Cold metal transfer additive manufacturing of HSLA steel: effects of process parameters on weld bead morphologies and process parameter optimization

Cold metal transfer (CMT) technology, with its outstanding advantages, has been widely applied in manufacturing, particularly in wire arc additive manufacturing (WAAM). Considering these advantages, exploring the implementation of CMT-WAAM for high-strength low-alloy (HSLA) steels is of considerable industrial relevance. Therefore, this work systematically examines the influence of major process variables, namely wire feed speed (WFS) and travel speed (V), on weld bead geometry and energy consumption. Experimental results together with Analysis of Variance (ANOVA) were used to establish and verify predictive models. The findings reveal that bead width is primarily governed by WFS, while V exerts the strongest effect on both bead height and energy consumption. ANOVA results confirm that all regression models exhibit high statistical significance, with coefficients of determination (R2) exceeding 97%, demonstrating good predictive capability. A multi-objective optimization based on the desirability function was conducted to simultaneously maximize bead dimensions and minimize energy consumption. The optimal parameter set was identified at WFS = 3.5 m/min and V = 40 cm/min, yielding good single-bead morphology and thin walls without detectable internal defects. This study provides a robust scientific basis for selecting optimal process parameters in CMT-WAAM for the fabrication of high-quality HSLA steel components.