火电厂低温再热器开裂原因分析

Crack Analysis of Low-temperature Reheater in Power Plant Boiler

某电厂锅炉在大修水压试验时发现低温再热器水平段定位卡附近存在裂纹,通过宏观检查、化学成分分析、有限元受力分析、扫描电镜观察、金相分析和硬度试验对其进行分析。结果表明,在内压和内外壁温差产生的热应力共同作用下,裂纹在应力集中处、材料薄弱的地方萌生,最后发展成穿透性裂纹。

Cracks had been found in the level part of low-temperature reheater where near the positioner when a power plant boiler was overhauling. By macroscopic inspection, chemical composition analysis, finite el- ement analysis, SEM, metallographic analysis and hardness test, it was found that in the effect of steam pressure and thermal stress,the crack was birth at the stress concentration and weakness point and at last grew to be a through wall flaw.