BazTech - Yadda

1

Narzędzia i metody wykorzystywane w tłoczeniu elementów karoserii

Borecki Przemysław, Giera Kacper

Stal, Metale & Nowe Technologie

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2023

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nr 5-6

42--44

PL

Jakie metody wykorzystywane są przy produkcji elementów karoserii w przemyśle motoryzacyjnym? Na jakie elementy trzeba zwrócić uwagę?

2

Hydroforming process of thin-walled tubular components with multiple local bulges

Cui Xiao-Lei, Guo Ju, Zhao Yuanyang, Lin Peng

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 3

art. no. e169, 2023

EN

In the hydroforming process of a thin-walled tubular component with multiple local bulges, the bulge in the middle position is almost impossible to be formed with a conventional one-step hydroforming process because of the difficult axial feeding. To solve this problem, a novel method is proposed by preforming wrinkles using selective induction heating at different positions of tube blank to aggregate materials in advance for the subsequent hydroforming of tubular component with multiple local bulges. In this paper, the wrinkling behavior of 5052 aluminum alloy tube blank under different conditions and the deformation behavior of the wrinkled tube blank in subsequent hydroforming process of tubular component with three bulges are analyzed. It is shown that the existence of wrinkles is beneficial to increase the ultimate expansion ratio of the tube blank. Moreover, the instability behavior of multiple wrinkles on 5052 aluminum alloy tube blanks under different conditions was investigated by experiments. The process parameters for prefabricating two or three wrinkles, including temperature, spacing between wrinkles, and internal pressure, were determined through a detailed experimental investigation. Finally, the defects including splitting and undercut that occur in the hydroforming of tubular component with three bulges are analyzed, and the thin-walled tubular component with three bulges was hydroformed successfully using a wrinkled tube blank obtained under the process parameters of 250 °C, 4 mm, 5.5 MPa/350 °C, 10 mm, 2 MPa/400 °C, 6 mm, 1.33 MPa. These results provide insights for the manufacturing of tubular component with multiple local bulges from hard-to-form materials.

3

Analysis of thickness variation and stress state in hydroforming of complex T-shaped tubular part of nickel-based superalloy

Cui Xiao-Lei, Yuan Shijian

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 3

458--471

EN

Stress states on a multi-branch tubular part are the most complicated change in all types of hydroforming process, which result in severe variation of thickness. In this paper, an experimental and numerical research was conducted on a multi-step hydroforming process including intermediate annealing treatment to obtain effect of stress state on the thickness variation of a superalloy GH4169 complex T-shaped tubular part with expanded diameter, which corresponds to a real product used in aerospace industry. The material flow behavior at typical points on hydroformed tube blank was first analyzed. Then, the thickness variation on the hydroformed GH4169 tube blanks was discussed in every step. It is shown that the materials have different flow directions to form the side branch, where the thickness is always thinned during the four-step hydroforming process. Large axial feeding induces a continuous thickening between transition areas and tube ends. The thickness invariant dividing line in the side branch zone moves toward the tube ends with forming going on. However, in the hemisphere zone, it moves slightly towards the center of the side branch. Moreover, the stress states at three typical positions, as well as their effect on the thickness variation, were analyzed based on a sequential correspondence law between stress and strain components. On this basis, the mechanism of thickening in the left transition area, thinning at the top of side branch and thickness variation at the hemispheric pole was revealed. These results are very important for obtaining the thickness distribution of a complex T-shaped tubular part in multi-step hydroforming, and revealing the thickness variation mechanism by using engineering plasticity theory.

4

The Analysis of Microhardness Variations of Hydroformed P265TR1 Steel Axisymmetric Elements from Tubes

Miłek T.

Archives of Foundry Engineering

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2020

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Vol. 20, iss. 3

74--78

EN

The paper discusses the effect of upsetting ratio on distribution of the microhardness in longitudinal sections of hydroformed axisymmetric elements made from P265TR1 steel. The experimental research of hydroforming was carried out at a special stand which included a press with tooling and a hydraulic feeding system of oil. The measurements of microhardness were taken with a MATSUZAWA MMT-X3 Vickers hardness tester at a load of 100 g. The samples used in the tests were prepared from tube segments with a thin-wall ratio of 0.045. In the experiment, steel components were formed at upsetting coefficients of 0.07 and 0.09. For an established course of pressure and upsetting force, a series of steel components with exact representation of the die-cavity was formed. The paper provides a comparison of the microhardness distributions in three zones of longitudinal sections of axisymmetric elements at different degrees of material deformation. The greatest values of microhardness occurred in the area of cap for components at an upsetting coefficient 0.09.

5

Exhaust system piping made by hydroforming: relations between stresses, microstructure, mechanical properties and surface

Kucharska Barbara, Moraczyński Oskar

Archives of Civil and Mechanical Engineering

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2020

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Vol. 20, no. 4

648--658

EN

The subject of research is car exhaust system piping made of chromium–nickel steel of grade AISI304L with a unique, complex shape that was obtained by hydroforming technology. The purpose of the research was to determine the relation between the microstructure features, surface condition, hardness and the stresses on the external surface as determined by the sin2ψ X-ray method. We found that the stresses were tensile and correlated with the steel hardness, i.e. they were greater where the hardness was higher. Moreover, longitudinal stresses showed a relationship with pipe wall thickness, while circumferential stresses did so only partially. According to our data, the greatest value of stress determined in the pipe amounted to 290 MPa, and was close to the yield point of the strain hardened 304L steel. As depicted via XRD and SEM examination, the pipe stress level and hardness were influenced by the transition γ→α’. Furthermore, in the region of higher stress and hardness, the amount of martensite was 10 vol.%. We also noted that the pipe’s outer surface when subjected to friction against the die shows lesser roughness compared to its inner surface upon exposure to water under pressure.

6

Identification of surface stress in the exhaust system pipe made by hydroforming technology based on diffractometric measurements

Kucharska Barbara

Eksploatacja i Niezawodność

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2019

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Vol. 21, no. 4

562--566

EN

In the work identificaton of surface stresses in the exhaust pipe made of Cr-Ni steel shaped with hydroforming technology. Stresses were determined by the non-destructive x-ray method sin2ψ. A complex state of tensile stresses with values in the range of 69÷240 MPa for circumferential stresses and 26÷290 MPa for longitudinal stresses was found on the surface of the pipe. The distribution of stresses on the circumference and length of the pipe was analyzed on the basis of coefficients of variation and wall thickness. A relationship was found between the value of surface stress and the wall thickness of the pipe. The highest stresses occurred in the areas of the pipe where the thickness of the wall was reduced the most. In the central part of the pipe, where the wall thickness reduction was the smallest, the stresses were also the smallest, but they were characterized by the highest dispersion of value. The distribution of surface stresses determined by diffractometric method was compared with the model of deformation of the pipe generated numerically.

PL

W pracy dokonano identyfikacji naprężeń powierzchniowych w rurze wydechowej ze stali Cr-Ni kształtowanej technologią hydroformowania. Naprężenia wyznaczono nieniszczącą rentgenowską metodą sin2ψ. Na powierzchni rury stwierdzono złożony stan naprężeń rozciągających o wartościach z zakresu 69÷240 MPa dla naprężeń obwodowych i 26÷290 MPa dla naprężeń wzdłużnych. Rozłożenie naprężeń na obwodzie i długości rury analizowano na podstawie współczynników zmienności i grubości ścianki. Stwierdzono zależność pomiędzy wartością naprężeń powierzchniowych a grubością ścianki rury. Największe naprężenia występowały w obszarach rury gdzie grubość ścianki była najsilniej zredukowana. W centralnej części rury gdzie redukcja grubości ścianki była najmniejsza naprężenia również były najmniejsze, ale cechowały się największym rozproszeniem wartości. Rozłożenie naprężeń powierzchniowych wyznaczonych metodą dyfraktometryczną porównano z modelem odkształceń w rurze wygenerowanym numerycznie.

7

Effects of superimposed hydrostatic pressure on bulging deformation and fracture of tubes in double-sided hydroforming

Cui Xiao-Lei, Yuan Shi-Jian

Archives of Civil and Mechanical Engineering

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2019

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Vol. 19, no. 2

569--583

EN

Finite element analysis and scanning electron microscope were conducted to investigate the bulging deformation and fracture of tubes in double-sided hydroforming. The effect of the external pressure imposed on the tube, which determines the magnitude of superimposed hydrostatic pressure, on the stress state, yield locus, fracture surface formation, and fracture strain was evaluated. The simulation results revealed that sufficiently high external pressure can change the stress state of the tube in double-sided hydroforming from an in-plane biaxial tensile stress state to a three-dimensional stress state, and it can increase its hydrostatic pressure in a superimposed manner. Moreover, double-sided free bulging and corner filling experiments were conducted on 5A02 aluminum alloy and 2A12 aluminum alloy tubes. It was found that the external pressure has a significant impact on the fracture behavior of these tubes. The increasing external pressure could change the type, number, size, and proportion of the dimples on the fractured surface, and transform the fracture mode from a void accumulation fracture to a pure shear fracture, which significantly improves the fracture limit of the tubes. These results are significant for the consolidation of the theoretical and numerical simulation prediction of the superimposed hydrostatic pressure effect in the hydroforming process.

8

The effect of laser welding on properties of stainless steel and prediction its formability by numerical simulation

Evin E., Tomas M.

Hutnik, Wiadomości Hutnicze

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2018

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Vol. 85, nr 10

341--343

EN

The paper deals with laser welding and its influence on the strength and plastic properties of stainless steel AISI 304 and AISI 430. The microstructure of samples laser welded by solid state fiber laser YLS-5000, made of stainless steel sheets with thickness 0,7 mm were researched. The effect of laser power and welding speed on the mechanical properties were measured by tensile test on specimens with weld in longitudinal direction. Microstructure of laser weld, heat affected zone and base material was analysed on perpendicular direction to laser weld by light microscopy. As it has been found, only the minor effect of laser welding on the mechanical properties of the stainless steel AISI 304 was found. Otherwise, the major effect of laser welding on the mechanical properties of the stainless steel AISI 430has been recorded. Applied formability of stainless steels was researched by numerical simulation of hydroforming of fuel tank.

PL

Artykuł dotyczy spawania laserowego i jego wpływu na wytrzymałość i właściwości plastyczne stali nierdzewnej AISI 304 i AISI 430. Dokonano analizy mikrostruktury próbek zgrzewanych laserem włókna stałego YLS-5000 wykonanego z blach ze stali nierdzewnej o grubości 0,7 mm. Wpływ mocy lasera i szybkości spawania na właściwości mechaniczne mierzono w próbach rozciągania na próbkach ze spoiną w kierunku wzdłużnym. Mikrostrukturę połączenia laserowego, strefy wpływu ciepła i materiału podstawowy analizowano w kierunku prostopadłym do spawania za pomocą mikroskopu świetlnego. Stwierdzono jedynie niewielki wpływ spawania laserowego na właściwości mechaniczne stali nierdzewnej AISI 304. Natomiast odnotowano znaczący wpływ spawania laserowego na właściwości mechaniczne stali AISI 430. Odkształcalność stali nierdzewnej zbadano za pomocą numerycznej symulacji hydroformowania.

9

Hydroformowanie wysokowytrzymałych blach stalowych dla motoryzacji

Grajcar A.

Stal, Metale & Nowe Technologie

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2015

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nr 3-4

28--31

PL

Ograniczenie emisji produkowanych przez samochody spalin do otoczenia wiąże się ściśle z ograniczeniem masy karoserii samochodów. Nowoczesne koncepcje nadwozi i podwozi wytwarzane ze stali wysokowytrzymałych z grupy AHSS wymagają zastosowania nowoczesnych technik kształtowania plastycznego, np. hydroformowania blach i elementów rurowych, które pozwalają na uzyskanie elementów karoserii o skomplikowanym kształcie. Zastosowanie hydroformowania eliminuje m.in. konieczność wykorzystywania dodatkowych wzmocnień, co zmniejsza masę elementu i ogranicza potrzebę stosowania technik spawalniczych.

EN

The reduction of the emission of exhaust gases produced by cars is strictly related to the decrease of the weight of their body-in-white structures. Modern concepts of the bodies and chassis manufactured of high-strength steels of the AHSS group require to use advanced forming techniques. These methods include sheet hydroforming and tube hydroforming, which enable to obtain body-in-white elements of a complicated shape. The use of hydroforming eliminates the need to apply additional reinforcement parts. It decreases the weight of elements and reduces the need to apply joining methods.

10

The wall thickness distributions in longitudinal sections hydromechanically bulged axisymmetric components made from copper and steel tubes

Miłek T.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 65, nr 1

20--25

EN

Purpose: The paper presents experimental results that concern hydromechanical bulging of copper and P265TR1 steel axisymmetric component whose relative wall thickness was s0/D=0.04 (where s0 is the wall thickness and D is outer diameter of tube segments). Design/methodology/approach: The basic parameters of the hydromechanical process of bulge forming are: liquid pressure and axial loading. The process is employed while manufacturing pipe connections, including axisymmetric components. Copper pipe connections are used in hydraulic, heating, gas and waste water systems. The technology involves placing a tube segment in a die-cavity, pouring some liquid over it, and sealing the faces. Findings: The experimental investigations, described in the paper, on hydromechanical bulge forming of copper and P265TR1 steel axisymmetric component with the ratio h/d1=0.67 (where h is height and d1 is diameter of spherical cup) aimed to compare the wall thickness distribution in longitudinal sections of axisymmetric components. Besides it, the aim of experimental inwestigations was to compare patterns of pressure changes and force at relative displacement up to ∆l/l0=0.06. Research limitations/implications: The results obtained in the experiment might be used as guidelines to develop a technological process for manufacturing such type of connections with the method of hydromechanical bulge forming. They also could be helpful while applying the method to industrial practice. Originality/value: The experimental investigations, described in the paper aimed to determine the possibility of hydromechanical bulge forming of axisymmetric components made from copper and steel tubes, compare force waveforms at the constant upsetting ratio, compare distribution of wall thickness.

11

Zastosowanie lutów twardych do łączenia części maszyn wytwarzanych w procesie hydroformowania

Demmler A., Vogler F., Elsenheimer D.

Przegląd Spawalnictwa

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2010

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R. 82, nr 9

20-23

PL

Wysokociśnieniowe łączenie elementów (IHF) bazuje na równoczesnym wykorzystaniu potencjału swobodnego kształtowania w procesie hydroformowania (IHU) z trwałym ich spajaniem. Powstają w tym procesie głównie połączenia mechaniczne w wyniku siły kształtującej i/lub dociskającej. Przyczyną prowadzonych badań było dążenie do zintegrowania w procesie IHF techniki lutowania, w celu otrzymania szczelnych, nierozłącznych połączeń lutowanych. Omówiono badania dotyczące łączenia materiałów stalowych i aluminiowych. Wyniki badań wykazały różny wpływ materiałów smarujących i oddzielających, stosowanych w procesie kształtowania, na skuteczność procesu lutowania a tym samym na jakość połączeń lutowanych. Lutowanie materiałów stalowych nie sprawia istotnych trudności, ale podczas łączenia aluminium już najmniejsze zanieczyszczenia powierzchni powodowały znaczne problemy ze zwilżaniem ich przez lut. Lutowanie prowadzono podczas kształtowania wyrobów stalowych, z użyciem lutów na osnowie miedzi. W pierwszych próbach i rozwiązaniach procesu równoczesnego lutowania i kształtowania wyrobów (proces IHF) stosowano niskotopliwe luty Zn-AI. Wyniki badań wskazują na poprawę właściwości uzyskanych połączeń mechanicznych w porównaniu z dotychczas wytwarzanymi w technologii IHF.

EN

High-pressure joining of elements (bases on simultaneous use of free forming potential in the hydroforming process with their permanent bonding. In such a process, mechanical joints are mainly formed basing on a shaping and/or pressing down force. Aspiration after integration of soldering technology in the IHF process to obtain leakproof, inseparable soldered joints was a motivation to tests being conducted. In the tests presented in the publication, investigations on joining of steel and aluminium materials were conducted. Results of tests showed various influence of lubricating and separating materials used in the forming process on efficiency of soldering process so on quality of soldered joints. In the soldering process of steel materials, essential difficulties were not found while during joining of aluminium, even the smallest contamination of surface led to considerable problems concerning their rewetting by solder. Soldering process conducted during forming of steel products was similar to that used with use of solders on the copper base. In the initial trials and solutions of the process of simultaneous soldering and forming of products (IHF process), low-melting Zn-AI solders were used. Results of tests indicate improvement of properties of mechanical joints obtained in comparision with those made in the IHF technology.

12

Prospects for the Use of New-Generation Steels of the AHSS Type for Collision Energy Absorbing Components

Gronostajski Z., Niechajowicz A., Polak S.

Archives of Metallurgy and Materials

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2010

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Vol. 55, iss. 1

221-230

EN

This paper discusses major problems relating to the design of collision energy absorbing components. The analysis is based on in-house research and the literaturę. The possibility of using advanced high-strength steels (AHSS) for such components is explored. It has been found that in order to fully exploit the potential of the TRIP and TWIP steels, the components should be manufactured by mainly hydroforming and deep drawing, instead of bending which has predominated till now.

PL

W pracy na podstawie własnych badań oraz literatury przedstawiono najistotniejsze problemy związane z projektowaniem elementów absorbujących energię zderzeń oraz przedstawiono możliwości zastosowania stali typu AHSS na tego typu elementy. Prowadzona analiza wykazała, że aby w pełni wykorzystać możliwości, które stwarzają nowe stale typu TRIP i TWIP, należy zmienić technologię wykonywania tych elementów i stosować głównie hydroformowanie i głębokie tłoczenia zamiast gięcia, które dotychczas dominowało.

13

Development of tools and machines for micro-hydroforming with improved accuracy

Hartl Ch., Lungershausen J., Anyasodor G., Ptaschlik T.

Zeszyty Naukowe Instytutu Pojazdów / Politechnika Warszawska

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2008

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z. 5/72

157--164

EN

Merchandised products within the field of micro-technology as well as research activities show an important demand in complex shaped tubular micro-components, for example for medical devices, micro-fluidic or micro-mechatronic applications. Concerning such microcomponents made from metal materials, manufacturing techniques for the economic mass production of adequate tubular parts are often missing. Hydroforming, as a proven technology in mass production of conventional sized tubular components, e.g. for automotive applications, offers miscellaneous advantages also for the manufacture of hollow shaped micro-parts. Against this background, a micro-hydroforming system has been developed, capable for series production, and experimental and theoretical investigations into this new technology have been carried out. Results of latest research are presented concerning the configuration of tools and machines, optimised with the aid of the Finite Element Method to improve the produced component accuracy.

14

Influence of design characteristics and manufacturing process parameters on the strength of tubular aluminium joints produced by hydroforming

Przybylski W., Wojciechowski J., Marre M., Kleiner M.

Archiwum Technologii Maszyn i Automatyzacji

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2007

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Vol. 27, nr 1

153-167

EN

Hydrobulging, which is one of the hydroforming techniques, appears to be an interesting method for the manufacturing of tubular joints. A special feature of this method is the lack of undesired heat effects, cleanness, and a quick joining procedure along with an easy implementation into practice. The basic incentive of the presented research work was to find out design and working conditions of producing resistant tubular joints by hydrobulging. The study comprised joining of specimen pairs type tube-ring. In the course of the research work different material combinations of the tube and the ring were tested, i.e. AA6060-AA6060, AA6060-AZ31, and AZ31-AA6060. Practical research was performed by testing the strength of the joint which was formed by hydrobulging. The research work was carried out on a special test stand which has been designed and manufactured at the Institute of Forming Technology and Lightweight Construction (University of Dortmund) within the scope of the Collaborative Research Centre TRANSREGIO 10, supported by the German Research Foundation (DFG).

PL

Rozpęczanie hydrauliczne, które jest jedną z technik hydroformowania, uznano za metodę dającą się zastosować także do wytwarzania złączy rurowych. Ważnymi cechami obróbki metodą rozpaczania hydraulicznego są: brak wpływu ciepła, czystość i szybkość procesu oraz łatwość stosowania w praktyce. Przedmiotem prezentowanej pracy badawczej było szukanie odpowiednich parametrów konstrukcyjnych i technologicznych do wytworzenia wytrzymałych złączy rurowych metodą rozpęczania hydraulicznego. Badania obejmowały łączenie próbek będących parami rura-pierścień. Uwzględniono różne zestawienia materiałowe obu łączonych elementów, tj. AA6060--AA6060, AA6060-AZ31 oraz AZ31-AA6060. Złącza uzyskane metodą rozpęczania hydraulicznego poddano próbom na rozłączanie siłą osiową na maszynie wytrzymałościowej. Badania wykonano na specjalnym stanowisku badawczym zaprojektowanym i wykonanym w ramach programu DFG - TRANSREGIO 10.