Weld metal hydrogen-assisted cracking of X70 linepipe steel using E6010 electrodes

Manual metal arc welding (MMAW) with cellulosic consumables is still widely used in Australia for field girth welding during the construction of small diameter gas transmission pipelines. Decomposition of the cellulosic electrode coating during welding introduces high levels of hydrogen into the arc and the resulting welds are potentially susceptible to weld metal hydrogen-assisted cold cracking (WMHACC). Although extensive weld metal hydrogen-assisted cold cracking has not been reported to date, WMHACC is not only possible, but likely under conditions promoting high weld hydrogen concentrations and restraint stresses. The mechanism of WMHACC in cellulosic weld deposits is, however, complex and the factors that influence the initiation and propagation of cracks in the weld metal not understood to date.