L51427 ERW Weld Zone Characteristics

The objective of this research project was to determine the fatigue characteristics of the weld zone of electric resistance welded (ERW) pipe. The project involved: (1) characterizing pipe samples in terms of initial defects, tensile and yield strength, chemistry, and fracture toughness, (2) evaluating the fatigue crack growth of base metal and the weld zone in air and a 3.5 wt% NaCl solution, and (3) evaluating the fatigue crack growth of machined defects in the weld zone of ERW pipe subjected to cyclic pressure loading. This study found that the weld zone and base metal exhibit the same fatigue crack growth rates, the weld zone is not more susceptible to corrosion fatigue damage, and the greatest variability in ERW pipe fatigue behavior lies in the initial defect distribution.