L51497 Investigating the Weldability of Quenched and Tempered Pipeline Materials

This program studied the effects of girth welding on the mechanical properties of four quenched and tempered pipeline materials. The study revealed the presence of low-toughness regions in the heat-affected zone of shielded metal arc welds in heavy-wall pipe and fitting materials rated for above-ground service. High-strength, microalloyed steels produced by other processes are also known to be susceptible to similar localized toughness degradation. Because the significance of these regions, with regards to service performance, is not fully understood, further research involving full-scale fracture testing is recommended.