一种超高碳钢的连续冷却转变

Continuous cooling transformation of an ultrahigh carbon steel

在Formastor-FⅡ型全自动相变测定记录仪上,利用膨胀法测定超高碳钢UHCS-6Al的膨胀曲线,结合金相-硬度法,获得了其连续冷却转变(CCT)曲线,并对不同冷速下的组织、硬度进行了研究。结果表明:超高碳钢UHCS-6Al的奥氏体转变温度范围为650~820℃,比GCr15钢奥氏体转变温度明显提高;其马氏体转变临界冷却速度为0.81℃/s,而UHCS-6Al钢的Ms点温度比GCr15钢低。UHCS-6Al钢可获得高硬的马氏体组织,并且其密度比GCr15钢轻9%,是一种良好的轴承钢备选材料。

The expansion curve of the ultra-high carbon steel UHCS-6 Al was measured by expansion method on Formastor-FⅡ type automatic transformation recorder,the continuous cooling transformation（ CCT） curves of the steel were obtained combined with the metallographichardness method,and the microstructure,hardness under different cooling rate of the steel were also studied. The results show that the austenite transformation temperature range of the steel UHCS-6 Al is between 650-820 ℃,which is significantly higher than that of GCr15 steel. The critical cooling rate for martensitic transformation of the steel UHCS-6 Al is 0. 81 ℃/s,and its Ms temperature is lower than that of GCr15 steel. The steel UHCS-6 Al can obtain martensitic microstructure with higher hardness,but its density is 9% lower than that of GCr15 steel,which is a good candidate steel for bearing-making.