Girth weldability evaluation for submarine pipeline laying

摘要

Based on the offshore standard DNV-OS-F101-2010,girth welding tests and girth weldability evaluations were carried out for the X65 and X70 UOE submarine pipelines of 3 wall thickness gauges,in which semi-automatic gas metal arc welding(GMAW)was adopted matched with metal powder flux cored wire.The girth welding procedure specification(WPS)was optimized to obtain good quality and cold-crack-free girth weld joint without preheating and post-weld heat treatment.At the same time,porosities,inclusions and incomplete fusion defects were avoided.Girth weld joints were evaluated for tensile strength,bending,Vickers hardness,charpy impact toughness and crack tip opening displacement(CTOD)fracture toughness.Results show that all the girth weld joints have good mechanical performances,indicating that the girth weldability of Baosteel’s UOE submarine pipelines is excellent in the case of semi-automatic GMAW.