Effect of Process Parameters on Joint Formation and Mechanical Performance in Friction Stir Blind Riveting of Aluminum Alloys

2018 ◽  
Vol 140 (6) ◽  
Author(s):  
YunWu Ma ◽  
YongBing Li ◽  
Blair E. Carlson ◽  
ZhongQin Lin
Keyword(s):  
Aluminum Alloys ◽  
Fracture Mode ◽  
Heat Input ◽  
Feed Rate ◽  
Spindle Speed ◽  
Cast Aluminum ◽  
Joint Formation ◽  
Friction Stir ◽  
Lap Shear ◽  
Dissimilar Aluminum Alloys

Aluminum alloys have been increasingly adopted in the fabrication of automotive body structures as an integral component of mass savings strategy. However, mixed use of dissimilar aluminum alloys, such as sheet metals, castings, and extrusions, poses significant challenges to the existing joining technologies, especially in regard to single-sided joint access. To address this issue, the current study applied the friction stir blind riveting (FSBR) process to join 1.2 mm-thick AA6022-T4 aluminum alloy to 3 mm-thick Aural-2 cast aluminum. A newly developed, robot mounted, servo-driven, FSBR equipment and the procedure using it to make FSBR joints were introduced systematically. The effect of rivet feed rate and spindle speed on joint formation and cross section geometry was investigated, and it was found that a high spindle speed and a low rivet feed rate, i.e., high heat input, are prone to produce good joints, and that low heat input can cause severe problems related to insufficient softening of the sheets. The rivet deformation, especially the notch location on the mandrel relative to the shank has significant influence on lap-shear strength and fracture mode of the final joints. A rivet pull-out fracture mode was observed at higher rivet feed rates and lower spindle speeds and exhibited significantly improved energy absorption capability, i.e., 62% higher compared to traditional blind riveted (BR) joints.

Joint Formation and Mechanical Performance of Friction Self-Piercing Riveted Aluminum Alloy AA7075-T6 Joints

2019 ◽  
Author(s):  
YunWu Ma ◽  
YongBing Li ◽  
ZhongQin Lin
Keyword(s):  
Aluminum Alloy ◽  
Failure Mode ◽  
Feed Rate ◽  
High Speed ◽  
Shear Failure ◽  
Shear Fracture ◽  
Peak Load ◽  
Spindle Speed ◽  
Friction Stir ◽  
Lap Shear

Abstract AA7xxx series aluminum alloys have great potentials in mass saving of vehicle bodies due to pretty high specific strength. However, the use of these high strength materials poses significant challenges to traditional self-piercing riveting (SPR) process. To address this issue, friction self-piercing riveting (F-SPR) was applied to join aluminum alloy AA7075-T6 sheets. F-SPR is realized by feeding a high speed rotating steel rivet to aluminum alloy sheets to form a dissimilar material joint. The effects of spindle speed and rivet feed rate on F-SPR joint cross-section geometry evolution, riveting force and energy input were investigated systematically. It was found that the rivet shank deformation, especially the buckling of the shank tip before penetrating through the top sheet has significant influence on geometry and lap-shear failure mode of the final joint. A medium rivet feed rate combined with a high spindle speed was prone to produce a defect free joint with sound mechanical interlocking. F-SPR joints with the failure mode of rivet shear fracture was observed to have superior lap-shear peak load and energy absorption over the joints with mechanical interlock failure. The optimized F-SPR joint in this study exhibited 67.6% and 13.9% greater lap-shear peak load compared to, respectively, SPR and refill friction stir spot welding joints of the same sheets. This research provides a valuable reference for further understanding the F-SPR process.

Joint Formation and Mechanical Performance of Friction Self-Piercing Riveted Aluminum Alloy AA7075-T6 Joints

2019 ◽  
Vol 141 (4) ◽  
Author(s):  
Yun Wu Ma ◽  
Yong Bing Li ◽  
Zhong Qin Lin
Keyword(s):  
Aluminum Alloy ◽  
Failure Mode ◽  
Feed Rate ◽  
Shear Failure ◽  
Mechanical Performance ◽  
Shear Fracture ◽  
Peak Load ◽  
Spindle Speed ◽  
Friction Stir ◽  
Lap Shear

AA7xxx series aluminum alloys have great potentials in mass saving of vehicle bodies due to pretty high specific strength. However, the use of these high strength materials poses significant challenges to the traditional self-piercing riveting (SPR) process. To address this issue, a novel process, friction self-piercing riveting (F-SPR), was applied to join aluminum alloy AA7075-T6 sheets. The effects of the spindle speed and rivet feed rate on F-SPR joint cross section geometry evolution, riveting force, and energy input were investigated systematically. It was found that the rivet shank deformation, especially the buckling of the shank tip before penetrating through the top sheet, has significant influence on geometry and lap shear failure mode of the final joint. A medium rivet feed rate combined with a high spindle speed was prone to produce a defect-free joint with sound mechanical interlocking. F-SPR joints with the failure mode of rivet shear fracture were observed to have superior lap shear peak load and energy absorption over the joints with mechanical interlock failure. The optimized F-SPR joint in this study exhibited 67.6% and 13.9% greater lap shear peak load compared with SPR and refill friction stir spot welding joints, respectively, of the same sheets. This research provides a valuable reference for further understanding the F-SPR process.

Metallurgical Studies on the Friction Stir Welding of Dissimilar A356 and A413 Alloys

2012 ◽  
Vol 488-489 ◽  
pp. 345-349
Author(s):  
G. Elatharasan ◽  
V.S. Senthil Kumar
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Structural Characteristics ◽  
Grain Structure ◽  
Cast Aluminum ◽  
Friction Stir ◽  
Dissimilar Aluminum Alloys ◽  
Cast Aluminum Alloys ◽  
Welding Defects

Friction stir welding is a technique useful for joining aluminum alloys that are difficult to weld. In recent years, however the focuses has been on welding dissimilar aluminum alloys, and analyze their mechanical properties and micro-structural characteristics. In the present study, the less investigated welding of cast aluminum alloys is considered. Cast aluminum alloys, A356 and A413, commonly used in automotive and aerospace industries, were friction-stir welded and their mechanical properties and micro-structural characteristics were analyzed. On testing their welded region, no welding defects were observed. The welded region exhibited a maximum tensile strength of 90 N/mm2 and Vickers micro-hardness of 56.8. The micro-structural observations at the nugget region revealed a refined grain structure.

scholarly journals Microstructural Characteristics and Mechanical Properties of Friction Stir Spot Welded 2A12-T4 Aluminum Alloy

2013 ◽  
Vol 2013 ◽  
pp. 1-10 ◽  
Author(s):  
Huijie Liu ◽  
Yunqiang Zhao ◽  
Xingye Su ◽  
Lilong Yu ◽  
Juncai Hou
Keyword(s):  
Mechanical Properties ◽  
Aluminum Alloy ◽  
Fracture Mode ◽  
Heat Input ◽  
Tensile Shear ◽  
Microstructural Characteristics ◽  
Friction Stir ◽  
Welding Heat Input ◽  
Mixed Fracture ◽  
Spot Welded

2A12-T4 aluminum alloy was friction stir spot welded, and the microstructural characteristics and mechanical properties of the joints were investigated. A softened microstructural region existed in the joint, and it consisted of stir zone (SZ), thermal mechanically affected zone (TMAZ), and heat affected zone (HAZ). The minimum hardness was located in TMAZ, and the average hardness value in SZ can be improved by appropriately increasing welding heat input. The area of complete bonding region at the interface increased with increasing welding heat input because more interface metals were mixed. In a certain range of FSSW parameters, the tensile shear failure load of the joint increased with increasing rotation speed, but it decreased with increasing plunge rate or decreasing shoulder plunging depth. Two kinds of failure modes, that is, shear fracture mode and tensile-shear mixed fracture mode, can be observed in the tensile shear tests, and the joint that failed in the tensile-shear mixed fracture mode possessed a high carrying capability.

Possibilities to Apply Friction Stir Processing FSP in Surface Engineering

2021 ◽  
Vol 890 ◽  
pp. 56-65
Author(s):  
Cristian Ciucă ◽  
Lia Nicoleta Boțilă ◽  
Radu Cojocaru ◽  
Ion Aurel Perianu
Keyword(s):  
Aluminum Alloys ◽  
Friction Stir Processing ◽  
Surface Engineering ◽  
Copper Alloys ◽  
Welding Process ◽  
Industrial Applications ◽  
Process Conditions ◽  
Cast Aluminum ◽  
Friction Stir ◽  
Cast Aluminum Alloys

The results obtained by ISIM Timisoara to the development of the friction stir welding process (FSW) have supported the extension of the researches on some derived processes, including friction stir processing (FSP). The experimental programs (the researches) were developed within complex research projects, aspects regarding the principle of the process, modalities and techniques of application, experiments for specific applications, being approached. The paper presents good results obtained by friction stir processing of cast aluminum alloys and copper alloys. The optimal process conditions, optimal characteristics of the processing tools were defined. The complex characterization of the processed areas was done, the advantages of the process applying being presented, especially for the cast aluminum alloys: EN AW 4047, EN AW 5083 and EN AW 7021. The characteristics of the processed areas are compared with those of the base materials. The results obtained are a solid basis for substantiating of some specific industrial applications, especially in the automotive, aeronautical / aerospace fields.

Friction Stir Welding of Dissimilar A319 and A413 Cast Aluminum Alloys

2014 ◽  
Vol 39 (8) ◽  
pp. 6363-6373 ◽  
Author(s):  
A. Karam ◽  
T. S. Mahmoud ◽  
H. M. Zakaria ◽  
T. A. Khalifa
Keyword(s):  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Cast Aluminum ◽  
Friction Stir ◽  
Cast Aluminum Alloys

Microstructural Characterization and Temperature Analysis in Friction Stir Welding of A383/5052 Dissimilar Aluminum Alloys

2007 ◽  
Vol 561-565 ◽  
pp. 279-282 ◽  
Author(s):  
Masafumi Kokubo ◽  
Shinichi Kazui ◽  
Takao Kaneuchi ◽  
Yoshimasa Takayama ◽  
Hajime Kato ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Aluminum Alloys ◽  
Analytical Model ◽  
Heat Generation ◽  
Microstructural Characterization ◽  
Joint Line ◽  
Experimental Temperature ◽  
Temperature Analysis ◽  
Friction Stir ◽  
Dissimilar Aluminum Alloys

Microstructural characterization and temperature analysis have been performed in friction stir welding (FSW) of A383 and 5052 dissimilar aluminum alloys. Marked difference in microstructure was observed between joints with different arrangements of materials. The temperature at four points on each side of the joint line was measured during FSW in various conditions. In addition, an analytical model assumed that the work generated by the rotation of the tool led to the work for stirring materials and heat generation of the material and the tool. The temperature of the retreating side (RS) for the joint of the advancing side (AS):A383/RS:5052 was about 50K higher than that of AS, while the temperatures of AS and RS for the joint of AS:5052/RS:A383 were almost the same. The experimental temperature could be calculated reasonably by using the model with assumption of the work for stirring the material.

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