Friction Stir Blind Riveting for Joining Dissimilar Cast Mg AM60 and Al Alloy Sheets

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Junying Min ◽  
Jingjing Li ◽  
Blair E. Carlson ◽  
Yongqiang Li ◽  
James F. Quinn ◽  
...  
Keyword(s):  
Loading Condition ◽  
Tensile Load ◽  
Strengthening Mechanism ◽  
Frictional Heat ◽  
Process Window ◽  
Al Alloy ◽  
Forming Process ◽  
Friction Stir ◽  
Lap Shear ◽  
Riveting Process

A new one-sided joining method, friction stirring blind riveting (FSBR) was successfully implemented to form lap-shear joints for dissimilar metals from pairs of 3.05 mm thick cast Mg AM60, rolled 1.5 mm thick Al AA6022, and extruded 3.15 mm thick Al AA6082 specimens. The concept of this process is riveting the two workpieces with reduced force under frictional heat and fastening the workpieces through blind riveting once the rivet is fully inserted. In this research, the process was experimentally analyzed and optimized for four joint combinations. It was demonstrated that switching the positions of Mg and Al alloy specimens has a significant effect on the process window and maximum tensile load of the joints. Three quality issues of the FSBR joints were observed and discussed. During tensile testing, the sheet closer to the rivet tail work-hardens due to tail forming process but has worse loading condition than the sheet closer to the rivet head. For AA6xxx sheets, precipitate hardening due to frictional heat is another strengthening mechanism in FSBR compared to the conventional riveting process, which leads to higher tensile loads in FSBR joints.

Friction Stir Blind Riveting for Dissimilar Cast MG AM60 and Al Alloy Sheets

2014 ◽  
Author(s):  
Junying Min ◽  
Jingjing Li ◽  
Weiming Wang ◽  
Blair E. Carlson ◽  
Yongqiang Li ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Joint Strength ◽  
Tensile Load ◽  
Frictional Heat ◽  
Process Window ◽  
Al Alloy ◽  
Dissimilar Metals ◽  
Friction Stir ◽  
Lap Shear ◽  
Process Material

A new one-sided joining method, friction stirring blind riveting (FSBR) was successfully implemented to form lap-shear joints for dissimilar metals from pairs of 3.05mm thick cast Mg AM60, rolled 1.5mm thick Al AA6022 and extruded 3.15mm thick Al AA6082 specimens. The concept of this process is riveting the two workpieces with reduced force under frictional heat and fastening the workpieces through blind riveting once the rivet is fully inserted. In this research the process was experimentally analyzed and optimized for four joint combinations. It was demonstrated that switching the positions of Mg and Al alloy specimens has a significant effect on the process window and maximum tensile load of the joints. Three quality issues of the FSBR joints were observed and discussed. The mechanisms associated with joint strength were discussed and explain the effects of FSBR process, material matching and sheet position on the joint tensile strength.

A New One-Sided Joining Process for Aluminum Alloys: Friction Stir Blind Riveting

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
Dalong Gao ◽  
Ugur Ersoy ◽  
Robin Stevenson ◽  
Pei-Chung Wang
Keyword(s):  
Aluminum Alloys ◽  
High Speed ◽  
Tensile Load ◽  
Operating Conditions ◽  
Frictional Heat ◽  
Operating Parameters ◽  
Friction Stir ◽  
Wide Range ◽  
Riveting Process ◽  
Joining Process

Friction stir blind riveting is a new joining process for one-sided joining (compared with the two-sided access required for, for example, self-piercing riveting) of aluminum alloys, which eliminates the need to predrill a hole for rivet insertion. A blind rivet rotating at high speed is brought into contact with the workpieces, thereby generating frictional heat between the rivet and the workpiece, which softens the workpiece material and enables the rivet to be driven into the workpieces under reduced force. Once fully inserted, the blind rivet is upset using the internal mandrel (as in a conventional blind riveting process) to fasten the workpieces together. Our study showed that friction stir blind riveting process can be carried out over a wide range of operating parameters. The resulting joints show consistent strength under tensile load with minimal influence of changes in operating parameters. The robustness of the process against variations in operating conditions shows that the process can be carried out without high-end equipment and without requiring precise initial setup. It also suggests that the process is feasible for rapid joint fabrication in volume production. Further study revealed superior static and fatigue strength from the friction stir blind riveting process, when compared with conventional spot welding, which suggests potential for reduction in the number of joints required in a structure.

Research on Synchronized Cooling Hot Forming Process of 6016 Aluminum Alloy

2012 ◽  
Vol 452-453 ◽  
pp. 81-85 ◽  
Author(s):  
Ming He Chen ◽  
Y.Y. Cao ◽  
W. Chen ◽  
Guo Liang Chen
Keyword(s):  
Aluminum Alloy ◽  
Process Parameters ◽  
High Strength ◽  
Strengthening Mechanism ◽  
Alloy Sheet ◽  
Hot Forming ◽  
Al Alloy ◽  
Forming Process ◽  
Process Step ◽  
6016 Aluminum Alloy

In order to improve formability of high strength Al-alloy sheet metal, in this paper, it come up with the synchronized cooling hot forming process. Taking the aluminum alloy of 6016 H18 aluminum alloy, which carried out its technology test by Gleeble3500 hot-mechanical simulator. The process parameters such as deformation temperature T, holding time t and cooling rate v is investigated by the orthogonal test and the microstructure is analyzed simultaneously. The results show that the synchronized cooling hot forming process can be applied to 6016 H18 aluminum alloy, it both improves the formability of 6016 H18 aluminum alloy significantly and obtains the high strength after forming, it can meet the purpose of implementing deformation and enhanced in one process step, the proper combination of process parameters are T=450 °C, t=210 s, v=60 °C/s. Strengthening mechanism is which there is a large number of strengthening phase precipitated from matrix in technology process, the strengthening phases are coarser and the dispersed uniformity is a bit worse compared with that of T4 state.

Joint Characteristics of Spot Friction Stir Welded 5052 Al Alloy Sheet

2006 ◽  
Vol 15-17 ◽  
pp. 345-350 ◽  
Author(s):  
Chang Yong Lee ◽  
Won Bae Lee ◽  
Yun Mo Yeon ◽  
Keun Song ◽  
Jeong Hoon Moon ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Fracture Mode ◽  
Shear Fracture ◽  
Alloy Sheet ◽  
Al Alloy ◽  
Shear Load ◽  
Insertion Depth ◽  
Friction Stir ◽  
Lap Shear ◽  
Joint Characteristics

The microstructure and mechanical properties of spot friction stir welded A 5052 alloy were investigated with insertion depth of welding tool. As the insertion depth of welding tool increased, the size of stirring zone increased and the thickness of upper sheet decreased. The value of shear load was the lowest at the shallowest insertion depth and increased to the highest value of 3.35 kN at a 1.6mm of insertion depth. An increase in the pin insertion depth beyond 1.6mm did not result in further increase in the lap shear load. Spot friction stir welded joints showed shear fracture mode at shallower insertion depths and fracture mode changed to plug fracture mode as the insertion depth was deeper.

scholarly journals Heat generation during plunge stage in friction stir welding

2013 ◽  
Vol 17 (2) ◽  
pp. 489-496 ◽  
Author(s):  
Darko Veljic ◽  
Marko Rakin ◽  
Milenko Perovic ◽  
Bojan Medjo ◽  
Zoran Radakovic ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Heat Generation ◽  
Slip Rate ◽  
Element Model ◽  
Numerical Results ◽  
Frictional Heat ◽  
Al Alloy ◽  
Arbitrary Lagrangian Eulerian ◽  
Workpiece Material ◽  
Friction Stir

This paper deals with the heat generation in the Al alloy Al2024-T3 plate under different rotating speeds and plunge speeds during the plunge stage of friction stir welding (FSW). A three-dimensional finite element model (FEM) is developed in the commercial code ABAQUS/Explicit using the arbitrary Lagrangian-Eulerian formulation, the Johnson-Cook material law and Coulomb?s Law of friction. The heat generation in FSW can be divided into two parts: frictional heat generated by the tool and heat generated by material deformation near the pin and the tool shoulder region. Numerical results obtained in this work indicate a more prominent influence from the friction-generated heat. The slip rate of the tool relative to the workpiece material is related to this portion of heat. The material velocity, on the other hand, is related to the heat generated by plastic deformation. Increasing the plunging speed of the tool decreases the friction-generated heat and increases the amount of deformation-generated heat, while increasing the tool rotating speed has the opposite influence on both heat portions. Numerical results are compared with the experimental ones, in order to validate the numerical model, and a good agreement is obtained.

scholarly journals Interfacial Bonding and Mechanical Properties of Al/Mg Dissimilar Refill Friction Stir Spot Welds Using a Grooved Tool

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 429
Author(s):  
Zhikang Shen ◽  
Xinyu Liu ◽  
Dongxiao Li ◽  
Yuquan Ding ◽  
Wentao Hou ◽  
...  
Keyword(s):  
Intermetallic Compound ◽  
Penetration Depth ◽  
Rotational Speed ◽  
Welded Joint ◽  
Interfacial Bonding ◽  
Welding Parameter ◽  
Al Alloy ◽  
Bonding Mechanism ◽  
Friction Stir ◽  
Lap Shear

Al/Mg dissimilar welds were successfully fabricated by refill friction stir spot welding using a grooved sleeve tool. Influences of sleeve penetration depth and rotational speed on the weld formation and mechanical performance were systematically evaluated in terms of welding parameter optimization, interfacial bonding mechanism, hardness distribution and welded joint strength. The results indicated that the success of joining Al alloy to Mg alloy significantly depends on tool sleeve penetration depth. The interfacial bonding mechanism compromised both metallurgical bonding and mechanical inter-locking. Intermetallic compound layers of Al3Mg2 and Al12Mg17 were formed at the Al/Mg interface. The thickness of the intermetallic compound (IMC) layer at the weld center increased from 20–30 μm to 40 μm when the rotational speed increased from 1000 to 2000 rpm. The minimum hardness was 80 HV in Al 7075 and 52 HV in ZEK 100; both were measured in the heat affected zone. The welded joint lap shear strength decreased, and the scatter increased with the increasing of rotation speed, whose maximum was 3.6 kN when the rotational speed was 1000 rpm. In addition, the failure mechanism was determined by tool rotational speed, and found to be interfacial failure under a rotational speed of 1000 rpm and nugget pullout under a rotational speed of 2000 rpm.

Fracture Behavior of Friction Stir Spot Welded Joint

2010 ◽  
Author(s):  
Abdel-Hamid I. Mourad ◽  
Khalifa H. Harib ◽  
Aly El-Domiaty
Keyword(s):  
Penetration Depth ◽  
Spot Welding ◽  
Fracture Behavior ◽  
Fracture Behaviour ◽  
Frictional Heat ◽  
Experimental Program ◽  
Main Process ◽  
Tensile Shear ◽  
Friction Stir ◽  
Lap Shear

The fracture behaviour of lap-shear joints manufactured by friction stir spot welding (FSSW) technique is examined in this paper. Two aluminium sheets of 2.8 mm thickness were welded using different process parameters to form a lap-shear joint. Special tool was designed and fabricated for the stir-spot welding process. Tensile-shear tests were performed to determine the tensile-shear load bearing capacity and toughness of the weld. The stress intensity factor and the J-integral around a weld are determined in order to characterize the fracture behavior. The effect of different main process controlling parameters, e.g., the tool prop pin rotating speed, duration action time and sinking/penetration depth into the lower welded sheet on the weld fracture behaviour has been investigated through an intensive experimental program. Optical and scanning electron microscopes fractographes were obtained to examine the weld fracture modes. The results show that higher frictional heat due to relatively higher tool probe pin rotational speed and penetration depth into the lower sheet produces improved joint static strength and toughness.

Effect of PWHT on Behaviors of Precipitates and Hardness Distribution of 6061 Al Alloy Joints by Friction Stir Welding Method

2004 ◽  
Vol 449-452 ◽  
pp. 601-604 ◽  
Author(s):  
Won Bae Lee ◽  
Hyung Sun Jang ◽  
Yun Mo Yeon ◽  
Seung Boo Jung
Keyword(s):  
Friction Stir Welding ◽  
Base Metal ◽  
Dynamic Recovery ◽  
Weld Zone ◽  
Frictional Heat ◽  
Al Alloy ◽  
Hardness Distribution ◽  
Friction Stir ◽  
Heat Treated ◽  
6061 Al Alloy

The hardness distribution related to the precipitates behaviors as friction stir welded and PWHT (post weld heat treated) 6061 Al alloy have been investigated. Frictional heat and plastic flow during friction stir welding created a fine, eqiuaxed and elongated microstructure near the weld zone due to dynamic recovery and recrystallization. A softened region which had been formed near the weld zone couldn't be avoidable due to the dissolution and coarsening of the strengthening precipitates. PWHT (SHT+ Aging) homogeneously recovered the hardness distribution over that of the base metal without softening region, resulted from non-homogeneously distributed hardness only aging treated. 36ks aging followed by SHT gave a higher hardness overall weld than that of the base metal due to a higher density of the spherical shaped precipitate.;

scholarly journals Optimum Rotational and Traverse Speeds of Al-Cu Joints Welded by FSW Based on the Formability of The Joint

2021 ◽  
Author(s):  
Hammed T. Elmetwally ◽  
Hani Nagiub SaadAllah ◽  
M.S. Abd-Elhady ◽  
Ragab K. Abdel-Magied
Keyword(s):  
Mechanical Properties ◽  
Strain Hardening ◽  
Tensile Load ◽  
Traverse Speed ◽  
Operating Conditions ◽  
Base Metals ◽  
Forming Process ◽  
Friction Stir ◽  
Hardness Tests ◽  
Punch Load

Abstract Joining of aluminum to copper using Friction Stir Welding (FSW) is a primary manufacturing process that is in most applications followed by a secondary forming process. The objective of this research is to determine the optimum rotational and traverse speeds of Al-Cu Welded by FSW based on the formability of the joint. The formability and strength of Al-Cu joined by FSW are investigated under different operating conditions. Aluminum and copper blanks are welded at three different rotational speeds that are 910, 1280 and 1700 rpm, under three different traverse speeds, which are 16, 29 and 44 mm/min. The base metal used in this study is Aluminum (Al-1050) and copper under two conditions, i.e. as received and annealed. The mechanical properties of base metals and produced joints are evaluated by tensile and hardness tests. The Al-Cu joints by FSW are drawn into flangeless U and cup shapes in order to examine the formability of the joint. The maximum tensile load, punch load and forming index were obtained when Al is welded to annealed Cu at 1700 rpm and 16 mm/min, i.e. highest rotational and lowest traverse speeds, and that is due to the strain hardening of the joint. However, the ductility was maximum at 1280 rpm and 44 mm/min, i.e. moderate rotational and highest traverse speed. It can be concluded that if the Al-Cu joint by FSW will be used further in a forming process, it should be welded at a moderate rotational and high traverse speed in order to avoid strain hardening and improve the ductility of the joint.

scholarly journals Influence of material velocity on heat generation during linear welding stage of friction stir welding

2016 ◽  
Vol 20 (5) ◽  
pp. 1693-1701
Author(s):  
Alin Murariu ◽  
Darko Veljic ◽  
Dragana Barjaktarevic ◽  
Marko Rakin ◽  
Nenad Radovic ◽  
...  
Keyword(s):  
Plastic Deformation ◽  
Friction Stir Welding ◽  
Heat Generation ◽  
Welding Process ◽  
Slip Rate ◽  
Frictional Heat ◽  
Al Alloy ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Tool Pin

The heat generated during friction stir welding (FSW) process depends on plastic deformation of the material and friction between the tool and the material. In this work, heat generation is analysed with respect to the material velocity around the tool in Al alloy Al2024-T351 plate. The slip rate of the tool relative to the workpiece material is related to the frictional heat generated. The material velocity, on the other hand, is related to the heat generated by plastic deformation. During the welding process, the slippage is the most pronounced on the front part of the tool shoulder. Also, it is higher on the retreating side than on the advancing side. Slip rate in the zone around the tool pin has very low values, almost negligible. In this zone, the heat generation from friction is very low, because the material is in paste-like state and subjected to intensive plastic deformation. The material flow velocity around the pin is higher in the zone around the root of the pin. In the radial direction, this quantity increases from the pin to the periphery of the tool shoulder.

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