Improving austenitic stainless steel resistance spot weld quality using external magnetic field

Li, Yong Bing; Zhang, Q. X.; Lin, Qi; David, S. A.

doi:10.1080/13621718.2018.1443997

Cited by 42 publications

(20 citation statements)

References 34 publications

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“…23 reported that solidification cracks in weld zone due to the solidification done in austenitic mode and it can be prevented by the presence of delta ferrite. 24…”

Section: Resultsmentioning

confidence: 99%

Influence of resistance spot welding process parameters on dissimilar austenitic and duplex stainless steel welded joints

Krishnan

Elayaperumal

Paramasivam

2020

Proceedings of the Institution of Mechanical Engineers, Part E:

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This paper examines the impact of welding parameters on tensile shear fracture load, nugget geometry and microstructure of resistance spot welds (RSW) of austenitic stainless steel AISI 316 L and duplex stainless steel 2205 under lap shear loading condition. The macroscopic examination resulted that many of the nugget lengths were nearer to and higher than the AWS recommended value 4√t and failed at higher tensile shear load. Nugget height for DSS 2205 side was higher in comparison with AISI 316 L due to higher thermal conductivity of duplex stainless steel. Three welding parameters mainly welding current of 9 kA, heating cycle of 9 and electrode tip diameter of 6 mm were discovered as most effectual parameters on the tensile shear load and microstructure of weldments. Heterogeneous hardness was observed in the fusion zone due to the transition of equiaxed to columnar grains takes place in the both sides of nugget edge. DSS HAZ nearby BM observed higher hardness and ASS HAZ nearby BM reported lower hardness. WMZ Microstructure confirmed that thickness of austenite layers increased with heat input. Also, an unmixed zone in the microstructure identified as HAZ which contains delta ferrite. Scanning Electron Microscope (SEM) images in the nugget zone for different welding parameters confirmed that Intra-Granular Austenite (IGA) highly developed at higher welding current. SEM fractrograph for the tensile sheared specimens at higher and lower heat input confirmed the ductile type fracture even failed at Inter-Facial (IF) mode. Nugget area and nugget hardness were positively correlated with Tensile Shear Fracture Load (TSFL).

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“…23 reported that solidification cracks in weld zone due to the solidification done in austenitic mode and it can be prevented by the presence of delta ferrite. 24…”

Section: Resultsmentioning

confidence: 99%

Influence of resistance spot welding process parameters on dissimilar austenitic and duplex stainless steel welded joints

Krishnan

Elayaperumal

Paramasivam

2020

Proceedings of the Institution of Mechanical Engineers, Part E:

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“…Literatürde harici manyetik alan kaynağı olarak mıknatıs kullanılan çoğu uygulama çalışmasında (Li ve ark. 2011, 2018…”

Section: Tartışma Ve Sonuçunclassified

Farklı Mıknatıs Geometrilerinin Manyetik Alan Destekli Direnç Punta Kaynağına Etkisi

Arslan

Karabaş

2019

Afyon Kocatepe University Journal of Sciences and Engineering

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In this study, state analysis of the magnet model placed in the E-Nose electrode geometry for DC spot welding systems was performed using the finite element method. For five different magnet configurations that are currently in production, the current density values of the welded material as well as the pushing forces of the magnets are evaluated. Block, ring and half ring magnet configurations are selected for analysis. The repelling force brought by the magnets placed in the electrodes (N-N or S-S) with the same polarity facing each other reduces the welding force on electrodes. In this regard, analysis has been carried out to increase the quality of the welding without reducing the effect of electrode force on resistance spot welding process. Firstly, the force values are calculated according to the change of the magnet geometry in the same welding current. Then, Optimization studies was carried out to ensure low force, high current density under same welding currents for these five different magnets. The optimal geometry resulting from the optimization studies is compared to the magnetless condition in terms of current density at different welding currents. Thus, it was tried to determine the best magnet geometry with this study. Besides, considering the positive effect of the welding quality of the external magnetic fields in the literature, the numerical study shows that the welding quality can be increased by the magnet placed on the DC spot welding electrode.

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“…To improve the weld quality in a energy-efficient method, magnetically assisted resistance spot welding (MA-RSW) technology was proposed by Shen et al (2011). Experimental studies on dual-phase steel (Qi et al, 2020), stainless steel (Li et al, 2018), aluminum CONTACT Yongbing Li yongbinglee@sjtu.edu.cn alloy (Huang et al, 2020), magnesium alloy (Yao et al, 2014) and Al/Ti dissimilar materials (Li et al, 2015) have shown that an external magnetic field (EMF) can enlarge the nugget size, reduce the shrinkage defects, and improve the mechanical performance of weld joints. However, these studies were based on experimental methods, and the control mechanism of an EMF on the flow behaviors of molten metal cannot be observed because the weld formation process is completely invisible, which limits further improvement of the weld performance.…”

Section: Introductionmentioning

confidence: 99%

Influencing mechanism of an external magnetic field on fluid flow, heat transfer and microstructure in aluminum resistance spot welding

Lin

Zhang

Niu

et al. 2021

Engineering Applications of Computational Fluid Mechanics

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The magnetically assisted resistance spot welding (MA-RSW) method provides a promising approach for improving weld performance. However, the MA-RSW process involves complex multiphysics fields that make numerical modeling very challenging. Thus, most resistance spot welding (RSW) models adopt electrothermal-mechanical coupling and ignore the influence of fluid flows caused by electromagnetic forces on nugget growth. In this paper, a magnetohydrodynamic (MHD) model, which couples the electric, thermal, magnetic and flow fields, is developed to explore the influencing mechanism of an external magnetic field (EMF) on the flow patterns and microstructures of aluminum resistance spot welds. Numerical results show that the application of an EMF can lead to the formation of Lorentz force in the liquid nugget, which transforms the flow pattern from an in-plane flow to a combined in-plane and out-of-plane flow. The flow velocity of molten metal in the MA-RSW process is 5 times higher than that of the RSW process, and the maximum temperature of the MA-RSW model is reduced from 774°C in the MHD RSW model to 725°C. Therefore, the MA-RSW joint exhibits a 25.5% larger nugget diameter, a more than 20% finer grain structure, and fewer defects than the RSW joint in the experimental results.

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Improving austenitic stainless steel resistance spot weld quality using external magnetic field

Cited by 42 publications

References 34 publications

Influence of resistance spot welding process parameters on dissimilar austenitic and duplex stainless steel welded joints

Influence of resistance spot welding process parameters on dissimilar austenitic and duplex stainless steel welded joints

Farklı Mıknatıs Geometrilerinin Manyetik Alan Destekli Direnç Punta Kaynağına Etkisi

Influencing mechanism of an external magnetic field on fluid flow, heat transfer and microstructure in aluminum resistance spot welding

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