Weldability Of Aluminum Alloys Research Articles

Weldability of aluminum alloys based upon the Al–Ca–Zn–Mg system

Weldability of aluminum alloys based upon the Al–Ca–Zn–Mg system

Mechanical characterization of friction stir welded dissimilar aluminium alloy using Taguchi approach

Friction stir welding (FSW), a type of solid-state welding, joins two metallic workpieces, whether they are the same or different, by plastically deforming the base metal. The metallic workpieces are heated by the friction between them, which results in plastic deformation and welding. The FSW parameters, however, are what primarily determine the weldability and strength of FSW joints. The research on the FSW parameters and their impact on the quality and weldability of aluminium alloys combined with comparable and dissimilar metals by the FSW method has been previously studied, and this review work highlights that research. The majority of comparable research studies concluded that important factors, such as welding speed, rotational speed, plunge depth, spindle torque, shoulder design, base material, pin profile and tool type have a significant impact on the weldability of the aluminium joint when using the FSW method. Aluminium alloy possesses high wear and corrosion resistance; it has to be used in numerous applications such as automobile field, marine and home appliances due to its low weight. This experimental work planned to weld of dissimilar aluminium alloys such as AA7020 and AA8014 through Friction Stir Welding (FSW) process. Taguchi optimization (L9) is considered for this experimental work to examining of mechanical strength such as tensile strength, tensile strength is conducted by using of Universal testing Machine (UTM). FSW parameters are selected as tool speed (1200 rpm, 1400 rpm and 1600 rpm), welding speed (200 mm/min, 300 mm/min and 400 mm/min) and axial force (4 kN, 6 kN and 8 kN). For the tensile strength analysis, the axial force is highly influenced and the maximum tensile strength of 175 MPa is attained.

The Effect of Friction Stir Welding Parameters on the Weldability of Aluminum Alloys with Similar and Dissimilar Metals: Review

The solid-state welding method known as friction stir welding (FSW) bonds two metallic work parts, whether the same or different, by plastically deforming the base metal. The frictional resistance between both metallic workpieces causes them to produce heat, which produces plastic deformation and welds them. However, the weldability and strength of FSW joints mainly depend on the FSW parameters. This review work highlights the previous research work on the FSW parameters and their effects on the weldability and quality of the aluminum alloys joined with similar and dissimilar metals through the FSW method. About 150 research studies were systematically reviewed, and the articles included data from peer-reviewed journals. It has been concluded that the key parameters, including welding speed, “rotational speed”, “plunge depth”, “spindle torque”, “shoulder design”, “base material”, “pin profile” and “tool type”, significantly affect the weldability of the aluminum joint through the FSW method. Also, the selection of these parameters is important and fundamental as they directly affect the joint. It is recommended that future work focuses on FSW for aluminum. Among these, the most essential is the application of artificial intelligence (AI) techniques to select the optimum FSW parameters for aluminum welding.

Effect of Gap Bridging Distance on the Weldability of Aluminum Alloy to Galvanized Steel Joints in AC Pulse GMAW

Effect of Gap Bridging Distance on the Weldability of Aluminum Alloy to Galvanized Steel Joints in AC Pulse GMAW

Resistance spot welding of Al6061 lap joints with a polyvinyl alcohol-bonded graphene interlayer

Abstract In order to increase the lap shear strength and weldability of aluminium alloy (Al6061), spot welding is done in lap configuration with an interlayer of graphene nano-platelets (GNPs). The GNPs are bonded using polyvinyl alcohol (PVA) and drop-casted on one of the mating surfaces of the lap joint before the resistance spot welding process. The experiment is carried out using different welding currents and time cycles at a constant load. It was found that the processing parameters and the presence of GNP interlayer play an important role in the performance of the lap joint. An increase of approximately 60% in the lap shear strength was observed with GNP interlayer at optimum processing conditions. Interfacial–microstructure characterisation was carried out across the fractured surface of the lap joint by using optical microscopy, scanning electron microscopy (SEM) and X-ray diffraction (XRD). An increase in hardness, a change in nugget diameter and the mode of failure were observed in the presence of the GNP interlayer. A detailed analysis of the possible weld strengthening mechanisms is included in this article.

Resistance Spot Weldability of Aluminum Alloy with 6 wt.% Magnesium

To ensure safety and reduce the weight of vehicles, studies are being actively conducted on different aluminum alloys that have strength higher than conventional aluminum alloys. The development of high-performance aluminum alloys through magnesium content control is underway. Research on manufacturing techniques, such as, welding for application to the car body parts of these materials is required. In this study, the resistance spot weldability of an aluminum alloy with 6 wt.% magnesium (Al-6Mg) was evaluated and compared with the commercial aluminum alloy 5052, 6061 (Al5052, Al6061). The suitable welding range of the Al-6Mg was found to have a welding current of 24 kA to 28 kA, and a similar level of Al6061. The welding heat input was almost the same for the three materials, which resulted in no difference in the diameter of the nuggets. There was no significant difference of the porosity ratio between Al-6Mg and Al5052; however, the porosity ratio of Al6061 was higher. The alloy with the highest tensile shear strength, hardness and energy absorption of a welded joint was Al-6Mg. The low porosity ratio and high hardness of the Al-6Mg alloy caused the relatively high tensile shear strength and energy absorption of the welded joint.

Tensile and shear strength evaluation in joining dissimilar plates of mild steel with aluminum alloy through explosive cladding approach

Explosive cladding is known for its ability to join a wide variety of metals that other welding methods cannot do. In this present work, the weldability of aluminium alloy and mild steel plates and their bonding strength through an explosive cladding process investigation is performed. Experiments are conducted in the open air using Gelatin (SG-90) variety explosive having a detonation velocity of 3400 m/sec. Experimental trials for single replications were adopted. Ram tensile test has been carried out to determine the bonding strength. The effects of angle of inclination, loading ratio and stand-off distance on the weld strength were analyzed. The possibility of obtaining a sound weld depends on the limiting conditions of the above parameters. The microstructure of the explosive clad joints is studied for varying process parameters which shows a wavy profile that produces higher strength. The strength of the weld in both tensile and shear strength obtained is good and is within the acceptable range. An increase in strength of welded joints is obtained for higher parameter range.

Vacuum laser beam welding characteristics for aluminum alloys and its effects on plasma plume generation and laser weldability

The laser weldability of aluminum alloy is unstable due to low laser beam absorption rate, low viscosity, and high thermal diffusivity. As a result, defects such as porosity and sagging are easily formed in the fusion zone. Vacuum laser beam welding (VLBW) has been introduced to ensure better weldability by using a relatively low ambient pressure. This allows for deep penetration depth and stable keyhole behavior compared to welding under atmospheric conditions. To evaluate the effects of ambient pressure on laser welding characteristics, VLBW was performed with similar and dissimilar aluminum alloys. Varying the pressure inside the vacuum chamber affected the welding characteristics. It is inferred that variation in ambient pressure changes the interactions between the laser source and substrate, such as the laser energy transfer, plasma plume generation, and the behavior of keyhole and molten pool. The penetration depth increased with decreasing ambient pressure for the same heat input conditions. Also, decreasing the ambient pressure reduced the formation of defects such as sagging, underfill, and porosity. Plasma plume generation was also varied depending on the ambient pressure, and plasma plume height and intensity were compared using a CCD camera. In this experiment, an ambient pressure of 10 mbar was sufficient to ensure good welding properties and stability. Below 10 mbar, the VLBW system is considered an effective alternative to processes that require high vacuum environments.

Weldability of Aluminum Alloy and Hot Dip Galvanized Steel by AC Pulse MIG Brazing

Weldability of Aluminum Alloy and Hot Dip Galvanized Steel by AC Pulse MIG Brazing

Theoretical Investigation of Friction Welding on Magnesium and Aluminium Alloy

In this study, the weld ability of Aluminium Alloys 5083, 6061, 7075 and Magnesium AZ31 was investigated using Friction Welding. Magnesium AZ31 is the base alloy used and other Aluminium alloys were welded with Magnesium Alloy. These Alloys are welded by changing the parameters. Parameters which were used are speed of the spindle, pressure applied during friction, time for which the materials are kept under friction time, Forging Pressure and Forging time. Once the materials are welded by the process of friction welding the weld specimen joints are examined for its changes in its microstructure by the Scanning Electron Microscope (SEM). In order to evaluate the welded specimens mechanical properties the tests such as tensile test and micro hardness tests are carried out. It is found that a specific strength by friction welding method is achieved by aa combination of Magnesium alloy AZ31 along with Alumunium alloys such as 5083, 6061, 7075 by the experimental results.

Effect of surface treatments and storage conditions on resistance spot weldability of aluminum alloy 5182

Surface treatment technologies represented by Ti/Zr conversion treatment and silane coupling agent (SCA) treatment are increasingly used to improve the adhesion property of aluminum alloys resulting from the existence of dense and tenacious surface oxide film. AA 5182-O is used to prospectively investigate the effects of protective layers and storage conditions on resistance spot weldability. The acid-pickling (AP) state specimens are chosen as a control group. Both Ti/Zr and SCA protective layers could effectively restrain the growth of the inner oxide film, and even the SCA protective layers are not as uniform dense as the Ti/Zr ones. The increscent surface resistance and chemical nature of the protective layers codetermine the nugget profile feature and the degree of internal defects, and Ti/Zr conversion coating is distinctly better than that of SCA. As a result, the mechanical performance follows the following sequence: Ti/Zr-30d > AP > SCA-30d > AP-30d. Among influence factors induced performance degradation, the effect of excessive internal defects is the most significant, followed by small nugget size. Besides, the storage conditions also have a significant impact on resistance spot weldability, and the storage duration has the most considerable influence, followed by humidity, and the smallest is the temperature.

Effects of Electrode Face Thickness on Resistance Spot Weldability of Aluminium Alloy 6061

Aluminium alloy sheets are being utilized in automotive parts such as hood, trunk, and tailgate. However, the spot welding of aluminium alloy has many problems, such as electrode sticking and expulsion, and therefore research on the resistance spot welding of aluminium alloy sheets is necessary. In this study, we evaluated the effects of electrode face thickness on the resistance spot weldability of aluminium alloy 6061. The two electrode face thickness conditions were compared, and the electrode face thickness was determined to be an important process variable that affected the spot weldability of aluminium alloy 6061. Key words: Resistance spot welding, Aluminium alloy, Electrode face thickness, Sticking, Expulsion, Radius type electrode

Study of Mechanical Properties and Weldability of Aluminium Alloy and Stainless steel by Gas Metal Arc Welding

Aluminium-Steel joints which find application in the area of aerospace, automotive and shipbuilding industry aims to reduce the weight of structure thereby enhancing the efficiency. Welding is a method of enduringly joining two materials (usual metals) through contained coalescence resulting from a suitable combination of temperature, pressure and metallurgical conditions. There is a huge difference in melting point between Aluminium alloy and steel which makes this a great disadvantage for the process. Conducted an experimental investigation to understand the weldability of Aluminium alloy to stainless steel using the GMAW process. Aluminum alloy A5086 and Stainless steel IS2062 were lap welded using Gas metal arc welding process using two types of fillers which are ER5356 (Set A) and ER308LSi (Set B). A comparison is made between the two types on the basis of their mechanical properties and microstructure of welded joints. The hardness values of the weld in Set A and Set B ranged from 55 to 95 HV and 170 to 220 HV, respectively. By using filler ER5356, a maximum tensile strength of 102.4 MPa was obtained. The tensile strength of Set A ranged between 46.3 to 102.4 which was higher than Set B which ranged between 18.24 to 59.76 MPa. The combination of ER5356 filler and voltage of 18V was the best optimum condition in joining Aluminium alloy A5086 and Steel IS2062 dissimilar metals.

Thermal efficiency decision of variable polarity aluminum arc welding through molten pool analysis

One of several solutions to enhance the weldability of aluminum alloy is removing the aluminum oxide layer on the surface by adopting variable polarity arc welding. The authors’ previous experimental research on the variable polarity arc welding of aluminum alloy showed that reverse arc polarity has larger heat input efficiency than a straight polarity. Furthermore, the authors have already developed a numerical analysis model and suggested a methodology of estimating the heat input efficiency through a comparison between three dimensional molten pool simulation and experiment with regard to the variable polarity GTA welding. This research is a follow-up of the previous study, and it reveals the heat input efficiency of reverse polarity arc in aluminum welding for the first time through the suggested method. As a result, the heat input efficiency of reverse polarity is 3.8 times larger than that of straight polarity in aluminum welding.

Resistance Spot Welding of Aluminum Alloy and Carbon Steel with Spooling Process Tapes

Many lightweight materials, including aluminum alloy, magnesium alloy, and plastic, have been used for automotives. Aluminum alloy—the most commonly utilized lightweight metal—has poor resistance spot weldability owing to its inherent properties, which demand the development of welding solutions. Various welding techniques are utilized to improve the resistance spot weldability of aluminum alloy, including DeltaSpot welding. However, the technological development for welding dissimilar metals (aluminum alloy and steel) required for vehicle body assembly is still in its nascent stages. This study proposes DeltaSpot welding (a resistance spot welding process with spooling process tapes) using the alloy combination of 6000 series aluminum alloy (Al 6K32) and 440 MPa grade steel (SGARC 440). The welding characteristics of the main process parameters in DeltaSpot welding were analyzed and the weldability of the combination of the aluminum alloy, Al 6K32, and 440 MPa grade steel was evaluated. In addition, the characteristics of the intermetallic compound layer between the 440 MPa grade steel and Al 6K32 sheets were identified via scanning electron microscopy/energy dispersive X-ray spectroscopy (SEM-EDS).

Effects of Electrode Face Radius and Force on Resistance Spot Weldability of Aluminium Alloy 6061

Recently, with automobile body weight reduction trend, aluminium alloy sheets are introduced to automotive moving parts such as hood, trunk, and tailgate. Researches about joining technologies on aluminium alloy sheet are necessary. However aluminium alloy has many troubles with spot weldability. In this study, we evaluate effects of electrode face radius and electrode force on weldability of resistance spot welding of aluminium alloy 6061. The two electrode face radius conditions showed the same acceptable welding current rage to produce acceptable spot welding quality. However, high electrode force showed larger welding current process window than low electrode force in resistance spot welding of aluminium alloy 6061 Key words: Resistance spot welding, Aluminium alloy, Electrode face radius, Radius type electrode, Electrode force

Ciclo térmico y soldabilidad de las aleaciones de aluminio

Las aleaciones de aluminio se caracterizan por su bajo peso y elevada resistencia mecánica, aunque no presentan buenas propiedades mecánicas cuando son soldadas mediante arco eléctrico a excepción de las aleaciones de la serie 5XXX y serie 6XXX. En este trabajo se realiza una revisión sobre el estado del arte del ciclo térmico y la soldabilidad de las aleaciones de aluminio, mostrando las diferentes reacciones de solidificación y la influencia que presenta la velocidad de enfriamiento en las aleaciones de aluminio representado mediante las curvas de enfriamiento, evaluando su influencia sobre las propiedades mecánicas de la unión soldada.

Weldability of Aluminium Alloys for Automotive Applications

Restrictions in CO2-emissions have caused increased demands on decreased weight and increased use of lightweight materials in the automotive industry. Aluminium has shown to be of great interest due to its beneficial weight to strength ratio, and are suitable for hang-on parts such as roof, doors etc. However, the use of aluminium requires reliable joining techniques. This project has been focusing on laser welding of aluminium. It have been reported earlier that hot cracks and porosity are common defects while joining aluminium with laser welding. The aim with this project has been to produce crack free laser welds while joining thin aluminium sheets. Two different optics have been used in this project, oscillating- and triple-spot optics. The results from the experiments show that both the oscillating optics and the triple-spot optics can produce crack free welds. The amount of pores is shown to be low for both cases. The results do also show that the amount of pores in the welds increases with the weld length while the flange length is of minor impact. The mechanical properties are similar for the both optics. The oscillation specimens receive a higher tensile strength while the triple-spot specimens receive a larger elongation at break value.

Influence of Laser Welding Speed on the Morphology and Phases Occurring in Spray-Compacted Hypereutectic Al-Si-Alloys

Normally, the weldability of aluminum alloys is ruled by the temperature range of solidification of an alloy according to its composition by the formation of hot cracks due to thermal shrinkage. However, for materials at nonequilibrium conditions, advantage can be taken by multiple phase formation, leading to an annihilation of temperature stress at the microscopic scale, preventing hot cracks even for alloys with extreme melting range. In this paper, several spray-compacted hypereutectic aluminum alloys were laser welded. Besides different silicon contents, additional alloying elements like copper, iron and nickel were present in some alloys, affecting the microstructure. The microstructure was investigated at the delivery state of spray-compacted material as well as for a wide range of welding speeds ranging from 0.5 to 10 m/min, respectively. The impact of speed on phase composition and morphology was studied at different disequilibrium solidification conditions. At high welding velocity, a close-meshed network of eutectic Al-Si-composition was observed, whereas the matrix is filled with nearly pure aluminum, helping to diminish the thermal stress during accelerated solidification. Primary solidified silicon was found, however, containing considerable amounts of aluminum, which was not expected from phase diagrams obtained at the thermodynamic equilibrium.

Numerical analysis of variable polarity arc weld pool

Aluminum alloys are the materials which face difficulties in weldability. One of solutions to increase the weldability of aluminum alloys is removing the oxide-layer on the surface of aluminum by adopting variable polarity arc welding. The authors’ previous experimental research about variable polarity arc welding of aluminum showed that reverse arc polarity has larger heat input efficiency than straight polarity. In this study, numerical analysis of molten pool in aluminum alloy by variable polarity GTAW has been introduced and developed. The arc heat source, arc pressure, electromagnetic force and Marangoni flow regarding the variable polarity GTAW have been applied as the boundary conditions and body force terms. Governing equations such as the conservation of the mass, momentum and energy are numerically solved to derive temperature and flow vector field. Additionally, volume of fluid method is adopted to track free surface of molten pool and it was implemented through using commercial package Flow-3D. Through the present analysis, mathematical model for variable polarity arc is newly suggested and following result successfully showed effect of different heat input efficiency for each straight and reverse polarity. The heat input efficiencies are arbitrarily decided here for feasibility but a methodology to numerically determine the exact value is suggested. The final goal of these research series is to determine the heat input efficiency of reverse polarity arc aluminum welding indirectly through simulation and experiment comparison.