Formularization of Angular Distortion Induced by Multiple Heat Sources on the Same Surface

A preceding heat welding is proposed for reducing weld distortion. In this welding process, MAG welding is followed by a preceding heating with TIG on the same surface side of welding. The influence of a distance between heat sources of TIG and MAG on the angular distortion is investigated by numerical simulation for a bead-on-plate welding performed using simulation software (SYSWELD). From the calculated results, it is found that the angular distortion is reduced and has a minimum value in the case where the distance between heat sources is shorter than a certain one according to a welding condition. The reduction in angular distortion is Discussed in accordance with the heat input parameter and the distribution of mechanical melting temperature region in the plate thickness section. In addition, the angular distortion induced by preceding heat welding can be formalized by using the maximum depth of mechanical melting temperature region in the plate thickness section as an explanatory variable