scholarly journals The effect of tool pin size and taper angle on the thermal process and plastic material flow in friction stir welding

2021 ◽  
Author(s):  
Jie Chen ◽  
Lei Shi ◽  
Chuansong Wu ◽  
Yuanning Jiang
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Thermal Process ◽  
Plastic Material ◽  
Taper Angle ◽  
Friction Stir ◽  
Tool Pin

scholarly journals The Effect of Tool Pin Size and Taper Angle on the Thermal Process and Plastic Material Flow in Friction Stir Welding

2021 ◽  
Author(s):  
Jie Chen ◽  
Lei Shi ◽  
Chuansong Wu ◽  
Yuanning Jiang
Keyword(s):  
Friction Stir Welding ◽  
Shear Layer ◽  
Layer Thickness ◽  
Material Flow ◽  
Horizontal Plane ◽  
Thermal Process ◽  
Plastic Material ◽  
Taper Angle ◽  
Friction Stir ◽  
Tool Pin

Abstract Friction stir welding (FSW) tool pin, as a critical component of FSW tool, plays an important role in determining the final joint properties by affecting the heat generation, plastic material flow, welding loads and so on. However, the influence of tool pin on heat and mass transfer in FSW are not elucidated. In the present study, a validated model was adopted to quantitatively analyze the effects of pin size and taper angle on the thermal process and plastic material flow in FSW. It reveals that the torque and transverse force imposed on the pin are increased with the increase of the pin diameters (including its root diameter, its tip diameter and its size in condition of constant taper angle), while the total tool torque various a little for the tool pin diameter considered in this study. When the pin diameters increase, the viscosity of the materials near the pin is decreased, while the temperature as well as the flow velocity is increased. More plastic material near the tool could rotate around the tool with an increase of the pin diameter. The TMAZ boundary is enlarged with larger pin diameters in FSW. Particularly, the shear layer thickness of the same horizontal plane in the range of 1 mm < z < 5 mm is significantly enlarged with an increase of pin root diameters. However, the shear layer thickness of the same horizontal plane in the region of z < 5 mm is increased when using a larger pin tip diameter. In addition, maximum width of TMAZ boundary at the top surface of workpiece was not affected by pin diameters. The model is validated by experimental results. It lays solid foundation for optimizing the tool pin size and taper angle in 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.

scholarly journals Numerical Simulation of Material Flow and Analysis of Welding Characteristics in Friction Stir Welding Process

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 621 ◽  
Author(s):  
Haitao Luo ◽  
Tingke Wu ◽  
Peng Wang ◽  
Fengqun Zhao ◽  
Haonan Wang ◽  
...  
Keyword(s):  
Finite Element ◽  
Friction Stir Welding ◽  
Finite Element Model ◽  
Material Flow ◽  
Welding Process ◽  
Element Model ◽  
Welding Seam ◽  
Friction Stir ◽  
Tool Pin ◽  
The Finite Element Model

Friction stir welding (FSW) material flow has an important influence on weld formation. The finite element model of the FSW process was established. The axial force and the spindle torque of the welding process were collected through experiments. The feasibility of the finite element model was verified by a data comparison. The temperature field of the welding process was analyzed hierarchically. It was found that the temperature on the advancing side is about 20 °C higher than that on the retreating side near the welding seam, but that the temperature difference between the two sides of the middle and lower layers was decreased. The particle tracking technique was used to study the material flow law in different areas of the weld seam. The results showed that part of the material inside the tool pin was squeezed to the bottom of the workpiece. The material on the upper surface tends to move downward under the influence of the shoulder extrusion, while the material on the lower part moves spirally upward under the influence of the tool pin. The material flow amount of the advancing side is higher than that of the retreating side. The law of material flow reveals the possible causes of the welding defects. It was found that the abnormal flow of materials at a low rotation speed and high welding speed is prone to holes and crack defects. The forming reasons and material flow differences in different regions are studied through the microstructure of the joint cross section. The feasibility of a finite element modeling and simulation analysis is further verified.

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 Temperature Monitoring and Material Flow Characteristics of Friction Stir Welded 2A14-t6 Aerospace Aluminum Alloy

Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3387 ◽  
Author(s):  
Tingke Wu ◽  
Fengqun Zhao ◽  
Haitao Luo ◽  
Haonan Wang ◽  
Yuxin Li
Keyword(s):  
Friction Stir Welding ◽  
Material Flow ◽  
Flow Model ◽  
Welding Process ◽  
Temperature Monitoring ◽  
Measuring System ◽  
Welding Parameters ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Tool Pin

Aiming at the problems that the temperature in the welding area of friction stir welding (FSW) is difficult to measure and the joints are prone to defects. Hence, it is particularly important to study the material flow in the welding area and improve the welding quality. The temperature of the tool shoulder and the tool pin was monitored by the wireless temperature measuring system. The finite element model of friction stir welding was established and the welding conditions were numerically simulated. The flow law of material of the friction stir welding process was studied by numerical simulation. The material flow model was established by combining the microstructure analysis results, and the forming mechanism of the defects was analyzed. The results show that the temperature in the welding zone is the highest at 1300 rpm, and the temperature at the tool shoulder is significantly higher than that at the tool pin in the welding stage. When high-rotation speeds (HRS) are chosen, the material beneath the tool shoulder tends to be extruded into the pin stirred zone (PSZ) after flowing back to the advancing side. This will cause turbulence phenomenon in the advancing side of the joint, which will easily lead to the formation of welding defects. In the future, temperature monitoring methods and the flow model of material can be used to optimize the welding parameters.

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.

An analytical and experimental investigation considering the effect of material flow velocity on tensile strength of a steel alloy joint produced by friction stir welding process

2020 ◽  
pp. 095440622093631
Author(s):  
Behzad Hadi ◽  
ME Aalami-Aleagha ◽  
Saeed Feli
Keyword(s):  
Friction Stir Welding ◽  
Flow Velocity ◽  
Analytical Method ◽  
Rotational Speed ◽  
Material Flow ◽  
Welding Process ◽  
Linear Speed ◽  
Friction Stir ◽  
Friction Stir Welding Process ◽  
Tool Pin

In this paper, the effects of linear speed, rotational speed, and tool radius of the pin and shoulder are investigated on the material flow velocity in friction stir welds. To obtain the maximum material flow velocity by an analytical method, a suggested relation is introduced for the rotational speed and tool optimum radius. The derived relation is based on the assumption of a velocity field in the stirring region. Besides, the effect of the linear speed on material flow velocity is investigated based on continuity and momentum equations. Finally, by using the experimental method and checking the mechanical properties of the welded parts obtained with different rotational speed, linear speed, and tool dimensions, the proposed analytical model is validated. The results indicate that in the friction stir welding process, the significant component effect on the stirring process is generated through the tool pin radius size. Besides, increasing the material flow velocity in the boundary layer increases the yield and ultimate strength of welds. To achieve the high-quality welds, rotational speed and other tool dimensions must be selected considering the equation extracted from the analytical method. Also, to make the maximum life for the pin and its components in friction stir welding of high melting point metals such as steel alloys, the operation is adjusted at a lower linear speed to prevent the destruction of the tool and improve the quality of the joint.

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