Effect of flux composition on element transfer during submerged arc welding (saw): a literature review

Submerged arc welding is widely used in the fabrication of pressure vessels, pipe lines and offshore structures because of its higher metal deposition rate, good strength of the joint and good surface appearance. The properties of the welded joint such as strength, toughness can be improved by controlling the microstructure of the welded joint. The element transfer from the flux has major influence on weld metal composition and weld metal properties. To predict weld metal properties, it is necessary to determine the weld composition, which primarily depends upon wire, flux, parent metal, slag metal reactions, process parameters, dilution and electrochemical reactions. Numerous investigators have attempted to determine, which flux components are of most importance in establishing the final weld chemistry. The weld chemistry is decided by the metallurgical reactions in SAW but to decide the extent of metallurgical reaction in saw is very difficult because of large variations in cycle temperature, reaction time, high heat input. In SAW due to short reaction time during SAW the reaction is not reached to its thermodynamic equilibrium, so the exact prediction of weld metal chemistry is difficult. The purpose of this literature review is to focus on an innovative approach which is needed while deciding weld chemistry. It would be worthwhile if one could develop a frame work to predict the Mn, Si, carbon, oxygen and other elements in the final weld metal, from a given combination of electrode, flux and base metal. The work done so far on Element transfer study is very limited.Much published information is not available about fluxes made by Industry professionals as they do not disclose the composition of the flux for which they claim higher strength and better mechanical properties. This literature review will provide the basis for researchers in the field of SAW.