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高温叶片钢12Cr12Mo Nb是在传统403型12%Cr钢的基础上,通过添加少量Nb元素发展而来。研究了该钢的高温拉伸性能、韧脆转变温度(FATT50)、旋转弯曲疲劳性能、热膨胀系数等性能,并介绍其强化机理。试验结果显示:(1)该叶片钢的拉伸性能随温度的变化符合12%Cr钢的一般规律,即强度随温度逐渐下降,在350~450℃范围内塑性最差;(2)钢的室温旋转弯曲疲劳强度优异,高达401.8 N/mm2;(3)钢所具有的优异的各项性能得意于板条马氏体、细小弥散分布的Nb C及回火后形成的富Nb的M2X析出物的强化作用。
High-temperature leaf steel 12Cr12MoNb is based on the traditional 403 12% Cr steel, by adding a small amount of Nb elements developed. The high temperature tensile properties, the toughness and brittle transition temperature (FATT50), the rotating and bending fatigue properties, the thermal expansion coefficient and other properties of the steel were studied. The strengthening mechanism was also introduced. The results show that: (1) The tensile properties of the blade steel conform to the general rule of 12% Cr steel with the temperature change, that is, the strength gradually decreases with temperature and the plasticity is the worst in the range of 350-450 ℃. (2) Bending fatigue strength at room temperature is excellent, up to 401.8 N / mm2; (3) excellent performance of the steel is favored slab martensite, finely dispersed NbC and Nb enriched M2X formed after tempering Material enhancement.