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    淬火-配分热处理对30Cr13模具钢组织与耐蚀性的影响

    Effects of Quenching & Partitioning Heat Treatment on Microstructure and Corrosion Resistance of Die Steel 30Cr13

    • 摘要: 采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、透射电子显微镜(TEM)等研究了淬火-配分(Q&P)热处理后30Cr13模具钢的物相组成和显微组织的演变规律,并利用动电位极化法对不同工艺热处理的模具钢在3.5%(质量分数)NaCl水溶液中的腐蚀行为进行了分析。结果表明:220Q盐浴淬火试样和220P一步法淬火-配分热处理试样的残余奥氏体体积分数小于3%,随着二步法淬火-配分热处理中配分温度从300℃上升至500℃,30Cr13模具钢的残余奥氏体含量呈现先增加而后降低的趋势,在配分温度为400℃时取得最大值;220Q和220P试样的组织都由板条状马氏体组成,经过二步法淬火-配分热处理后,模具钢的基体组织也由板条马氏体组成,此外在马氏体板条间有白亮条状或者颗粒状M3C型碳化物出现;不同淬火-配分热处理的30Cr13模具钢的耐均匀腐蚀性能差别不大;二步法淬火-配分热处理模具钢试样的点蚀电位高于盐浴淬火试样和一步法淬火-配分热处理试样的。

       

      Abstract: The phase composition and microstructure evolution of die steel 30Cr13 after quenching and partitioning (Q&P) heat treatment were studied by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM). And the corrosion behavior of the die steel treated in different heat treatment processes was analyzed in 3.5% (mass) NaCl solution by method of dynamic potential polarization. The results show that residual austenite content in 220Q sample quenched in salt bath and 220P sample treated by one-step Q&P heat treatment were smaller than 3% (volume). When the partitioning temperature in two-step Q&P process rose from 300℃ to 500℃, the content of residual austenite in the die steel increased first and then decreased, and got the maximum value when the partition temperature was 400℃. The microstructure of 220Q and 220P samples was composed of lath martensite. The microstructure of samples after Q&P heat treatment was also composed of lath martensite, and there were white bright bar or granular M3C carbides between martensite laths. The difference between uniform corrosion resistance of the die steels treated in different Q&P processes was little. The two-step Q&P treated die steel samples had higher pitting potential than salt bath quenched sample and one-step Q&P treated sample.

       

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