A Study on the Effects of Offset and Welding Speed on Bead Shape and Welding Defects in the FCA Fillet Welding Process

Abstract

Many industries, such as automobile, aerospace, heavy industries, etc, have been interested in welding automation due to cost reduction and improving productivity. For welding automation, seam tracking plays an important role for the quality of welds. If the seam is misaligned, it can cause troubles such as weld defects and poor appearance. Most of previous studies have analyzed the influence on the bead shape and weld defects by current, voltage, welding speed, but there is lack of research regarding the effects of misaligned seam, called offset. Thus, in this study, fillet welds were conducted with flux-cored arc welding, which has high welding efficiency and low cost. To find out the guideline of offset, various offsets were intentionally applied to the welding experiments, and the changes in bead shape were observed and weld defects were detected for various combination of offset and welding speed. In addition, the grades of weld defect in each condition were evaluated by ISO 5817, which illustrates the international standard of weld defects. Based on the results, the guidelines of offset was suggested to avoid weld defects.