EFFECT OF A MAGNETIC FIELD ON THE MICROSTRUCTURE AND PROPERTIES OF RESISTANCE SPOT WELDED JOINTS OF 444 FERRITIC STAINLESS STEEL/6082 ALUMINUM ALLOY
Abstract
To improve the welding quality of resistance spot welding joints of steel/aluminum lightweight structures, the steady magnetic field-assisted resistance spot welding method was used to weld 444 ferritic stainless steel and 6082 aluminum alloy, both with a thickness of 1 mm. Under the same welding parameters, the effect of a magnetic field on the microstructure and mechanical properties of the joint was analyzed. It was found that the Lorentz force generated by the addition of a magnetic field promoted the circumferential movement of the molten metal in the nugget zone, increased the size of the Fe/Al contact interface in the joint along the horizontal direction, and made an effective use of the heat generated during resistance spot welding. Although the intermetallic compounds in the intermediate transition layer of the two welded materials were mainly composed of (Fe, Cr, Si)Al2 and (Fe, Cr, Si)Al3, relatively low contents of (Fe, Cr, Si)Al2 and (Fe, Cr, Si)Al3 were found and a there was a significant decrease in the thickness of the intermetallic compound layer when the magnetic field was applied. Compared with the welded joint devoid of a magnetic field, the tensile strength and ductility of the joint were effectively improved, and the dimples in the fracture surface became relatively deep and numerous. In essence, resistance spot welding joints of steel/aluminum obtain better comprehensive mechanical properties when a magnetic field is applied.
References
[2] Deepati A K , Alhazmi W , Benjeer I .Mechanical characterization of AA5083 aluminum alloy welded using resistance spot welding for the lightweight automobile body fabrication, Materials Today: Proceedings, 45(2021): 5139-5148, DOI:10.1016/j.matpr.2021.01.646
[3] Ogawa Y , Ohara I , Arakawa J ,et al. Effects of welding defects on the fatigue properties of spot welded automobile steel sheets and the establishment of a fatigue life evaluation method, Welding in the World, 64 (2022):745-752,DOI:10.1007/s40194-021-01238-5
[4] Qiu R , Iwamoto C , Satonaka S .The influence of reaction layer on the strength of aluminum/steel joint welded by resistance spot welding[J].Materials Characterization, 2009, 60(2):156-159.DOI:10.1016/j.matchar.2008.07.005.
[5] Baskoro A S , Muzakki H , Kiswanto G ,et al.Mechanical Properties and Microstructures on Dissimilar Metal Joints of Stainless Steel 301 and Aluminum Alloy 1100 by Micro-Resistance Spot Welding[J].Springer India, 2019(2).DOI:10.1007/s12666-018-1500-z.
[6] Muzakki H , Baskoro A S , Kiswanto G ,et al.Mechanical Properties of the Micro Resistance Spot Welding of Aluminum Alloy to Stainless Steel with a Zinc Interlayer[J].International Journal of Technology, 2018, 9(4):686.DOI:10.14716/ijtech.v9i4.1867.
[7] Sridharan N , Poplawsky J , Vivek A ,et al.Cascading microstructures in aluminum-steel interfaces created by impact welding[J].Materials Characterization, 2019, 151:119-128.DOI:10.1016/j.matchar.2019.02.019.
[8] Li YB, ZhangQX, Qi L, et al. Improving austenitic stainless steel resistance spot weld quality using external magnetic field. Sci TechnolWeld Join. 2018;23:619–627.
[9]Qi L, Li FZ, Chen RM, et al. Improve resistance spotweld qualityofadvancedhighstrengthsteels using bilateral external magnetic field. J ManufProcess. 2020;52:270–280.
[10] Zhou J , Shen J , Hu S ,et al.Microstructure and mechanical properties of AISI 430 ferritic stainless steel joints fabricated by cold metal transfer welding[J].Materials Research Express, 2019, 6(11).DOI:10.1088/2053-1591/ab4770.
[11] Xin Z , Yang Z , Zhao H ,et al.Comparative Study on Welding Characteristics of Laser-CMT and Plasma-CMT Hybrid Welded AA6082-T6 Aluminum Alloy Butt Joints[J].Materials, 2019, 12(20):3300-.DOI:10.3390/ma12203300.
[12] Li YB, Lin ZQ, Lai XM, et al. Induced electromagnetic stirring behavior in a resistance spot weld nugget. Sci China Technol Sci. 2010;53:1271–1277.
[13] Li YB, Li DL, David SA, et al. Microstructures of magnetically assisted dual-phase steel resistance spot welds. Sci Technol Weld Join. 2016;21:555–563.
[14] Wan ZX, Wang HP, Wang M, et al. Numerical simulation ofresistance spot welding ofAl to zinc-coated steel with improved representation of contact interactions. Int J Heat Mass Tran. 2016;101:749–763.
[15] Zhang Y , Sun D .Microstructures and Mechanical Properties of Steel/Aluminum Alloy Joints Welded by Resistance Spot Welding[J].Journal of Materials Engineering & Performance, 2017, 26(6):1-14.DOI:10.1007/s11665-017-2731-6.
[16] Shen Q, Li YB, Lin ZQ, et al. Effect of external constant magnetic field on weld nugget of resistance spot welded dual-phase steel DP590. IEEE T Magn. 2011;47:4116–4119.
[17] Sun J , Yan Q , Gao W ,et al.Investigation of laser welding on butt joints of Al/steel dissimilar materials[J].Materials and Design, 2015, 83(oct.15):120-128.DOI:10.1016/j.matdes.2015.05.069.
[18] R. Qiu, C. Iwamoto, and S. Satonaka, Interfacial Microstructure andStrength of Steel/Al Alloy Joints Welded by RSW with Cover Plate, J.Mater. Process. Technol., 2009, 209(8), p 4186–4193
[19] Sun DQ, Zhang YY, Liu YJ, et al. Microstructures andmechanical properties of resistance spot welded joints of 16Mn steel and 6063-T6 aluminum alloy with different electrodes. Mater Design. 2016;109:596–608.
