Investigation into the Influence of Calcium Treatment on Submerged-Arc Weld Metal and HAZ Toughness of Microalloyed C-Mn Steel

TWI Industrial Member Report Summary 256/1984

By P L Harrison

Background

The present report is concerned with the influence of calcium treatment on HAZ and submerged-arc weld metal Charpy toughness properties. Bead-on-plate and bead-in-groove submerged-arc welds were made on calcium free and calcium treated API 5LX-65 and API 5LX-70 pipe materials. Two welding conditions and two basic fluxes were investigated using the same 1.5%Mn, 0.5%Mo wire. For the steels investigated, the results show that calcium treatment has no direct influence on weld metal or HAZ toughness and, although some variations in weld metal microstructure and toughness were observed, these may be explained in terms of differences in weld metal aluminium content. The benefit of using a higher oxygen potential flux to reduce the detrimental influence of high aluminium content was demonstrated.