The article analyzes the reliability factors of pipeline transport facilities related to the quality of welded joints. These factors include: deviations in the manufacturing welding process, unacceptable defects in longitudinal and circumferential welds, high sulfur and phosphorus content in the weld area metal, high content of non-metallic inclusions being local source of cracks, low ductility and impact strength of various weld sections, structural heterogeneity of various weld zones, factors associated with pipeline operation (development of extended pits for repairs and diagnostics, installation of soil supports, etc.). Based on many years of research, the authors analyze common causes of deteriorated durability of both longitudinal factory and circumferential field welds. The article shows typical groups of defects that can be detected in welded connections. The main causes of certain weld defects, external signs, preventing methods and detection strategies are presented. The authors provide references to regulatory documentation that reflects standard requirements for welded joints of piping products both at the national and industry level. The regulatory documentation contains requirements for the geometry of longitudinal welds, requirements for mechanical properties of longitudinal weld metals, quality assessment methods and non-destructive testing methods for welded pipe joints. As a comprehensive survey of weld quality factors, the authors propose a standard algorithm of studying such objects, as well as the list of required tests and examinations.
References
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