Laser welding in the pipeline industry

The construction of pipelines, in the plant or in the field, is an expensive process that requires reproducible high-quality welds because of the possible environmental and economic effects of weld defects, particularly those leading to breaks. This requirement has been accentuated by the shift to highstrength low-alloy (HSLA) steels for pipelines, with increasingly stringent demands on welding procedures. Rothwell et al.1 report that “As new materials and design approaches for the pipeline construction industry are developed and economic pressures increase, methods which revolve around craft skills and arbitrary workmanship standards become less appropriate… given the intrinsically repetitive nature of cross-country pipeline welding, new, mechanized and automatic approaches will be sought, in which the quality of welds, and the way in which it is assessed, are related to prior engineering decision, rather than to individual craft performance in the field.”