高温过热器开裂失效分析

Cracking Failure Analysis for a High-temperature Superheater

对某电站开裂破坏的高温过热器弯管处纵向和环向裂纹产生的原因,进行了宏观形貌、化学、力学、金相、裂纹微观的分析。结果表明:弯管部位产生的纵向裂纹是在应力腐蚀的作用下由管内壁扩展至外壁,环向裂纹是在腐蚀疲劳的作用下由管外壁向内壁扩展。

To find the causes leading to longitudinal and circumferential cracks on elbow of a high- temperature superheater, a series of tests were conducted, such as visual examination, chemical composition analysis, mechanical property analysis, metallographic examination and microstructure analysis, etc. Results show that the longitudinal cracks spreading from inner to outer wall surface at the bending area are caused by strcss corrosion, while the circumferential cracks spreading from outer to inner wall surface are caused by corrosion fatigue.