制氢装置中废热锅炉的失效分析

Failure Analysis of the Exhaust Heat Boiler in the Hydrogen Producing Plant

通过对废热锅炉锥形封头、人孔筒件、环缝区的化学成分、力学性能、金相组织、断口形貌、扫描电镜ＤＥＡＸ检测等试验研究。全面阐述了由于蠕变断裂机理、晶界弱化而造成废热锅炉环形焊缝过热区在服役条件下开裂，并确认其裂纹类型为再热裂纹。除此，还发现隐藏在蓝脆区的氢诱发裂纹。

This paper comprehensively gives an exposition of the crack forming under the service condition at the overheat zone of the circumferential welds of the exhaust heat boiler caused by creep rupture and crystal boundary weakening mechanism by means of the tests and investigations of the chemical compositions, mechanical properties, metallurgical microstructures, fracture features, electron microscopic scanning, EDAX examinations of the circumferential weld areas of the shell, conical head and manhole. Through this investigation,the type of cracking had been confirmed as a reheat cracking.Besides,the hydrogen induced cracking hidden at the blue brittleness area had been also discovered.