Analysis of Micro Cracks Near Weld Line in ERW Pipe of API 5L X70M Grade
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A metallurgical root cause analysis was performed on Electric Resistance Welded (ERW) pipes having Ultrasonic Test (UT) indication near the weld line. Fine subsurface cracks have been observed in the ERW cracks which are found to be parallel to the weld flow line. A metallurgical cross section was drawn at UT indicated area on the ERW pipes of 406.40 mm (16 inch) diameter by 7.40 mm wall thickness and API 5L X70 PSL2 grade. Failure analysis is carried out by optical microscope and scanning electron microscopy with energy dispersive spectroscopy.
KeywordERW Subsurface crack Oscillation marks Mold powder Meniscus
The authors are grateful to ERW Plant and MSU Baroda for supporting part of this analysis. The authors also would like to thank Welspun Management for permitting to publish this work.
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