time of aging. Despite that the three types of bainites shared similar constituent of carbides after the aging for 2-100 h, the constituent of the upper bainite (M7C3 + M23C6 + MC) was different from that of granular bainite and lower bainite (M7C3 + M23C6 + MC + M6C) after the aging for 500 h. The concentration of the enrichment of alloying elements in ferrite matrix plays a dominant role in governing the precipitation of carbides in the aged steel.
Keywordsaging bainitic hardening carbide Cr-Mo-V steel
This work was financially supported by the Grant “Shanghai Universities Gaoyuan Discipline (Mechanical Engineering),” as sponsored by Shanghai Municipal Education Commission, the Training Scheme of Shanghai Higher Education Youth Teacher and the Grant of Innovation through the Institute of Heavy Forging Manufacturing Technology, Shanghai Dianji University. One of the authors (PL) gratefully acknowledges the financial support from Shanghai Collaborative Innovation Center for Heavy Casting/Forging Manufacturing Technology.
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