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一、前言七十年代初,我国火力发电厂的主蒸汽管道,采用了从西德进口的10C,M_o910钢。它的元素平均含量为C:0.10%,C_r:2.25%,M_o:1%。供货状态的热处理是:885～980℃/空冷或炉冷+G50～780℃/空冷,其原始组织为贝氏体;珠光体+铁素体;珠光体+贝氏体等。在高温和应力长时间作用下,10C_rM_o910钢明显地出现碳化物析出。固溶体中的强化元素逐渐转移到碳化物中,同时亦发生不同类型相的转变,致使钢材的热强性能逐渐降低。由于钢的原始组织状态不同,碳化物在析出种类、数量等有差异,因此,试验必须取主蒸汽管道监视段的原始段和不同运行时间的对应切割段。根据高井电站6号炉10C_rM_o910钢主蒸汽管道不同运行时间、碳化物析出,看该钢种微观方面的变化反映于宏观机械性能。
I. Introduction In the early seventies, the main steam pipelines of thermal power plants in China adopted 10C and M_o910 steel imported from West Germany. The average content of its elements is C: 0.10%, C_r: 2.25%, M_o: 1%. The state of the heat treatment is: 885 ~ 980 ℃ / air cooling or furnace cooling + G50 ~ 780 ℃ / air cooling, the original organization of bainite; pearlite + ferrite; pearlite + bainite. Under the action of high temperature and stress for a long time, carbide precipitated obviously in 10C_rM_o910 steel. The strengthening elements in the solid solution are gradually transferred to the carbides, and at the same time, the transformation of different types of phases also occurs, resulting in the gradual decrease of the thermal properties of the steel. Due to the different initial state of the steel, the type and quantity of carbide precipitated are different. Therefore, the test must take the original section of the main steam pipe monitoring section and the corresponding cutting section of different running time. According to the different operation time of main steam pipe of No.10C_rM_o910 steel furnace of No.6 furnace at Gaojing Hydropower Station, the carbides are precipitated and the microscopic changes of the steel are reflected in macroscopic mechanical properties.