scholarly journals The Influence of Tool Wear on the Mechanical Performance of AA6061-T6 Refill Friction Stir Spot Welds

Materials ◽  
2021 ◽  
Vol 14 (23) ◽  
pp. 7252
Author(s):  
Willian S. de Carvalho ◽  
Maura C. Vioreanu ◽  
Maxime R. A. Lutz ◽  
Gonçalo P. Cipriano ◽  
Sergio T. Amancio-Filho
Keyword(s):  
Tool Wear ◽  
Mechanical Performance ◽  
Welding Parameters ◽  
Fracture Mechanisms ◽  
Friction Stir ◽  
Lap Shear ◽  
Tool Wear Mechanisms ◽  
Local Mechanical Property ◽  
Property Changes ◽  
Aluminum And Magnesium Alloys

The Refill Friction Stir Spot Welding (RFSSW) process—an alternative solid-state joining technology—has gained momentum in the last decade for the welding of aluminum and magnesium alloys. Previous studies have addressed the influence of the RFSSW process on the microstructural and mechanical properties of the AA6061-T6 alloy. However, there is a lack of knowledge on how the tool wear influences the welding mechanical behavior for this alloy. The present work intended to evaluate and understand the influence of RFSSW tool wear on the mechanical performance of AA6061-T6 welds. Firstly, the welding parameters were optimized through the Designing of Experiments (DoE), to maximize the obtained ultimate lap shear force (ULSF) response. Following the statistical analysis, an optimized condition was found that reached a ULSF of 8.45 ± 0.08 kN. Secondly, the optimized set of welding parameters were applied to evaluate the wear undergone by the tool. The loss of worn-out material was systematically investigated by digital microscopy and the assessment of tool weight loss. Tool-wear-related microstructural and local mechanical property changes were assessed and compared with the yielded ULSF, and showed a correlation. Further investigations demonstrated the influence of tool wear on the height of the hook, which was located at the interface between the welded plates and, consequently, its effects on the observed fracture mechanisms and ULSF. These results support the understanding of tool wear mechanisms and helped to evaluate the tool lifespan for the selected commercial RFSSW tool which is used for aluminum alloys.

scholarly journals Improvement on Mechanical Properties of Submerged Friction Stir Joining of Dissimilar Tailor Welded Aluminum Blanks

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
R. Suryanarayanan ◽  
V. G. Sridhar ◽  
L. Natrayan ◽  
S. Kaliappan ◽  
Anjibabu Merneedi ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Friction Stir Welding ◽  
Mechanical Performance ◽  
Weld Zone ◽  
Tensile Tests ◽  
Welding Parameters ◽  
Negative Effects ◽  
Friction Stir ◽  
Tailor Welded Blanks ◽  
Secondary Precipitates

Friction stir welding is a solid-state welding method that produces joints with superior mechanical and metallurgical properties. However, the negative effects of the thermal cycle during welding dent the mechanical performance of the weld joint. Hence, in this research study, the joining of aluminum tailor welded blanks by friction stir welding is carried out in underwater conditions by varying the welding parameters. The tensile tests revealed that the underwater welded samples showed better results when compared to the air welded samples. Maximum tensile strength of 229.83 MPa was obtained at 1000 rpm, 36 mm/min. The improved tensile strength of the underwater welded samples was credited to the suppression of the precipitation of the secondary precipitates due to the cooling action provided by the water. The lowest hardness of 72 HV was obtained at the edge of the stir zone which indicated the weakest region in the weld zone.

Comparison of tool wear during friction stir welding of Al alloy and Al-SiC metal matrix composite

2021 ◽  
pp. 095440892110059
Author(s):  
Ashish Bist ◽  
JS Saini ◽  
Vikas Sharma
Keyword(s):  
Surface Roughness ◽  
Friction Stir Welding ◽  
Tool Wear ◽  
Rotational Speed ◽  
Welding Parameters ◽  
Aluminum Matrix Composites ◽  
Al Alloy ◽  
Friction Stir ◽  
Prolonged Contact ◽  
Tool Pin

Aluminum matrix composites have received considerable attention due to their high specific strength and specific stiffness, high hardness, and wear resistance along with being light in weight. These composites are preferably joined using friction stir welding process. The major concern in friction stir welding is the wear of the welding tool pin which is the backbone of the process. The wear is due to the prolonged contact between the tool and the harder reinforcements in the composite materials. The present work deals with the study of tool wear and its surface roughness with respect to different selected friction stir welding parameters such as rotational speed, transverse speed, length of weld, and different composition of Aluminum composite. It was found that the total amount of material removed from the tool and the surface roughness of the tool is in direct proportion to the rotational speed of the tool and the length of the weld but inversely proportional to the transverse rate. The increase in wt.% of SiC reinforcement leads to the higher tool wear but reduces the surface roughness of the tool.

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.

Mechanical Properties and Fracture Behavior of Friction Stir Spot Welded AZ61 Magnesium Alloys

2010 ◽  
Vol 154-155 ◽  
pp. 498-507 ◽  
Author(s):  
Ben Yuan Lin ◽  
Ju Jen Liu ◽  
Lee Der Lu
Keyword(s):  
Fracture Behavior ◽  
Shear Failure ◽  
Shear Loading ◽  
Stir Zone ◽  
Welding Parameters ◽  
Tensile Shear ◽  
Friction Stir ◽  
Lower Sheet ◽  
Lap Shear ◽  
Spot Welded

In this study, the tensile shear strength and the fracture behavior of friction stir spot welded AZ61 joints in lap-shear configuration were investigated. The heat input was measured in FSSW to help analyze the effect of welding parameters on the strength. The tensile shear failure test was performed in a material testing system. The cross section of the joints and the fracture surface of the failed specimens were analyzed using optical microscopy and scanning electron microscopy. Results show that the weld diameter and the tensile shear load increase with increasing the input heat. The path of the material flow formed during FSSW process would provide a good way for crack propagation. All failed specimens in this study appear the same fracture features and show a circumferential failure mode under tensile shear loading conditions. The failure is initiated from a notch tip in the upper sheet loading side, and then propagates along the interface of the upper and lower sheets, then through the stir zone circumference; finally, a small portion of the lower sheet in the lower sheet loading side is torn off with some part of the stir zone.

Friction stir lap welding thin aluminum alloy sheets

2020 ◽  
Vol 39 (1) ◽  
pp. 663-670
Author(s):  
Tao Wang ◽  
Xue Gong ◽  
Shude Ji ◽  
Gang Xue ◽  
Zan Lv
Keyword(s):  
Aluminum Alloy ◽  
Failure Load ◽  
Tensile Fracture ◽  
Welding Parameters ◽  
Plunge Depth ◽  
Friction Stir ◽  
Lap Shear ◽  
Thin Aluminum ◽  
Wide Range ◽  
Good Material

AbstractIn this work, thin aluminum alloy sheets with thickness of 0.8 mm were friction stir lap welded using small shoulder plunge depths of 0 and 0.1 mm. The joint formation, microstructure and mechanical properties were investigated. Results show that voids appear inside the stir zone when the small plunge depth of 0 mm is used because the tool shoulder cannot exert a good material-collecting effect at such low plunge depth. A plunge depth of 0.1 mm causes tight contact between the shoulder and the material and thus results in good material-collecting effect, which is helpful to eliminate the void. Sound joints are attained at a wide range of welding parameters when using the shoulder plunge depth of 0.1 mm. No crack is observed inside the bonding ligament. The joints own higher failure loads when the retreating side (RS) of the joint bares the main load during the lap shear tests. The shear failure load first increases and then decreases with increasing the rotating and welding speeds, and the maximum failure load of 6419 N is obtained at 600 rpm and 150 mm/min. The hardness of the joint presents a “W” morphology and the minimum hardness is obtained at the heat affected zone. The joints present tensile fracture and shear fracture when the advancing side and RS bare the main loads, respectively.

Effects of Tool Design and Friction Stir Welding Parameters on Weld Morphology in Aluminum Alloys

2010 ◽  
Vol 638-642 ◽  
pp. 1261-1266 ◽  
Author(s):  
Christian A. Widener ◽  
Dwight A. Burford ◽  
Sarah Jurak
Keyword(s):  
Electrical Conductivity ◽  
Friction Stir Welding ◽  
Grain Orientation ◽  
Mechanical Performance ◽  
Tool Design ◽  
Welding Parameter ◽  
Welding Parameters ◽  
Microstructural Changes ◽  
Mechanical Process ◽  
Friction Stir

Friction stir welding (FSW) is a complex thermo-mechanical process which produces wrought microstructure with microstructural gradients in grain size, grain orientation, dislocation density, and precipitate distribution. The type and degree of microstructural modification is a function of the particular alloy chosen, its initial temper, the tool design and corresponding weld process parameter window, and other variables like material thickness, size, fixturing, etc. Since the microstructural changes produced can dramatically affect resultant mechanical performance and corrosion response, a thorough understanding of the variables involved in those changes is needed. A design of experiments approach was used to study the effects of welding parameter selection on the microstructural changes wrought by FSW with two different sizes of the same FSW tool design. A combination of microhardness mapping and electrical conductivity testing was used to investigate potential differences. The importance of these factors and the means for characterizing them for developing standards and specifications are also discussed.

scholarly journals Influences of Welding Parameters on Friction Stir Welding of Aluminum and Magnesium: A Review

2021 ◽  
Keyword(s):  
Friction Stir Welding ◽  
Industrial Applications ◽  
Frictional Heat ◽  
Welding Parameters ◽  
Welding Quality ◽  
Micro Hardness ◽  
Friction Stir ◽  
Increasing Demand ◽  
Aluminum And Magnesium Alloys ◽  
Joining Process

Abstract. Friction stir welding (FSW) is an important joining process wherein two dissimilar metals and alloys are welded together using frictional heat produced in a revolving tool and workpiece. FSW is playing an important role in dissimilar material joining of Magnesium (Mg) and Aluminum (Al) materials due to the increasing demand for their industrial applications. In this review article, the research background of FSW processes, and influences of joining factors on tensile strength, micro-hardness, and microstructures of FSW of Al-Mg alloy materials have been studied. The effects of joining factors for example axial force, tool revolving speed, tool incline, speed, and offset on welding characterizes have been enlightened to make defect-free FSW of aluminum and magnesium alloys. The microstructural behaviors of intermetallic formation and material drift in FSW zones of Al-Mg were also studied to find the scope to improve the welding quality.

Microstructure and Mechanical Performance of Cold Metal Transfer Spot Joints of AA6061-T6 to Galvanized DP590 Using Edge Plug Welding Mode

2016 ◽  
Vol 138 (7) ◽  
Author(s):  
Haiyang Lei ◽  
Yongbing Li ◽  
Blair E. Carlson ◽  
Zhongqin Lin
Keyword(s):  
Mechanical Performance ◽  
Welding Process ◽  
Metal Transfer ◽  
Weld Nugget ◽  
Weld Strength ◽  
Welding Parameters ◽  
Feed Speed ◽  
Cold Metal Transfer ◽  
Lap Shear ◽  
Cold Metal

Dissimilar joining of aluminum to steel poses a challenge for arc welding. In this study, aluminum AA6061-T6 and hot dipped galvanized DP590 steel were joined using the Fronius cold metal transfer (CMT) welding process applying an edge plug welding mode (EPW). The correlation of the welding parameters, weld characteristics, and weld strength was systematically investigated. It was found that the EPW mode created a zinc-rich zone at the weld root along the Al–steel faying interface which transitioned to a continuous and compact intermetallic compounds (IMC) layer in the middle portion of the joint. The fracture propagation in lap-shear specimens was affected by this increase of IMC layer thickness. At a wire feed speed (wfs) of 5.6 m/min, the fracture initiated along the zinc-rich layer at the faying interface and then, upon meeting the compact IMC layer, propagated into the aluminum weld nugget. Propagation followed a path within the weld nugget along the boundary between columnar and equiaxed grains leading to weld nugget pullout upon fracture. For IMC layer peak thicknesses below 10 μm, the strength increased as a function of weld nugget diameter. However, larger heat inputs resulted in IMC layer thicknesses greater than 10 μm and interfacial fracture.

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