Influence of the bar shape on the welding quality of friction hydro pillar processing

Abstract

Traditional underwater arc welding methods, for example, TIG and MIG, are generally expensive and complex to implement under water. Besides, the welding quality decreases significantly with the increase of depth of water. So a new-style solid phase welding method called friction stitch welding (FSW) is introduced, since the welding quality of which is almost insensitive to water. This article studies the influence of the bar shape on the welding quality. In the experiments, three typical kinds of shape combinations are adopted. Argon is used as protecting gas, and the flux of which is 30L/min. The feed speed of the spindle is 0.5 mm/s, the rotation speed is 4000r/min. Through the comparison of the macro features and microstructure of the welded joints, the influence of the bar shape on the welding quality is analyzed, and static stress distribution along with the influence on welding temperature by different shapes are investigated. The results indicate that the welding quality obtained by using straight bars with round head is much better than the other shape combinations, the welding defects are reduced and the welded material is much finer. © 2011 Springer-Verlag Berlin Heidelberg.