Measurement of Tool-Workpiece Interface Temperature Distribution in Friction Stir Welding

2014 ◽  
Vol 136 (2) ◽  
Author(s):  
Axel Fehrenbacher ◽  
Joshua R. Schmale ◽  
Michael R. Zinn ◽  
Frank E. Pfefferkorn
Keyword(s):  
Friction Stir Welding ◽  
Temperature Distribution ◽  
Process Control ◽  
Model Verification ◽  
Interface Temperature ◽  
Transfer Model ◽  
Friction Stir ◽  
Dynamic Temperature ◽  
Tool Pin ◽  
Welding Processes

The objective of this work is to develop an improved temperature measurement system for friction stir welding (FSW). FSW is a solid-state joining process enabling welds with excellent metallurgical and mechanical properties, as well as significant energy consumption and cost savings compared to traditional fusion welding processes. The measurement of temperatures during FSW is needed for process monitoring, heat transfer model verification and process control, but current methods have limitations due to their restricted spatial and temporal resolution. Previous work showed that temperatures at the tool shoulder-workpiece interface can be measured and utilized for closed-loop control of temperature. Adding an additional thermocouple at the tool pin-workpiece interface and performing a calibration of the measurement to gain better insight into the temperature distribution in the weld zone improved the method. Both thermocouples were placed in through holes right at the interface of tool so that the sheaths are in direct contact with the workpiece material. This measurement strategy reveals dynamic temperature variations at the shoulder and the pin within a single rotation of the tool in real-time. It was found that the highest temperatures are at the shoulder interface between the advancing side and the trailing edge of the tool, closer to the advancing side. The temperature distribution was mostly affected by travel speed and the temperature difference within one tool rotation was found to be between 10 °C and 50 °C, depending on the process parameters. The dynamic temperature measurements obtained with the current system are of unmatched resolution, fast, and reliable and are likely to be of interest for both fundamental studies and process control of FSW.

Tool-Workpiece Interface Temperature Measurement in Friction Stir Welding

2012 ◽  
Author(s):  
Axel Fehrenbacher ◽  
Joshua R. Schmale ◽  
Michael R. Zinn ◽  
Frank E. Pfefferkorn
Keyword(s):  
Heat Transfer ◽  
Friction Stir Welding ◽  
Process Control ◽  
Temperature Measurement ◽  
Weld Zone ◽  
Model Verification ◽  
Phase Lag ◽  
Weld Quality ◽  
Friction Stir ◽  
Dynamic Temperature

The objectives of this work are to develop an improved temperature measurement system for Friction Stir Welding (FSW). FSW is a novel joining technology enabling welds with excellent metallurgical and mechanical properties, as well as significant energy consumption and cost savings compared to traditional fusion welding processes. The measurement of temperatures during FSW is employed for process monitoring, heat transfer model verification and process control, but current methods have limitations due to their restricted spatial and temporal resolution and have found only few industrial applications so far. Thermocouples, which are most commonly used, are either placed too far away from the weld zone or are destructively embedded into the weld path, and therefore fail to provide suitable data about the dynamic thermal phenomena at the tool-workpiece interface. Previous work showed that temperatures at the tool shoulder-workpiece interface can be measured and utilized for closed-loop control of temperature. The method is improved by adding an additional thermocouple at the tool pin-workpiece interface to gain better insight into the temperature distribution in the weld zone. Both thermocouples were placed in through holes right at the interface of tool and workpiece so that the sheaths are in contact with the workpiece material. This measurement strategy reveals dynamic temperature variations at the shoulder and the pin within a single rotation of the tool in real-time. Due to the thermocouple’s limited response time and inherent delays due to physical heat conduction, the temperature response is experiencing attenuation in magnitude and a phase lag. Heat transfer models were constructed to correct for this issue. It was found that the highest temperatures are between the advancing side and the trailing edge of the tool. Further work is needed to increase the accuracy of the correction. Experimental results show that the weld quality is sensitive to the measured interface temperatures, but that temperature is not the only factor influencing the weld quality. The dynamic temperature measurements obtained with the current system are of unmatched resolution, fast and reliable and are likely to be of interest for both fundamental studies and process control of FSW.

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.

scholarly journals Numerical Studies on Temperature and Material Flow During Friction Stir Welding using Different Tool Pin Profiles

2021 ◽  
Vol 83 (1) ◽  
pp. 91-104
Author(s):  
M. D. Bindu ◽  
P. S. Tide ◽  
A. B. Bhasi
Keyword(s):  
Friction Stir Welding ◽  
Temperature Distribution ◽  
Material Flow ◽  
Three Dimensional ◽  
Friction Stir ◽  
Specific Strength ◽  
Numerical Studies ◽  
Computational Fluid Dynamics Cfd ◽  
Tool Pin ◽  
Metal Hardness

A three dimensional computational fluid dynamics (CFD) model has been developed to study the effect of tool pin profile on the material flow and temperature development in friction stir welding (FSW) of high specific strength AA 7068 alloy. Numerical simulations were carried out using a RNG k-e turbulence model. Three tool pin profiles, viz. cylindrical, conical and straight cylindrical threaded were considered for the simulation. The temperature distribution and material flow pattern obtained from the simulation were compared for different pin profiles. Simulation results predicted Temperature distribution and material maxing was better in straight cylindrical tapered thread pin welds. Weld joints were fabricated using the straight cylindrical threaded pin with the same parametric combinations as in the simulation. Peak temperature measured in the experiment was less than that obtained by simulation. Hardness measurements taken at different weld regions has showed that about 71% of that of the base metal hardness is obtained with the threaded tool pin. The microstructure study revealed a defect free weld joint. Precipitates distributed in the microstructure indicate sufficient heat input to join the material without dissolving precipitates. The developed numerical model is helpful in optimising FSW process parameters.

A thermal-plastic model of friction stir welding in aluminum alloy

2017 ◽  
Vol 24 (3) ◽  
pp. 439-446
Author(s):  
Zhang Peilei ◽  
Yan Hua ◽  
Li Chonggui ◽  
Yu Zhishui ◽  
Lu Qinghua
Keyword(s):  
Plastic Deformation ◽  
Friction Stir Welding ◽  
Three Dimensional ◽  
Transfer Model ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Moving Coordinate ◽  
Model Of Friction ◽  
Tool Pin ◽  
Good Agreement

AbstractA three-dimensional heat transfer model for friction stir welding is presented in this paper. A moving coordinate was introduced to reduce the difficulty of modeling the moving tool. Heat input from the tool shoulder and the tool pin were considered in the model. The plastic deformation heat was introduced into the model, too. It is clear that the heat production increased owing to plastic deformation, and this process depends on the stress level. Temperature measurement experiments were done to validate the calculated results. The calculated results were in good agreement with the experimental results. Preheating the workpiece is beneficial to obtain a good weld seam.

System Identification Based Controller Design for Friction Stir Welding Process During Joining of Aluminium Metal Matrix Composites

2020 ◽  
Vol 17 (7) ◽  
pp. 3293-3311
Author(s):  
S. G. Rahul ◽  
S. Kripa ◽  
R. Chitra
Keyword(s):  
Friction Stir Welding ◽  
System Identification ◽  
Process Parameters ◽  
Metal Matrix ◽  
Spindle Speed ◽  
Smith Predictor ◽  
Interface Temperature ◽  
Friction Stir ◽  
Tool Pin ◽  
Aluminium Metal

Friction Stir Welding (FSW) process was initially implemented by modifying the milling machines. With the advancements in robotics and automation, movement along three primary axes are made controllable using computer integration. FSW being a temperature-dependent process, the temperature at the weld zone affects the weld quality since the microstructure is totally altered by the temperature variations. If welding is done at constant process parameters by ignoring the process disturbances, it would also result in undesirable material properties. From research studies, it is understood that tool pin position and spindle speed are significant process parameters contributing to heat generation during the joining process. In this study, an attempt is made to control the spindle speed of the rotating tool by measuring tool-workpiece interface temperature and vibrational disturbances during joining of Aluminium Metal Matrix Composite (Al-MMC) plates. The system model is estimated from the experimental data using the concept of system identification. Followed by, a Smith Predictor control scheme is developed and validated in a closed loop FSW system to examine the tensile strength.

Analytical Modeling and Analysis of the Matter Flow during Friction Stir Welding

2019 ◽  
Vol 297 ◽  
pp. 1-16
Author(s):  
Zineelabidine Harchouche ◽  
Mokhtar Zemri ◽  
Abdelkader Lousdad
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Solid Phase ◽  
Welding Process ◽  
Computational Time ◽  
Modeling And Analysis ◽  
Friction Stir ◽  
Tool Pin ◽  
Welding Processes ◽  
Matter Flow

Friction stir welding is a solid-phase welding process based on the mixing of the pasty material in the stirred zone. The main advantage of this technique is the ability to weld metal alloys which are generally difficult to weld by conventional welding processes. In this paper an analytical model is proposed for the description in 2D the distribution of the material (fluid) flow in the vicinity of the tool pin during friction stir welding process "FSW". For this reason, the analytical solutions are built on the basis of traditional problem of mechanics of the fluids which is used to solve the equation associated with this problem. Furthermore, the aim is to make an analytical study of these aspects for a better understanding of this phenomenon. This method provides a reduction in computational time compared to those required for finite or differential elements methods. Moreover, it highlights on the effects of the different parameters on the material flow during welding.

scholarly journals Effect of tool pin side area ratio on temperature distribution in friction stir welding

2019 ◽  
Vol 15 ◽  
pp. 102814 ◽  
Author(s):  
A.M. Sadoun ◽  
A. Wagih ◽  
A. Fathy ◽  
A.R.S. Essa
Keyword(s):  
Friction Stir Welding ◽  
Temperature Distribution ◽  
Area Ratio ◽  
Friction Stir ◽  
Tool Pin

A Study of Material Flow Behavior in Thickness Direction in Friction Stir Welding of 7075 Alloy Plate

2013 ◽  
Vol 652-654 ◽  
pp. 2315-2319
Author(s):  
Zheng Hua Guo ◽  
Wen Long Liu ◽  
Cheng Zhong Li ◽  
Jun Hua Cui ◽  
Gang Yao Zhao
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Rotation Speed ◽  
Flow Behavior ◽  
Dissimilar Materials ◽  
Thickness Direction ◽  
Alloy Plate ◽  
Friction Stir ◽  
Tool Pin ◽  
Welding Processes

Friction stir welding, which is considered to be a solid-state welding, possesses several advantages over conventional welding processes, is an effective approach to weld high-strength, large thickness and dissimilar materials. Material flow behavior on FSW was generally acknowledged to have effects on weld property. The material flow behavior in thickness direction of advancing and retreating side was analyzed by a numerical model established with cone-shape tool pin. Numerical results indicate that there exist material flow in thickness direction on both sides and the behavior was affected by welding and tool pin rotation speed. Decrease welding speed or increase rotation speed would make material deformation intensified, and increase the fluidity of the material.

Analysis of the Temperature Distribution in Friction Stir Welding Using the Finite Element Method

2013 ◽  
Vol 758 ◽  
pp. 11-19 ◽  
Author(s):  
Mauricio Rangel Pacheco ◽  
Pedro Manuel Calas Lopes Pacheco
Keyword(s):  
Finite Element ◽  
Friction Stir Welding ◽  
Temperature Distribution ◽  
Plastic Strain ◽  
Heat Source ◽  
Translational Motion ◽  
Welding Process ◽  
Welding Parameters ◽  
Friction Stir ◽  
Welding Processes

Welding is a fabrication process widely used in several industrial areas. The welding of metallic alloys presents some basic characteristics as the presence of a localized intensive heat input that promotes mechanical and metallurgical changes. Different from conventional welding processes, where macroscopic fusion is observed, friction welding is a solid state welding process where the joint is produced by the relative rotational and/or translational motion of two pieces under the action of compressive forces producing heat and plastic strain on the friction surfaces. Friction Stir Welding (FSW) process has received much attention for its special characteristics, like the high quality of the joints. Although there are several experimental works on the subject, numerical modeling is not well stated, as the process is very complex involving the coupling of several non-linear phenomena. In this contribution a tridimensional finite element model is presented to study the temperature distribution in plates welded by the FSW process. A weld heat source is proposed to represent the heat generated during the process. The heat source model considers several contributions present in the process as the friction between the tool and the piece and the plastic power associated to the plastic strain developed. Numerical results show that the model is in close agreement with experimental results, indicating that the model is capable of capturing the main characteristics of the process. The proposed model can be used to predict important process characteristics, like the TAZ (Thermal Affected Zone), as a function of the welding parameters.

scholarly journals Optimal Parameter Determination on Friction Stir Welding Process of AA6061 using Grey Taguchi Method

2019 ◽  
Vol 8 (2S3) ◽  
pp. 46-50
Keyword(s):  
Friction Stir Welding ◽  
Taguchi Method ◽  
Fatigue Behavior ◽  
Welding Process ◽  
Parameter Determination ◽  
Friction Stir ◽  
Friction Stir Welding Process ◽  
Tool Pin ◽  
Welding Processes ◽  
Taguchi Orthogonal Design

The Friction Stir Welding (FSW) process is an innovative technique to join metals in the plasticity field, thus not reaching the melting temperature and consequently the liquid state as it happen in traditional welding processes. This feature of the FSW proved an enhancement of the fatigue behavior and strength of the joints, leading some companies to adopt the process for the manufacturing of airplanes fuselages and cryogenic tanks for Space launch vehicles. The ultimate goal of this paper is to determine the optimal influencing parameter of Friction Stir welding process using Taguchi method of optimization. Here we used L9 Taguchi orthogonal design for designing the experiment. Three major controllable parameters are welding speed or feed, rotational speed and length of the tool pin are used for the present work. To convert the multi objectives like Tensile strength and the Hardness of the welded work pieces, Grey relation analysis is used. The graph plots the Signal to Noise ratio which identifies the optimal process parameters. The work material used for experimental work is aluminium alloy AA 6061

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