scholarly journals Analysis of Tools used in Friction Stir Welding process

Author(s):  
Akshansh Mishra ◽  
Adarsh Tiwari ◽  
Mayank Kumar Shukla ◽  
A. Razal Rose

A relatively new joining process, friction stir welding (FSW) produces no fumes; uses no filler material; and can join aluminium alloys, copper, magnesium, zinc, steels, and titanium. FSW sometimes produces a weld that is stronger than the base material. The tool geometry plays a critical role in material flow and governs the transverse rate at which FSW can be conducted. The tool serves three primary functions, i.e., (a) heating of the work piece, (b) movement of material to produce the joint, and (c) containment of the hot metal beneath the tool shoulder. Heating is created within the work piece by friction between both the rotating tool pin and shoulder and by severe plastic deformation of the work.

Friction Stir Welding (FSW) is a topical and propitious solid-state joining process producing economical and strengthened joints of age-hardened and heat-treatable Aluminium Alloy AA 6082-T6. Mechanical and fractural behaviour of weldments were investigated in order to find crack initiation and necking on the weld zone thereby perceiving the complete behaviour of fracture occurred near the weld zone. Weldments are fabricated by employing four tool pin profiles namely MX-TRIVEX, A-SKEW, Three flat threaded and Concave shouldered MX-TRIFLUTE tools at various rotational speeds 1000 rpm, 1200 rpm and 1400 rpm at single traverse speed 25 mm/min. EXCETEX-EX-40 CNC wire cut EDM with 0.25 mm brass wire diameter has been employed to perform the extraction of tensile test specimens from the weldments according to ASTM E8M-04 standard. Tensile test was performed on elctromechanically servo controlled TUE-C-200 (UTM machine) according to ASTM B557-16 standards Maximum Ultimate Tensile Strength (UTS) of 172.33 MPa (55.5% of base material) and 0.2% Yield Stress (YS) of 134.10 MPa (51.5% of base material) were obtained by using A-SKEW at 1400 rpm, 25 mm/min and maximum % Elongation (%El) of 11.33 (113.3% of base material) was obtained at MX-TRIVEX at 1000 rpm, 25 mm/min. Minimum UTS of 131.16 MPa (42.30% of base material) and 0.2% YS of 105.207 MPa (40.46% of base material )were obtained by using Concave shouldered MX-TRIFLUTE at 1400 rpm, 25 mm/min. Minimum % El of 5.42 ( 54.2% of base material) was obtained by using A-SKEW at 1000 rpm, 25 mm/min.


Author(s):  
Hosein Atharifar ◽  
Radovan Kovacevic

Minimizing consumed energy in friction stir welding (FSW) is one of the prominent considerations in the process development. Modifications of the FSW tool geometry might be categorized as the initial attempt to achieve a minimum FSW effort. Advanced tool pin and shoulder features as well as a low-conductive backing plate, high-conductive FSW tools equipped with cooling fins, and single or multi-step welding processes are all carried out to achieve a flawless weld with reduced welding effort. The outcomes of these attempts are considerable, primarily when the tool pin traditional designs are replaced with threaded, Trifiute or Trivex geometries. Nevertheless, the problem remains as to how an inclined tool affects the material flow characteristics and the loads applied to the tool. It is experimentally proven that a positive rake angle facilitates the traverse motion of the FSW tool; however, few computational evidences were provided. In this study, numerical material flow and heat transfer analysis are carried out for the presumed tool rake angle ranging from −4° to 4°. Afterwards, the effects of the tool rake angle to the dynamic pressure distribution, strain-rates, and velocity profiles are numerically computed. Furthermore, coefficients of drag, lift, and side force and moment applied to the tool from the visco-plastic material region are computed for each of the tool rake angles. Eventually, this paper confirms that the rake angle dramatically affects the magnitude of the loads applied to the FSW tool, and the developed advanced numerical model might be used to find optimum tool rake angle for other aluminum alloys.


Friction stir welding is a solid state welding which uses non consumable welding tool. It is an automatic process which generally performs on the vertical milling machine. In this type of welding, the relative motion between the tools and work piece creates heat which uses the region of work piece to be welded get softened and to joint the two work pieces. Friction stir welding process is more reliable for the materials which are generally non heat treatable. In this present investigation it will observe that how the rotational speeds of the tool and different shapes of the tool pins effects the mechanical properties of the aluminium alloy 6082. For this purpose three tools with different profiles, i.e triangular, cylindrical and square was designed and fabricated. At three different rotational speeds of 560 rpm, 900 rpm, 1800 rpm work pieces are joined using vertical milling machine. Specimens are prepared and tested for mechanical properties, tensile, impact, and hardness tests are performed and to detect the defects and voids x-ray test performed on the weld joints. And it was observed that highest tensile strength was presented when the square pin tool used at 560 rpm. The rotational speed increased mechanical properties are reducing significantly.


2021 ◽  
Vol 40 ◽  
pp. 1-11
Author(s):  
Gagandeep Singh ◽  
Khushdeep Goyal ◽  
Baljinder Ram ◽  
Bal Krishan

In this research paper, two different metal plates of aluminum alloy viz. AA6061 and AA6101 were welded with friction stir welding process. Round tool and square tool pin profiles were used to weld the alloys. Weld microstructures, hardness, and tensile properties were evaluated in as-welded condition. The tensile strength of the joints fabricated with round tool pin profile were lower than the square tool pin profile because of the pulsating effect, in square tool pin profile this effect was produced along with the higher frictional forces. The micro-hardness of friction stir zone was higher than the base material due to active recrystallization occurrence which resulted in fine grain size in case of weld joint with round pin profile. Microstructure indicated uniformly distribution of materials with minimum heat affected zone and dense welded zone without any defects.


2014 ◽  
Vol 592-594 ◽  
pp. 312-315 ◽  
Author(s):  
P. Sevvel ◽  
V. Jaiganesh

In this paper, a detailed experimental investigation was carried on the impact of the effects of tool pin and shoulder diameter in joining the Al 63400 aluminium alloy using FSW process. Flat plates of 6 mm thickness have been selected as the base material for obtaining single butt welded joints. The tool materials used for joining these base material plates are High Speed Steel (HSS) and High Chromium High Carbon Steel (HCHCr). This paper experimentally investigates and suggests the appropriate, suitable tool material & tool geometry for producing good quality welds in joining of Al 63400 alloy using FSW process.


Materials ◽  
2019 ◽  
Vol 12 (20) ◽  
pp. 3387 ◽  
Author(s):  
Tingke Wu ◽  
Fengqun Zhao ◽  
Haitao Luo ◽  
Haonan Wang ◽  
Yuxin Li

Aiming at the problems that the temperature in the welding area of friction stir welding (FSW) is difficult to measure and the joints are prone to defects. Hence, it is particularly important to study the material flow in the welding area and improve the welding quality. The temperature of the tool shoulder and the tool pin was monitored by the wireless temperature measuring system. The finite element model of friction stir welding was established and the welding conditions were numerically simulated. The flow law of material of the friction stir welding process was studied by numerical simulation. The material flow model was established by combining the microstructure analysis results, and the forming mechanism of the defects was analyzed. The results show that the temperature in the welding zone is the highest at 1300 rpm, and the temperature at the tool shoulder is significantly higher than that at the tool pin in the welding stage. When high-rotation speeds (HRS) are chosen, the material beneath the tool shoulder tends to be extruded into the pin stirred zone (PSZ) after flowing back to the advancing side. This will cause turbulence phenomenon in the advancing side of the joint, which will easily lead to the formation of welding defects. In the future, temperature monitoring methods and the flow model of material can be used to optimize the welding parameters.


2016 ◽  
Vol 20 (5) ◽  
pp. 1693-1701
Author(s):  
Alin Murariu ◽  
Darko Veljic ◽  
Dragana Barjaktarevic ◽  
Marko Rakin ◽  
Nenad Radovic ◽  
...  

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.


2019 ◽  
Vol 8 (4) ◽  
pp. 10975-10980

This review paper will discuss about the joining process of Aluminium 3D printing materials by using friction stir welding process. Currently, the studies on the joining of 3D printing materials by friction stir welding are very limited. Through this review, the joining materials characteristics such as weld efficiency, hardness and microstructure after friction stir welding process will be discussed to identify the behavior of weld joint materials. Understanding the friction stir welding process on 3D printing materials is importance in order to support the future advancement of 3D printing technology in terms of 3D printing part repairing activity and the secondary process such as the joining of 3D printing parts. In this paper, the fundamental concept of friction stir welding and powder bed fusion 3D printing is discussed. At the end of the review, the summary of friction stir welding process on Aluminium 3D printing materials concluded that the joining process is feasible to weld the materials with joint efficiency 83.3% and modify the base material characteristic of the 3D printing materials.


Author(s):  
Bambang Kusharjanta ◽  
Rudy Soenoko ◽  
Anindito Purnowidodo ◽  
Yudy Surya Irawan

The aim of this study was to investigate the crystallinity changes and degradation of polypropylene due to heat generated by friction stir welding, i.e., heat generated by friction between the rotation tool and the welded materials. The tool pin was rotated at 620 rpm in the welding process. The travelling speed was varied between 7.3 mm/minute and 13 mm/minute. A cylindrical tool pin, 4.5 mm in diameter and 5.7 mm in length, was used in this experiment. The shoulder dimension was 18 mm in diameter and 90 mm in length. A conventional milling machine was used in the friction stir welding process. The crystallinity test was carried out with X-ray diffraction, hardness was observed using a Shore Type-D durometer, and polymer degradation data was obtained by thermogravimetry analysis. The areas compared were base material, weld nugget area, and thermomechanical affected zone. The results showed that there was a change in the percentage of crystallinity in areas that had undergone friction stir welding, and that the change was inversely proportional to the traveling rate of the friction stir welding process. The friction stir welding process was affected by the initial degradation temperature and hardness property of the polypropylene. This result shows that it is possible to choose specific parameters of friction stir welding in order to obtain good weld joint properties.


2017 ◽  
Vol 61 (4) ◽  
pp. 296 ◽  
Author(s):  
Kayode Oyedemi ◽  
Patrick McGrath ◽  
Hannalie Lombard ◽  
Balázs Varbai

This paper presents research work conducted to experimentally establish the process response of two diverse shaped tool-pin profiles for friction stir welding (FSW) AA6082-T6 aluminium. The dwell time was optimised by plunging each tool-pin into a plate sample until the spindle torque stabilised thus ensuring sufficient plasticised material in contact with tool shoulder and the tool-pins. The welds were conducted by employing the optimised dwell time, which in turn revealed a minimised process response time and distance to reach weld stability with respect to (1) the force exerted on the tool-pin in the welding direction, Fx , and (2) the spindle torque, T, during the welding process. Both Fx and T stabilised well within the set (pre-determined) ramp-up distance of 20 mm, indicating that the effective (useful) weld length is maximised. The macrographs also revealed good dynamic material flow within the nugget zone regions and more evident in the nugget zone of the flared tool.


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