| 摘要: |
| P92钢作为新一代耐热钢，其服役温度正随着超超临界机组的不断推广而逐渐提高，而高温疲劳性能对保证电厂的安全运行具有重大作用.文中通过P92钢630℃下的疲劳试验，研究了其在不同应变幅和应变速率下的疲劳寿命以及应力—应变关系，并结合断口形貌分析了P92钢的断裂机理.结果表明，P92钢属于高温循环软化材料，其疲劳寿命随塑性应变幅的增大而呈指数下降，同时应变速率的增大会导致其疲劳寿命的增大.P92钢疲劳断口分为疲劳源区、裂纹扩展区以及断裂区.高应变幅下蠕变孔洞和二次裂纹的增加是导致其疲劳寿命降低的主要原因. |
| 关键词: P92钢 高温低周疲劳 疲劳寿命 疲劳断口 |
| DOI：10.12073/j.hjxb.2018390170 |
| 分类号:TG142.1 |
| 基金项目:国家自然科学基金资助项目（51475326） |
|
| Study on high temperature low cycle fatigue behavior of P92 steel under 630℃ |
|
JING Hongyang, SU Dingbang, XU Lianyong, ZHAO Lei1,2
|
1. School of Materials Science and Engineering Tianjin University,Tianjin 300072, China;2.
2. Tianjin Key Laboratory of Advanced Joining Technology, Tianjin 300072, China
|
| Abstract: |
| P92 steel has been widely applied in high temperature components of power plants. With the development of the ultra supercritical power plants, the operating temperature of P92 steel has been promoted. The high temperature fatigue performance of P92 steel has a significant effect on the safety of power plants. Therefore, the fatigue test of P92 steel under 630℃ was conducted, and the effects of the strain amplitude and strain rate on the fatigue life was studied. In addition, the fatigue fracture mechanism for P92 steel was investigated by the fracture morphology analysis. The results indicated that P92 steel exhibited a cyclic softening behavior at high temperatures. The fatigue life decreased exponentially with the increasing of plastic strain amplitude. In contrast, the improvement of strain rate would promote the fatigue life. Furthermore, the fatigue fracture surface of P92 steel consisted of three zones, including fatigue source region, fatigue crack growth zone and fracture zone. The decrease of fatigue life at high strain amplitude was mainly induced by the increase of creep cavities and secondary cracks. |
| Key words: P92 steel high temperature low cycle fatigue fatigue life fatigue fracture |
