Application of Electric Current in Friction Stir Welding

2010 ◽  
Author(s):  
Matthew Pitschman ◽  
Jacob W. Dolecki ◽  
Garret W. Johns ◽  
Jun Zhou ◽  
John T. Roth
Keyword(s):  
Friction Stir Welding ◽  
Electric Current ◽  
Mechanical Energy ◽  
Welding Process ◽  
High Strength ◽  
Work Piece ◽  
Friction Stir ◽  
Weld Metals ◽  
Weld Properties ◽  
Electrically Enhanced

Friction Stir Welding (FSW) is a relatively new joining technique and has many applications. In FSW, heat generated due to friction between FSW tool and work-piece material softens the material and allows the materials in work-pieces to be stirred and joined together. FSW allows the work-pieces to be joined without reaching the melting point of the material, thus resulting in better welds. However, a large amount of mechanical energy has to be consumed for FSW of high-strength, difficult-to-weld metals such as titanium alloys. Hence, new FSW methods should be investigated to reduce the required energy. In this study, an innovative electrically-enhanced friction stir welding (EEFSW) has been developed. Electric current is passed in welding coupons of Aluminum 6061 plates and its effect on welding process and welds are examined. The results indicate that, with the aid of electric current, improvement in welding speed and reduction in energy consumption is obtainable, which enhances the productivity and widens the range of applications of FSW. Weld properties are found to be affected by the introduced current as well.

Study of the Key Issues of Friction Stir Welding of Titanium Alloy

2010 ◽  
Vol 638-642 ◽  
pp. 1185-1190 ◽  
Author(s):  
Hui Jie Liu ◽  
Li Zhou ◽  
Yong Xian Huang ◽  
Qi Wei Liu
Keyword(s):  
Titanium Alloy ◽  
Friction Stir Welding ◽  
Melting Point ◽  
Titanium Alloys ◽  
Welding Process ◽  
High Strength ◽  
Liquid Cooling ◽  
Friction Stir ◽  
Key Issues ◽  
Aluminum And Magnesium Alloys

As a new solid-state welding process, friction stir welding (FSW) has been successfully used for joining low melting point materials such as aluminum and magnesium alloys, but the FSW of high melting point materials such as steels and titanium alloys is still difficult to carry out because of their strict requirements for the FSW tool. Especially for the FSW of titanium alloys, some key technological issues need to solve further. In order to accomplish the FSW of titanium alloys, a specially designed tool system was made. The system was composed of W-Re pin tool, liquid cooling holder and shielding gas shroud. Prior to FSW, the Ti-6Al-4V alloy plates were thermo-hydrogen processed to reduce the deformation resistance and tool wear during the FSW. Based on this, the thermo-hydrogen processed Ti-6Al-4V alloy with different hydrogen content was friction stir welded, and the microstructural characterizations and mechanical properties of the joints were studied. Experimental results showed that the designed tool system can fulfill the requirements of the FSW of titanium alloys, and excellent weld formation and high-strength joint have been obtained from the titanium alloy plates.

On the problem of tool destruction when obtaining fixed joints of thick-walled aluminum alloy blanks by friction welding with mixing

2021 ◽  
Vol 23 (3) ◽  
pp. 72-83
Author(s):  
Kirill Kalashnikov ◽  
◽  
Andrey Chumaevskii ◽  
Tatiana Kalashnikova ◽  
Aleksey Ivanov ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Friction Welding ◽  
Welding Process ◽  
High Strength ◽  
Heterogeneous Structure ◽  
Adhesive Interaction ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Electric Erosion

Introduction. Among the technologies for manufacturing rocket and aircraft bodies, marine vessels, and vehicles, currently, more and more attention is paid to the technology of friction stir welding (FSW). First of all, the use of this technology is necessary where it is required to produce fixed joints of high-strength aluminum alloys. In this case, special attention should be paid to welding thick-walled blanks, as fixed joints with a thickness of 30.0 mm or more are the target products in the rocket-space and aviation industries. At the same time, it is most prone to the formation of defects due to uneven heat distribution throughout the height of the blank. It can lead to a violation of the adhesive interaction between the weld metal and the tool and can even lead to a destruction of the welding tool. The purpose of this work is to reveal regularities of welding tool destruction depending on parameters of friction stir welding process of aluminum alloy AA5056 fixed joints with a thickness of 35.0 mm. Following research methods were used in the work: the obtaining of fixed joints was carried out by friction welding with mixing, the production of samples for research was carried out by electric erosion cutting, the study of samples was carried out using optical metallography methods. Results and discussion. As a result of performed studies, it is revealed that samples of aluminum alloy with a thickness of 35.0 mm have a heterogeneous structure through the height of weld. There are the tool shoulder effect zone and the pin effect zone, in which certain whirling of weld material caused by the presence of grooves on tool surface is distinctly distinguished. It is shown that the zone of shoulders effect is the most exposed to the formation of tunnel-type defects because of low loading force and high welding speeds. It is revealed that tool destruction occurs tangentially to the surface of the tool grooves due to the high tool load and high welding speeds.

Process Parameter Optimization of Friction Crush Welding (FCW) of AISI 304 Stainless Steel

2017 ◽  
Author(s):  
Gurinder Singh Brar ◽  
Manpreet Singh ◽  
Ajay Singh Jamwal
Keyword(s):  
Stainless Steel ◽  
Friction Stir Welding ◽  
Welding Process ◽  
Pressure Vessels ◽  
304 Stainless Steel ◽  
Welding Parameters ◽  
Work Piece ◽  
Aisi 304 Stainless Steel ◽  
Aisi 304 ◽  
Friction Stir

AISI 304 stainless steel is one of the grades of steel widely used in engineering applications particularly in chemical equipments, food processing, pressure vessels and paper industry. Friction crush welding (FCW) is type of friction welding, where there is a relative motion between the tool and work-piece. In FCW process, the edges of the work-piece to be joined are prepared with flanged edges and then placed against each other. A non-consumable friction disc tool will transverse with a constant feed rate along the edges of the work-piece, which leads to welding. The joint is formed by the action of crushing a certain amount of additional flanged material into the gap formed by the contacting material. The novelty of present work is that FCW removes the limitations of friction stir welding and Steel work pieces can be economically welded by FCW. Taguchi method of Design of Experiments (DOE) is used to find optimal process parameters of Friction Crush Welding (FCW). A L9 Orthogonal Array, Signal to Noise ratio (S/N) and Analysis of Variance are applied to analyze the effect of welding parameters (welding speed, RPM, tool profile) on the weld properties like bond strength. Grain refinement takes place in friction crush welding as is seen in friction stir welding. Friction crush welding process also has added advantage in reducing distortion and residual stresses.

Influence of Tool Rotational Speed on the Mechanical Properties of Friction Stir Welded Al-Cu-Li Alloy

2016 ◽  
Vol 857 ◽  
pp. 228-231
Author(s):  
Ho Sung Lee ◽  
Ye Rim Lee ◽  
Kyung Ju Min
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Space Shuttle ◽  
Welding Process ◽  
High Strength ◽  
Fusion Welding ◽  
Welding Parameters ◽  
Friction Stir ◽  
Mechanical And Microstructural Properties ◽  
Tool Rotation

Aluminum-Lithium alloys have been found to exhibit superior mechanical properties as compared to the conventional aerospace aluminum alloys in terms of high strength, high modulus, low density, good corrosion resistance and fracture toughness at cryogenic temperatures. Even though they do not form low-melting eutectics during fusion welding, there are still problems like porosity, solidification cracking, and loss of lithium. This is why solid state friction stir welding is important in this alloy. It is known that using Al-Cu-Li alloy and friction stir welding to super lightweight external tank for space shuttle, significant weight reduction has been achieved. The objective of this paper is to investigate the effect of friction stir tool rotation speed on mechanical and microstructural properties of Al-Cu-Li alloy. The plates were joined with friction stir welding process using different tool rotation speeds (300-800 rpm) and welding speeds (120-420 mm/min), which are the two prime welding parameters in this process.

Investigation of Vibration Assisted Friction Stir Welding

2012 ◽  
Vol 504-506 ◽  
pp. 741-746 ◽  
Author(s):  
Hamid Montazerolghaem ◽  
Mohsen Badrossamay ◽  
Alireza Fadaei Tehrani
Keyword(s):  
Friction Stir Welding ◽  
Axial Force ◽  
Process Condition ◽  
Welding Process ◽  
High Strength ◽  
State Spaces ◽  
Friction Stir ◽  
Fsw Simulation ◽  
Resultant Forces ◽  
Welding Force

Friction Stir Welding (FSW) is a relatively new solid state joining method that can be used to achieve very good weld quality. This technique is energy efficient, environment friendly, and versatile. The FSW process utilizes a rotating tool in which includes a pin and shoulder to perform the welding process. FSW applications in high strength alloys, such as stainless steel remain limited due to large welding force and consequent tool wear. It has been shown that applying the ultrasonic vibration on some processes such as turning and drilling the resultant forces are decreased and process condition is improved. In this paper the influence of applying vibration on FSW is investigated in simulating tools. For FSW modeling a proper transfer function of axial force has been proposed. The resultant axial force of conventional FSW and Vibration Assisted FSW (VAFSW) are compared in frequency and time domain state spaces. A good correlation between FSW simulation and experiments is observed. For further investigation of VAFSW the response surface of design of experiment (DOE) method is utilized. The influence of changing VAFSW process parameters is investigated. The simulation results indicate that vibration helps to decrease the welding force. Using DOE method the effects of implemented frequency and vibration speed amplitude in FSW are found.

Numerical Simulations of Friction Stir Welding Process and Subsequent Post Weld Cold Rolling Process

2009 ◽  
Vol 419-420 ◽  
pp. 433-436 ◽  
Author(s):  
Yu Jie Sun ◽  
Yong Zang ◽  
Qing Yu Shi
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Three Dimensional ◽  
Welding Process ◽  
Rolling Process ◽  
Mechanical Analysis ◽  
Fusion Welding ◽  
Work Piece ◽  
Friction Stir ◽  
Longitudinal Residual Stress

A sequential coupled three-dimensional thermo-mechanical analysis was conducted first to simulate friction stir welding (FSW) of aluminum alloy. In thermal analysis, the model included adaptive heat source, contact heat transfer both between work piece and clamps and between work piece and backing board etc; in the mechanical analysis, the model involved contact interaction both between work piece and clamps and between work piece and backing board, mechanical load of tool etc. The simulation results indicate that the longitudinal residual stress is unsymmetrical about weld centerline; the magnitude of longitudinal residual stress for FSW process is lower than that for fusion welding process. Based on simulated results of FSW process, a three-dimensional elastic-plastic analysis was then carried out to simulate rolling process, the simulation result show that rolling process not only causes a marked reduction in the longitudinal tensile residual but also reverse the sign of the longitudinal residual stress.

scholarly journals Effect of Shoulder–Workpiece Interference Depth on the Quality of Friction Stir Welding of AA7075-T6 Aluminium Alloy

2019 ◽  
Vol 26 (1) ◽  
pp. 150-159
Author(s):  
Abbas Akram Abbas ◽  
Hazim H. Abdulkadhum
Keyword(s):  
Friction Stir Welding ◽  
Aluminium Alloy ◽  
Welding Process ◽  
High Strength ◽  
Filling Defect ◽  
Welding Quality ◽  
Left Hand ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Welding Surface

The joining of high strength aluminium alloy AA7075-T6 sheets of 3 mm thickness was an attempt utilizing friction stir welding process. The effect of interference depth between tool shoulder and surface workpiece on the welding quality and its effect on the mechanical and metallography properties of welded joints were studied. This process is carried out using a composite tool consists of a concave shoulder made of H13 tool steel and cylindrical left-hand thread with 1mm pitch pin (probe) made of cobalt-based alloy MP159. The dimensions of tools were 14mm shoulder diameter and the pin has 5mm diameter and 2.7mm length. The tool rotation speed and welding speed were 981 rpm 169 mm/min respectively, and the tilt angle was 2°. The range of interference depth between the shoulder and workpiece was selected (0.05, 0.1, 0.15, 0.2, 0.25, and 0.3) mm. various tests were executed to evaluate the welding quality. The results show that lack of filling defect appeared on the welding surface at the interference depth 0.05 mm. An invisible tunnel and lack of penetration in the bottom of the stir zone appeared when the interference depths were 0.1 mm and 0.15 mm. Defect-free welds obtained when interference depths were (0.2, 0.25, and 0.3) mm. The welding efficiency of the defect-free welds was in the range (85.3-92.3%) depending on the ultimate tensile strength of the parent alloy.

scholarly journals Temperature fields in linear stage of friction stir welding: Effect of different material properties

2019 ◽  
Vol 23 (6 Part B) ◽  
pp. 3985-3992
Author(s):  
Darko Veljic ◽  
Marko Rakin ◽  
Bojan Medjo ◽  
Mihailo Mrdak ◽  
Aleksandar Sedmak
Keyword(s):  
Friction Stir Welding ◽  
Numerical Models ◽  
Welding Process ◽  
High Strength ◽  
Temperature Fields ◽  
Arbitrary Lagrangian Eulerian ◽  
Friction Stir ◽  
Strain And Strain Rate ◽  
The Difference ◽  
Weld Area

Friction stir welding is one of the procedures for joining the parts in solid state. Thermo-mechanical simulation of the friction stir welding of high-strength aluminium alloys 2024 T3 and 2024 T351 is considered in this work. Numerical models corresponding to the linear welding stage are developed in Abaqus software package. The material behaviour is modelled by Johnson-Cook law (which relates the yield stress with temperature, strain and strain rate), and the Arbitrary Lagrangian-Eulerian technique is applied. The difference in thermo-mechanical behaviour between the two materials has been analysed and commented. The main quantities which are considered are the temperature in the weld area, plastic strain, as well as the rate of heat generation during the welding process.

scholarly journals Influence of Tool Pin Profile and Tool Rotating Speed on Mechanical Properties of Al6082 Alloy

2019 ◽  
Vol 8 (12) ◽  
pp. 3342-3345
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Welding Process ◽  
Automatic Process ◽  
Work Piece ◽  
Milling Machine ◽  
Friction Stir ◽  
Vertical Milling ◽  
Vertical Milling Machine ◽  
Tool Pin

Friction stir welding is a solid state welding which uses non consumable welding tool. It is an automatic process which generally performs on the vertical milling machine. In this type of welding, the relative motion between the tools and work piece creates heat which uses the region of work piece to be welded get softened and to joint the two work pieces. Friction stir welding process is more reliable for the materials which are generally non heat treatable. In this present investigation it will observe that how the rotational speeds of the tool and different shapes of the tool pins effects the mechanical properties of the aluminium alloy 6082. For this purpose three tools with different profiles, i.e triangular, cylindrical and square was designed and fabricated. At three different rotational speeds of 560 rpm, 900 rpm, 1800 rpm work pieces are joined using vertical milling machine. Specimens are prepared and tested for mechanical properties, tensile, impact, and hardness tests are performed and to detect the defects and voids x-ray test performed on the weld joints. And it was observed that highest tensile strength was presented when the square pin tool used at 560 rpm. The rotational speed increased mechanical properties are reducing significantly.

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