مقاله جوشکاری با عنوان :Effects of Welding Parameters and Surface Pretreatments on ResistanceSpot Welding of AZ31B Mg AlloyShiquan Zhou1, Lei Liu2,3, Jae Pil Jung4,*, Mok-Young Lee5, and Y. Norman Zhou3چکیده :The resistance spot weldability of AZ31B magnesium alloy using AC (alternating current) was investigatedin this paper. The surfaces of sheet coupons were prepared by acetone cleaning (as-received) and some couponswere also cleaned with chromic acid (H2Cr2O7) after acetone cleaning (acid-cleaned). The surfaces of theas-received AZ31B sheets consisted of MgO, Mg(OH)2, and MgCO3. The extent and thickness of the surfaceoxide/reaction layer of the sheets varied according to the fabrication process of the sheets, and resulted indifferent contact resistance. Effects of welding current and weld time were investigated while the electrodeforce was kept constant. The results indicated that the as-received sheets produced expulsion both at thefaying surface and at the work piece/electrode interface due to high contact resistance. Diluted chromic acidcleaning reduced contact resistance and produced good weld quality. Increasing the welding current and weldtime enhanced not only the nugget size and joint strength, but also increased indentation on the weld surfaces.A weld lobe was established considering the minimum joint strength, weld expulsion, and surface indentationbased on a relevant American Welding Society Standard.
مقاله جوشکاری با عنوان :Effects of Welding Parameters and Surface Pretreatments on ResistanceSpot Welding of AZ31B Mg AlloyShiquan Zhou1, Lei Liu2,3, Jae Pil Jung4,*, Mok-Young Lee5, and Y. Norman Zhou3چکیده :The resistance spot weldability of AZ31B magnesium alloy using AC (alternating current) was investigatedin this paper. The surfaces of sheet coupons were prepared by acetone cleaning (as-received) and some couponswere also cleaned with chromic acid (H2Cr2O7) after acetone cleaning (acid-cleaned). The surfaces of theas-received AZ31B sheets consisted of MgO, Mg(OH)2, and MgCO3. The extent and thickness of the surfaceoxide/reaction layer of the sheets varied according to the fabrication process of the sheets, and resulted indifferent contact resistance. Effects of welding current and weld time were investigated while the electrodeforce was kept constant. The results indicated that the as-received sheets produced expulsion both at thefaying surface and at the work piece/electrode interface due to high contact resistance. Diluted chromic acidcleaning reduced contact resistance and produced good weld quality. Increasing the welding current and weldtime enhanced not only the nugget size and joint strength, but also increased indentation on the weld surfaces.A weld lobe was established considering the minimum joint strength, weld expulsion, and surface indentationbased on a relevant American Welding Society Standard.