Allowance of Deviation and Gap in Butt Joint on Friction Stir Welding

Abstract

Friction Stir Welding (FSW) has special properties for its low distortion, low residual stress of the joints and needless skilled worker. Application of three-dimensional FSW can apply many industry, etc automobile industry or airplane industry. However, FSW is only applicable to use linier welding at present. To realize three-dimensional FSW, it is most important to improve operation accuracy. On the other hand, it is also important to clarify "the allowance of operation" for application.In this work (A) the influence of deviation; the mismatching between the butt line and the center of tool traveling line, and (B) the influence of gap; the spacing between two plates at butt line, on tensile properties of FSW joints are investigated. A5083-O alloy plates with 3 mm thickness were welded in various deviation or gap spacing conditions by a gate type FSW machine with sufficient rigidity and accuracy. It was found that the allowance of deviation is a half of probe diameter of FSW tool in the case of the butt line was set on the advancing side of tool rotation. So we have the one-fourth of probe diameter allowance in both sides by setting the butt line from the probe center in a quarter of the probe diameter to advancing side. Beyond this allowance range, tensile properties rapidly decreased. Contrary to this, the gap spacing within 2 mm did not affect the tensile properties in this experiment, and the joint strength and ductility over 2 mm gap showed a gradual decrease.

Investigation of vertical compensation friction stir-welded 7N01-T4 aluminum alloy

“…Elemental analysis of the cross section characteristic of VCFSW joint was performed by SEM equipped with an energy-dispersive X-ray spectroscopy (EDX). [14][15][16]. Because 7N01 alloy belongs to highstrength aluminum alloy, insufficient frictional heat results in big flow stress and then causes worse material flow behavior.…”

“…During the repairing of defect process, if no material is added into the groove or tunnel, it easily leads to thickness reduction and then decreases the ability of loading bearing, deteriorating mechanical properties. Besides the groove and tunnel defects, a gap before welding at the interface between two workpieces, resulted from the extrusion effect of FSW or accumulation of some manufacturing errors of large structures, cannot be neglected, which always leads to the reduction of joint quality [11][12][13][14][15][16]. Seidel et al [11] found that the occurrence of gap could not only make plasticized materials flow into gap resulting in the loss of materials and then produces the lack of root penetration but also lead to thickness reduction of joint.…”

“…Seidel et al [11] found that the occurrence of gap could not only make plasticized materials flow into gap resulting in the loss of materials and then produces the lack of root penetration but also lead to thickness reduction of joint. Yang et al [14], Wanjara et al [15], and Shultz et al [16] also investigated the effect of gap during FSW process and expounded that a gap could lead to the decrease of effective contact area or appearance of wormhole, fabricating an unsuitable weld. Therefore, in order to eliminate the adverse effect caused by gap, tunnel, or groove defect, a vertical compensation friction stir welding (VCFSW) method has been put forward by Ji and Meng et al [17].…”

Optimization of Welding Condition for Nonlinear Friction Stir Welding

“…It is clarified that the R-side deviations of butt line from tool center have no tolerance in our study. 7,8) The strength deteriorates only in the case of turn to the A-side.…”

Optimum Processing and Tool Controls for Three-Dimensional Friction Stir Welding

“…[4][5][6][7][8] However, it is difficult to maintain all welding parameters in appropriate permissible ranges because of the method's limited degrees of freedom for tool control. [9][10][11][12][13] Furthermore, it is also difficult for 3D welding to maintain the steady state of welding conditions as linear welding. Especially, in the area processed with rapid or discontinuous changes of welding parameters, which are unavoidable in 3D welding.…”