Cause of Angular Distortion in Fusion Welding: Asymmetric Cross-Sectional Profile along Thickness

Abstract

Angular distortion is a common problem in fusion welding, especially when it comes to thick plates. Despite the fact that various processes and influencing factors have been discussed, the cause of the angular distortion has not been clearly revealed. In this research, the asymmetry of cross-sectional profile along thickness is considered of great importance to the angular distortion. A theoretical model concerning the melting-solidification process in fusion welding was established. An expression of the angular distortion was formulated and then validated by experiments of laser welding 316L stainless steel. The results show that the asymmetric cross-sectional profile is a major contributory factor towards the angular distortion mechanism. The asymmetry of cross-section profile along thickness causes the difference between two bending moments in the lower and upper parts of the joint. This is the difference that drives the angular distortion of the welded part. Besides, the asymmetry of cross-section profile is likely to be influenced by various processes and parameters, thereby changing the angular distortion.

Prediction and Characteristics of Angular Distortion in Multi-Layer Butt Welding

“…In this case, the shrinkage has the maximum instead. In other words, the deformation up to the second pass was sensitive to the amount of weld deposition, the temperature gradient through the thickness, and the surrounding constraint [11,12,13,14]. These phenomena can be deduced from Figure 6a by extrapolating the data.…”

“…The distortion is susceptible to the amount of weld deposition, temperature gradient through the thickness, and constraint. Through the laser welding experiment and their theoretical model, Xie et al [11] revealed that the direction and size of the angular distortion are dependent on the asymmetry of the cross-sectional profile of the bead. The bead deposition of the cross-section can change with various processes and conditions.…”

Analytical Model for Angular Distortion in Multilayer Welding under Constraints

“…In addition, the reverse distorted shape generated during heating might be maintained until being completely cooled down. Xie et al [21] has reported that the distortion direction can be affected by the asymmetry of the cross-sectional profile along the thickness direction and even pores generated by insufficient flow of the molten pool. Consequently, it is almost impossible to quantitatively predict the amount and direction of deformation above the threshold.…”

Numerical Analysis and Experiments of Butt Welding Deformations for Panel Block Assembly

“…They developed the parameter of mechanical melting region on the plate thickness and found that it was the dominant factor for accurately quantifying angular distortions. Xie et al revealed the mechanism of angular distortion in fusion welding and how the welding processes and factors influence the angular distortion [22]. They established a theoretical model concerning the melting-solidification process and formulated an expression for angular distortion.…”