摘要
研究了服役16年的汽轮机30Cr1Mo1V高中压转子钢的组织结构与疲劳断裂性能。选取转子高应力段、高温段和中压段等3个典型部位的平面应变断裂韧性和疲劳裂纹扩展速率性能比较试验。结果表明,高温段的性能劣化最严重,高应力段次之。微观组织观察表明30Cr1Mo1V钢原始的回火索氏体组织发生了明显的分解,碳化物球化,晶界碳化物粗化严重,在高温段的晶界处发现了少量的蠕变孔洞,这些现象可能是材料力学性能退化的组织结构原因。可见,因工作温度和应力差异,转子不同部位性能下降和组织结构退化状态出现明显分化,温度影响最明显。
Fracture toughness and fatigue crack growth behavior of a steam turbine rotor steel 30Crl MolV were examined after service for 16 years. Samples taken from three typical sections of the examined rotor, high temperature part, high stress and medium stress part, were tested at room temperature. The results show that the mechanical properties of the rotor steel are deteriorated after long-term service, and the properties of the high temperature section are degraded severely and the high stress part takes the second place for the property deterioration. The corresponding microstructure observations show that the orginal sorbite microstructure is almost completely decomposed in elevated temperature section with coarsened and spheroidized carbides at grain boundaries, and a few microvoids are also observed at grain boundaries for the steel after long-term service. The same damage characters are observed in high stress part but no microvoid is found, however, the sorbite is decomposed only partly in the medium pressure section. The evolution of the microstructure is responsible for the property degradation. It indicates that the property degradation and microstructure damage of the examined rotor is uneven, and the service condition of high temperature is the main reason for the deterioration of the rotor steel.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2013年第1期60-63,共4页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金项目(50871076)
上海科委重点项目(09521101305)
