Causes of pipeline cracking
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As shown in the picture, a 3" pipeline cracked longitudinally during the welding process with the mother pipe. The pipeline is marked 06Cr19Ni10. There is no problem in using it for full quantitative spectral composition analysis. The location of the crack is at the final closing point of the welding circle. I wonder if it is caused by stress build-up caused by excessive current and excessive temperature.
Seeing images is caused by stress. If diagonal welding is performed in stages, such a problem may not occur. For reference.
From the picture, the pipe should be relatively thin, and if the pipes are welded vertically, a saddle-shaped curve should be made and beveled to reduce stress concentration.
Judging by the color of the weld, the temperature control is okay and the current is not an issue. There are generally two types of cracks:: The material itself is defective and a chip is formed when it is cut, or it is cut by a thermal process and defects are produced. Furthermore, due to the large thickness difference, structural reasons and the internal force generated by welding, the material is pulled away from this position.
Thanks for sharing! Rare to see! !
It was my first time to see cracked stainless steel like this. It was eye-opening.
The pipe itself may be defective. In my project, I encountered a batch of stainless steel pipes with cracks on the surface, and there was no problem with spectroscopy.
Surface cracks are visible to the naked eye, right?