Effects of flux composition on the element transfer and mechanical properties of weld metal in submerged arc welding

Abstract

Submerged arc welding was performed using metal-cored wires and fluxes with different compositions. The effects of wire/flux combination on the chemical composition, tensile strength, and impact toughness of the weld metal were investigated and interpreted in terms of element transfer between the slag and the weld metal, i.e., △ quantity. Both carbon and manganese show negative △ quantity in most combinations, indicating the transfer of the elements from the weld metal to the slag during welding. The amount of transfer, however, is different depending on the flux composition. More basic fluxes yield less negative △ C and △ Mn through the reduction of oxygen content in the weld metal and presumably higher Mn activity in the slag, respectively. The transfer of silicon, however, is influenced by Al2O3, TiO2 and ZrO2 contents in the flux. △ Si becomes less negative and reaches a positive value of 0.044 as the oxides contents increase. This is because Al, Ti, and Zr could replace Si in the SiO2 network, leaving more Si free to transfer from the slag to the weld metal. Accordingly, the Pcm index of weld metals calculated from chemical compositions varies from 0.153 to 0.196 depending on the wire/flux combination, and it almost has a linear relationship with the tensile strength of the weld metal.

Experimental study on effect of flux composition on element transfer during submerged arc welding

“…However, this increase is very less as the changes in Al 2 O 3 content of the fluxes are also not very significant. This also has been verified by Bang et al [34].…”

“…Low carbon is mainly due to the oxidation of available oxygen in the weld. In these welds, high carbon content may also be attributed to low silicon content for the following reason: if the silicon content is in a particular range, it suppresses the formation of CO and less carbon may be removed from the weld [34,35]. The reaction of carbon is given by the equation…”

Effect of Flux Composition on the Percentage Elongation and Tensile Strength of Welds in Submerged Arc Welding

“…The C and Mn transfers are also increased with the increase of the basicity index of the flux. The fluxes containing high basicity index reduces the Mn transfer from the weld to the slag [22]. The increase of C and Mn contents might affect the UTS of the welds.…”

Effects of Electrode Types on the Microstructure, Tensile and Hardness Properties of 304 L Austenitic Stainless Steel Heat-Affected Zone (HAZ)

“…Thereafter, the specimens were then etched in a solution of 1 ml HCL + 3 ml HNO 3 + 1 ml glycerol and the microstructures examined at a magnification of 400× × using metallurgical microscope. volume fraction of ferrite observed may be due to difference in cooling rates that resulted from heat inputs of the electrodes [15]. It is well known that, electrode heat input varies, and can be classified into high and low heat inputs [5].…”