Advances in friction stir welding by separate control of shoulder and probe

AbstractFriction stir welding (FSW) has developed into a reliable and increasing used industrial joining technology. Various tool configurations can be used for FSW, each of which has advantages and challenges. State-of-the-art FSW employs various tool configurations, including the conventional, the stationary shoulder, and the dual-rotational configuration which is characterized by separate control of shoulder and probe. In this study, an innovative method to combine various tool configurations was developed by a novel FSW spindle stack construction. With an additional servomotor, existing FSW systems can be extended by separate control of shoulder and probe so that varying rotational speeds and rotational directions can be set. This allows enhanced possibilities (a) to adjust frictional heat generation and (b) to apply several tool configurations. The main advantages of this enhanced type of FSW are demonstrated in three ways: increased weld penetration depth, reduction of undesirable machine vibrations, and the combination of varying tool configurations such as stationary shoulder and conventional FSW. The investigations were carried out with 2-mm EN AA 5754 H22 sheets and performed on a robotized FSW setup.

Download Full-text

Effect of Stirring Pin Rotation Speed on Microstructure and Mechanical Properties of 2A14-T4 Alloy T-Joints Produced by Stationary Shoulder Friction Stir Welding

Materials ◽

10.3390/ma14081938 ◽

2021 ◽

Vol 14 (8) ◽

pp. 1938

Author(s):

Haifeng Yang ◽

Hongyun Zhao ◽

Xinxin Xu ◽

Li Zhou ◽

Huihui Zhao ◽

...

Keyword(s):

Mechanical Properties ◽

Friction Stir Welding ◽

Rotation Speed ◽

Weld Nugget ◽

Al Alloy ◽

Nugget Zone ◽

T Joints ◽

Friction Stir ◽

Stationary Shoulder ◽

Microstructure And Mechanical Properties

In this study, 2A14-T4 Al-alloy T-joints were prepared via stationary shoulder friction stir welding (SSFSW) technology where the stirring pin’s rotation speed was set as different values. In combination with the numerical simulation results, the macro-forming, microstructure, and mechanical properties of the joints under different welding conditions were analyzed. The results show that the thermal cycle curves in the SSFSW process are featured by a steep climb and slow decreasing variation trends. As the stirring pin’s rotation speed increased, the grooves on the weld surface became more obvious. The base and rib plates exhibit W- or N-shaped hardness distribution patterns. The hardness of the weld nugget zone (WNZ) was high but was lower than that of the base material. The second weld’s annealing effect contributed to the precipitation and coarsening of the precipitated phase in the first weld nugget zone (WNZ1). The hardness of the heat affect zone (HAZ) in the vicinity of the thermo-mechanically affected zone (TMAZ) dropped to the minimum. As the stirring pin's rotation speed increased, the tensile strengths of the base and rib plates first increased and then dropped. The base and rib plates exhibited ductile and brittle/ductile fracture patterns, respectively.

Download Full-text

Effect of Friction Stir Welding Parameters on Thermal and Tensile Behavior of Aluminum Weldments Using Double Shoulder Tools

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.622-623.323 ◽

2012 ◽

Vol 622-623 ◽

pp. 323-329

Author(s):

Ebtisam F. Abdel-Gwad ◽

A. Shahenda ◽

S. Soher

Keyword(s):

Tensile Strength ◽

Friction Stir Welding ◽

Welding Process ◽

Tensile Behavior ◽

Frictional Heat ◽

Welding Parameters ◽

Friction Stir ◽

Aluminum Base ◽

Tool Pin ◽

Strength And Ductility

Friction stir welding (FSW) process is a solid state welding process in which the material being welded does not melt or recast. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters and tool pin profile play major roles in deciding the weld quality. In this investigation, an attempt has been made to understand effects of process parameters include rotation speeds, welding speeds, and pin diameters on al.uminum weldment using double shoulder tools. Thermal and tensile behavior responses were examined. In this direction temperatures distribution across the friction stir aluminum weldment were measured, besides tensile strength and ductility were recorded and evaluated compared with both single shoulder and aluminum base metal.

Download Full-text

A Study on Friction Stir Welding Process for AA2219/AA2195 Joints

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.762.339 ◽

2018 ◽

Vol 762 ◽

pp. 339-342

Author(s):

Ho Sung Lee ◽

Koo Kil No ◽

Joon Tae Yoo ◽

Jong Hoon Yoon

Keyword(s):

Friction Stir Welding ◽

Welded Joints ◽

Rotation Speed ◽

Microstructural Analysis ◽

Frictional Heat ◽

Welding Parameters ◽

Manufacturing Cost ◽

Significant Saving ◽

Friction Stir ◽

Rotation Direction

The object of this study was to study mechanical properties of friction stir welded joints of AA2219 and AA2195. AA2219 has been used as an aerospace materials for many years primarily due to its high weldability and high specific strength in addition to the excellent cryogenic property so to be successfully used for manufacturing of cryogenic fuel tank for space launcher. Relatively new Aluminum-Lithium alloy, AA2195 provides significant saving on weight and manufacturing cost with application of friction stir welding. Friction stir welding is a solid-state joining process, which use a spinning tool to produce frictional heat in the work piece. To investigate the effect of the rotation direction of the tool, the joining was performed by switching the positions of the two dissimilar alloys. The welding parameters include the travelling speed, rotation speed and rotation direction of the tool, and the experiment was conducted under the condition that the travelling speed of the tool was 120-300 mm/min and the rotation speed of the tool was 400-800 rpm. Tensile tests were conducted to study the strength of friction stir welded joints and microhardness were measured with microstructural analysis. The results indicate the failure occurred in the relatively weaker TMAZ/HAZ interface of AA2219. The optimum process condition was obtained at the rotation speed of 600-800 rpm and the travelling speed of 180-240 mm/min.

Download Full-text

A Comparative Investigation on Conventional and Stationary Shoulder Friction Stir Welding of Al-7075 Butt-Lap Structure

Metals ◽

10.3390/met9121264 ◽

2019 ◽

Vol 9 (12) ◽

pp. 1264 ◽

Cited By ~ 1

Author(s):

Yu Chen ◽

Huaying Li ◽

Xiaoyu Wang ◽

Hua Ding ◽

Fenghe Zhang

Keyword(s):

Friction Stir Welding ◽

Material Flow ◽

Comparative Investigation ◽

Flow Mode ◽

Nugget Zone ◽

Friction Stir ◽

Stationary Shoulder ◽

Average Grain Size ◽

Al 7075

Both conventional friction stir welding (C-FSW) and stationary shoulder friction stir welding (S-FSW) were employed to join the Al-7075 butt-lap structure, then the microstructural evolution and mechanical characterization of all FSW joints were systematically studied. The C-FSW joint exhibited a rough surface with flashes and arc corrugations, while the surface of the S-FSW joint became smooth. Moreover, for the S-FSW joint, the shoulder-affected zone got eliminated and the material flow mode during FSW was changed owning to the application of stationary shoulder. Furthermore, in comparison to C-FSW, the lower welding heat input of S-FSW decreased the average grain size in the nugget zone and inhibited the coarsening of strengthening precipitates in the heat-affected zone, elevating the overall hardness for the S-FSW joint. In addition, the tensile strength of the S-FSW joint became higher compared to the C-FSW joint, and all the FSW joints failed inside the nugget zone attributing to the existence of hook defect. The sharp-angled hook defect deteriorated the plasticity of the C-FSW joint further, which was only 70% that of the S-FSW joint.

Download Full-text

Probing residual stresses in stationary shoulder friction stir welding process

The International Journal of Advanced Manufacturing Technology ◽

10.1007/s00170-019-04570-9 ◽

2019 ◽

Vol 106 (5-6) ◽

pp. 1573-1586 ◽

Cited By ~ 5

Author(s):

B. Vicharapu ◽

H. Liu ◽

H. Fujii ◽

K. Narasaki ◽

N. Ma ◽

...

Keyword(s):

Friction Stir Welding ◽

Residual Stresses ◽

Welding Process ◽

Friction Stir ◽

Friction Stir Welding Process ◽

Stationary Shoulder

Download Full-text

Probeless Tool Aided Friction Stir Welding as a Fabrication Technique for Tungsten Embedded Mechanical Composite of Copper

Volume 6B: Materials and Fabrication ◽

10.1115/pvp2014-28571 ◽

2014 ◽

Author(s):

Yogita Ahuja ◽

Raafat Ibrahim ◽

Anna Paradowska ◽

Daniel Riley

Keyword(s):

Friction Stir Welding ◽

Solid State ◽

Base Metal ◽

Parametric Study ◽

Effective Parameter ◽

Frictional Heat ◽

Fabrication Technique ◽

Shear Testing ◽

Friction Stir ◽

Parameter Combination

Friction stir welding (FSW) is a relatively new solid state metallurgical joining technique. It flourishes on the simple principle of utilising frictional heat by the stirring motion of a non-consumable rotating tool to create the seam. Feasibility of FSW aided by a newly designed probeless tool was investigated for fabricating copper-tungsten mechanical composite. The most effective parameter combination was determined by conducting a parametric study of the probeless tool aided FSW copper. Strength of the mechanical composite fabricated at this condition was evaluated through punch shear testing. Punch shear testing established that the friction stir welded interface of the copper-tungsten composite was 87% as strong as the base metal (i.e. copper). Advantages of the designed technique have been summarised.

Download Full-text

Stationary shoulder supporting and tilting pin penetrating friction stir welding

Journal of Materials Processing Technology ◽

10.1016/j.jmatprotec.2018.01.010 ◽

2018 ◽

Vol 255 ◽

pp. 596-604 ◽

Cited By ~ 8

Author(s):

Huijie Liu ◽

Yanying Hu ◽

Huan Wang ◽

Shuaishuai Du ◽

Dusan P. Sekulic

Keyword(s):

Friction Stir Welding ◽

Friction Stir ◽

Stationary Shoulder

Download Full-text

A Study on the Thermal Deformation of Fillet Joint Friction Stir Welding

Volume 2B: Structures, Safety, and Reliability ◽

10.1115/omae2020-18526 ◽

2020 ◽

Author(s):

Sungwook Kang ◽

Jaewoong Kim ◽

Donghyun Kim ◽

Kwangjin Lee ◽

Yoonchul Jung

Keyword(s):

Friction Stir Welding ◽

Heat Source ◽

Welding Process ◽

Frictional Heat ◽

Process Conditions ◽

Joint Friction ◽

Friction Stir ◽

Tool Shoulder ◽

Tool Shape ◽

Fillet Joint

Abstract In this study, experiments and simulations were performed for fillet joint friction stir welding according to tool shape and welding conditions. Conventional butt friction stir welding has good weldability because heat is generated by friction with the bottom of the tool shoulder. However, in the case of fillet friction stir welding, the frictional heat is not sufficiently generated at the bottom of the tool shoulder due to the shape of the tool and the shape of the joint. Therefore, it is important to sufficiently generate frictional heat by slowing the welding speed as compared to butt welding. In this study, experiments and simulations were carried out on an aluminum battery housing made by friction stir welding an extruded material with a fillet joint. The temperature of the structure was measured using thermocouple during welding, and the heat source was calculated through correlation analysis. Thermal elasto-plastic analysis of the structure was carried out using the calculated heat source and geometric boundary conditions. It is confirmed that the experimental results and the simulation results are well matched. Based on the results of the study, the deformation of the structure can be calculated through simulation even if the tool shape and welding process conditions change.

Download Full-text

Influences of Tool pin Profile and Tool Shoulder Curvature on the Formation of Friction Stir Welding Zone in AA6061 Aluminium Alloy

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.445.789 ◽

2012 ◽

Vol 445 ◽

pp. 789-794 ◽

Cited By ~ 1

Author(s):

Vahid Moosabeiki ◽

Ghasem Azimi ◽

Mostafa Ghayoor

Keyword(s):

Friction Stir Welding ◽

Aluminium Alloy ◽

Frictional Heat ◽

Welding Parameters ◽

Zone Formation ◽

Friction Stir ◽

Tool Pin Profile ◽

Tool Shoulder ◽

Aa6061 Aluminium Alloy ◽

Tool Pin

Friction stir welding (FSW) process is an emerging solid state joining process in which the material that is being welded does not melt and recast. This process uses a non-consumable tool to generate frictional heat in the abutting surfaces. The welding parameters such as tool rotational speed, welding speed, axial force, etc., and tool pin profile play a major role in deciding the weld quality. Friction stir tool plays a major role in friction stir welding process. In this investigation, it is tried to evaluate the effect of tool pin thread and tool shoulder curvature on FSW zone formation in AA6061 aluminium alloy. In this regard, six different tool pin geometries (threadless triangular pin with/without conical shoulder, threaded triangular pin with conical shoulder, threadless square pin with/without conical shoulder, threaded square pin with conical shoulder) are used to fabricate the joints. The formation of FSP zones are analyzed macroscopically. Tensile properties of the joints are evaluated and correlated with the FSP zone formation. Consequently, it is obtained that welding creates a higher quality compared to other tool pin profiles using the square tool with curved shoulder and having threaded pin.

Download Full-text