Small ball rebound hardness tests demonstrated characteristic hardening at 700 K in the ultra-low carbon and pearlitic steels. The equilibrium phase diagram of Fe-C binary alloy calculated using Thermo-Calc exhibited dissolving of cementite above 700 K. Moreover, in-situ heating neutron diffraction measurement demonstrated the increase of lattice parameter by dissolving of cementite above 700 K. Therefore, it can be concluded that the characteristic hardening above 700 K can be attributed to the solid solute carbon.

中文翻译：

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溶质碳对高温钢的特征硬化的影响

小球回弹硬度测试表明，超低碳和珠光体钢在700 K时具有特征性硬化。使用Thermo-Calc计算的Fe-C二元合金的平衡相图显示700 K以上的渗碳体溶解。此外，原位加热中子衍射测量表明，溶解700 K以上的渗碳体可提高晶格参数。结论是700 K以上的特性硬化可以归因于固体溶质碳。