Optimization of Welding and Heat Treatment Parameters for Enhanced Mechanical Performance in Micro-Alloyed Steel Components

Authors: *Adzor, S.A., Afabor, A.M., Pullah, A. And Utu, O.G.

DOI Info: http://doi.org/10.5281/zenodo.10441775

ABSTRACT

This research study explores the significant impact of welding current and post-weld heat treatment parameters on the mechanical properties of micro-alloyed steel components in engineering structures, with a focus on ensuring their long-term durability and preventing costly failures. The investigation assesses the combined influence of welding current, tempering temperature, and soaking time on the impact strength of E7018 electrode-welded and tempered micro-alloyed steel. To optimize these parameters, response surface methodology was employed within an optimal experimental design framework, utilizing a polynomial regression model with quadratic terms and analysis of variance. The results indicate the model's strong significance (p<0.0001) in predicting the impact strength of the welded and tempered steel, with high adjusted coefficient of multiple determination (97.67%), coefficient of multiple determination (99.83%), and a predicted R-squared value (98.38%), demonstrating its precision in representing the response surface. The study identifies the optimal welding conditions for maximum impact strength as 102 A for welding current, 120 min for soaking time, and 450 °C for tempering temperature, resulting in an impact strength of 29.7 J. Through the optimization process, the highest impact strength of 29.9 J is projected under predicted conditions: 101.37 A for welding current, 120 min for soaking time, and 450 °C for tempering temperature, with minimal deviations (-0.67%) from experimental results, well within acceptable margins. This research validates the reliability of the optimization process by fine-tuning welding and heat treatment parameters.

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