Enhancement of the tensile shear strength for joining low-ductility aluminium to high-strength steel by using electrically-assisted mechanical clinching (EAMC)

2021 ◽  
pp. 095440542199565
Author(s):  
Abozar Barimani-Varandi ◽  
Abdolhossein Jalali Aghchai
Keyword(s):  
Shear Strength ◽  
High Strength Steel ◽  
High Strength ◽  
Fe Model ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Electroplastic Effect ◽  
Fracture Displacement ◽  
Electrically Assisted ◽  
Mechanical Clinching

The present work studied the enhancement of the tensile shear strength for joining AA6061-T6 aluminium to galvanized DP590 steel via electrically-assisted mechanical clinching (EAMC) using an integrated 2D FE model. To defeat the difficulties of joining low-ductility aluminium alloy to high-strength steel, the electroplastic effect obtained from the electrically-assisted process was applied to enhance the clinch-ability. For this purpose, the results of experiments performed by the chamfering punches with and without electrically-assisted pre-heating were compared. Joint cross-section, failure load, failure mode, fracture displacement, material flow, and failure mechanism were assessed in order to study the failure behaviour. The results showed that the joints clinched at the EAMC condition failed with the dominant dimpled mechanism observed on the fracture surface of AA6061 side, achieved from the athermal effect of the electroplasticity. Besides, these joints were strengthened 32% with a much more fracture displacement around 20% compared with non-electrically-assisted pre-heating.

scholarly journals Effect of Microstructure and Texture on Mechanical Properties of Resistance Spot Welded High Strength Steel 22MnB5 and 5A06 Aluminium Alloy

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 685
Author(s):  
Xiaoqing Jiang ◽  
Shujun Chen ◽  
Jinlong Gong ◽  
Zhenyang Lu
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Aluminium Alloy ◽  
High Strength Steel ◽  
High Strength ◽  
Welding Parameters ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Resistance Spot ◽  
Effect Of Microstructure

The present study aims to investigate the effect of microstructure and texture on mechanical properties of resistance spot welding of high strength steel 22MnB5 and 5A06 aluminium alloy as a function of welding parameters. The pseudo-nugget zones (NZs) at the steel side have undergone full recrystallisation with a fine-grained ferrite structure containing a small amount of retained austenite and a high hardness of approximately 500 HV, which is a 35% increase in hardness compared to the base material (BM) with fine lath martensitic structure. The NZs at the Al side contain both a recrystallisation texture and shear texture. Higher tensile shear strength with increasing weld time could be linked to the random texture at the Al side. The highest tensile shear strength was achieved at an intermetallic layer thickness of 4 mm.

Behavior and Quality Evaluation of Electroplastic Self-Piercing Riveting of Aluminum Alloy and Advanced High Strength Steel

2013 ◽  
Vol 135 (1) ◽  
Author(s):  
Ming Lou ◽  
YongBing Li ◽  
YaTing Li ◽  
GuanLong Chen
Keyword(s):  
Shear Strength ◽  
Aluminum Alloy ◽  
High Strength Steel ◽  
High Strength ◽  
Tensile Shear Strength ◽  
Advanced High Strength Steel ◽  
Tensile Shear ◽  
Cold Forming ◽  
Riveting Process ◽  
Cross Tension

The hybrid use of dissimilar lightweight materials, such as aluminum alloy and advanced high strength steel (AHSS), has become a critical approach to reduce the weight of ground transportation vehicles. Self-piercing riveting (SPR) as a preferred cold-forming fastening method is facing problems like weak interlocking and insufficient penetration, due to the reduced formability of AHSS. In this paper, a new process named electroplastic self-piercing riveting (EP-SPR) was proposed to reduce the deformation resistance of AHSS DP780, by applying a direct current (dc) to it during the riveting process. The influence of dc on force and displacement characteristics throughout the riveting process, joint physical attributes and quasi-static performances for two sheet combinations, e.g., AA6061-T6 to DP780 (combination 1) and DP780 to AA6061-T6 (combination 2), were studied and compared with the traditional SPR joints. The results showed that compared with the traditional SPR joints, the EP-SPR ones increased by 12.5% and 23.3% in tensile-shear strength and cross-tension strengths for combination 1, respectively. For combination 2, even though the EP-SPR joints decreased by 5.8% in tensile-shear strength, it could reduce the penetration risk of bottom AA6061-T6, and present a better energy absorption capability for the increased undercut amount. In addition, the corresponding cross-tension strength of EP-SPR joints still increases by 6.1%.

scholarly journals Porosity Characteristics and Effect on Tensile Shear Strength of High-Strength Galvanized Steel Sheets after the Gas Metal Arc Welding Process

Metals ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 1077 ◽  
Author(s):  
Seungmin Shin ◽  
Sehun Rhee
Keyword(s):  
Shear Strength ◽  
Arc Welding ◽  
Gas Metal Arc Welding ◽  
Welding Process ◽  
High Strength ◽  
Galvanized Steel ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Tensile Test Specimen ◽  
Metal Arc Welding

In this study, lap joint experiments were conducted using galvanized high-strength steel, SGAFH 590 FB 2.3 mmt, which was applied to automotive chassis components in the gas metal arc welding (GMAW) process. Zinc residues were confirmed using a semi-quantitative energy dispersive X-ray spectroscopy (EDS) analysis of the porosity in the weld. In addition, a tensile shear test was performed to evaluate the weldability. Furthermore, the effect of porosity defects, such as blowholes and pits generated in the weld, on the tensile shear strength was experimentally verified by comparing the porosity at the weld section of the tensile test specimen with that measured through radiographic testing.

Effect of Initial Gap on Tensile Strength of Resistance Spot Welded Joints

2010 ◽  
Vol 154-155 ◽  
pp. 325-328
Author(s):  
Hai Jun Yang ◽  
Yan Song Zhang ◽  
Jie Shen ◽  
Xin Min Lai
Keyword(s):  
Tensile Strength ◽  
Shear Strength ◽  
Welded Joints ◽  
Fe Model ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Resistance Spot ◽  
Nugget Formation ◽  
Spot Welded

It has been proved that the initial gap has obvious influence on nugget formation, but little works focused on the effect of initial gap on the tensile strength of resistance spot welded (RSW) joints. In this paper, a 3D FE model was built for solving this question. The results show that, even though there are some fluctuations of weld diameter and tensile strength of RSW joints with initial gap, the tensile strength and weld diameter of welded joints with initial gap are still larger than that of welded joints without gap, which confirm that the influence of initial gap on tensile shear strength is little significant. The computation results agree well with experiment.

scholarly journals Electrically-assisted mechanical clinching of AA6061-T6 aluminum to galvanized DP590 steel: effect of geometrical features on material flow and mechanical strength

2020 ◽  
Vol 21 (5) ◽  
pp. 529
Author(s):  
Abozar Barimani-Varandi ◽  
Abdolhossein Jalali Aghchai
Keyword(s):  
Mechanical Strength ◽  
Material Flow ◽  
Failure Modes ◽  
High Strength ◽  
Fe Model ◽  
Electrically Assisted ◽  
Geometrical Features ◽  
Mechanical Clinching ◽  
Failure Loads ◽  
Joint Section

The mechanical clinching as an alternative joining process for fabricating lightweight aluminum to steel assemblies may face the challenges when joining low-ductility aluminum alloy to high-strength steel. Several researches have been focused on applying the electrically-assisted processes in various fields due to energy efficiency as well as practical simplicity, in order to improve the formability. This paper concentrates on the electrically-assisted mechanical clinching (EAMC) of AA6061-T6 aluminum to galvanized DP590 steel. To this end, a combination of experimental and numerical clinching tests was performed using extensible die at different penetration depths, in which controlling the material flow was obtained by applying newly defined chamfer ratio RC in order to guarantee the strong mechanical interlock. The joint section parameters, failure loads, and failure modes were measured. The effects of the geometrical features on material flow and mechanical strength of clinched joints were analyzed using a FE model. The results showed that the defined parameter RC greatly increased the strength with the use of the EAMC process, which came with a reduction in forming load.

scholarly journals Optimization of the tensile-shear strength of laser-welded lap joints of ultra-high strength abrasion resistance steel

2021 ◽  
Vol 11 ◽  
pp. 1434-1442
Author(s):  
Mikko Hietala ◽  
Mohammed Ali ◽  
Ali Khosravifard ◽  
Markku Keskitalo ◽  
Antti Järvenpää ◽  
...  
Keyword(s):  
Shear Strength ◽  
Abrasion Resistance ◽  
High Strength ◽  
Lap Joints ◽  
Tensile Shear Strength ◽  
Tensile Shear

scholarly journals Effect of Surface Texture on Tensile Shear Strength of 1060Al-PET Welding Joints

2021 ◽  
Vol 34 (1) ◽  
Author(s):  
Jia Liu ◽  
Yuchi Dai ◽  
Yan Shi ◽  
Wenfu Cui ◽  
Tao Jiang
Keyword(s):  
Shear Strength ◽  
Laser Irradiation ◽  
Surface Texture ◽  
Laser Power ◽  
Heat Dissipation ◽  
High Strength ◽  
Width Ratio ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Shear Process

AbstractJoining metal to plastic can lighten weight of products to reduce energy consumption. However, it is difficult to achieve high-strength welding between metal and plastic. To address this problem, the methods of surface texture pretreatment and laser irradiation welding was proposed to achieve the high-strength connection of metal and plastic. In this study, with different parameters of laser power and texture morphology, 1060 Al with surface texture treatment was joined to polyethylene terephthalate (PET) by laser irradiation welding from metal side. Study showed that as the laser power increased, the tensile shear strength of joints increased first, and decreased thereafter. Tensile shear tests demonstrated that the mechanical force of joint was strengthened contributed to mechanical anchorage formed by surface texture. The depth-width ratio of the texture grooves affected the tensile shear process of the joint. According to the result of temperature simulation, the existence of texture grooves reduced the heat transfer efficiency, and the heat dissipation at interface was also impeded in course of laser welding. Finally, the maximum tensile strength of 1060Al-PET joint reached 48.4 MPa, which was close to the strength of PET matrix. The bonding mechanism of the 1060Al-PET joints was composed of mechanical bonding and chemical bonding. This study proposes an effective method to join metal to plastic which achieved high-strength connection between metal and plastic.

scholarly journals Prediction of the Weld Qualities Using Surface Appearance Image in Resistance Spot Welding

Metals ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 831 ◽  
Author(s):  
Choi ◽  
Hwang ◽  
Kim ◽  
Kang ◽  
Kang
Keyword(s):  
Shear Strength ◽  
Fracture Mode ◽  
High Strength ◽  
Tensile Shear Strength ◽  
Tensile Shear ◽  
Surface Appearance ◽  
Resistance Spot ◽  
Steel Sheets ◽  
Nugget Diameter ◽  
Resistance Spot Weld

The quality of the resistance spot weld is predicted qualitatively using information from the weld’s external apparent image. The predicting tool used for weld qualities was a convolution neural network (CNN) algorithm with excellent performance in pattern recognition. A heat trace image of the weld surface was used as information on the external apparent image of welds. The materials used in the experiment were advanced high strength steel (AHSS) with 980 MPa strength, and uncoated cold-rolled (CR) steel sheets and galvannealed (GA) steel sheets were used. The quantitatively predicted weld quality information contained tensile shear strength, nugget diameter, fracture mode of welds, and expulsion occurrence. The predicted performance of the verification step of the model determined through the learning process was as follows; the predicted error rate for tensile shear strength and nugget diameter were 2.2% and 2.6%, respectively. And the predicted accuracy on fracture mode and expulsion occurrence was 100%.

scholarly journals Mechanical clinching and self-pierce riveting for sheet combination of 780-MPa high-strength steel and aluminium alloy A5052 sheets and durability on salt spray test of joints

2021 ◽  
Vol 113 (1-2) ◽  
pp. 59-72
Author(s):  
Yohei Abe ◽  
Ken-ichiro Mori
Keyword(s):  
Aluminium Alloy ◽  
High Strength Steel ◽  
Salt Spray ◽  
High Strength ◽  
Alloy Sheet ◽  
Galvanized Steel ◽  
Load Reduction ◽  
Minimum Thickness ◽  
Steel Sheets ◽  
Mechanical Clinching

AbstractTo increase the usage of high-strength steel and aluminium alloy sheets for lightweight automobile body panels, the joinability of sheet combinations including a 780-MPa high-strength steel and an aluminium alloy A5052 sheets by mechanical clinching and self-pierce riveting was investigated for different tool shapes in an experiment. All the sheet combinations except for the two steel sheets by self-pierce riveting, i.e., the two steel sheets, the two aluminium alloy sheets, and the steel-aluminium alloy sheets, were successfully joined by both the joining methods without the gaps among the rivet and the sheets. Then, to show the durability of the joined sheets, the corrosion behaviour and the joint strength of the aged sheets by a salt spray test were measured. The corrosion and the load reduction of the clinched and the riveted two aluminium alloy sheets were little. The corrosion of the clinched two steel sheets without the galvanized layer progressed, and then the load after 1176 h decreased by 85%. In the clinched two galvanized steel sheets, the corrosion progress slowed down by 24%. In the clinched steel and aluminium alloy sheets, the thickness reduction occurred near the minimum thickness of the upper sheet and in the upper surface on the edge of the lower aluminium alloy sheet, whereas the top surface of the upper sheet and the upper surface of the lower sheet were mainly corroded in the riveted joint. The load reduction was caused by the two thickness reductions, i.e., the reduction in the minimum thickness of the upper sheet and the reduction in the flange of the aluminium alloy sheet. Although the load of the clinched steel without the galvanized coating layer and aluminium alloy sheets decreased by about 20%, the use of the galvanized steel sheet brought the decrease by about 11%. It was found that the use of the galvanized steel sheets is effective for the decrease of strength reduction due to corrosion.

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