Weldbond and its Performance in Aluminum Automotive Body Sheet

IN WELDBONDING, a joint is produced by (a) spotwelding through an uncured adhesive bondline or (b) flowing adhesive by capillary action into the bond area after spotwelding. Weldbonding can offer higher joint strength, reduced joint weight, improved fatigue life and, in some aircraft-oriented investigations, showed reduced manufacturing costs^(1,2).

Although weldbonding has had repeated use in the Russian aircraft industry^(3,4), it has not been widely employed in American manufacturing to date. The most intensive efforts to develop the process have resulted from contracts sponsored by the U. S. Air Force⁽⁴⁾. The only aluminum alloys used in these investigations were the high strength aircraft alloys and the emphasis was to develop the highest strength weldbond joints with economics a secondary consideration. These studies usually included the use of special surface treatments on the aluminum, special adhesives, and carefully controlled curing conditions. No information has been available in the literature on weldbonding of the aluminum alloys currently suggested as automotive body sheet nor the adhesives and curing procedures commonly used in automotive, truck and trailer manufacturing processes⁽⁵⁾. This investigation was undertaken to develop some of the fundamental information necessary to adapt the weldbond process to those industries using materials and test procedures described in an earlier paper on adhesive bonding of aluminum auto body sheet alloys⁽⁶⁾.