In this study, the influence of impurity elements to the weld metal crack susceptibility in the electron beam welding of a pipeline steel was investigated. 19 mm thick API 5L-X65 steel plates with different sulfur, silicon and phosphorus content levels were welded and the extent of the weld crack occurrence was compared. As the result of the variance analysis of the experimental data, sulfur was found to be the most harmful element to the crack occurrence. The Auger electron spectroscopy analysis also showed the segregation of sulfur to the fracture surface of the weld cracking.
To clarify the upper limit of the sulfur content for the prevention of the weld cracking, commercially available test pipes with different sulfur contents were welded. As the result, it was confirmed that the sulfur content should be kept no more than 0.002% to prevent the weld cracking in the all position electron beam welding process.
