The present paper studies stress, temperature and heat dependence of creep rupture life of 9Cr-1.8W-0.5Mo-VNb (Gr. 92) steel with creep rupture data of 4 heats reported in National Institute for Materials Science Creep Data Sheet 48B. In creep of Gr. 92 steel there are four regions, H, M, L and G, showing different stress and temperature dependence of creep rupture life. Creep rupture life of Gr. 92 steel increases with increasing hardness after tempering in Regions H and M (high and medium stress), and with increasing prior austenite grain size in long-term Region G. Its creep rupture life is insensitive to the heats in low-stress Region L. Creep rupture lives of the steel are formulated in each region as a function of stress, temperature and a metallurgical variable determining its creep rupture life. Two types of breakdown in creep strength (substantial decrease in stress exponent for creep rupture life) take place in Gr. 92 steel; one from Region M to Region L, and the other from Region M or L to Region G. Since Gr. 92 steel is used in Region G in steam power boilers, the second breakdown to Region G is of engineering importance. Causes of the second breakdown are discussed with creep rupture data of four grades of creep strength enhanced ferritic steels.

本文利用美国国家材料科学研究院蠕变数据表48B中报告的4种热量的蠕变断裂数据研究了9Cr-1.8W-0.5Mo-VNb（Gr.92）蠕变断裂寿命的应力，温度和热依赖性。在Gr蠕变中 92钢有四个区域，H，M，L和G，显示出不同的应力和温度依赖性的蠕变断裂寿命。Gr的蠕变断裂寿命。H区和M区（高应力和中应力）中，回火后硬度增加，而L区中的长期奥氏体晶粒尺寸增加，92钢的蠕变断裂寿命对低应力区L的热量不敏感。在每个区域中，钢的蠕变断裂寿命是根据应力，温度和确定其蠕变断裂寿命的冶金变量而制定的。Gr中发生了两种类型的蠕变强度破坏（蠕变断裂寿命的应力指数显着降低）。92钢; 自Gr以来，一个从M区域到L区域，另一个从M或L区域到G区域。G区的蒸汽动力锅炉使用92钢，对G区的第二次故障具有工程重要性。用四种等级的蠕变强度增强铁素体钢的蠕变断裂数据讨论了第二次击穿的原因。