Groove angle and quenching medium in shielded metal arc welding of mild steel: Multi-criteria decision analysis, machine learning and energy absorption
Year: 2026
Type: article
Abstract: Weld groove geometry and post-weld cooling regime are among the least systematically investigated factors influencing the performance of arc-welded joints, and even when they have been studied, the analysis has almost always been limited to a single optimisation criterion. This paper re-examines shielded metal arc welding of AISI/SAE 1020 mild steel across a 55–60° single-V groove range and three quenching media (air, water, palm oil), using six mechanical responses, and advances the analysis in four directions. First, a normalised Type III effect-share analysis establishes the practical rather than merely statistical weight of each factor: the quenching medium accounts for 70.3–94.6% of the estimated effect across the six responses, while groove angle accounts for 4.4–25.7%, and the factor interaction never exceeds 3.2%. Second, the tensile records are reconciled against the reported applied loads, recovering the specimen cross-sections actually used and permitting two derived responses that the original analysis did not report: the modulus of toughness, which orders the media 8.68, 5.96 and 3.66 MJ m⁻³ for air, water and palm oil, and the Hollomon strain-hardening exponent, obtained on true stress and true plastic strain axes, which falls from 0.528 for air-cooled weldments to 0.292 and 0.253 for water- and oil-quenched material. Third, four independent multi-criteria schemes, namely Shannon-entropy-weighted grey relational analysis, equal-weight grey relational analysis, the technique for order of preference by similarity to ideal solution, and Derringer–Suich desirability, are applied to the same candidate set, and all four return the same ordering. Fourth, machine-learning surrogates of the recovered stress–strain records locate where the medium acts: over the strain interval common to all three media a functional analysis of variance attributes only 1.16% of the stress variance to the medium, and truncating the comparison at that strain reverses the ordering, so the advantage of air cooling is one of extensibility rather than strength. Gaussian-process sampling returns credible intervals near ±9% on the toughness values and preserves the ranking in every draw. The convergence of four aggregation philosophies, combined with the independent evidence of the energy-absorption analysis, establishes a 60° single-V groove with unforced air cooling as a weight-robust rather than merely method-dependent optimum for structural weldments in thin-section low-carbon steel.
Source: Next Materials
Language: English
Subfield: Mechanical Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $1,280
OpenAlex ID: W7214895210