scholarly journals Mathematical Simulating of the Process of Friction Stir Welding for the Manufacture of Tank Bottoms in Aerospace Construction

2020 ◽  
Vol 35 ◽  
pp. 04014
Author(s):  
Pavel V. Kruglov ◽  
Alexey G. Ponarin ◽  
Irina A. Bolotina

In modern aerospace technology, one of the perspective ways of assembly parts of thin metal plates is friction stir welding. The advantage of this method is the higher strength of the welds of aluminum alloy joints, compared with the traditional MIG welding for the assembly of rockets and space constructions. However, the lack of friction stir welding is a necessity of formation of the system “machine –tool - part” significantly more effort, which is caused by the need to stir the material in the weld zone in a plastic state. Friction stir welding is used to connect the individual elements of tanks and bodies, in particular, panels, elements of the bottoms with each other. In this paper, is consider the typical design for rocket and space technology bottoms of large tanks. For industrial robot equipped with a special head for friction welding with mixing, a mathematical model of obtaining a spherical bottom from individual segments is proposed. The paper presents a mathematical model describing the geometry of a spherical bottom with a flap articulation and a working zone of an industrial robot, which allows defining constraints on process operation continuous seam welding for standard designs of bottoms and hulls of rocket and space technology. The dependences allowing determining the initial position of the robot relative to the bottom for performing friction stir welding of the continuous seam are proposed.

2005 ◽  
Vol 486-487 ◽  
pp. 249-252 ◽  
Author(s):  
Chang Yong Lee ◽  
Won Bae Lee ◽  
Yun Mo Yeon ◽  
Seung Boo Jung

Friction stir welding of dissimilar formed Mg alloys(AZ31/AZ91) was successfully carried out at the limited welding conditions. In a sound joint, SZ was mainly consisted of AZ31 Mg alloy which was located the retreating side. Dynamic recrystallization and grain growth occurred and β intermetallic compounds of AZ 91 Mg alloy was not observed in SZ. BM had a higher hardness than that of the weld zone. The fracture location was not weld zone but BM of the AZ91 Mg alloy in tensile test.


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.


1998 ◽  
Vol 4 (S2) ◽  
pp. 530-531
Author(s):  
R. D. Flores ◽  
L. E. Murr ◽  
E. A. Trillo

Although friction-stir welding has been developing as a viable industrial joining process over the past decade, only little attention has been given to the elucidation of associated microstructures. We have recently produced welds of copper to 6061 aluminum alloy using the technique illustrated in Fig. 1. In this process, a steel tool rod (0.6 cm diameter) or head-pin (HP) traverses the seam of 0.64 cm thick plates of copper butted against 6061-T6 aluminum at a rate (T in Fig. 1) of 1 mm/s; and rotating at a speed (R in Fig. 1) of 650 rpm (Fig. 1). A rather remarkable welding of these two materials results at temperatures measured to be around 400°C for 6061-T6 aluminum welded to itself. Consequently, the metals are stirred into one another by extreme plastic deformation which universally seems to involve dynamic recrystallization in the actual weld zone. There is no melting.


Author(s):  
Xun Liu ◽  
Sheng Zhao ◽  
Kai Chen ◽  
Jun Ni

In this study, the friction stir welding (FSW) of aluminum alloy 6061-T6511 to TRIP 780 steel is analyzed under various process conditions. Two FSW tools with different sizes are used. To understand the underlying joining mechanisms and material flow behavior, nano-computed tomography (nano-CT) is applied for a 3D visualization of material distribution in the weld. With insufficient heat input, steel fragments are generally scattered in the weld zone in large pieces. This is observed in a combined condition of big tool, small tool offset, and low rotating speed or a small tool with low rotating speed. Higher heat input improves the material flowability and generates a continuous strip of steel. The remaining steel fragments are much finer. When the volume fraction of steel involved in the stirring nugget is small, this steel strip can be in a flat shape near the bottom, which generally corresponds to a better joint quality and the joint would fracture in the base aluminum side. Otherwise, a hook structure is formed and reduces the joint strength. The joint would fail with a combined brittle behavior on the steel hook and a ductile behavior in the surrounding aluminum matrix.


2015 ◽  
Vol 63 (2) ◽  
pp. 475-478
Author(s):  
I. Küçükrendeci

Abstract In the study, the mechanical and microstructural properties of friction stir welded EN AW-6060 Aluminum Alloy plates were investigated. The friction stir welding (FSW) was conducted at tool rotational speeds of 900, 1250, and 1500 rpm and at welding speeds of 100, 150 and 180 mm/min. The effect of the tool rotational and welding speeds such properties was studied. The mechanical properties of the joints were evaluated by means of micro-hardness (HV) and tensile tests at room temperature. The tensile properties of the friction stir welded tensile specimens depend significantly on both the tool rotational and welding speeds. The microstructural evolution of the weld zone was analysed by optical observations of the weld zones


2011 ◽  
Vol 230-232 ◽  
pp. 1255-1259
Author(s):  
T. Khairuddin Jauhari ◽  
I.P. Almanar ◽  
Hussain Zuhailawati

Major works concentrated on the energy conversion from mechanical friction work to heat; emphasized on the immediate contact surface of work material and rotating welding tool but with no in-depth analytical study to relate the loads that are transferred to the work material and the welding fixture especially at early stage of heat generation. In this work, a mathematical model is developed to predict three-dimensional force components and axial torque of the rotating tool based on contact mechanic principle in relation to Al6061 temperature-dependent material properties. The model shows the ability to be possibly adapted for different metallic material and physical properties. It suggests the exerted torque and loads calculation endured by work material involving friction and shear mechanism of two static-dynamic contacting surface; rotating rotational tool and the fixed work material, to be used as one of the option for optimization of the welding process such as to determine the ratio of slip, non-slip contact condition through comparisons of experimental and computer simulation on the Friction Stir Welding process.


Author(s):  
Wei Tang ◽  
Maxim Gussev ◽  
Zhili Feng ◽  
Brian Gibson ◽  
Roger Miller ◽  
...  

Abstract The mitigation of helium induced cracking in the heat affected zone (HAZ), a transition metallurgical zone between the weld zone and base metal, during repair welding is a great challenge in nuclear industry. Successful traditional fusion welding repairs are limited to metals with a maximum of a couple of atomic parts per million (appm) helium, and structural materials helium levels in operating nuclear power plants are generally exceed a couple of appm after years of operations. Therefore, fusion welding is very limited in nuclear power plants structural materials repairing. Friction stir welding (FSW) is a solid-state joining technology that reduces the drivers (temperature and tensile residual stress) for helium-induced cracking. This paper will detail initial procedural development of FSW weld trials on irradiated 304L stainless steel (304L SS) coupons utilizing a unique welding facility located at one of Oak Ridge National Laboratory’s hot cell facilities. The successful early results of FSW of an irradiated 304L SS coupon containing high helium are discussed. Helium induced cracking was not observed by scanning electron microscopy in the friction stir weld zone and the metallurgical zones between the weld zone and base metal, i.e. thermal mechanical affected zone (TMAZ) and HAZ. Characterization of the weld, TMAZ and HAZ regions are detailed in this paper.


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