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在一项较早的工作中已开发出了一种命名为0．3C—CrMoV ESR(0．3C-1．0Mo-0．3V)的超高强度钢,这是一种通过将碳含量从0．15增加到0．28%和通过电渣精炼(ESR)并在ESR期间以铌或者锆对该钢进行孕育处理而得到的改进型AFNOR 15CDV6钢。根据淬火速度,该钢铸态热处理后的极限拉伸强度(UTS),0．2%屈服应力(PS),百分延伸和夏氏U型缺口试件冲击能值分别在1550～1560MPa,1500～1520MPa,8～12．5%和370～790kJm~(-2)的范围内变动。所报道的0．3C—CrMoV钢的显微组织由马氏体和贝氏体组成。在现行的研究中,通过增加0．3C-CrMoV钢的铬含量到4%及将该钢经过ESR以钛进行孕育处理,其UTS和0．2%PS分别进一步增加到1740～1760MPa和1570～1610MPa。有意思的是随着UTS和PS的增长其百分延伸率也同时增长了14%,而其夏氏U型缺口试件冲击能值无任何跌落。此钢的力学性能随着铬含量的增加而提高可以归因于其马氏体和贝氏体混合显微组织中马氏体的体积百分数增加之故。
In an earlier work, an ultra-high strength steel named 0.3C-CrMoV ESR (0.3C-1.0Mo-0.3V) has been developed, 0.15 up to 0.28% and improved AFNOR 15CDV6 steel obtained by ESR and inoculation of the steel with niobium or zirconium during ESR. According to the quenching speed, the ultimate tensile strength (UTS), 0.2% yield stress (PS), percentage elongation and Charpy U-notch impact energy of the steel after as-cast heat treatment are respectively 1550 ~ 1560MPa, 1500 ~ 1520MPa, 8 ~ 12.5% and 370 ~ 790kJm ~ (-2). The reported microstructure of 0.3C-CrMoV steel consists of martensite and bainite. In the current study, the UTS and 0.2% PS were further increased to 1740 ~ 1760MPa and 1570 ~ 1760MPa respectively by increasing the chromium content of 0.3C-CrMoV steel to 4% and the steel was inoculated with titanium via ESR. 1610MPa. Interestingly, the percent elongation also increased 14% at the same time as the UTS and PS increased, while the Charpy U-notch specimens showed no drop in impact energy. The mechanical properties of this steel increase with the increase of chromium content can be attributed to the increase of the volume percentage of martensite in the mixed microstructure of martensite and bainite.