Modernistic Method of Enhancing Productivity by Reusing of Slag as Flux in Submerged Arc Welding & Study of its Impact on Mechanical Properties

Submerged arc welding (SAW) is an industrial welding process in which the joint is obtained by heating the metal with an arc set between bare electrode and work piece. Intense heat produced during the process fuses the metal and filler metal. Flux is used as a shielding agent to protect the molten weld pool from atmospheric contamination. This flux gets converted into slag after solidification at the surface of welding metal. This slag is thrown away after performing welding. This leads to increase in the cost of process hence reuse of slag is a cost effective method. In this present work different flux and slag compositions are used to analyse the effect of slag & flux mixture on mechanical properties of submerged arc welded joint performed on mild steel plates. Further this work is an attempt to utilize the mixture of slag and flux and reduce the cost of SAW welding process. For the investigation, 6 different compositions of slag and flux are made by varying slag percentage in each sample starting from 0 % to 100 %. The different output parameters of interest are studied such as Penetration, Bead Width, Reinforcement, Microstructure, Tensile Strength and Hardness. The best slag composition which is inferred from the test results are found to be Composition No 2(20% Slag) & Composition No 3 (40% Slag).