Flux modification for AC-TIG braze welding of aluminium to stainless steel

Abstract

A modified flux consisting of KAlF 4 and aluminium powder was developed for AC-TIG braze welding of aluminium to stainless steel. By employing the flux, the arc instability and wetting angle was decreased significantly, and therefore a good joint shape was obtained. The wetting and spreading behaviour as well as the action mechanism of the flux were changed. Microstructure analysis suggested that the intermetallic compound (IMC) thickness increased obviously when the addition percentage of aluminium powder in the flux exceeded 40 wt-%. Results of tensile tests illustrated that a significant improvement in mechanical properties of the butt joint was obtained with the modified flux, and tensile strength increased from 125 to 170 MPa in maximum. Relationships between aluminium powder content in the flux and wetting angle, IMC thickness as well as tensile strength were established. Results indicated that the joint strength was affected both by weld shape and IMC thickness.

Effect of Interfacial Intermetallic Compounds Morphology on Mechanical Properties of Laser Brazing of Aluminum to Steel

“…The increased brazed joint length and the decreased wetting angle of the brazed joint affect the joint strength, as indicated in the literature [27,28]. In this study, the brazed joint length between the filler metal and steel and the wetting angle significantly increased and decreased, respectively.…”

Hardness and tensile properties of dissimilar welds joints between SAF 2205 and AISI 316L

“…Welding is an important fabrication technique for stainless steels, and generally, the stainless steels are considered as weldable materials. [1][2][3][4] Austenitic stainless steels represent the largest of the general groups of stainless steels due to the excellent properties such as corrosion resistance, ductility, toughness and weldability. Duplex stainless steels are compositionally formulated and thermomechanically processed to provide a two-phase microstructure exhibiting nearly equal proportions of ferrite and austenite.…”

Numerical modelling of gas metal arc joining of aluminium alloy and galvanised steels in lap joint configuration

“…Formation and growth of the interfacial IMC layer and consequent joint strengths are examined in GMA, [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18] gas tungsten arc (GTA) [19][20][21][22][23][24] and laser beam joining of Al alloy to galvanised steel sheets in thickness ranges of 0.8-3.0 mm. [25][26][27][28][29][30] However, these studies depict wide variations in the suggested heat input, resulting IMC layer thickness and the joint strength.…”

“…[31][32][33] In particular, a fair joint strength for an IMC layer thickness of around 1.6 μm is reported using coldArc, which is a specialised low heat input, pulsed current GMA process with a controlled short-circuiting metal transfer. 5 The measured values of the failure strength of aluminium to steel joints were reported to vary from 80 to 220 MPa in GMA, [4][5][6][7][9][10][11][12][13][14][15][16][17] and 120 to 180 MPa in GTA [19][20][21][22][23][24] and laser beam [25][26][27][28][29] joining techniques. These experimental studies have provided significant insights on the type of Fe-Al IMC phases and their effects on the joint strength in joining of aluminium and galvanised steel with a filler wire.…”