TWI Industrial Member Report Summary 116/1980
By M L E Davis, R J Pargeter and N Bailey
The effects of boron additions to submerged-arc fluxes on weld chemistry and microstructure have been studied by adding different boron compounds to a range of commercial submerged-arc fluxes. All welds were single wire bead-on-plate deposits at 3kJ/mm using A1 treated steels of two different manganese levels.
Boron recoveries in the weld were greatest when the borides of titanium, zirconium and lanthanum were added to the flux and least with nickel boride and borax. The recoveries were improved if a deoxidant, ferro-titanium, was also added to the flux and varied with the flux type. The only welding problem encountered was with high boron contents above 0.01%; many such deposits suffered solidification cracking.
The Fe-Ti deoxidant addition alone was capable of promoting the formation of fine acicular ferrite even with a manganese silicate flux, which gave welds containing ~0.12% oxygen.