长期服役后高中压转子30Cr1Mo1V钢的性能研究

Mechanical Properties of 30Cr1Mo1V HP-IP Rotor Steel After Long-term Service

通过室温拉伸、高温拉伸和冲击等试验研究了经过长期服役后的高中压转子30Cr1Mo1V钢不同位置的性能变化,并分析了转子强度和韧性变化的原因.结果表明:转子服役温度高的部位碳化物的形貌、分布和大小均发生变化,贝氏体和铁素体中的碳化物析出、聚集或长大,而原奥氏体晶界和贝氏体与铁素体边界处碳化物析出增多,碳化物颗粒变得粗大;不同位置的拉伸性能差别不大,服役温度最高位置的拉伸强度最低,冲击韧性下降;不同部位总冲击能量的降低主要表现为裂纹形成能的降低,而裂纹扩展能区别很小;高中压转子30Cr1Mo1V钢服役时高温位置的韧脆性转变温度(FATT50)比低温位置明显升高.

Mechanical properties of 30Cr1Mo1V steel samples taken from different areas of an HP-IP turbine rotor after long-term service were studied by tensile,impact and FATT50 tests respectively at room and high temperatures,after which causes leading to the material changes in strength and toughness were analyzed.Results show that in areas of rotor enduring high service temperatures,the morphology,distribution and sizes of carbides may change a lot;the carbides precipitated from bainite and ferrite will aggregate and grow;carbides may gradually precipitate and get coarsening at the boundary of original austenite grain and that between bainite and ferrite.The degradation of tensile properties differs slightly at different locations,and the greatest degradation occurs in the area enduring highest service temperatures,where the corresponding toughness will reduce accordingly.The decrease of total impact energy is mainly from the decrease of the crack forming energy,and the crack propagation energy doesn’t show large difference for all locations.Compared with areas enduring low service temperatures,the fracture appearance transition temperature（FATT50） in areas enduring high service temperatures is obviously higher.