scholarly journals Ultrasonic Spot Welding of Similar and Dissimilar Alloys for Automotive Applications

2021 ◽  
Author(s):  
Andrew Macwan
Keyword(s):  
Diffusion Layer ◽  
Spot Welding ◽  
Frictional Heating ◽  
Hsla Steel ◽  
Weight Ratio ◽  
High Strength ◽  
Phase Identification ◽  
Welding Time ◽  
Interface Diffusion ◽  
Lap Shear

Lightweighting has been regarded as a key strategy in the automotive industry to improve fuel efficiency and reduce anthropogenic environment-damaging, climate-changing, and costly emissions. Magnesium (Mg) alloys and Aluminum (Al) alloys are progressively more used in the transportation industries to reduce the weight of vehicles due to their high strength-to-weight ratio. Similarly, high strength low alloy (HSLA) steel is widely used to reduce gauge thickness and still maintain the same strength, and thereby reduce vehicle weight as well. A multi-material design of automotive structures and parts inevitably involve similar Mg-to-Mg and dissimilar Mg-to-Al, Al-to-steel, and Mg-to-Cu joints. Ultrasonic spot welding (USW) – a solid-state joining technique has recently received significant attention due to its higher efficiency in comparison with conventional fusion welding techniques. In this study, USW was used to generate similar joints of low rare-earth containing ZEK100 Mg alloy sheets and dissimilar ZEK100-to-Al5754, Al6111-to-HSLA steel, and Mg-to-Cu joints at different levels of welding energy or welding time. To optimize welding process and identify key factors affecting the weld strength, microstructural evolution, microhardness test, tensile lap shear test, fatigue test, and fracture analysis were performed on similar and dissimilar ultrasonic spot welded (USWed) joints. Dynamic recrystallization and grain coarsening were observed during Mg-to-Mg similar welding while rapid formation and growth of interface diffusion layer were observed in all dissimilar joints in the present study. It was due to significantly high strain rate (~103 s-1) and high temperature generated via frictional heating during USW. The interface diffusion layer was analyzed by SEM, EDS and XRD phase identification techniques which showed the presence of eutectic structure containing intermetallic compounds (IMCs). As a result, brittleness at the interface increased. The Zn coating in dissimilar USWed Al-to-steel joints eliminated the formation of brittle IMCs of Al-F, which were replaced by relatively ductile AlZn eutectic. The optimum welding energy or welding time during similar and dissimilar USW of lightweight alloys with a sheet thickness of 1-2 mm was in the range of ~500 J to 2000 J (~0.25 s to 1 s).

scholarly journals Ultrasonic Spot Welding of Similar and Dissimilar Alloys for Automotive Applications

2021 ◽  
Author(s):  
Andrew Macwan
Keyword(s):  
Diffusion Layer ◽  
Spot Welding ◽  
Frictional Heating ◽  
Hsla Steel ◽  
Weight Ratio ◽  
High Strength ◽  
Phase Identification ◽  
Welding Time ◽  
Interface Diffusion ◽  
Lap Shear

Lightweighting has been regarded as a key strategy in the automotive industry to improve fuel efficiency and reduce anthropogenic environment-damaging, climate-changing, and costly emissions. Magnesium (Mg) alloys and Aluminum (Al) alloys are progressively more used in the transportation industries to reduce the weight of vehicles due to their high strength-to-weight ratio. Similarly, high strength low alloy (HSLA) steel is widely used to reduce gauge thickness and still maintain the same strength, and thereby reduce vehicle weight as well. A multi-material design of automotive structures and parts inevitably involve similar Mg-to-Mg and dissimilar Mg-to-Al, Al-to-steel, and Mg-to-Cu joints. Ultrasonic spot welding (USW) – a solid-state joining technique has recently received significant attention due to its higher efficiency in comparison with conventional fusion welding techniques. In this study, USW was used to generate similar joints of low rare-earth containing ZEK100 Mg alloy sheets and dissimilar ZEK100-to-Al5754, Al6111-to-HSLA steel, and Mg-to-Cu joints at different levels of welding energy or welding time. To optimize welding process and identify key factors affecting the weld strength, microstructural evolution, microhardness test, tensile lap shear test, fatigue test, and fracture analysis were performed on similar and dissimilar ultrasonic spot welded (USWed) joints. Dynamic recrystallization and grain coarsening were observed during Mg-to-Mg similar welding while rapid formation and growth of interface diffusion layer were observed in all dissimilar joints in the present study. It was due to significantly high strain rate (~103 s-1) and high temperature generated via frictional heating during USW. The interface diffusion layer was analyzed by SEM, EDS and XRD phase identification techniques which showed the presence of eutectic structure containing intermetallic compounds (IMCs). As a result, brittleness at the interface increased. The Zn coating in dissimilar USWed Al-to-steel joints eliminated the formation of brittle IMCs of Al-F, which were replaced by relatively ductile AlZn eutectic. The optimum welding energy or welding time during similar and dissimilar USW of lightweight alloys with a sheet thickness of 1-2 mm was in the range of ~500 J to 2000 J (~0.25 s to 1 s).

Similar and Dissimilar Ultrasonic Spot Welding of 5754 Aluminum Alloy for Automotive Applications

2016 ◽  
Vol 877 ◽  
pp. 561-568 ◽  
Author(s):  
A. Macwan ◽  
F.A. Mirza ◽  
S.D. Bhole ◽  
Dao Lun Chen
Keyword(s):  
Spot Welding ◽  
Hsla Steel ◽  
Weight Ratio ◽  
Eutectic Structure ◽  
Al Alloys ◽  
Vehicle Body ◽  
Dissimilar Welding ◽  
Al Alloy ◽  
Lap Shear ◽  
Steel Joints

Aluminum (Al) alloys are increasingly used in the transportation industry to reduce the weight of vehicles due to their high strength-to-weight ratio. These applications unavoidably involve similar and dissimilar joining of an automotive grade 5754 Al alloy to manufacture multi-material vehicle body structures and parts. Ultrasonic spot welding (USW), an emerging and promising solid-state joining technology, can be suitably applied to join Al alloys. In this study, 5754 Al alloy was welded in similar (Al5754-Al5754) and dissimilar (Al5754-ZEK100 Mg alloy, Al5754-HSLA steel) configurations at varying levels of welding energy. It was observed that USW had a strong effect on the interface microstructure, with fine grains present at the weld interface via dynamic recrystallization in the similar welding, while an interface diffusion layer formed in the dissimilar welding. The tensile lap shear strength increased with increasing welding energy, reached its optimum value, and then decreased with further increasing welding energy. The strength of dissimilar Al5754-ZEK100 and Al5754-HSLA steel joints was about 55% and 88% of that of the similar Al-Al joints, respectively. The dissimilar Al5754-HSLA steel joints exhibited the longest fatigue life due to the reduced stress concentration and additional strengthening arising from the brazing effect of the squeezed-out Al-Zn eutectic structure at the nugget edge.

Study on Resistance Spot Welding Technology and Properties of TRIP800 High Strength Steel Sheet

2011 ◽  
Vol 391-392 ◽  
pp. 661-665
Author(s):  
Yan Yu ◽  
Feng Xue Wang ◽  
Zai Dao Yang
Keyword(s):  
Mechanical Properties ◽  
High Strength Steel ◽  
Spot Welding ◽  
Welding Current ◽  
High Strength ◽  
Welding Parameters ◽  
Welding Time ◽  
Test Analysis ◽  
Welding Technology ◽  
Welding Electrode

A series of spot welding technology, joint mechanical properties and microhardness test analysis of TRIP800 high strength steel were researched. Based on these experiments and analysis, effect of spot welding parameters such as welding current, welding time and electrode pressure on joint mechanical properties were explored. The relevant spot welding parameters of TRIP800 high strength steel of spot welding were recommended, such as welding current is7.5~8.0KA, electrode pressure is 450 kgf and welding time is 20cyc. Welding electrode should be to ensure that as much as possible and clean the surface,to avoid welding current and welding time is too high or too long, as well as forging lack of power, to prevent the occurrence of welding defects.

Numerical Simulation of Friction Stir Spot Welding

2016 ◽  
Vol 834 ◽  
pp. 43-48 ◽  
Author(s):  
Marius Adrian Constantin ◽  
Ana Boşneag ◽  
Monica Iordache ◽  
Claudiu Bădulescu ◽  
Eduard Niţu
Keyword(s):  
Numerical Simulation ◽  
Numerical Model ◽  
Spot Welding ◽  
Frictional Heating ◽  
Three Dimensional ◽  
High Strength Steels ◽  
High Strength ◽  
Friction Stir Spot Welding ◽  
Fe Model ◽  
Friction Stir

Friction Stir Spot Welding (FSSW) is a solid state joining process that relies on frictional heating and plastic deformation realized at the interaction between a non-consumable welding tool that rotates on the contact surfaces of the workpieces. Friction Stir Spot Welding (FSSW) is an evolving technique that has received considerable attention from automotive industries to replace electric resistance spot welding, which shows poor weldability for advanced high-strength steels as well as aluminium alloys. Because of the interest shown by the industry towards this process, an attempt to optimize it is imperative. But the experiments are often time consuming and costly. To overcome these problems, numerical analysis has frequently been used in the last years. The purpose of this paper is to develop a three-dimensional fully coupled thermal-stress finite element (FE) model of FSSW process for thin aluminium alloy Al 6061-T6. Numerical simulation being helpful for better understanding and observation of the influence of input parameters on the resulting phenomena. It is described the algorithm and are presented the activities needed to be performed in order to develop a valid numerical model for FSSW. The validation of the numerical model being achieved by comparing the resulted temperatures from the numerical simulation with the experimentally determined temperatures for the same material

Process Feasibility Analysis of Self-Pierce Riveting High Strength Low Alloy Steel

2010 ◽  
Author(s):  
L. Han ◽  
M. Thornton ◽  
R. Hewitt ◽  
A. Chrysanthou ◽  
M. Shergold
Keyword(s):  
Spot Welding ◽  
Hsla Steel ◽  
Sheet Material ◽  
Dissimilar Materials ◽  
High Strength ◽  
Feasibility Analysis ◽  
Low Alloy Steel ◽  
Automotive Body ◽  
Body In White ◽  
Selection Of

Self-Piercing Riveting (SPR) has been widely used in automotive Body in White (BIW) assembly as an alternative to Resistance Spot Welding (RSW), in particular for joining of dissimilar materials, for example Steels to Aluminium. A study examining the process feasibility of SPR of Aluminium alloy AA5754 and High Strength Low Alloy (HSLA) steel in various thicknesses has been conducted. It has been shown that the process is capable of joining the two materials together. However, it was also observed that the selection of rivet and die is limited when joining HSLA. The setting force required to drive the rivet into the sheet material to be joined tends to be high. This leads to potential tooling life concerns. It was also shown that the arrangement of the high strength steel joined to aluminium can have a significant effect on the process feasibility.

Failure modes of gas metal arc welds in lap-shear specimens of high strength low alloy (HSLA) steel

2014 ◽  
Vol 131 ◽  
pp. 74-99 ◽  
Author(s):  
Catherine M. Amodeo ◽  
Wei-Jen Lai ◽  
Jaewon Lee ◽  
Jwo Pan
Keyword(s):  
Failure Modes ◽  
Hsla Steel ◽  
High Strength ◽  
Lap Shear

Investigation of Polyurethane Bonding to Steel in Sandwich Panels

2017 ◽  
Vol 890 ◽  
pp. 401-405 ◽  
Author(s):  
Meyrick Pereira ◽  
Maziar Ramezani ◽  
Timotius Pasang ◽  
Ben Withy
Keyword(s):  
Sandwich Structure ◽  
Load Transfer ◽  
Sandwich Panels ◽  
Weight Ratio ◽  
High Strength ◽  
Lap Shear ◽  
Bending Resistance ◽  
Point Bend Test ◽  
Three Point Bend Test ◽  
Point Bend

Sandwich panels made of thin and stiff skins, connected by a thick and soft core are widely used in load-bearing components mainly due to their high strength to weight ratio. To improve the reliability in using sandwich beams, it is necessary to understand their responses under external mechanical and environmental stimuli. This paper investigates the construction of steel-polyurethane-steel sandwich panels and their mechanical properties. Key properties of a sandwich structure are the adhesion between the skins and the sandwich material, and the load transfer from the outer skin to the inner skin. Lap shear specimens were selected to give an indication of the bond strength of the polyurethane to steel, whilst three point bend test specimens were selected to indicate the degree of load transfer between the skins and the bending resistance provided by the sandwich structure.

scholarly journals Metallographic evaluation of the weldability of high strength aluminium alloys using friction spot welding

2017 ◽  
Vol 8 (1) ◽  
pp. 8
Author(s):  
Jeroen Vercauteren ◽  
Koen Faes ◽  
Wim De Waele
Keyword(s):  
Aluminium Alloys ◽  
Spot Welding ◽  
High Strength ◽  
Frictional Heat ◽  
Friction Spot Welding ◽  
Lap Shear ◽  
Spot Joining ◽  
Published Research ◽  
Interface Imperfections ◽  
Welding Technique

Friction spot welding is a recent solid-state welding technique well suited for spot-joining lightweight materials in overlap condition. Aerospace and transport industries show great interest in this technique to join high-strength aluminium alloys, but published research is still limited. In this project, the link between process parameters and weld quality is investigated for EN AW-7075-T6 material. Techniques used are metallographic qualification, measurement of hardness reduction and lap shear strength. This paper focusses on the metallographic investigation of the weld region and its imperfections. Increasing joining time and heat input creates an easier material flow resulting in fewer imperfections. Limited plunge depths lead to typical interface imperfections. Variation in the rotational speed shows distinctive stir zone shapes as a consequence of severe stirring and frictional heat.

Precipitation in Al-Li-Zr alloys

1992 ◽  
Vol 50 (1) ◽  
pp. 186-187
Author(s):  
D.M. Vanderwalker
Keyword(s):  
Fracture Toughness ◽  
Precipitation Hardening ◽  
Weight Ratio ◽  
High Strength ◽  
Transmission Electron ◽  
Water Quench ◽  
Aluminum Lithium ◽  
Aluminum Lithium Alloys ◽  
Lithium Alloys ◽  
Zr Alloys

Aluminum-lithium alloys have a low density and high strength to weight ratio. They are being developed for the aerospace industry.The high strength of Al-Li can be attributed to precipitation hardening. Unfortunately when aged, Al-Li aquires a low ductility and fracture toughness. The precipitate in Al-Li is part of a sequence SSSS → Al3Li → AlLi A description of the phases may be found in reference 1 . This paper is primarily concerned with the Al3Li phase. The addition of Zr to Al-Li is being explored to find the optimum in properties. Zirconium improves fracture toughness and inhibits recrystallization. This study is a comparision between two Al-Li-Zr alloys differing in Zr concentration.Al-2.99Li-0.17Zr(alloy A) and Al-2.99Li-0.67Zr (alloy B) were solutionized for one hour at 500oc followed by a water quench. The specimens were then aged at 150°C for 16 or 40 hours. The foils were punched into 3mm discs. The specimens were electropolished with a 1/3 nitric acid 2/3 methanol solution. The transmission electron microscopy was conducted on the JEM 200CX microscope.

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