Friction Stir Welding of Tailored Blanks of Aluminum and Magnesium Alloys

2013 ◽  
Vol 549 ◽  
pp. 492-499 ◽  
Author(s):  
Jean Pierre Bergmann ◽  
René Schürer ◽  
Kevin Ritter
Keyword(s):  
Friction Stir Welding ◽  
Magnesium Alloys ◽  
Welding Process ◽  
Intermetallic Phases ◽  
Fusion Welding ◽  
Tool Geometry ◽  
Process Variables ◽  
Friction Stir ◽  
Tailored Blanks ◽  
Aluminum And Magnesium Alloys

The following paper describes a feasibility study of butt joining friction stir welding between aluminum alloy AA6016 and magnesium alloys AZ91 and AM50. Because of the variety of inimitable properties according to lightweight design and constructions, the interest in aluminum and magnesium alloys is increasing in many fields of industry. Due to the low solubility of aluminum in magnesium and inverse, these alloys tend to the formation of intermetallic phases during the joining process. This leads to an increasing micro hardness within the seam, which should be avoided. By the use of joining methods with low process temperatures, the formation of intermetallic phases is reduced. According to this circumstance, friction stir welding is an excellent alternative to fusion welding techniques used to join this alloys. The main welding process variables were exposed in the studies of similar butt joints of Al/Al and Mg/Mg. These were examined in connection to their transferability to the dissimilar joints and tailored blanks. Furthermore, the influence of different tool geometry on seam quality was investigated. The effect of process variables (mainly welding speed and revolution speed) were correlated to the results of tensile strength test. The welded samples were assayed in the presence of intermetallic phases.

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.

scholarly journals The Effects of In-Process Cooling during Friction Stir Welding of 7475 Aluminium Alloy

2021 ◽  
Vol 50 (9) ◽  
pp. 2743-2754
Author(s):  
Ashish Jacob ◽  
Sachin Maheshwari ◽  
Arshad Noor Siddiquee ◽  
Abdulrahman Al-Ahmari ◽  
Mustufa Haider Abidi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Welded Joints ◽  
Positive Impact ◽  
Welding Process ◽  
Fusion Welding ◽  
Friction Stir ◽  
Cooling Conditions ◽  
Zero Degree ◽  
Welding Technique

Certain age hardenable alloys such as AA7475 cannot be joined with perfection using fusion welding techniques. This requires non-conventional welding technique such as friction stir welding process to join these ‘difficult to weld’ alloys. In this study, three different cooling conditions i.e. cryogenic, sub-zero, and zero-degree Celsius temperature conditions have been analyzed to understand its impact on the welding process. In-process cooling was found to behave effectively and also enhanced the mechanical properties of the welded joints. A stable microstructure was clearly seen in the images observed under the metallurgical microscope. The weld efficiencies were found to be good in each of the samples which are indicative of a strong metallic joint. The effective cooling conditions employed had an overall positive impact on the joint.

Friction Stir Welding of Aluminum 6061-T6 and Multi-Purpose Copper 11000 Alloy

2017 ◽  
Author(s):  
Lewis N. Payton
Keyword(s):  
Friction Stir Welding ◽  
Copper Alloy ◽  
Tangential Velocity ◽  
Nuclear Industry ◽  
Fusion Welding ◽  
Alternative Methods ◽  
Friction Stir Weld ◽  
Tool Geometry ◽  
Work Piece ◽  
Friction Stir

Friction Stir Welding (FSW) is a solid-state joining process invented by The Welding Institute (TWI, United Kingdom) in 1991 in partnership with the National Aeronautics Space Agency. The process is emerging as one of the preferred alternative methods to permanently join materials that are difficult to join with traditional fusion methods (e.g., MIG, TIG, etc.). The welding of various copper alloys to various aluminum alloys is of great interest to the nuclear industry and the electrical distribution industry. The very different melting points of these two alloys preclude traditional fusion welding. Since the pin tool is simultaneously rotating and traversing through the work piece, flow around the tool is asymmetrical. This has led to designating one side of the tool as advancing and the opposite side as retreating. On the advancing side of the weld, the tool has a tangential velocity in the same direction as the weld is being created. The retreating side of the weld tool is the opposite. It can be can expected that asymmetric heating and deformation will occur in the weld due to this advancing/retreating nature of the FSW pin tool. Although previous studies have been performed that have observed this asymmetric behavior in both similar and dissimilar materials, the resulting welds have been of a poor quality. Large statistical experiments were conducted locally to study the effects of tool geometry, process parameters, and material composition have upon the friction stir butt welding of aluminum alloy 6061-T6 to copper alloy 11000 using a modern conventional 3-axis CNC vertical mill. The research seeks to determine (1) which direction a dissimilar metal friction stir weld between aluminum and copper should be executed, (2) the optimal shoulder diameter to be used when friction stir welding aluminum and copper on a CNC mill, and (3) the addition of a third material to act as an aide. The extensive statistical interactions between these parameters is also documented. A weld schedule was developed that resulted in an ultimate tensile strength (UTS) surpassing (greater than 90% of the weaker, more ductile copper alloy UTS strength) what has been documented in the current literature despite the machine limitations of the CNC vertical mill. Proper optimization of the welding schedule developed may approach 100 percent of the basic copper 11000 properties across the welded zone into the aluminum 6061-T6 alloy.

Computer Aided Design of an Effective Fixture for FSW Processes of Titanium Alloys

2011 ◽  
Vol 473 ◽  
pp. 304-309
Author(s):  
Gianluca Buffa ◽  
Livan Fratini
Keyword(s):  
Titanium Alloys ◽  
Computer Aided Design ◽  
Welding Process ◽  
Optimal Solution ◽  
Fusion Welding ◽  
Material Behavior ◽  
Viscoplastic Material ◽  
3D Fem ◽  
Friction Stir ◽  
Aluminum And Magnesium Alloys

During the last years welded titanium components have been extensively applied in aeronautical and aerospace industries because of their high specific strength and corrosion resistance properties. Friction Stir Welding (FSW) is a solid state welding process, currently industrially utilized for difficult to be welded or “unweldable” aluminum and magnesium alloys, able to overcome the drawbacks of traditional fusion welding techniques. When titanium alloys are concerned, additional problems arise as the need for very high strength and high temperature resistant tools, gas shield protection and high stiffness machines. Additionally, the process is characterized by an elevated sensitivity to temperature variations, which, in turn, depends on the main operative parameters. Numerical simulation represents the optimal solution in order to perform an effective process optimization with affordable costs. In this paper, a fully 3D FEM model for the FSW process is proposed, that is thermo-mechanically coupled and with rigid-viscoplastic material behavior. Experimental clamping parts are modeled and the thermal loads are calculated at the varying of the cooling strategy. Finally, the effectiveness of the cooling systems is evaluated through experimental tests.

scholarly journals Friction stir welding of Aluminium matrix composites – A Review

2018 ◽  
Vol 144 ◽  
pp. 03002 ◽  
Author(s):  
Prabhu Subramanya ◽  
Murthy Amar ◽  
Shettigar Arun ◽  
Herbert Mervin ◽  
Rao Shrikantha
Keyword(s):  
Friction Stir Welding ◽  
Welding Process ◽  
Fusion Welding ◽  
Aluminium Matrix ◽  
Future Research ◽  
Matrix Composites ◽  
Aluminium Matrix Composites ◽  
Friction Stir ◽  
Tool Profiles ◽  
Welding Technique

Friction stir welding (FSW) is established as one of the prominent welding techniques to join aluminium matrix composites (AMCs). It is a solid state welding process, takes place well below the melting temperature of the material, eliminates the detrimental effects of conventional fusion welding process. Although the process is capable to join AMCs, challenges are still open that need to be fulfill to widen its applications. This paper gives the outline of the friction stir welding technique used to join AMCs. Effect of process variables on the microstructure and mechanical properties of the joints, behavior of reinforcing materials during welding, effect of tool profiles on the joint strength are discussed in detail. Few improvements and direction for future research are also proposed.

Effect of Tool pin Profile and Axial Force on Tensile Behavior in Friction Stir Welding of Dissimilar Aluminum Alloys

2011 ◽  
Vol 415-417 ◽  
pp. 1140-1146 ◽  
Author(s):  
R. Palanivel ◽  
P. Koshy Mathews ◽  
M. Balakrishnan ◽  
I. Dinaharan ◽  
N. Murugan
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Axial Force ◽  
Aluminium Alloys ◽  
Welding Process ◽  
Fusion Welding ◽  
Friction Stir ◽  
Tool Pin Profile ◽  
Dissimilar Aluminum Alloys ◽  
Tool Pin

Aluminium alloys generally has low weldability by traditional fusion welding process. The development of the Friction Stir Welding (FSW) has provided an alternative improved way of producing aluminium joints, in a faster and reliable manner. FSW process has several advantages, in particular the possibility to weld dissimilar aluminium alloys. This study focuses on the behavior of tensile strength of dissimilar joints of AA6351-T6 alloy to AA5083-H111 alloy produced by friction stir welding was analysed. Five different tool pin profile such as Straight Square (SS), Tapered Square (TS), Straight Hexagon (SH), Straight Octagon (SO) and Tapered Octagon (TO) with three different axial force (1tonne, 1.5tonne, 2 tonne) have been used to weld the joints. The effect of pin profiles and axial force on tensile properties and material flow behaviour of the joint was analyzed and it was found that the straight square pin profile with 1.5 tonne produced better tensile strength then other tool pin profile and axial force.

Numerical Study of the Tool Rake Angle Effect on the Material Flow in Friction Stir Welding Process

2007 ◽  
Author(s):  
Hosein Atharifar ◽  
Radovan Kovacevic
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Numerical Study ◽  
Welding Process ◽  
Rake Angle ◽  
Heat Transfer Analysis ◽  
Tool Geometry ◽  
Friction Stir ◽  
Tool Pin ◽  
Welding Processes

Minimizing consumed energy in friction stir welding (FSW) is one of the prominent considerations in the process development. Modifications of the FSW tool geometry might be categorized as the initial attempt to achieve a minimum FSW effort. Advanced tool pin and shoulder features as well as a low-conductive backing plate, high-conductive FSW tools equipped with cooling fins, and single or multi-step welding processes are all carried out to achieve a flawless weld with reduced welding effort. The outcomes of these attempts are considerable, primarily when the tool pin traditional designs are replaced with threaded, Trifiute or Trivex geometries. Nevertheless, the problem remains as to how an inclined tool affects the material flow characteristics and the loads applied to the tool. It is experimentally proven that a positive rake angle facilitates the traverse motion of the FSW tool; however, few computational evidences were provided. In this study, numerical material flow and heat transfer analysis are carried out for the presumed tool rake angle ranging from −4° to 4°. Afterwards, the effects of the tool rake angle to the dynamic pressure distribution, strain-rates, and velocity profiles are numerically computed. Furthermore, coefficients of drag, lift, and side force and moment applied to the tool from the visco-plastic material region are computed for each of the tool rake angles. Eventually, this paper confirms that the rake angle dramatically affects the magnitude of the loads applied to the FSW tool, and the developed advanced numerical model might be used to find optimum tool rake angle for other aluminum alloys.

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.

Numerical Simulation of Friction Stir Welding of Aluminum Alloys: A Brief Review

2015 ◽  
Vol 809-810 ◽  
pp. 467-472
Author(s):  
Marius Adrian Constantin ◽  
Ana Boşneag ◽  
Monica Iordache ◽  
Eduard Niţu ◽  
Doina Iacomi
Keyword(s):  
Numerical Simulation ◽  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Copper Alloys ◽  
Tool Geometry ◽  
Friction Stir ◽  
Complex Process ◽  
Scientific Papers ◽  
Fsw Simulation ◽  
Aluminum And Magnesium Alloys

Friction Stir Welding (FSW) is the latest innovative and most complex process which is widely applied to the welding of lightweight alloys, such as aluminum and magnesium alloys, and most recently, titanium alloys, copper alloys, steels and super-alloys. Friction stir welding is a highly complex process comprising several highly coupled physical phenomena. The experiments are often time consuming and costly. To overcome these problems, numerical analysis has frequently been used in the last ten years. In this paper is presented a brief review of scientific papers in recent years on numerical simulation of Friction Stir Welding of aluminum alloys. The main elements analyzed by FSW simulation, and briefly in this paper are: temperature and residual stress distribution; work tool geometry (size and shape of the pin); distribution of equivalent plastic deformation; main areas resulted after welding; distribution of microstructure (grain size); parameters and optimization of the FSW process.

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