Development of Heavy Gauge X80 Linepipe

New large diameter pipeline projects for transmission of gas from western Canada propose the use of operating pressures as high as 12kPa (1740 psi). These operating pressures will require linepipe with increased wall thickness. As well, X80 grades are now an economic alternative to X70 for these major projects. X80 was first commercially produced in North America by IPSCO in 1994. However, to extend IPSCO’s capability to heavier gauges, a significant metallurgical development program was necessary. Particular attention has focussed on achieving more demanding impact toughness requirements. This program has resulted in the successful production of X80 linepipe in gauges as heavy as 15.3 mm. The paper will review the experimental development of heavy gauge linepipe.