scholarly journals Hybrid Welding of Metal-Polymer Composites with a Non- Conducting Polymer Layer

2021 ◽  
pp. 33-40
Author(s):  
Paweł Kustroń ◽  
Marcin Korzeniowski ◽  
Tomasz Piwowarczyk ◽  
Paweł Sokołowski

Metal-polymer composites (MPCs) are becoming increasingly popular primarily because of their high strength-to-weight ratio. Metal-polymer composites consist of three layers, i.e. two external metallic sheets (linings) and the core made of plastic. The presence of the internal plastic layer makes MPCs impossible to join using conventional welding processes, which significantly limits their usability. One of the solutions to the problem involves the use of hybrid methods, e.g. ultrasonic method-aided resistance welding. The research work discussed in the article involved the development of a prototype test rig and a technology enabling the joining of the Litecor® composite with steel DP600. The joining process consisted of two stages. The first stage involved the removal of the non-conducting layer of polymer from the welding area and the making of an appropriate electric contact for resistance welding. The second stage was the classical resistance spot welding process. The development of the concept posed a challenge as it was necessary to develop an appropriate acoustic waveguide for high-power ultrasonic waves which, at the same time, could transfer loads in the form of electrode force as well as provide appropriate electric and thermal conductivity without compromising acoustic parameters during the welding process. The development of the test rig was followed by the performance of numerous tests aimed to identify the appropriate window of process parameters. Test joints were subjected to macrographic, strength, ultrasonic and topographic tests.

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
T. Sathish ◽  
S. Tharmalingam ◽  
V. Mohanavel ◽  
K. S. Ashraff Ali ◽  
Alagar Karthick ◽  
...  

Aluminium and its alloys play a significant role in engineering material applications due to its low weight ratio and superior corrosion resistance. The welding of aluminium alloy is challenging for the normal conventional arc welding processes. This research tries to resolve those issues by the Tungsten Inert Gas welding process. The TIG welding method is an easy, friendly process to perform welding. The widely applicable wrought aluminium AA8006 alloy, which was not considered for TIG welding in earlier studies, is considered in this investigation. For optimizing the number of experiments, the Taguchi experimental design of L9 orthogonal array type experimental design/plan was employed by considering major influencing process parameters like welding speed, base current, and peak current at three levels. The welded samples are included to investigate mechanical characterizations like surface hardness and strengths for standing tensile and impact loading. The results of the investigation on mechanical characterization of permanent joint of aluminium AA8006 alloy TIG welding were statistically analyzed and discussed. The 3D profilometric images of tensile-tested specimens were investigated, and they suggested optimized process parameters based on the result investigations.


Author(s):  
Santosh Kumar ◽  
KK Singh

Application of fibre-reinforced polymer composites has increased over the last two decades as compared to conventional materials. This improvement in the application of fibre-reinforced polymer composites is attributed to their unique material properties, such as high strength and stiffness-to-weight ratio, specific modulus and internal vibration damping. However, in most of the industrial applications, composite materials encounter tribological complications. Economic indicators and market dynamics suggested that the market for composite materials is booming and the dominant materials are carbon fibres, glass fibres and thermoset polymer (polyester resin) in resin segments. That is why tribological characteristics are crucial in designing carbon and glass-based fibre-reinforced polymer components. Owing to this importance, the study of tribological behaviour of fibre-reinforced polymer composite materials has expanded significantly. The present study has made an attempt to review the fundamental tribological applications and critical aspects of fibre-reinforced polymers, based on research work, which has been carried out over the past couple of decades. This work has primarily focused on the fibre-reinforced polymer composites, based on carbon and glass fibres with thermosets as the matrix material for probing into tribological behaviours. In the process, the focus has largely been on the most commonly occurring erosive and abrasive mode of wear process.


2021 ◽  
Author(s):  
Bazani Shaik ◽  
Gosala Harinath Gowd ◽  
Bandaru Durga Prasad

Today is an era of metals including Aluminum alloys owing to a fundamental paradigm shift in research objectives. In addition to superior performance and lightweight criteria that are used to define the innovations of yore, scientists today are compelled to take into consideration the environment-friendliness of the new and novel materials being developed due to the concerns of maintaining a sustainable and safe existence. The solid-state Friction stir welding process has immense potential in the areas of automobiles, aerospace and construction industries due to its overwhelming advantages over the conventional fusion welding process of aluminum alloys. The thesis presents an experimental investigation of friction stir welding of dissimilar aluminum alloys AA7075T651 and AA6082T651. Mathematical modeling equations are developed to predict the tensile strength, impact strength, elongation, and micro-hardness of the dissimilar FSW joints AA7075T651 and AA6082T651. The process parameters are optimized for maximum tensile strength and hardness values. Post weld heat treatment is conducted and the metallurgical properties of the FS welded AA7075T651 and AA6082T651 are presented for different combinations of tool rotational speeds. Aluminum and its alloys are widely used in nonferrous alloys for many industrial applications. Aluminum exhibits a combination of an excellent mechanical strength with lightweight and thus it is steadily replacing steel in industrial applications where the strength to weight ratio plays a significant role. In conventional welding, the joining of aluminum is mainly associated with a high coefficient of thermal expansion, solidification shrinkage and dissolution of harmful gases in the molten metal during welding. The weld joints are also associated with segregation of secondary alloys and porosities which are detrimental to the joint qualities. Friction Stir Welding (FSW) and Friction Welding (FW) are the most popular emerging solid welding techniques in aircraft and shipbuilding industries. FSW is mainly used for the joining of metal plates and FW is mainly used for the joining of rods. Both techniques are suitable for high strength material having less weight. These techniques are environmentally friendly and easy to execute. Hence, the study of these techniques can contribute much to the field of green technology. This research work is dealt with the experimental and numerical investigations on FSW and FW of aluminum alloys.


Author(s):  
Afif Mohamad Hanapiah ◽  
Sumaiya Islam ◽  
Neamul Khandoker ◽  
Mazid Abdul Md

By virtue of high-strength verses weight ratio aluminium alloys are achieving attentions in automobile, marine, and aircraft industries as it reduces the fuel consumption for running the vehicles. But their main drawback is the destruction of their carefully engineered microstructures by high heat generated in traditional welding processes. Friction Stir Welding (FSW) minimizes excessive heat in the welding zone and does not   influence the microstructural features.  FSW is currently one of the recommended solutions for manufacturing aluminium alloy welded machine parts. In this study, AA6061 Al-alloy strips were lap joined using the improvised FSW setup tool clamping it on the spindle of a CNC milling machine with the speed rate varied from 1000 rpm to 3000 rpm, and three different feed rates 5, 15, and 25 mm/min. Shear strength experiments of these joints revealed that samples created with the speed rate of 1000 rpm and feed rate of 25 mm/min performed best showing the highest load carrying capacity of 8976 N with elongation of 1.04%. They also demonstrated highest Vickers hardness value of 31 at the centre of the weldment.


Author(s):  
Sadaf Batool ◽  
Mushtaq Khan ◽  
Syed Husain Imran Jaffery ◽  
Ashfaq Khan ◽  
Aamir Mubashar ◽  
...  

This research work focuses on comparison of the weld geometry, distortion, microstructure and mechanical properties of thin SS 304 L sheets (0.8 mm thickness) welded using micro-plasma arc welding and tungsten inert gas welding process. Initial experiments were performed to identify suitable processing parameters for micro-plasma arc welding and tungsten inert gas welding processes. Microstructures of welds were analysed using scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate that the joint produced by micro-plasma arc welding exhibited higher tensile strength, higher ductility, smaller dendrite size and a narrow heat affected zone. Samples welded by micro-plasma arc welding process had lower distortion as compared to that welded by tungsten inert gas process. Micro-plasma arc welding was shown to be the suitable process for welding of thin 304 L sheets owing to its higher welding speed and better weld properties as compared to the tungsten inert gas welding process.


Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3233
Author(s):  
Paweł Kustroń ◽  
Marcin Korzeniowski ◽  
Tomasz Piwowarczyk ◽  
Paweł Sokołowski

Metal–plastic composites (MPCs) are gaining importance mainly due to high strength to weight ratio. They consist of three layers, two outer metallic cover sheets, and a plastic core. The presence of that inner plastic layer makes them rather unsuitable for joining by means of any conventional welding processes, which significantly reduces the application range of MPC. In this work, three various resistance spot welding (RSW)-based concepts were developed to overcome that limitation and join Litecor to DP600 steel. In all cases, a dedicated initial stage was implemented to RSW, which was aimed at removing the non-conductive polymer layer from the welding zone and creating the proper electrical contact for the resistance welding. These were, namely: (i) shunt current-assisted RSW; (ii) induction heating-assisted RSW; and (iii) ultrasonic-assisted RSW. The development of each concept was supported by finite element modeling, which was focused on setting the proper process parameters for polymer layer removal. Finally, the macro- and microstructure of exemplary RSW joints are shown and the most common spot weld features as well as the further development possibilities are discussed.


Open Physics ◽  
2018 ◽  
Vol 16 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Ilona Iatcheva ◽  
Denitsa Darzhanova ◽  
Marina Manilova

AbstractThe aim of this work is the modeling of coupled electric and heat processes in a system for spot resistance welding of cross-wire reinforced steel bars. The real system geometry, dependences of material properties on the temperature, and changes of contact resistance and released power during the welding process have been taken into account in the study.The 3D analysis of the coupled AC electric and transient thermal field distributions is carried out using the finite element method. The novel feature is that the processes are modeled for several successive time stages, corresponding to the change of contact area, related contact resistance, and reduction of the released power, occurring simultaneously with the creation of contact between the workpieces. The values of contact resistance and power changes have been determined on the basis of preliminary experimental and theoretical investigations.The obtained results present the electric and temperature field distributions in the system. Special attention has been paid to the temperature evolution at specified observation points and lines in the contact area. The obtained information could be useful for clarification of the complicated nature of interrelated electric, thermal, mechanical, and physicochemical welding processes. Adequate modeling is also an opportunity for proper control and improvement of the system.


Author(s):  
Soo-sung Kim ◽  
Geun-il Park ◽  
Jung-won Lee ◽  
Jin-hyun Koh

A remote welding machine for a DUPIC (Direct Use of spent PWR fuel In CANDU reactors) bundle fabrication was designed to establish the optimum welding processes in a hot cell environment. An initial investigation for hands-on fabrication outside the hot cell was performed in the consideration of the constraints of welding machine in the hot cell conditions. Gas tungsten arc welding (GTAW), laser beam welding (LBW), friction welding (FW), and resistance welding (RW) process were assessed as candidates for this application. A preliminary welding investigation to improve the RW process was also performed. The RW process was determined to be the most suitable process in a hot cell environment for joining an endplate to an endcap. An advantage of RW would be a qualified process for overlapped plates welding for which there is extensive production experience were available. A preliminary investigation for a hands-on fuel fabrication outside the hot cell was conducted in the consideration of the constraints caused by a welding in a hot cell. The optimum resistance welding parameters for the endplate welding process were obtained in terms of the current, electrode pressure and welding cycle. This paper presents an outline of the developed RW machine for a DUPIC bundle fabrication and reviews the conceptual design of a remote RW welder by using a master-slave manipulator. The design of RW machine by using the 3D modeling method was also designed. Furthermore the integrity of the welds by the resistance welding was confirmed by the results of the torque test, an examination of the microstructure and the fracture surfaces of the welds.


2021 ◽  
pp. 7-14
Author(s):  
Mariusz Stępień ◽  
Zygmunt Mikno

The article presents selected aspects of the FEM-based analysis concerning resistance welding processes performed using multispot welding systems. The analysis was based on a three-spot welding machine used for the joining bars in the cruciform configuration. Both two and three-dimensional modelling was performed as the comparative analysis of two computing software packages, i.e. the commercial ANSYS Mechanical software package and the ARTAP software package, available on an open access basis. The research work involved the determination of current propagation in various welding process configurations as well as the identification of the percentage loss of welding current and power resulting from the bridging of current by neighbouring welds. The article discusses the effect of the method of the power supply and the earthing of the system of electrodes along with the welded material on the manner of current propagation. The analyses presented in the article were performed in relation to the DC power supply (inverter welding machine). Related calculations were performed using averaged (in terms of heat and resistance) material parameters.


Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2560
Author(s):  
Guowei Zhang ◽  
Ting Lin ◽  
Ling Luo ◽  
Boming Zhang ◽  
Yuao Qu ◽  
...  

Thermoplastic composites (TPCs) are promising materials for aerospace, transportation, shipbuilding, and civil use owing to their lightweight, rapid prototyping, reprocessing, and environmental recycling advantages. The connection assemblies of TPCs components are crucial to their application; compared with traditional mechanical joints and adhesive connections, fusion connections are more promising, particularly resistance welding. This study aims to investigate the effects of process control parameters, including welding current, time, and pressure, for optimization of resistance welding based on glass fiber-reinforced polypropylene (GF/PP) TPCs and a stainless-steel mesh heating element. A self-designed resistance-welding equipment suitable for the resistance welding process of GF/PP TPCs was manufactured. GF/PP laminates are fabricated using a hot press, and their mechanical properties were evaluated. The resistance distribution of the heating elements was assessed to conform with a normal distribution. Tensile shear experiments were designed and conducted using the Taguchi method to evaluate and predict process factor effects on the lap shear strength (LSS) of GF/PP based on signal-to-noise ratio (S/N) and analysis of variance. The results show that current is the main factor affecting resistance welding quality. The optimal process parameters are a current of 12.5 A, pressure of 2.5 MPa, and time of 540 s. The experimental LSS under the optimized parameters is 12.186 MPa, which has a 6.76% error compared with the result predicted based on the S/N.


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