Experimental studies on micro alloyed steel used in oil and gas industries

This research involved cold cracking in microalloyed steels, scrutinizing its corrosive impact on physical and mechanical attributes. A comprehensive analysis covers the base material, heat-affected zone, and weld material through microstructural examinations, hardness tests, fracture resistance tests, etc. The heat affected zone exhibits finer grain structures, elevating hardness. The weld region’s fracture toughness is compromised by finefeatures, inducing tear ridge, and micro-cracks, collectively diminishing overall toughness. Fractography identifies fracture causes and flaws. Non-destructive dye crack test detects surface very micro crack on the surface, while fracture analysis explores hydrogen’s influence. Findings reveal a substantial reduction in CTOD and J-fracture resistance in the weld zone decrease that is attributed to lower weld zone ductility. Weld regions exhibit 35 % lower ductility than the base material, with fractography revealing reduced energy absorption and diminished fracture toughness. The study guides improvements in oil and gas pipeline for safety and durability measures.