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The advantages of mechanized welding for onshore pipelines in North America are well known, as evident in the high proportion of large diameter pipelines that use variations of the technology. However, smaller diameter (20-24鈥�) onshore pipelines are still primarily welded using 鈥渟tovepipe鈥� techniques with cellulosic electrodes, a process with well-known disadvantages, particularly with cold and/or windy ambient conditions.

This study evaluated and tested different options for mechanized, low-hydrogen, welding of 24鈥� pipe. All of the developed process combinations employed rutile flux core arc welding consumables for fill and cap passes. The produced welds met the NDE requirements of CSA Z662-11, and mechanical properties were found to be suitable for typical pipeline applications.

Implications of this technology include: the mitigation of risks related to hydrogen-assisted cracking; the ability to weld higher strength pipe; and higher joint-to-joint repeatability.