The weld cracking failure of a boil of gas (BOG) booster pipeline in a liquefied natural gas (LNG) receiving station was investigated through macroscopic observation, physical and chemical inspection, optical microscope, scanning electron microscopy (SEM) and energy dispersive spectrometry techniques (EDS). The finite simulation analysis (FEA) method was used to examine the effect of compressor vibrations on the welding. The results showed that the crack originated from the outer surface of the butt weld between the main and supporting branch pipes. Due to the poor machining dimensional accuracy of the welding fit, three pass welding with a large amount of metal filling was processed to connect the weld. The microstructure analysis results of the weld indicated that several solidification cracks were generated between the welding passes. Moreover, many inclusions and harmful super-sized second phases were generated in the weld, with several microcracks occurred around these inclusions and second phases. The finite element analysis (FEA) calculation results showed that the vibration of the compressor did not directly lead to weld cracking, however, under the influence of the vibration, the multi-source solidification cracks and microcracks originated from the surface of the butt weld, and propagated through the whole weld, which were lead to the cracking failure. Several suggestions to prevent such a failure were proposed to avoid the occurrence of similar accidents.

通过宏观观察，理化检查，光学显微镜，扫描电子显微镜（SEM）和能量色散光谱技术，研究了液化天然气（LNG）接收站中的燃气沸腾（BOG）增压管道的焊接开裂失败（ EDS）。有限模拟分析（FEA）方法用于检查压缩机振动对焊接的影响。结果表明，裂纹起源于主支管和支管之间的对接焊缝的外表面。由于焊接配件的加工尺寸精度差，因此需要进行大量金属填充的三道焊来连接焊缝。焊缝的显微组织分析结果表明，在焊道之间产生了一些凝固裂纹。此外，焊缝中产生许多夹杂物和有害的超大型第二相，在这些夹杂物和第二相周围出现了一些微裂纹。有限元分析（FEA）计算结果表明，压缩机的振动并没有直接导致焊缝开裂，但是，在振动的影响下，多源凝固裂纹和微裂纹起源于对接焊缝表面，并在整个焊缝中扩散，从而导致开裂失败。为避免发生类似事故，提出了一些防止此类故障的建议。有限元分析（FEA）计算结果表明，压缩机的振动并没有直接导致焊缝开裂，但是，在振动的影响下，多源凝固裂纹和微裂纹起源于对接焊缝表面，并在整个焊缝中扩散，从而导致开裂失败。为避免发生类似事故，提出了一些防止此类故障的建议。有限元分析（FEA）计算结果表明，压缩机的振动并没有直接导致焊缝开裂，但是，在振动的影响下，多源凝固裂纹和微裂纹起源于对接焊缝表面，并在整个焊缝中扩散，从而导致开裂失败。为了避免类似事故的发生，提出了一些防止此类故障的建议。