Effect of welding groove geometry variation on flatness deviation in GMAW joints

Abstract The study analyzed how variations in welding groove geometric parameters (groove angle, root gap, root face) affect joint flatness deviations, maintaining a cross-sectional area tolerance within 2.3% to eliminate boundary condition variations. Welded joints were scanned using an ATOS 5 M blue light scanner to evaluate geometric means and standard deviations. The results fill a literature gap by demonstrating that the root gap is the dominant parameter influencing flatness deviation distributions along the groove, while other parameters showed no significant impact. Quantitatively, the maximum difference in geometric mean flatness deviation reached 23% for the Go6 configuration compared to the reference geometry Go1. High process variability was observed, with a maximum-to-minimum standard deviation ratio of 8.3 between Go5 and Go2, causing 40% of the expected flatness deviation results for Go6 to exceed reference values. Statistical testing (Q crit = 0.941, α = 0.05) rejected no outliers, but highlighted that three repetitions ( n = 3) are insufficient for full process estimation. The empirical dataset, encompassing groove widths from 4.61 to 5.77 mm and centroid positions from 1.67 to 2.03 mm, provides a reliable basis for high-range calibration of FEM numerical models. Moreover, the obtained results provide an important technological reference for the design and fabrication of thin-walled welded enclosures manufactured by single-pass welding for industry applications using high-alloy austenitic steels.