Wyniki wyszukiwania - BazTech

1

Modeling and parametric optimization of friction stir welding of aluminium alloy AA7068-T6 using response surface methodology and desirability function analysis

Bindu M. D., Tide P. S., Bhasi A. B., Ramachandran K. K.

Bulletin of the Polish Academy of Sciences. Technical Sciences

|

2021

|

Vol. 69, nr 4

art. no. e137936

EN

In this investigation, high specific strength precipitation hardenable alloy AA7068-T6 was joined using friction stir welding. Experiments were carried out using the three factor-three level central composite face-centered design of response surface methodology. Regression models were developed to assess the influence of tool rotational speed, welding speed, and axial force on ultimate tensile strength and elongation of the fabricated joints. The validity of the developed models was tested using the analysis of variance (ANOVA), actual and adjusted values of the regression coefficients, and experimental trials. The analysis of the developed models together with microstructural studies of typical cases showed that the tool rotational speed and welding speed have a significant interaction effect on the tensile strength and elongation of the joints. However, the axial force has a relatively low interaction effect with tool rotational speed and welding speed on the strength and elongation of the joints. The process variables were optimized using the desirability function analysis. The optimized values of joint tensile strength and elongation – 516 MPa and 21.57%, respectively were obtained at a tool rotational speed of 1218 rpm, welding speed of 47 mm/ min, and an axial force of 5.3 kN.

2

Friction stir welding of wrought aluminium alloy EN AW-6082

Miara Damian

Biuletyn Instytutu Spawalnictwa w Gliwicach

|

2021

|

Vol. 65, No. 4

15--24

EN

The article presents results of the friction stir welding of 6 mm thick plates made of wrought aluminium alloy EN AW-6082. Tests discussed in the article involved the identification of the effect of primary welding process parameters on the quality of welds. Test welds were subjected to visual tests, measurements of temperature (inside the weld), tensile strength tests as well as macro and microscopic metallographic tests and structural tests (performed using a scanning electron microscope). The application of the appropriate values of the primary welding process parameters (i.e. the tool rotation rate and the welding rate) enabled the obtainment of the high and repeatable quality of FSW joints made of aluminium alloy EN AW-6082. The test results presented in the article can offer technological solutions for potential users representing, among others, the railway, automotive or aviation industries.

PL

W artykule przedstawiono wyniki badań dotyczące zgrzewania metodą FSW płyt ze stopu aluminium przerabianego plastycznie EN AW-6082 o grubości 6 mm. Sprawdzono wpływ głównych parametrów procesu zgrzewania na jakość zgrzein. Przeprowadzono badania jakości zgrzein, w tym badania wizualne, pomiary temperatury wewnątrz zgrzeiny, badania: wytrzymałości zgrzein na rozciąganie oraz metalograficzne makro- i mikroskopowe, a także struktury na skaningowym mikroskopie elektronowym. Zastosowanie odpowiednich wartości głównych parametrów technologicznych zgrzewania, tj. prędkości obrotowej narzędzia oraz prędkości zgrzewania, umożliwia uzyskanie wysokiej i powtarzalnej jakości złączy FSW ze stopu aluminium EN AW-6082. Wyniki badań pozwolą opracować rozwiązanie technologiczne, które może zostać wykorzystane przez przedsiębiorców z branży kolejowej, motoryzacyjnej i lotniczej.

3

Wpływ wybranych parametrów procesu zgrzewania tarciowego z mieszaniem na jakość złączy aluminiowych

Adamus J., Winowiecka J.

Rudy i Metale Nieżelazne Recykling

|

2018

|

R. 63, nr 4

3--9

PL

Zgrzewanie tarciowe z mieszaniem (ang. friction stir welding) jest opatentowaną w latach 90. XX w. metodą łączenia blach, która umożliwia zgrzewanie elementów o różnych właściwościach i grubościach. Proces zgrzewania tarciowego z mieszaniem może być stosowany do zgrzewania materiałów, których łączenie klasycznymi metodami spawalniczymi jest trudne lub niemożliwe. Z powodzeniem zgrzewane są trudnospawalne lotnicze stopy aluminium z serii 2xxx i 7xxx. Przedmiotem analiz w niniejszym artykule jest określenie wpływu parametrów procesu liniowego zgrzewania z mieszeniem na jakość złączy wykonanych z blach aluminiowych. Badaniami objęto blachy z aluminium 7075 T6. Łączono blachy o grubościach 1,6 i 0,8 mm. Analizowano wpływ prędkości obrotowej, prędkości liniowej oraz sposobu mocowania próbek podczas statycznej próby rozciągania na nośność złączy. Przedstawiono makrostrukturę złączy, omówiono rodzaje wad i ich wpływ na nośność złączy.

EN

Friction Stir Welding (FSW) is a process invented in the 1990s that enables welding of the materials with different properties and thicknesses. Friction stir welding can be used for the materials that are poorly weldable or non-weldable by conventional fusion welding methods. Poorly weldable aluminum alloys of 2xxx and 7xxx series are easily joined by FSW technology. Determination of the influence of the FSW parameters on the quality of aluminum joints is the object of the work. The study includes 7075 T6 aluminum sheets. The sheets with thickness of 1.6 and 0.8 mm were joined. The influence of rotational speed, linear velocity and loading type during tensile tests on joint load capacity was analyzed. The macrostructure of the joints was presented. The typical defects and their impact on joint load capacity was described.

4

Solid state friction stir welding using square groove butt joint

Thamizhmanii S., Mohideen R., Mujahid A., Zaidi A., Hasan S.

Journal of Achievements in Materials and Manufacturing Engineering

|

2015

|

Vol. 73, nr 2

118--123

EN

Purpose: of this paper is to high light the application of Friction Stir Welding (FSW) process using square butt joint. Design/methodology/approach: The design adopted was tool spindle speed, tool plunge depth and transverse movement of the work piece. Findings: The findings are encouraging. It is possible to increase the strength of the joint by 22.45% from the basic tensile strength. The optimum tensile stress obtained was at spindle speed of transverse speed of 700 RPM at transverse speed 325 mm/min taking into consideration the fracture of the materials. The optimum travel speed for the spindle speed 700 RPM is 325 mm/min, this is because the heat generation and the time for the material to joint was increased. But the 200 mm/min is not optimum for the spindle speed 700 rpm because, there is too much heat generation and the welded part become soft by the welding. When there is not enough heat generated, the stir between materials or part will not occur or not properly welded. Research limitations/implications: The limitations in this research were proper fixture. Machine should have variable tool rotation instead of fixed machine spindle speed. Practical implications: It is possible to weld by FSW process and not tested in any application. Originality/value: The research on FSW The limitations in this research were proper fixture. Machine should have variable tool rotation instead of fixed machine spindle speed. is upcoming project and not much work done in this field. Using square shaped joint unique and no references so far using this square groove. Many of the research were by straight butt joint.

5

Natural Aging Behavior Of Friction Stir Welded Al-Zn-Mg-Cu Aluminum Alloys

Kalemba I., Kopyściański M., Hamilton C., Dymek S.

Archives of Metallurgy and Materials

|

2015

|

Vol. 60, iss. 2A

875--879

EN

The long term natural aging behavior of friction stir welded aluminum 7136-T76 and 7042 T6 extrusions was investigated. The microstructural characteristics and mechanical properties in the as-welded and six years naturally aged conditions were studied and correlated to a coupled thermal/material flow model of the joining process. Hardness profiles for the 7136 alloy taken along the mid-plane thickness of the workpiece displayed the characteristic W-shape. With natural aging, hardness recovery occurred on both sides of the weld, but the position of the hardness minima, particularly on the advancing side, shifted away from the weld centerline. The hardness profile for the 7042 alloy displayed U-shape in the as-welded condition and W-shape after natural aging. The hardness behavior upon natural aging correlated to the temperature profile developed during welding and the degree to which phase dissolution occurred in the regions adjacent to the stir zone.

PL

W artykule przedstawiono wyniki badań dotyczące długoterminowego starzenia naturalnego złączy stopów aluminium 7136-T76 i 7042-T6 wykonanych metodą zgrzewania tarciowego z mieszaniem materiału. Złącza w stanie po zgrzewaniu oraz po 6 latach starzenia naturalnego scharakteryzowano pod względem mikrostrukturalnym oraz mechanicznym. Wyniki badań skorelowano z modelem termicznym i modelem płynięcia materiału podczas zgrzewania. Profil twardości złącza stopu 7136 wykazuje charakterystyczny kształt litery „W”. Starzenie naturalne powoduje wzrost twardości, przy czym minimum twardości, szczególnie po stronie natarcia, odsuwa się od środka złącza. Profil twardości złącza stopu 7042 przyjmuje kształt litery „U” po zgrzewaniu i kształt litery „W” po starzeniu naturalnym. Takie zachowanie twardości po starzeniu naturalnym jest związane z temperaturą podczas procesu zgrzewania oraz stopniem, w jakim rozpuszczają się fazy w obszarach sąsiadujących ze strefą mieszania.

6

Zastosowanie technologii FSW w strukturach aluminiowych

Lacki P., Derlatka A.

Obróbka Plastyczna Metali

|

2013

|

T. 24, nr 3

205--218

PL

W pracy omówiono zastosowanie technologii zgrzewania tarciowego z mieszaniem do budowy aluminiowych struktur lotniczych. Przedstawiono sposób badania złączy FSW w celu określenia wytrzymałości na rozciąganie. Dokonano oceny mikrostruktury złącza. W celu określenia obciążeń działających na złącze FSW przeprowadzono obliczenia numeryczne. W pracy podano wyniki analizy numerycznej fragmentu struktury aluminiowej stosowanej w konstrukcjach lotniczych. Analizę numeryczną przeprowadzono dla dwóch kategorii struktur, różniących się geometrią. Pierwsza analizowana struktura zbudowana jest z arkusza blachy, ramek, podłużnic i podpórek. Druga analizowana struktura składa się z blachy, podłużnic i podpórek. W każdej kategorii analizowanych struktur rozważano model powierzchniowy i objętościowy. Oceniano przemieszczenia oraz naprężenia w warunkach obciążenia ciśnieniem działającym prostopadle do powierzchni blachy.

EN

The paper discusses the application of friction stir welding technology for the construction of aluminum aircraft structures. The method of testing FSW welds to determine their tensile strength is presented. An assessment of the weld microstructure was conducted. To determine the loads acting on the FSW weld, numerical calculations were carried out. This paper presents the results of numerical analysis of a part of the aluminum structure used in aircraft construction. Numerical analysis was carried out for two categories of structures with different geometry. The first analyzed structure is made of sheet metal, frames, stringers and supports. The second analyzed structure consists of sheet metal, stringers and supports. Within each of the analyzed structures, surface and volume models were considered. Displacement and stress were evaluated in conditions of pressure load acting perpendicularly to the sheet surface.

7

FSW characterization of 6082 aluminium alloys sheets

Mroczka K., Pietras A.

Archives of Materials Science and Engineering

|

2009

|

Vol. 40, nr 2

104-109

EN

Purpose: The purpose of the investigations was to elaborate a set of FSW parameters for connecting 6082 aluminium alloy sheets allowing to produce welds of highest strength. Design/methodology/approach: The FSW was tried at different speeds and at additional cooling. The welds microstructure was studied using optical and scanning electron microscopes. The mechanical properties of produced connections are discussed regarding their tensile test and microhardness measurements. Findings: The FSW welds, aside some zigzag lines connected probably with the incorporation of the surface oxides, were found to be devoid of any macro defects. The weld microstructure showed strong grain refining with the smallest of ~14 μm located in their centre. The highest ultimate tensile strength of such connections of ~230 MPa was obtained for experiments performed at a linear velocity of 710 rpm, rate of rotation 560 mm/min and applied intensive cooling of the joined plates. The welds showed lowest hardness in the centre rising by ~20% at its sides. The friction stir welding connections retain plastic properties of 6082 aluminium alloy presenting ductile fracture. Research limitations/implications: In the further studies bending tests and transmission electron microscopy investigations are planned. Additionally, the stability of microstructure of the welds at higher temperature will be analysed. Practical implications: The elaborated parameters for FSW of 6082 welding can be applied as starting data for industry FSW tests for such alloy. Originality/value: The results of present experiments are adding new information on FSW of the aluminium alloys, especially 6082 type. The applied welding parameters provide good quality of welds.