加氢装置螺纹锁紧环换热器壳体焊缝开裂原因分析

Cause Analysis of Crack Occurred in Weld in Shell of Heat Exchanger with Screw-lock Ring Used in Hydrogenation Unit

加氢装置螺纹锁紧环换热器壳体焊缝运行中发生多处开裂,经金相检测、断口分析、硬度检查等,判断开裂属于应力腐蚀开裂和氢致开裂。焊缝经切除加工后,重新焊接并热处理,设备修复后运行情况正常。

Several cracks occurred at the welds in the shell of heat exchanger with screw-lock ring used in hydrogenation unit in its operation. With metallographic examination, fracture surface analysis and hardness measurement, the crack was determined that it was induced from stress corrosion and hydrogen. The weld with crack was cut, and welding and heat treatment were carried out again, which made equipment recovered to normal condition and operation.