Failure mode of HSLA/DQSK dissimilar steel resistance spot welds

Pouranvari, M.; Ranjbarnoodeh, E.

doi:10.1179/1743281212y.0000000044

Cited by 13 publications

(10 citation statements)

References 17 publications

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“…Increments in current resulted in increment in tensile shear strength (peak load).This is in line with the findings of many studies reported earlier, by various researchers [9,14]. It was noticed that, above a current value of 13 KA, increase in current resulted in decrease in peak load value, due to expulsion.…”

Section: Current and Tensile Shear Strengthsupporting

confidence: 92%

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Mechanical Properties and Microstructure of Resistance Spot Welded Joints of AISI 409M Ferritic Stainless Steel

Subrammanian

Jabaraj

Raja

2015

Trans Indian Inst Met

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Resistance spot welding is widely used as a sheet metal joining process, especially in automotive and rail coach manufacturing industries. Ferritic stainless steel (FSS) is used for structural applications in these areas, owing to its superior corrosion resistance compared to conventional carbon steels. In this paper, mechanical properties and microstructure of resistance spot welded FSS joints to grade AISI 409M was investigated. Tensile shear test and micro hardness test were carried out to assess the mechanical properties and failure characteristics of weld joints. Microstructure was evaluated with optical microscopy. The effect of welding current on nugget growth, peak load, fusion zone (FZ) hardness, failure energy and failure mode were analyzed at various current ratings, keeping electrode force, weld cycle time and electrode tip diameter as constants. The results showed that, with the increment in welding current, tensile shear strength increased. Nugget diameter was found to be increasing with increase in current, in expulsion free welds. At low currents, failure mode was found to be interfacial and the pull out mode of failure occurred, at relatively higher current values. Average FZ hardness was found to be more than that of base metal (BM) but less than that of maximum hardness at heat affected zone. Grain enlargement was noticed at high temperature heat affected zone. FZ microstructure consists of predominantly columnar ferrite. Failure occurred at the BM region in all the samples welded above 10 KA current.

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Section: Current and Tensile Shear Strengthsupporting

confidence: 92%

“…It is made up of copper-chromium alloy, and is water cooled type. A total of eight sets of trials were conducted, with current values ranging between 7 KA (Kilo Ampere) and 14 …”

Section: Welding Processmentioning

confidence: 99%

Mechanical Properties and Microstructure of Resistance Spot Welded Joints of AISI 409M Ferritic Stainless Steel

Subrammanian

Jabaraj

Raja

2015

Trans Indian Inst Met

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“…The lack interfacial failure of the tensile-shear results can be indicate that the optimum welding parameters were selected in this study. The failure mode of welded joints preferred as pull-out failure mode after the tensile-shear test [20,21].…”

Section: Tensile and Tensile-shear Testmentioning

confidence: 99%

Mechanical properties and corrosion behavior of similar/dissimilar resistance spot welded automotive aluminum alloys

Kaya,

Başer,

Kahraman

2023

Materialwissenschaft Werkst

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Recently, usage of high strength aluminum alloys in automotive applications increase. The reasons for that increase are the light‐weight, high strength, good formability, weldability and corrosion resistance of the aluminum alloys to improve fuel economy as well as decreasing carbon dioxide emission. Automotive hybrid structures are commonly manufactured using dissimilar AA5000‐AA6000 joints to improve mechanical requirements and corrosion resistance of the parts. In this study, AA5754 H111‐AA6063 T4 materials were joined both similarly and dissimilarly by resistance spot welding method. Within the study, a mid‐frequency direct current technology was used instead of conventional alternative current technology. The welded zone was investigated by micro hardness measurements and microstructural characterization. Tensile‐shear and cross‐tension tests were performed. The welded zone of all welded specimens was subjected to salt spray corrosion test. A nugget pull‐out fracture mode was observed on the fracture surface of the all welded joints after tensile‐shear and cross‐tension tests. The lowest hardness values were measured from the weld metals for all welded joints. Porosity and inclusion were observed in the weld nugget with minor cracks in heat affected zone by optical microscope investigations.

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“…It is well documented that the size of the fusion zone is the key physical weld attribute controlling the failuremode transition of spot welds. 5,[12][13][14][15][16][17][18][19] The effect of the welding current on the FZ size is shown in Figure 4 indicating an enlargement of the weld nugget by increasing the welding current and generating a higher heat at the sheet/sheet interface. According to Figure 4, the failure mode during the CT loading was changed from the IF to the PF by increasing the welding current and the FZ size.…”

Section: Failure Modementioning

confidence: 99%

“…The transition from the IF mode to the PF mode is generally related to the increase in the size of the fusion zone above the minimum value. 5,[14][15][16][17][18][19] There are several sizing criteria for resistance spot welds including industrial standards. The effectiveness of these criteria for evaluating an AHSS spot weld, however, was not adequately addressed in the automotive welding community; it was simply adopted from the mild-steel practice and applied to AHSS spot welds.…”

Section: Introductionmentioning

confidence: 99%

DP780 dual-phase-steel spot welds: critical fusion-zone size ensuring the pull-out failure mode

Pouranvari¹,

Marashi²,

Jaber³

2015

Mater. Tehnol.

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This paper addresses the transition from the interfacial to the pull-out failure mode for DP780 dual-phase-steel resistance spot welds under tensile-shear and cross-tension loading conditions. It was studied whether industrial weld-size criteria can produce pull-out failure modes. Based on the failure mechanism of the spot welds in a cross-tension test, a simple analytical model is proposed to predict the critical FZ size to ensure the pull-out failure mode. According to the findings, the sheet thickness, the hardness ratio of the fusion zone to the sub-critical heat-affected zone, the amount of shrinkage voids in the fusion zone and the width of the HAZ are the main controlling factors for the transition from the interfacial to the pull-out failure mode in cross-tension loading. The fusion-zone size was proved to be the key factor controlling the cross-tension and tensile-shear strengths of DP780 resistance spot welds.

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Failure mode of HSLA/DQSK dissimilar steel resistance spot welds

Cited by 13 publications

References 17 publications

Mechanical Properties and Microstructure of Resistance Spot Welded Joints of AISI 409M Ferritic Stainless Steel

Mechanical Properties and Microstructure of Resistance Spot Welded Joints of AISI 409M Ferritic Stainless Steel

Mechanical properties and corrosion behavior of similar/dissimilar resistance spot welded automotive aluminum alloys

DP780 dual-phase-steel spot welds: critical fusion-zone size ensuring the pull-out failure mode

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