Effect Of Surface Treatments And Storage Conditions On Resistance Spot Weldability Of Aluminum Alloy 5182

Surface treatment technologies represented by Ti/Zr conversion treatment and silane coupling agent (SCA) treatment are increasingly used to improve the adhesion property of aluminum alloys resulting from the existence of dense and tenacious surface oxide film. AA 5182-O is used to prospectively investigate the effects of protective layers and storage conditions on resistance spot weldability. The acid-pickling (AP) state specimens are chosen as a control group. Both Ti/Zr and SCA protective layers could effectively restrain the growth of the inner oxide film, and even the SCA protective layers are not as uniform dense as the Ti/Zr ones. The increscent surface resistance and chemical nature of the protective layers codetermine the nugget profile feature and the degree of internal defects, and Ti/Zr conversion coating is distinctly better than that of SCA. As a result, the mechanical performance follows the following sequence: Ti/Zr-30d > AP > SCA-30d > AP -30d. Among influence factors induced performance degradation, the effect of excessive internal defects is the most significant, followed by small nugget size. Besides, the storage conditions also have a significant impact on resistance spot weldability, and the storage duration has the most considerable influence, followed by humidity, and the smallest is the temperature.