TWI Industrial Member Report Summary 229/1983
By S B Dunkerton
The technique of using a silver electroplated interlayer when friction welding aluminium alloys to stainless steels has been investigated for two aluminium alloys (5083 and 5154A) and three component geometries (25mm diameter solid, 25mm o.d. by 6mm wall tube and 38mm o.d. by 6mm wall tube). In the 5083 aluminium alloy to stainless steel combination, 25mm diameter welds have been produced with high strength but relatively low ductility. An increase in component size to 38mm diameter tube still allowed the production of high strength welds but considerable scatter occurred in the test results. Also, the welds produced in this size of component were not strictly comparable with the smaller diameter welds because of limited welding pressures available within the capacity of the friction welding machine. Welds between 5154A aluminium alloy and stainless steel can have properties very similar to those of the weaker strength parent metal. Weld quality is shown to be relatively tolerant to changes in welding parameters particularly for 25mm diameter welds. A determination of the effect of parent stainless steel (BS 970, 304315, 316S16 or 321812) on weld quality revealed good weld properties can be achieved with each steel. Factors affecting electroplating quality (adherence), such as cleanliness and surface finish, need to be carefully controlled to maintain good joint integrity.