scholarly journals Effect of High Rotational-Speed Friction-Stir Welding on Microstructure and Properties of Welded Joints of 6061-T6 Al Alloy Ultrathin Plate

Materials ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6012
Author(s):  
Hao Zhang ◽  
Shujin Chen ◽  
Yuye Zhang ◽  
Xinyi Chen ◽  
Zhipeng Li ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Rotational Speed ◽  
Heat Dissipation ◽  
Temperature Drop ◽  
Precipitation Amount ◽  
Large Angle ◽  
Welding Process ◽  
Al Alloy ◽  
High Rotational Speed ◽  
Friction Stir

The butt joint of an Al alloy ultrathin plate with a thickness of 0.5 mm is realized by a high rotational-speed friction-stir welding process. It overcomes the welding difficulty that the ultrathin plate is often torn, and it cannot be formed by conventional friction-stir welding. The results show that the weld surface is well-formed at a high-rotational speed (more than 8000 rpm), and there are no obvious defects in each area of the joint section. The nugget zone (NZ) is a recovery recrystallization structure dominated by large-angle grain boundaries, with a grain size of about 4.9 μm. During grain growth, the texture is randomly and uniformly distributed, and the strength is balanced. The microhardness of the NZ increases significantly with the increase in rotational speed, and the fluctuation range of hardness value is small. The NZ β–Mg2Si is finer and significantly less than the base metal (BM). The heat dissipation of the thin plate is fast, so a Cu plate is used as the backing plate to slow down the steep temperature-drop process in the weld area. Compared with a low rotational speed, the precipitation amount of brittle phase Al–Cu–Mg–Cr and Al–Fe–Si–Mn is significantly reduced, which is conducive to improving the mechanical properties of the joint. At a high rotational speed, 12,000 rpm, the best tensile strength of the joint is 220 MPa, which is about 76% of the BM (290 MPa), and the highest elongation is 9.3%, which is about 77.5% of the BM (12%). The fracture mode of the joint is a typical plastic fracture.

scholarly journals Wear Inducing Phase Transformation of Plasma Transfer Arc Coated Tools during Friction Stir Welding with Al Alloy

2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Kuan-Jen Chen ◽  
Fei-Yi Hung ◽  
Truan-Sheng Lui ◽  
Yong-Ren Shih
Keyword(s):  
Wear Resistance ◽  
Phase Transformation ◽  
Friction Stir Welding ◽  
High Speed ◽  
Phase Transfer ◽  
Welding Process ◽  
High Speed Steel ◽  
Al Alloy ◽  
Transfer Layer ◽  
Friction Stir

The friction stir welding process (friction stir welding/processing, FSW/FSP) has wear problems related to stirring tools. In this study, the plasma transfer arc (PTA) method was used with stellite 1 powders (Co-based) to coat on the head of a SKD61 stirring tool (SKD61-ST1) in order to investigate the wear performance and phase transformation of SKD61-ST1 after FSW. Under the same experimental parameters, the wear data were compared with the high-speed steel SKH51 (tempering material SKH51-T and annealed material SKH51-A) and tungsten-carbide cobalt (TCC). Results showed the PTA coating was a γ-Co solidification matrix with M7C3 and M23C6 carbides. After FSW, the wear resistance of SKD61-ST1 was better than that of SKH51-A and SKH51-T and lower than that of TCC. The SKD61-ST1, SKH51-A, and SKH51-T stirring tools exhibited sliding wear after FSP, where the pin and shoulder of the stirring tool formed a phase transfer layer on the surface, and the peeling of the phase transfer layer caused wear weight loss. The main phase of the phase transfer layer of the SKD61-ST1 tool was Al9Co2. The affinity and adhesion energy of the Co-Al phase was lower than that of Fe-Al phase, and the phase transfer layer of the SKD61-ST1 tool was thinner and had lower coverage, thereby increasing the wear resistance of the SKD61-ST1 stirring tools during FSW.

scholarly journals Experimental Investigation of Friction Stir Welding on 6061-T6 Aluminum Alloy using Taguchi-Based GRA

Metals ◽  
2020 ◽  
Vol 10 (11) ◽  
pp. 1480
Author(s):  
Assefa Asmare ◽  
Raheem Al-Sabur ◽  
Eyob Messele
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Process Parameters ◽  
Rotational Speed ◽  
Weight Ratio ◽  
Welding Process ◽  
Quality Criteria ◽  
Alloy Sheet ◽  
Friction Stir ◽  
Weld Joints

The use of aluminum alloys, nowadays, is swiftly growing from the prerequisite of producing higher strength to weight ratio. Lightweight components are crucial interest in most manufacturing sectors, especially in transportation, aviation, maritime, automotive, and others. Traditional available joining methods have an adverse effect on joining these lightweight engineering materials, increasing needs for new environmentally friendly joining methods. Hence, friction stir welding (FSW) is introduced. Friction stir welding is a relatively new welding process that can produce high-quality weld joints with a lightweight and low joining cost with no waste. This paper endeavors to deals with optimizing process parameters for quality criteria on tensile and hardness strengths. Samples were taken from a 5 mm 6061-T6 aluminum alloy sheet with butt joint configuration. Controlled process parameters tool profile, rotational speed and transverse speed were utilized. The process parameters are optimized making use of the combination of Grey relation analysis method and L9 orthogonal array. Mechanical properties of the weld joints are examined through tensile, hardness, and liquid penetrant tests at room temperature. From this research, rotational speed and traverse speed become significant parameters at a 99% confidence interval, and the joint efficiency reached 91.3%.

Influence of Different Anvil Back Plates on Heat Dissipation Velocity of the Micro-Friction Stir Welding Process

2015 ◽  
Vol 786 ◽  
pp. 415-420 ◽  
Author(s):  
Wan Shun Chu ◽  
Farazila binti Yusof
Keyword(s):  
Aluminum Alloy ◽  
Friction Stir Welding ◽  
Heat Dissipation ◽  
Welding Process ◽  
Temperature Fields ◽  
Thin Sheets ◽  
Friction Stir ◽  
Conventional Steel ◽  
Back Plate ◽  
Two Temperature

The objective of this study is to investigate effects of different anvil back plates on heat dissipation velocity of the micro-friction stir welding (micro-FSW or) process. For this purpose, temperature field simulations are conducted for the micro-friction stir welding of AA5083-H323 aluminum alloy thin sheets by using the ceramic anvil back plate and conventional steel anvil back plate, respectively. Comparing the obtained two temperature fields, it is found that the ceramic anvil back plate significantly decreases the heat dissipation velocity of the micro-FSW process.

Study of Heat Dissipation Generated in Tool Designed for Friction Stir Welding Process (FSW)

2015 ◽  
Vol 1125 ◽  
pp. 171-175
Author(s):  
G. Paramo ◽  
A. Benitez
Keyword(s):  
Friction Stir Welding ◽  
Heat Dissipation ◽  
Welding Process ◽  
Experimental Tests ◽  
Tool Design ◽  
Milling Machine ◽  
Technical Parameters ◽  
Friction Stir ◽  
Heat Dispersion ◽  
The Right

Friction stir welding (FSW) is an alternative method of joining materials with low melting point, patented in 1991 by the American Welding Institute (UK). This method uses the heat generated by mechanical friction between two moving parts, one is the tool rotates and is fastened on the spindle of a conventional milling machine and the other is the part that is attached and is gagged on the bed of the machine. Among the variables identified as the most important for a successful run of the process are the revolutions per minute (RPM) at which the tool rotates, the speed advance at which the workpiece and the tool design as such moves [1]. In this paper the design of several tools applied to FSW process is studied in specific dissipation of heat generated by mechanical friction between the parts, its relation to tool design and qualities of successful meetings is presented, the methodology to achieve this goal was first identify the possible and applicable materials for the tools, second his respective designs to ensure the right function for operation, and finally define FSW technical parameters (RPM, Head angle, speed advance) for experimental tests. The findings and conclusions attribute a novel analysis in the design of tools for this innovative manufacturing process, in the analysis of the results obtained for each of the assemblies experimentation it was discovered that the use of rings at the parts are not decisive for a good weld even heat dispersion is not good.

scholarly journals Investigation of mechanical and micro structural properties of ST14 steel sheet joints by friction stir welding process

2020 ◽  
Author(s):  
Mahmoud Afshari ◽  
Ehsan Salahshour Rad ◽  
Hossein Norozi Foroushani ◽  
Iraj Sattari Far
Keyword(s):  
Friction Stir Welding ◽  
Tungsten Carbide ◽  
Rotational Speed ◽  
Welding Process ◽  
Linear Motion ◽  
Friction Stir ◽  
Friction Stir Welding Process ◽  
Motion Speed ◽  
St14 Steel ◽  
Carbide Particles

Abstract High strength and ductility are some of reasons that make ST14 steel one of the most widely used steels in automotive and aerospace industries. FSW is one of the new methods of solid-state welding that is proposed as a method with desirable mechanical properties.In this study, mechanical and microstructural properties of 1.5mm thick ST14 steel sheets were investigated in the friction stir welding process. The results showed that the welded specimen with rotational speed of 800 rpm and linear motion speed of 80 mm/min had the highest tensile strength of 305MPa. In addition, results of metallographic test showed that the sample with 1000 rpm rotational speed and 50 mm/min linear motion speed had the highest heat input to the piece, and therefore the tungsten carbide particles were separated from the instrument and entered the stirred zone. Also the results of micro hardness test showed that in the welded specimen with rotational speed of 1000 rpm and linear motion speed of 50 mm/min, hardness increased to 115H1 HV in the stirred zone, which is higher than hardness of other samples in same region. It can be claimed that tungsten carbide particles are present in this area.

Experimental investigation and optimization of mechanical properties on combination of higher and lower strength of aluminum alloys

2021 ◽  
pp. 095440892110606
Author(s):  
C Ganesan ◽  
K Manonmani
Keyword(s):  
Mechanical Properties ◽  
Friction Stir Welding ◽  
Welding Speed ◽  
Rotational Speed ◽  
Axial Load ◽  
Welding Process ◽  
Process Parameter ◽  
Nugget Zone ◽  
Friction Stir ◽  
Tool Pin

Friction stir welding is a high potential technology for joining similar and dissimilar aluminum materials, utilized extensively in aerospace and automotive industrial applications to eradicate the problems like hot cracking, porosity, element loss, etc. due to the fusion welding process. This Research addresses the joining of two dissimilar materials of AA 5754 – H32 and AA 8090T6511 – Al-Li and their mechanical properties analysis with the effects of friction stir welding process parameters like tool rotational speed, welding speed and axial load on weld nugget zone formation quality. The significant roles of different tool pin profiles are also emphasized. A mathematical modeling equation was formed by using regression analysis to optimize the process parameter and found the best tool pin profile for defect-free weld nugget zone and higher tensile and hardness properties. This research also portrays the contribution of various pin profiles and each process parameter on the ultimate tensile strength by response surface methodology. The results indicate that the defect-free weld joints are observed with 1800 r/min of rotational speed, welding speed of 15 mm min−1 and 8.5 kN of axial load with hexagonal pin profile.

Effects of Heat Dissipation from Friction Stir Welding to Microstructures of Semi-Solid Cast 6063 Al Alloy

2021 ◽  
Vol 904 ◽  
pp. 70-75
Author(s):  
Chaiyoot Meengam ◽  
Kittima Sillapasa ◽  
Yotsakorn Pratumwal ◽  
Somboon Otarawanna
Keyword(s):  
Friction Stir Welding ◽  
Heat Dissipation ◽  
Maximum Temperature ◽  
Al Alloy ◽  
Element Analysis ◽  
Friction Stir ◽  
Tool Shoulder ◽  
Measurement Results ◽  
6063 Al Alloy ◽  
Semi Solid

In this work, temperature distribution in semi-solid cast 6063 aluminum alloy workpieces during friction stir welding (FSW) was determined by finite element analysis (FEA). The FEA results were validated by comparing them with the measurement results from thermocouples. The maximum temperature of 534.2oC was predicted at the workpiece surface contacted with the tool shoulder. The temperature profiles obtained from FEA were used to explain microstructural changes during FSW. It was observed that relatively high temperature made α-Al grains became elongated and Mg2Si intermatalics turned into a rod-like morphology with round edges.

Effect of Shoulder Diameter on the Resulting Interfacial Regions of Friction Stir Welds between Aluminium and Copper

2011 ◽  
Vol 299-300 ◽  
pp. 1146-1150
Author(s):  
Esther Titilayo Akinlabi ◽  
Stephen Akinlabi
Keyword(s):  
Friction Stir Welding ◽  
Feed Rate ◽  
Rotational Speed ◽  
Force Feedback ◽  
Welding Process ◽  
Microstructural Characterization ◽  
Stir Zone ◽  
Vertical Force ◽  
Friction Stir ◽  
Shoulder Diameter

This paper reports the effect of shoulder diameter on the resulting interfacial regions of joints between aluminium and copper produced by the friction stir welding process. The welds were produced using three shoulder diameter tools, viz; 15, 18 and 25 mm. This paper focuses on welds produced at a constant rotational speed of 600 rpm and feed rate of 50 mm/min varying the shoulder diameters. Analysis of the force feedback revealed that the advancing force, the downward vertical force and the torque increases as the shoulder diameter increases. Microstructural characterization was conducted on the joint interfaces and it was observed that the widths of the interfacial regions comprising of the Stir Zone and the Thermo – Mechanically Affected Zone (TMAZ) increases as the shoulder size increases.

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.

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