Resistance element welding of magnesium alloy and austenitic stainless steel in three-sheet configurations
Document Type
Article
Publication Date
1-1-2019
Abstract
The Mg alloy and two austenitic stainless steel sheets were joined together by a metallurgical bond across the rivet and two austenitic stainless steel sheets. More heat was generated at the austenitic stainless/austenitic stainless interface than at the rivet/ austenitic stainless steel interface, leading to larger nugget size at the austenitic stainless steel /austenitic stainless steel interface at all welding currents. Thus, the nugget size at the austenitic stainless steel /austenitic stainless steel interface mainly influenced the transition from interfacial to pullout failure modes. The fusion zone microstructure consisted of ferrite and austenite. The microstructure in the edges of the nugget (both in the rivet and ASS) consisted of fine columnar dendritic grains. Owing to variation of temperature gradient and solidification growth rate, the grains morphology changed from columnar dendritic to equiaxed dendritic in the nugget center. The fine grains resulted in high fusion zone hardness. Digital image correlation analysis revealed that the joints could experience joining zone rotation/out-of-plane displacement during lap-shear tests, which reduced the magnitude of strain sustained by the joints in the loading direction. The joint configuration that did not undergo joining zone rotation and failed via pullout failure in the austenitic stainless steel sheet exhibited superior lap-shear performance. © 2019
Keywords
Resistance element welding, Resistance spot welding, Multi-sheet joining, Magnesium alloy, Austenitic stainless steel
Divisions
fac_eng
Funders
National Key R&D Program of China ( No.2018YFB1107900 ),Natural Science Foundation of Tianjin City ( No. 18JCQNJC04100 ),National Natural Science Foundation of China ( No. 51575383 )
Publication Title
Journal of Materials Processing Technology
Volume
274
Publisher
Elsevier