TWI Industrial Member Report Summary 154/1981
By R J Pargeter
As part of a programme of work to investigate the effects of deoxidant additions to submerged-arc fluxes for the welding of carbon and carbon manganese steels, this report is concerned with the microstructure and toughness properties of the weld metal. In this phase of the work titanium additions, both in the form of ferrotitanium and rutile, were investigated.
Two flux types were employed, namely alumina basic and basic, the former being used with single arc welding over a range of arc energies from 2 to 4kJ/mm on 32mm plate, and the latter with a range of tandem arc welding conditions, all at about 4.5kJ/mm on 40mm plate. Microstructures were examined under an optical microscope, and toughness was assessed using the Charpy test and discussed in terms of the 355 transition temperature. The penetration pass was tested in each case.
In the case of the alumina basic flux (single arc) welds, Fe-Ti additions led to competition between slightly beneficial microstructural effects and slightly detrimental compositional effects, resulting in an overall beneficial effect on toughness. In the basic flux (tandem arc) welds, both these effects were slightly detrimental, and there was a consistent rise in transition temperature with Fe-Ti additions. The effects of rutile additions were beneficial with respect to toughness in the alumina basic flux welds, but unclear for the basic flux welds.
No relationship with arc energy was found for the alumina basic (single arc) welds. In the basic flux (tandem arc) welds, transition temperature rose and then fell to a lower temperature with increasing Current and travel speed for all fluxes except that with a rutile addition, where there was a steady rise in transition temperature.