Wyniki wyszukiwania - BazTech

1

Deep Convolutional Neural Network Algorithm for Prediction of the Mechanical Properties of FSW Copper Welds from its Microstructure

Mishra Akshansh, Suman Asmita

Welding Technology Review

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2023

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R. 95

25--31

EN

Convolutional Neural Network (CNN) is a special type of Artificial Neural Network which takes input in the form of an image. Like Artificial Neural Network they consist of weights that are estimated during training, neurons (activation functions), and an objective (loss function). CNN is finding various applications in image recognition, semantic segmentation, object detection, and localization. The present work deals with the prediction of the welding efficiency of the Friction Stir Welded joints on the basis of microstructure images by carrying out training on 3000 microstructure images and further testing on 300 microstructure images. The loss function decreased for both training and testing set decreased with the increasing number of epochs. The obtained results showed an accuracy of 80 % on the validation dataset.

2

Numerical analysis of stress and temperature in the friction stir welding (FSW) process of steel

Szczecina Michał

Structure and Environment

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2023

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Vol. 15, no. 4

196--207

EN

Friction stir welding (FSW) is a modern technology for joining various metals, which has already undergone many laboratory tests, but still requires the development of numerical models. Author of the paper decided to summarize the current state of scientific knowledge regarding the modelling of the FSW process using the finite element method (FEM) and showed the main directions of development of numerical research on this process. Very advanced models are a combination of solid mechanics and fluid dynamics, but they often require expanding the computing environment with its own subroutines, as well as calibration and validation of some material parameter and constants occurring e.g. in the heat generation and heat flow laws. The Author of the paper proposed his own, simplified model, based on the computational solid mechanics and Lagrangian formulation. The model turned out to be an effective tool to reproduce stress and temperature fields during the FSW process.

PL

Zgrzewanie tarciowe z przemieszaniem (FSW) jest nowoczesną technologią łączenia różnych metali, posiadającą wiele zalet w porównaniu z tradycyjnym spawaniem. Zgrzewanie tarciowe zostało do tej pory poddane licznym badaniom laboratoryjnym, natomiast wymaga ciągłego rozwoju modeli numerycznych do symulacji tego procesu metodą elementów skończonych (MES). Autor artykułu postanowił dokonać podsumowania aktualnego stanu wiedzy dotyczącej modelowania zgrzewania tarciowego przy użyciu MES oraz wskazać główne kierunki rozwoju symulacji numerycznych tego procesu. Zaawansowane modele numeryczne zgrzewania tarciowego są kombinacją mechaniki ciała stałego z dynamiką płynów, a więc często wymagają rozbudowania środowiska obliczeniowego za pomocą własnych podprogramów, jak również kalibracji i walidacji wielu parametrów i stałych wymaganych do zdefiniowania np. prawa wytwarzania ciepła i prawa przepływu strumienia ciepła. Autor zaproponował swój własny uproszczony model bazujący na mechanice ciała stałego i opisie Lagrange’a. Model okazał się efektywnym narzędziem do odtworzenia naprężeń i pola temperatury w procesie zgrzewania tarciowego z przemieszaniem.

3

Wykonywanie połączeń różnoimiennych ze stopów aluminium metodami spawania łukowego i FSW

Węglowska Aleksandra, Rykała Janusz, Pfeifer Tomasz, Pietrzak Jacek

Maszyny Elektryczne : zeszyty problemowe

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2023

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Nr 1 (128)

103--107

PL

Przedstawiono wyniki badań spawania TIG i MIG oraz zgrzewania FSW złączy z blach ze stopu aluminium EN AW6082, EN AW 5754 oraz odlewniczego stopu EN AC-43200. Scharakteryzowano stopy Al-Mg oraz Al-Mg-Si i ich spawalność. W ramach realizowanych badań przeprowadzono dobór warunków spawania i zgrzewania różnoimiennych stopów aluminium. Złącza poddano badaniom wizualnym, metalograficznym makroskopowym, penetracyjnym (złącza spawane) oraz własności mechanicznych w statycznej próbie rozciągania i zginania (złącza zgrzewane FSW). Na podstawie wyników badań realizowanych w Łukasiewicz – GIT oceniono, że jakość złączy spawanych zależy od przygotowania elementów do spawania, natomiast złączy zgrzewanych od parametrów zgrzewania i ustawienia stopów Al w złączu względem ruchu obrotowego narzędzia.

EN

Results of TIG, MIG and FSW welding technologies of joints made of EN AW-6082, EN AW 5754 aluminum alloy sheets and EN AC-43200 casting alloy are presented. This article briefly presents the characteristics of Al-Mg and Al-Mg-Si alloys and their weldability. As part of the research welding conditions for dissimilar aluminum alloys were selected. The joints were subjected to the visual and penetrant tests (TIG, MIG joints), light microscopy examination as well as tensile and bend tests (FSW joints). Based on the test results obtained in Łukasiewicz – GIT, it was found that the quality of arc welded joints depends on the preparation of the elements for welding, while the quality of FSW joints depends on the welding parameters and the positioning of Al alloys in the joint in relation to the rotational movement of the tool.

4

Research on the post-weld explosive hardening of AA7075-T651 friction stir welded butt joints

Kosturek Robert, Lewczuk Rafał, Torzewski Janusz, Wachowski Marcin, Słabik Piotr, Maranda Andrzej

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2023

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Vol. 71, nr 4

art. no. e145685

EN

In this paper, the post-weld explosive hardening of a 5 mm AA7075-T651 plate welded via FSW was performed. To investigate the possibility of increasing FSW joint mechanical properties, the welded plate was explosively treated with four various explosive materials (ammonal, emulsion explosive, FOX-7, and PBX) in two different hardening systems. As part of the investigation, the observations of the surface and macrostructure of the treated plates were described. The obtained microhardness distribution allowed us to register the increase in hardness of the SZ up to 6%, but no increase in hardness of the LHZ was reported. In most cases, the influence of explosive treatment on the mechanical properties of the welded joint was disadvantageous as ultimate tensile strength and ductility were reduced. The only positive effect which was observed is the increase in the value of yield strength up to 27% corresponding to 77 MPa, achieved by explosive materials with detonation velocity below 3000 m/s.

5

The Effects of Friction Stir Welding Parameters on Microstructure, Fatigue Life and Tensile Properties of Aluminum 2024-T3 Alloy

Şık Aydın, Özer Alpay

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 2

499--505

EN

In this study, Al 2024-T3 alloy plates were joined by using friction stir welding. Welding was performed at a rotational speed of 930, 1450, 2280 rpm and a welding feed rate of 180 mm min-1. The welded samples were analyzed at the microstructural level. Moreover, both bending fatigue tests and tensile tests were performed on samples. At the end of the microstructural examination of the samples welded at the rotational speed of 930 rpm and the welding feed rate of 180 mm min-1, the formation of tunnel defects was observed. The highest fatigue life was obtained at 2280 rpm and 180 mm min-1. The lowest fatigue life was obtained at 930 rpm and 180 mm min -1. The highest ultimate tensile stress was obtained at 2280 rpm/180 mm min-1 sample, which shows about a 12% reduction relative to the base material. The lowest ultimate tensile stress was obtained at 930 rpm/180 mm min-1 sample. The ultimate tensile stress value of the 930 rpm/180 mm min-1 sample decreased by approximately 25%.

6

Effect of Welding Conditions on Microstructural Evolution of Friction-Stir-Welded Ti-Cu Plate

Lee Yong-Jae, Jeong Won-Ki, Lee Seung-Jun, Fujii Hidetoshi, Shin Se Eun, Lee Dong-Geun

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 1

131--135

EN

Fusion welding of Ti-Cu is difficult because of big difference of melting points and formation of brittle intermetallic compounds. Friction stir welding is carried out by solid-state joining, thermo-mechanical stirring, and friction heat. Ti-Cu FSW dissimilar welding can supply a very sound joint area with a few intermetallic compounds. Optimized welding process conditions are essential to obtain suitable microstructure and mechanical properties of welded zones. Different welding speeds affect the evolution of microstructure and mechanical properties due to changes of input heat and internal stored deformation energy. The correlation of microstructure and mechanical properties of Ti-Cu welded zone according to welding speeds were investigated and analyzed. As the higher the welding speed, the lower the heat input and the lower the temperature rise. Ti-Cu 75 has the smallest grain size at 13.9 μm, but the optimum mechanical properties and the integrity of welding were shown in Ti-Cu 50.

7

Influence of tool pin profile and welding parameters on microstructure and mechanical properties of dissimilar friction stir welded AA2024 to AA7075 alloys

Mohammed H. B., Naemah I. M., Jomah A. J. S., Alrubaiy A. A. A. G.

Archives of Materials Science and Engineering

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2023

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Vol. 124, nr 1

14--24

EN

Purpose: The paper aims to produce aluminium welds in the solid state with good specifications and the least amount of welding defects by using the friction stir welding method (FSW) and different tool pin profiles and welding parameters. The research investigated the mechanical characteristics and microstructure of a friction stir welded dissimilar aluminium alloy (2024-T3 to 7075-0) through thickness produced by varying welding settings and three different FSW tool pin shapes. Design/methodology/approach: The objective is to obtain the welds with the least amount of welding defects in the solid state by using the friction stir welding method (FSW), designing the tool pin profiles, and changing the rotation speeds. Findings: According to tensile strength and micro-hardness tests, tool rotation of 2000 rpm and square pin profile were the best compared to other working parameters. The greatest hardness and highest tensile strength of FSWed dissimilar aluminium joints have been 144 HV and 215 MPa, respectively, when using the square pin profile at a tool rotation speed of 2000 rpm. The hardness and tensile strength of FSWed dissimilar aluminium alloy joints increase with the tool rotation speed. Microstructural observations of the FSWed dissimilar aluminium joints using a square pin profile at the tool rotation speed of 2000 rpm exhibited the weld zone's high weld quality. Additionally, there were no defects in the weld zone. The fracture surface of the FSWed joint indicated a ductile fracture type. Research limitations/implications: With many regions on either side of the weld with varied compositions, microstructures, and characteristics, the resulting welds of dissimilar alloys might result in unsatisfactory weld joints. Practical implications: The weld zone's exceptional weld quality was demonstrated by microstructural investigations of the FSWed dissimilar aluminium connections utilising a square pin profile at a tool rotation speed of 2000 rpm and feed rate of 20 mm per minute. Application in aerospace, shipbuilding and marine, railway, construction, electrical industries, and land transportation. Originality/value: The original value of the paper is the production of welds from dissimilar aluminium alloy (2024-T3 to 7075-0) with the least amount of welding defects by changing the tool pin profiles and tool rotation speeds using the friction stir welding method.

8

Computed Tomography and Scanning Electron Microscopy Analysis of a Friction Stir Welded Al-Cu Joint

Depczyński Wojciech P., Bańkowski Damian, Młynarczyk Piotr S.

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 4

65--71

EN

The study aimed touse3D computed tomography (CT) to analyse a joint between two dissimilar materials produced by friction stir welding (FSW). As the materials joined, i.e., aluminum and copper, differ in properties (e.g., density and melting point), the weld is predicted to have an inhomogeneous microstructure. The investigations involved applying microfocus computed tomography (micro-CT) to visualize and analyze the volumetric structure of the joint. Volume rendering is extremely useful because, unlike computer modelling, which requires many simplifications, it helps create highly accurate representations of objects. Image segmentation into regions was performed through global gray-scale thresholding. The analysis also included elemental mapping of the weld cross-sections using scanning electron microscopy (SEM) and examination of its surface morphology by means of optical microscopy (OP). The joint finds its use in developing elements used in the chemical, energetics and aerospace industries, due to the excellent possibilities of combining many different properties, and above all, reducing the weight of the structure.

9

Enhancing the properties of friction stir welded joints of L-PBF printed AlSi10Mg alloy via multi-variable optimization

Minhas Navdeep, Sharma Varun, Bhadauria Shailendra Singh

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e60, 2023

EN

The feasibility study to join the laser powder bed fused AlSi10Mg alloy sheets using different friction stir welding parameters was investigated in the present work. Fifteen butt-welded joints using varied parametric combinations were developed based on the design of the experiment's approach. An empirical model between the process parameters and tensile strength was developed and used to understand the mechanical behavior of the welded joints w.r.t. the FSW parameters, followed by the attainment of optimized welding conditions using response surface methodology. The results inferred that the weldability was most significantly influenced by the tool rotational speed, followed by the tool tilt angle and tool traverse speed. The microstructure and mechanical properties of the optimized welded joint were compared with the as-built alloy and the welded joint yielding minimum tensile strength. The electron back scattered diffraction analysis revealed the reduction of average grain size of the stir zone of the joints by 21% for the optimized weld, as compared to the as-built alloy. The welded zones of the joints showed a reduction in hardness by 40-50% and formed the stir zone as the weakest link. The parametric combinations of the optimized weld improved the joint efficiency by ≈ 20% compared to the other weld, followed by an improvement in ductility, which was further characterized using scanning electron microscopy.

10

Advances in friction stir welding of Ti6Al4V alloy complex geometries: T-butt joint with complete penetration

Ambrosio Danilo, Wagner Vincent, Vivas Javier, Dessein Gilles, Aldanondo Egoitz, Cahuc Olivier

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e182, 2023

EN

In this work, the friction stir weldability of Ti6Al4V T-joints has been investigated. Its aims are: (i) to study the influence of tool and welding parameters on weld quality, (ii) to assess the joints’ mechanical strength to foresee future applications, and (iii) to characterize Co-based FSW tools’ wear by following the wear during the tests. Welds’ defectivity is studied by cross-section macrographies analysis. Independently from welding parameters and tools, internal voids are avoided, and a suitable weldability window is identified. Microstructure observations have corroborated temperatures below the -transus point even in the nugget zone, guaranteeing joints’ maximum mechanical strengths at 96% and 87% of the base material for UTS and Y, respectively. Contrarily, elongation at break is very low, without reaching 20% of the base material. The failure is linked to section thinning and kissing bond defects at the joints’ corners. Additionally, tool wear proved to be a critical issue while friction stir welding Ti6Al4V. The inner part of the shoulder is the most sensitive to wear. The consequent high wear rate might be a problem for mass production. The work established the pertinence of assembling complex geometries of Ti6Al4V using friction stir welding, considering weld quality and the mechanical strength achieved. However, critical factors such as section thinning, kissing bond, and tool wear must be carefully addressed to avoid joints’ low elongation at break and to guarantee their mechanical strength.

11

The Effect of Brushing on Residual Stress and Surface Roughness of EN AW-2024-T3 Aluminum Alloy Joints Welded Using the FSW Method

Bucior Magdalena, Kluz Rafał, Kubit Andrzej, Ochał Kamil

Advances in Science and Technology. Research Journal

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2023

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Vol. 17, no 1

86--93

EN

This article presents the influence of the brushing process on residual stress and surface roughness of EN AW-2024-T3 aluminum alloy joints welded using the Friction Stir Welding (FSW) method. Butt joints with thicknesses of 2 mm were brushing with using ceramic brush. The aim of the study was to find optimal parameters of the brushing process, which would significantly improve the functional properties of welded joints. The experiments were carried out in two steps. In the first stage of the research, the feed rate was changed in the range f = 40 ÷ 120 mm / min with a constant brushing depth d = 0.5 mm. The roughness decreased from Sa = 5.285 µm for the specimen after welding to Sa = 2.460 µm for the f = 120 mm/min and d = 0.5 mm. The change in the parameters of the brushing process did not have a significant impact on the state of residual stresses. Hence, in the second step, the brushing depth was increased in steps of 0.1 mm. The best properties were obtained for f = 120 mm / min and d = 0.6 mm (variant 6A), where roughness was Sa = 0.443 µm and compressive stresses σ = -118 MPa.

12

Mechanical and corrosion properties of Friction Stir Welded and Tungsten Inert Gas welded phosphor bronze

Gopi S., Mohan Dhanesh G., Natarajan Elango

Advances in Materials Science

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2023

|

Vol. 23, nr 4(78)

83--98

EN

This study investigated the mechanical and corrosion properties of Friction Stir Welded (FSW) and Tungsten Inert Gas (TIG) welded phosphor bronze (CuSn4) joints. Corrosion tests were conducted on the welded joints, and the percentage of weight loss due to corrosion was measured at different time intervals. Results revealed that the percentage of weight loss due to corrosion of the TIG joint increased with time, whereas the percentage of weight loss due to corrosion of the FSW welded joint remained constant. This could be attributed to recrystallisation that happened in the solid-state welding, which reduced corrosion in the FSW welded joint. In addition, tensile tests were conducted to evaluate the strength of the joints. FSW with a spindle speed of 1300 rpm, weld speed of 0.06mm/sec, plunge depth of 0.25mm, pin profile of pentagon, and flat shoulder profile was found to produce good results. TIG welding with a welding speed of 1.75mm/sec, a gas flow rate of 7.5 cm3/min and an amperage of 120A also produced good results. The tensile strength of FSW was found to be approximately 1.6 times higher than that of TIG welding.

13

A new tooling approach for friction stir welding of thin sheet AA2024-T3 - optimization of welding parameters

Myśliwiec Piotr

Zeszyty Naukowe Politechniki Rzeszowskiej. Mechanika

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2022

|

z. 94

37--50

EN

In this study a new ceramics tools with different groove distributions were designed and manufactured in order to enrich technological storage of joining thinwall structures and obtain sound joint with high quality of Alclad AA2024-T3 alloy of 0.5 mm in thickness. Four types of tools were tested, without grooves, with 1, 2 and 6 grooves. The tools are made of two materials. The straight shank is made from tungsten carbide and tool body made from ceramics strengthened with whiskers. The influence of technological parameters on the strength of FSW joints was tested by the Response Surface Methodology (RSM) and Analysis of Variance (ANOVA) method. The least durable weld is produced by a tool without grooves. The single and double flute tool produces a good quality weld over a wide range of tool speeds. It has been shown that the grooves on the tool shoulder significantly affect the quality of the obtained FSW joint.

PL

W pracy zaprojektowano i wykonano nowe narzędzia ceramiczne o różnym rozkładzie rowków w celu wzbogacenia technologii łączenia konstrukcji cienkościennych i uzyskania wysokiej jakości połączenia blach ze stopu aluminium AA2024-T3 Alclad o grubości 0,5 mm. Przetestowano cztery typy narzędzi, bez rowków, z 1, 2 i 6 rowkami. Narzędzia wykonano z dwóch materiałów. Część chwytową wykonano z węglika wolframu, a korpus narzędzia z ceramiki wzmocnionej whiskerami. Wpływ parametrów technologicznych na wytrzymałość złączy FSW badano metodami analizy powierzchni odpowiedzi (RSM) oraz analizy wariancji (ANOVA). Najmniej trwałą spoinę wytworzyło narzędzie bez rowków. Narzędzie z pojedynczym i podwójnym rowkiem zapewniło dobrej jakości spoinę w szerokim zakresie prędkości obrotowych narzędzia. Wykazano, że rowki na kołnierzu narzędzia istotnie wpływają na jakość uzyskanego połączenia FSW.

14

Zastosowanie zgrzewania tarciowego z przemieszaniem (FSW) do wykonywania połączeń doczołowych wysokowytrzymałych stopów aluminium stosowanych w przemyśle zbrojeniowym

Kosturek Robert

Stal, Metale & Nowe Technologie

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2022

|

nr 9-10

38--41

PL

Otrzymywanie wysokiej jakości połączeń spójnościowych umacnianych wydzieleniowo stopów aluminium stanowi jedną z decydujących batalii na froncie rozwoju współczesnej techniki, będąc istotnym motorem postępu przemysłu motoryzacyjnego, lotniczego i zbrojeniowego.

EN

This paper presents selected results of research concerning AA2519-T62 and AA7075-T651 butt joints produced with the FSW technique, including macroscopic observations, microhardness distributions and tensile tests. The applied welding technique enabled obtaining high-quality welds of the 87% and 77% joint efficiencies for AA2519-T62 and AA7075- -T651 respectively.

15

Zgrzewanie tarciowe z przemieszaniem blach cienkościennych z zastosowaniem podgrzewania

Ochałek Krzysztof

Hutnik, Wiadomości Hutnicze

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2022

|

Vol. 89, nr 1

10--13

PL

W pracy przedstawiono podstawowe informacje na temat zgrzewania tarciowego z przemieszaniem. Skupiono się na problemie, jakim są występujące podczas zgrzewania odkształcenia cienkościennych blach ze stopu 2024 T351. W celu zniwelowania deformacji zaprojektowano i wykonano uchwyt z płytą podgrzewającą elementy zgrzewane. Zabieg podgrzewania zgrzewanych blach ma na celu obniżenie naprężeń chwilowych, a co za tym idzie zmniejszenie ich a wykonywano przy tych samych parametrach.

EN

The paper depicts basic information concerning Friction Stir Welding. The main focus revolves around a problem which is deformation of thin-walled plates made out of 2024 T351 alloy which occurs when the plates are welded. In order to reduce these deformations a mount with panel that heats up welded elements has been designed and produced. The procedure of heating up welded plates intends to reduce temporary tensions and as a consequence of that it also reduces the deformation of the plates. All tests of welding were conducted under the same parameters.

16

Investigating the FSW parameter’s role on microstructure and mechanical properties of welding AZ31B–AA8110 alloy

Dharmalingam S., Lenin K., Srinivasan D.

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2022

|

Vol. 70, nr 1

art. no. e140098

EN

The influence of friction stir welding (FSW) in automotive applications is significantly high in recent days as it can boast beneficial factors such as less distortion, minimized residual stresses and enhanced mechanical properties. Since there is no emission of harmful gases, it is regarded as a green technology, which has an energy efficient clean environmental solid-state welding process. In this research work, the FSW technique is employed to weld the AA8011–AZ31B alloy. In addition, the L16 orthogonal array is employed to conduct the experiments. The influences of parameters on the factors such as microstructure, hardness and tensile strength are determined. Microstructure images have shown tunnel formation at low rotational speed and vortex occurrence at high rotational speed. To attain high quality welding, the process parameters are optimized by using a hybrid method called an artificial neural network based genetic algorithm (ANN-GA). The confirmation tests are carried out under optimal welding conditions. The results obtained are highly reliable, which exhibits the optimal features of the hybrid method.

17

Extended friction stir welding applications and the use of an innovative FSW head

Nowak Mirosław, Szostek Paweł, Nowak Marcin

Biuletyn Instytutu Spawalnictwa w Gliwicach

|

2022

|

Vol. 66, No. 5

61--72

EN

The article presents general information about friction stir welding process (FSW) as a welding method involving the stirring of the weld material, discusses the course of the welding process itself, describes the structure of the FSW joint, presents advantages and disadvantages of the method as well as discusses factors affecting the quality of FSW joints. In addition, the article describes an innovative FSW head (designed by Stirweld (France) and installed on CNC machines) as well as illustrates the operation of the head and enumerates the advantages resulting from the use of the head in comparison with those characteristic of “conventional” friction stir welding machines.

PL

W artykule przedstawiono ogólne informacje na temat metody zgrzewania z mieszaniem materiału zgrzeiny FSW (Friction Stir Welding). Scharakteryzowano przebieg procesu zgrzewania, opisano budowę złącza, przedstawiono i omówiono wady oraz zalety metody, a także czynniki wpływające na jakość połączeń. W publikacji opisano innowacyjną głowicę do zgrzewania FSW firmy Stirweld (Francja), instalowaną na frezarkach CNC. Zilustrowano proces działania głowicy oraz omówiono korzyści wynikające z jej zastosowania w porównaniu ze zgrzewarkami FSW.

18

Effect of Tool Pin Profile on Friction Stir Welding of Dissimilar Materials AA5083 and AA7075 Aluminium Alloy

Azmi Muhammad Haziq, Hasnol Muhammed Zakariya, Zaharuddin Mohd Faridh Ahmad, Sharif Safian, Rhee Sehun

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

465--470

EN

Friction stir welding (FSW) currently contributes a significant joining process for welding aluminium, magnesium, and other metals in which no molten or liquid state were involved. It is well known that aluminium alloys are more effective, promising for different applications light weight, strength and low cost. This study aims to determine how such tools geometry and tool speed can be related to dissimilar material in the joining process. Specifically, it investigates whether the distribution of the weld zone particularly between tool pin profile to rotational speed. In this context, the influence of tool pin profile and tool rotational speed in relation to the mechanical properties and microstructure of friction stir welded. The aim of this study is also to test the hypothesis that better mixing between dissimilar metals at higher tool rotational speed along the weld path. Three different tool profiles were configured with AA5083 and AA7075. During welding, notable presence of various types of defects such as voids and wormholes in the weld region. The results of this work showed that the tool pin profile and weld parameter are significant in determining mechanical properties at different tool rotational speed. The highest tensile strength achieved was about 263 MPa and the defectfree joint was obtained by using the threaded tapered cylindrical pin tool at a rotational speed of 800 rpm. These findings indicate that different tool profiles influence differently on the formation of defects at welds. On this basis, the tool geometry should be considered when designing experimental friction stir welded joint.

19

Investigation on the microstructural and mechanical behavior of the friction stir welded RZ5/8 wt% TiB2 magnesium matrix composites

Meher Arabinda, Mahapatra Manas Mohan

Archives of Civil and Mechanical Engineering

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2022

|

Vol. 22, no. 4

art. no. e178, 2022

EN

Understanding the microstructural and mechanical behavior of the friction stir welded magnesium matrix composites is necessary for different applications in automobile and aerospace components such as fuel tanks, steering wheels, chassis, seat frames, etc. In the present study, friction stir welding of magnesium RZ5/8 wt% TiB2 metal matrix composites is carried out at different joining conditions. FESEM micrograph showed the refined equiaxed grains in the nugget zone and elongated grains in the thermo-mechanically affected zone. Better grain refinement with uniform distribution is achieved at the tool rotational speed of 931 rpm and traverse speed of 20 mm/min. During the joining of RZ5/8 wt% TiB2 composites, the maximum temperature measured in the nugget zone is 511 °C at the rotational tool speed of 1216 rpm and traverse speed of 20 mm/min. Hardness is maximum at the nugget zone, which is 30% higher than the base material. The heat-affected zone showed the lowest hardness due to the annealing induced grain growth. Tensile strength is maximum during the joining of the RZ5/8 wt% TiB2 composites at a tool rotational speed of 931 rpm because of the better grain refinement with uniform reinforcement distribution in the weld zone. The tensile residual stress is observed to be a maximum of 71.41 MPa at a depth of 2.5 mm from the top surface and compressive residual stress of 60.98 MPa at the bottom surface of the nugget zone. The residual stress increased with an increase in tool rotational speed due to the increase in shrinkage of the materials at the higher temperature.

20

Prediction of filler added friction stir welding parameters for improving corrosion resistance of dissimilar aluminium alloys 5052 and 6082 joints

Sasikumar A., Gopi S., Mohan Dhanesh G.

Advances in Materials Science

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2022

|

Vol. 22, nr 3(73)

79--95

EN

The aluminium alloys 5052 and 6082 are extensively used in manufacturing lighter structural members, having improved strength and resistance to corrosion. Magnesium (Mg) and Chromium (Cr) powder were the filler materials selected for enhanced corrosion protection properties in this investigation. Friction stir welding (FSW) process parameters viz., spindle speed, welding speed, shoulder penetration, the centre distance between the holes and filler ratio are used to forecast the minimum corrosion rate from different weld regions of AA5052-AA6082 dissimilar joints. Response surface methodology based on a central composite design was used to evolve the mathematical models and estimate dissimilar FSW joints’ corrosion rates. Response optimization shows that the minimum corrosion rate was achieved by the welding parameters of spindle speed 1000 rev/min, welding speed 125 mm/min, holes spacing of 2 mm and filler ratio 95% of Mg and 5% of Cr.