Prediction and optimization of weld bead volume for the submerged arc process - Part 1

Because of its high quality and reliability, submerged are welding (SAW) is one of the chief metal-joining processes employed in industry for the manufacture of steel pipes used for various applications. This paper highlights a study and analysis of various process-control variables and important weld bead quality parameters in SAW of pipes manufactured out of structural steel (IS: 2062). Mathematical models were developed for the submerged are welding of 6-mm-thick structural steel plates using 3.15-mm-diameter steel electrodes. The models were developed using the five-level factorial technique to relate the important process-control Variables welding voltage, wire feed rate, welding speed and nozzle-to-plate distance - to a few important bead-quality parameters - penetration, reinforcement, bead width, total volume of the weld bead and dilution. The models developed were checked for their adequacy with the F test. Using the models, the main and interaction effects of the process-control variables on important bead geometry parameters were determined quantitatively and presented graphically. The developed models and the graphs showing the direct and interaction effects of process variables on the bead geometry are very useful in selecting the process parameters to achieve the desired weld-bead quality. Also, the precision of the results obtained with the mathematical models were tested by using conformity test runs. The test runs were conducted nearly two years after the development of mathematical models with the same experimental setup, and it was found the accuracy of the predicted results is about 98%. Further, these mathematical models help to optimize SAW to make it a more cost-effective process.