A novel technology has been developed to recycle steel slag as a flux for the submerged arc welding process. The chemical, mechanical, and metallurgical properties of welds produced using recycled slag have been evaluated and compared with that of fresh flux available in the market. The tensile strengths of weld metal prepared with recycled slag and fresh flux are 462.25 MPa and 471.49 MPa, which are comparable. The impact strength of welds produced using recycled slag is 83.66 J which is acceptable in accordance with AWS SFA 5.17 specifications. The welds produced were subjected to non-destructive tests such as radiography and also dye-penetration test apart from visual inspection to ascertain the soundness of welds produced. Metallurgical investigations were carried out, and a favorable microstructure containing acicular ferrite was obtained in welds deposited using recycled slag. Similar trends of microhardness survey have been observed in both the welds produced.

A novel study on structural analysis of crystalline phases present in steel slag was conducted, which advocates the utilisation of steel slag for developing welding flux. This study plans to characterise chemical and thermal analysis of waste steel slag generated by steel making plant to ensure its compatibility and suitability for manufacturing of flux required for the submerged arc welding process. Based on these studies, five fluxes using steel slag as raw material were developed by the agglomeration process. The required deoxidisers and alloying elements were added during recycling to enhance their performance. The Spectro analysis of weld metal revealed that the carbon content of weld metal has increased from 0.04 to 0.06% with the addition of CaCO₃ from 10 to 12%.

A novel methodology has been established which allows to recycle steel slag as a suitable flux for submerged arc welding. The flux produced using waste slag as a raw material has been applied to deposit beads on plates. The bead geometry is dependent on welding parameters; hence optimization of parameters is essential. In this cut throat competition, researchers are striving to minimize the cost of experimentation using various experimental and optimization techniques to reduce number of experiments for save time, money, and resources. In this article various techniques have been explored for better optimized results. The welding parameters have been optimized to obtain desired bead geometry using various optimization techniques such as genetic and teaching–learning-based optimization algorithm, and desirability. It was observed that the genetic algorithm technique provides better results having a minimum error of penetration, bead width, and reinforcement (i.e. 1.12%, 1.83%, and 2.46%, respectively), as compared with other techniques applied. It is further observed that flux manufactured from waste slag is capable to produce desired bead profile which is similar with that of the fresh flux. Recycled slag is capable to produce optimum bead geometry having maximum penetration of 11.52 mm, bead width 20.73 mm, and reinforcement 3.24 mm.

The slag generated by steel-making plant has been employed to manufacture flux essential for submerged arc welding process. The developed flux has been used for depositing beads on plates, and the weld metal chemistry has been evaluated. The effect of welding conditions and flux composition on element transfer behavior has been investigated. The experiments were carried out as dictated by the design matrix generated using CCRD in response surface methodology. The data generated during experimentation was used to develop mathematical models. The developed models were tested for their adequacy through the ANOVA technique in design expert software. It is interesting to note that the recycled slag provided the chemistry of weld metal which is accepted as per ASME specifications. The rise in welding current increases the amount of carbon in weld metal from 0.11 to 0.14 wt.%, whereas it decreases with increasing travel speed. Manganese content decreases (1.28 wt.% to 0.795 wt.%) with increasing welding current (250 A to 650 A). The increase in welding speed from 4.44 mm/s to 8.88 mm/s results in an increment in manganese content from 0.87 wt.% to 1.21 wt.%. Since increasing travel speed decreases heat input per unit length of the weld, evaporation of manganese is suppressed. Therefore, the highest manganese content was achieved at a lower current (250 A) and higher speed (8.88 mm/s). Smooth beads with evenly distributed ripples free from surface defects like undercuts, porosity, pockmarks, etc., were achieved.