A review on welding of high strength oil and gas pipeline steels

Owing to the findings of new locations for crude oil and natural gas, the need of high strength materials that can be used for pipes and their joining has gained paramount importance. Welded pipes have to bear internal fluid pressure in addition to the adverse external conditions. Welding of high strength pipeline materials is also a challenge for engineers in construction of pipes as well as oil and gas transportation lines. To increase reliability and profitability in this industry, effective welding techniques are needed for these materials. To understand the issues related with the welding of these high strength steels, requirements of chemical composition and mechanical properties for these materials are discussed in detail. Through this review article, an attempt has been made to critically analyse the issues and challenges associated with the weldability of high strength pipeline materials. Status of current research for weld corrosion, hydrogen embrittlement, residual stress, weld repairing and deteriorated heat affected zone is also summarized. Current development trends are discussed with a view to envisage future directions. Findings of this review work emphasize the need to shift the research focus from currently used grades X65, X70 and X80 to the advanced grades X90, X100 and X120.