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 HARDNESS AND TENSILE BEHAVIOR OF FRICTION STIR WELDED ALUMINUM AA6351 ALLOY

2014 ◽  
Vol 44 (1) ◽  
pp. 23-26
Author(s):  
G. Gopala Krishna ◽  
P. Ram Reddy ◽  
M. Manzoor Hussain
Keyword(s):  
Friction Stir Welding ◽  
Solid State ◽  
Rolling Direction ◽  
Welding Process ◽  
Fusion Welding ◽  
Frictional Heat ◽  
Work Piece ◽  
Friction Stir ◽  
Superior Mechanical Properties ◽  
Transverse Weld

Friction Stir Welding (FSW) is a solid state welding process gaining more applications in various industries due to better quality of the joint as it has no effect on parent metal. In FSW process a non consumable rotating welding tool is used to generate frictional heat between tool and abutting surface of work piece and plastic dissipation of energy to accomplish the weld. Being a solid state joining process, friction stir welding process offers various advantages like low distortion, absence of melt related defects, high joint strength etc. as compared to other conventional fusion welding techniques.Experiments were conducted on 6 mm thickness Aluminum AA6351-T4, commercially available plates. The seplates are joined by FSW along the rolling direction (longitudinal weld orientation) and across the rolling direction (transverse weld orientation). The hardness and tensile strength results of the weldments are presented. Results show superior mechanical properties for the joints with plates along the rolling direction as compared with the joints obtained by across the rolling direction.DOI: http://dx.doi.org/10.3329/jme.v44i1.19494

scholarly journals Effect of Trailing Intensive Cooling on Residual Stress and Welding Distortion of Friction Stir Welded 2060 Al-Li Alloy

2018 ◽  
Vol 37 (5) ◽  
pp. 397-403 ◽  
Author(s):  
Shude Ji ◽  
Zhanpeng Yang ◽  
Quan Wen ◽  
Yumei Yue ◽  
Liguo Zhang
Keyword(s):  
Residual Stress ◽  
Friction Stir Welding ◽  
Plastic Strain ◽  
Welding Process ◽  
Butt Joint ◽  
Welding Distortion ◽  
Welding Temperature ◽  
Friction Stir ◽  
Numerical Simulation Methods ◽  
Conventional Cooling

AbstractTrailing intensive cooling with liquid nitrogen has successfully applied to friction stir welding of 2 mm thick 2060 Al-Li alloy. Welding temperature, plastic strain, residual stress and distortion of 2060 Al-Li alloy butt-joint are compared and discussed between conventional cooling and trailing intensive cooling using experimental and numerical simulation methods. The results reveal that trailing intensive cooling is beneficial to shrink high temperature area, reduce peak temperature and decrease plastic strain during friction stir welding process. In addition, the reduction degree of plastic strain outside weld is smaller than that inside weld. Welding distortion presents an anti-saddle shape. Compared with conventional cooling, the reductions of welding distortion and longitudinal residual stresses of welding joint under intense cooling reach 47.7 % and 23.8 %, respectively.

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.

Process - Property Correlation of Friction Stir Welding of Marine Grade Aluminium Alloy 5083 Using Finite Element Analysis

2021 ◽  
Vol 163 (A2) ◽  
Author(s):  
M Sahu ◽  
A Paul ◽  
S Ganguly
Keyword(s):  
Mechanical Properties ◽  
Residual Stress ◽  
Finite Element ◽  
Friction Stir Welding ◽  
Residual Stresses ◽  
Process Variables ◽  
Friction Stir ◽  
Stress Region ◽  
Longitudinal Residual Stress ◽  
Process Property

In this article, a 3D finite element based thermo-mechanical model for friction stir welding (FSW) of a marine-grade aluminium alloy 5083 is proposed. The model demonstrates the thermal evaluation and the distribution of residual stresses and strains under the variation of process variables. The temperature profile of the weld joint during the FSW process and the mechanical properties of the joints are also experimentally evaluated. The necessary calibration of the model for the correct implementation of the thermal loading, mechanical loading, and boundary conditions was performed using the experimental results. The model simulation and experimental results are analyses in view of the process-property correlation study. The residual stress was evaluated along, and across the weld, centreline referred as longitudinal and transverse residual stresses, respectively. The magnitude of longitudinal residual stress is noted 60-80% higher than that of the transverse direction. The longitudinal residual stress generated a tensile oval shaped stress region around the tool shoulder confined to a maximum distance of about 25mm from the axis of the tool along the weld line. It encompasses the weld-nugget to thermo-mechanically affected zone (TMAZ), while the parent metal region is mostly experiences the compressive residual stresses. However, the transverse residual stress region appears like wing shaped region spread out in both the advancing and retreating side of the weld and occupying approximately double the area as compared to the longitudinal residual stresses. Overall, the study revealed a corelation between the FSW process variables such as welding speed and the tool rotational speed with the residual stress and the mechanical properties of the joint.

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.

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.

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.

Computational Analysis on Weld Formation Mechanism during Self-Reacting Friction Stir Welding

2020 ◽  
pp. 1-15
Author(s):  
Chenyu Zhao ◽  
Xun Liu
Keyword(s):  
Boundary Condition ◽  
Shear Stress ◽  
Friction Stir Welding ◽  
Shear Layer ◽  
Formation Mechanism ◽  
Fluid Model ◽  
Three Dimensional ◽  
Welding Process ◽  
Weld Formation ◽  
Friction Stir

Abstract Three-dimensional computational fluid dynamics models are developed to understand physical principles of self-reacting friction stir welding process. A novel approach of predicting the weld microstructure based on plastic strain distribution at cross-section behind the tool is proposed and verified with experimental results. Limitations and credibility of shear stress and velocity tool/workpiece boundary condition are evaluated from the perspective of the weld formation mechanism. The importance of the shear layer and its sticking/sliding transition state in weld formation mechanism is emphasized. From modeling perspective, shear stress boundary, which only represents a sliding condition, neglects the movement and effects of this shear layer. When shear layer is formed, due to the velocity discontinuity which could not be captured in fluid model, velocity boundary condition, which represents an averaging effect of sticking/sliding transition between tool and shear layer, is needed.

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