Optimization of short-circuit transition parameters of Q235B steel GMAW weld short circuit based on orthogonal gray relational analysis

In gas metal arc welding (GMAW) process, the short-circuit transition was the most typical transition observed in molten metal droplets. This paper used orthogonal tests to explore the coupling effect law of welding process parameters on the quality of weld forming under short-circuit transition, the design of 3 factors and 3 levels of a total of 9 groups of orthogonal tests, welding current, welding voltage, welding speed as input parameters: effective area ratio, humps, actual linear power density, aspect ratio, Vickers hardness as output parameters (response targets). Using range analysis and trend charts, we can visually depict the relationship between input parameters and a single output parameter, ultimately determining the optimal process parameters that impact the single output index. Then combined with gray theory to transform the three response targets into a single gray relational degree (GRG) for analysis, the optimal combination of the weld morphology parameters as follows: welding current 100 A, welding voltage 25 V, welding speed 30 cm/min. Finally, validation experiments were conducted, and the results showed that the error between the gray relational degree and the predicted value was 2.74%. It was observed that the effective area ratio of the response target significantly improved, validating the reliability of the orthogonal gray relational method.