Study on the Solid Welding Conditions of Hollow Extrusion of 7075 Aluminum Alloy

Author(s):  
Quang-Cherng Hsu ◽  
Shu-Ping Shi ◽  
Chi-Peng Hsu

Direct extrusion by port hole–bridge die configuration has been successfully used to fabricate products with hollow cross sections for 6000 series aluminum alloys. When these aluminum alloys flow through the upper die (with bridge and port hole) material flows separately. These separate materials contact together when they flow through the lower die (with welding chamber). The contacting and welding processes occurs naturally if the material temperature and contact pressure are suitable; then the product with hollow and complicated cross section will be obtained when the material flow through bearing regions in lower die. This solid welding process for 6000 series aluminum alloys is without any problem. However, if for 7000 series aluminum alloys this situation alerts since different alloy compositions such as Zn and Cu causing welding process in lower die failed. It will impede the success of industry application with light and high strength aluminum alloys. In order to determine the solid welding conditions during hollow extrusion with port-hole die structure for high strength aluminum alloy such as 7000 series, an easy tooling configuration has been designed. Based on this approach, two split and half die components with taper angle feature were inserted into an outer steel ring. In the beginning, some clearances happen between inner die and outer ring result from design in purpose. When the upper punch continues to press the testing billet, the clearance disappears gradually due to the designed taper angle of inner die and outer ring. However, when the pushing pressure from upper punch is over 350 Mpa and billet temperature is maintained at about 480C below melting temperature, small gaps between the two split half die components occur automatically. During this situation, two small flashes can flow into the opening gaps both from the upper and lower billets which then can weld together. However, these two upper and lower billets in direct pressing zone did not weld together. Several experiments at different pressure have been conducted and the best solid welding condition has been obtained. The proposed method (die configuration) is easy and cheap because there is no necessary to conduct experiment in controlled environment such as in vacuum chamber of Gleeble test or in a protective atmosphere. The grain size and grain structure as well as grain flow have been discussed in the proposed paper for testing parts in direct pressing zone and in flash zone. Some SEM photos and EDS analysis have been prepared and will be presented in this paper.

2011 ◽  
Vol 479 ◽  
pp. 62-73 ◽  
Author(s):  
Quang Cherng Hsu ◽  
Kun Hong Kuo ◽  
Chi Peng Hsu

Direct extrusion by porthole – bridge die configuration has been successfully used to fabricate products with hollow cross sections for 6000 series aluminum alloys. However, if for 7000 series aluminum alloys, this situation alerts since different alloy composition such as Cu causing hollow extrusion failed due to not enough welding strength in seam. In order to determine the solid welding conditions during hollow extrusion with porthole die structure for high strength aluminum alloy, an easy tooling configuration has been designed. The proposed method is easy and cheap because there is no necessary to conduct experiment in controlled environment such as in vacuum chamber of Gleeble test or in a protective atmosphere. A seam and hollow extrusion for square tube has been conducted to obtain the welding strength comparison to the proposed solid welding method which shows good agreement.


2021 ◽  
Vol 11 (12) ◽  
pp. 5728
Author(s):  
HyeonJeong You ◽  
Minjung Kang ◽  
Sung Yi ◽  
Soongkeun Hyun ◽  
Cheolhee Kim

High-strength steels are being increasingly employed in the automotive industry, requiring efficient welding processes. This study analyzed the materials and mechanical properties of high-strength automotive steels with strengths ranging from 590 MPa to 1500 MPa, subjected to friction stir welding (FSW), which is a solid-phase welding process. The high-strength steels were hardened by a high fraction of martensite, and the welds were composed of a recrystallized zone (RZ), a partially recrystallized zone (PRZ), a tempered zone (TZ), and an unaffected base metal (BM). The RZ exhibited a higher hardness than the BM and was fully martensitic when the BM strength was 980 MPa or higher. When the BM strength was 780 MPa or higher, the PRZ and TZ softened owing to tempered martensitic formation and were the fracture locations in the tensile test, whereas BM fracture occurred in the tensile test of the 590 MPa steel weld. The joint strength, determined by the hardness and width of the softened zone, increased and then saturated with an increase in the BM strength. From the results, we can conclude that the thermal history and size of the PRZ and TZ should be controlled to enhance the joint strength of automotive steels.


Coatings ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 4
Author(s):  
Dmitry V. Dzhurinskiy ◽  
Stanislav S. Dautov ◽  
Petr G. Shornikov ◽  
Iskander Sh. Akhatov

In the present investigation, the plasma electrolytic oxidation (PEO) process was employed to form aluminum oxide coating layers to enhance corrosion resistance properties of high-strength aluminum alloys. The formed protective coating layers were examined by means of scanning electron microscopy (SEM) and characterized by several electrochemical techniques, including open circuit potential (OCP), linear potentiodynamic polarization (LP) and electrochemical impedance spectroscopy (EIS). The results were reported in comparison with the bare 6061-O aluminum alloy to determine the corrosion performance of the coated 6061-O alloy. The PEO-treated aluminum alloy showed substantially higher corrosion resistance in comparison with the untreated substrate material. A relationship was found between the coating formation stage, process parameters and the thickness of the oxide-formed layers, which has a measurable influence on enhancing corrosion resistance properties. This study demonstrates promising results of utilizing PEO process to enhance corrosion resistance properties of high-strength aluminum alloys and could be recommended as a method used in industrial applications.


Author(s):  
Elisan dos Santos Magalhaes ◽  
Cristiano Pedro da Silva ◽  
Ana Lúcia Fernandes Lima e Silva ◽  
Sandro Metrevelle Marcondes Lima e Silva

Purpose The purpose of this article is the determination of the temperature fields in a weld region has always been an obstacle to the improvement of welding processes. As an alternative, the use of inverse problems to determine the heat flux during the welding process allows an analysis of these processes. Design/methodology/approach This paper studies an alternative for the thermal analysis of the tungsten inert gas welding process on a 6,060 T5 aluminum alloy. For this purpose, a C++ code was developed, based on a transient three-dimensional heat transfer model. To estimate the amount of heat delivered to the plate, the specification function technique was used. Lab experiments were carried out to validate the methodology. A different experimental methodology is proposed to estimate the emissivity (radiation coefficient). Findings The maximum difference between experimental and numerical temperatures is lower than 5 per cent. The determined emissivity value for the aluminum 6,060 T5 presented a good agreement with literature values. The thermal fields were analyzed as function of the positive polarity. The specification function method proved to be an adequate tool for heat input estimation in welding analysis. Originality/value The proposed methodology proves to be a cheaper way to estimate the heat flux on the sample. The estimated power curves for the welding process are presented. The methodology to calculate the emissivity (radiation coefficient) was validated.


2021 ◽  
Vol 23 (3) ◽  
pp. 72-83
Author(s):  
Kirill Kalashnikov ◽  
◽  
Andrey Chumaevskii ◽  
Tatiana Kalashnikova ◽  
Aleksey Ivanov ◽  
...  

Introduction. Among the technologies for manufacturing rocket and aircraft bodies, marine vessels, and vehicles, currently, more and more attention is paid to the technology of friction stir welding (FSW). First of all, the use of this technology is necessary where it is required to produce fixed joints of high-strength aluminum alloys. In this case, special attention should be paid to welding thick-walled blanks, as fixed joints with a thickness of 30.0 mm or more are the target products in the rocket-space and aviation industries. At the same time, it is most prone to the formation of defects due to uneven heat distribution throughout the height of the blank. It can lead to a violation of the adhesive interaction between the weld metal and the tool and can even lead to a destruction of the welding tool. The purpose of this work is to reveal regularities of welding tool destruction depending on parameters of friction stir welding process of aluminum alloy AA5056 fixed joints with a thickness of 35.0 mm. Following research methods were used in the work: the obtaining of fixed joints was carried out by friction welding with mixing, the production of samples for research was carried out by electric erosion cutting, the study of samples was carried out using optical metallography methods. Results and discussion. As a result of performed studies, it is revealed that samples of aluminum alloy with a thickness of 35.0 mm have a heterogeneous structure through the height of weld. There are the tool shoulder effect zone and the pin effect zone, in which certain whirling of weld material caused by the presence of grooves on tool surface is distinctly distinguished. It is shown that the zone of shoulders effect is the most exposed to the formation of tunnel-type defects because of low loading force and high welding speeds. It is revealed that tool destruction occurs tangentially to the surface of the tool grooves due to the high tool load and high welding speeds.


Materials ◽  
2019 ◽  
Vol 12 (24) ◽  
pp. 4157 ◽  
Author(s):  
Isidro Guzmán ◽  
Everardo Granda ◽  
Jorge Acevedo ◽  
Antonia Martínez ◽  
Yuliana Dávila ◽  
...  

Precipitation hardening aluminum alloys are used in many industries due to their excellent mechanical properties, including good weldability. During a welding process, the tensile strength of the joint is critical to appropriately exploit the original properties of the material. The welding processes are still under study, and gas metal arc welding (GMAW) in pulsed metal-transfer configuration is one of the best choices to join these alloys. In this study, the welding of 6061 aluminum alloy by pulsed GMAW was performed under two heat treatment conditions and by using two filler metals, namely: ER 4043 (AlSi5) and ER 4553 (AlMg5Cr). A solubilization heat treatment T4 was used to dissolve the precipitates of β”- phase into the aluminum matrix from the original T6 heat treatment, leading in the formation of β-phase precipitates instead, which contributes to higher mechanical resistance. As a result, the T4 heat treatment improves the quality of the weld joint and increases the tensile strength in comparison to the T6 condition. The filler metal also plays an important role, and our results indicate that the use of ER 4043 produces stronger joints than ER 4553, but only under specific processing conditions, which include a moderate heat net flux. The latter is explained because Mg, Si and Cu are reported as precursors of the production of β”- phase due to heat input from the welding process and the redistribution of both: β” and β precipitates, causes a ductile intergranular fracture near the heat affected zone of the weld joint.


2014 ◽  
Vol 548-549 ◽  
pp. 305-309
Author(s):  
Chin Chun Chang ◽  
Che Kai Chan ◽  
Ching Lung Chen ◽  
Gao Yu Hsiung ◽  
June Rong Chen

This paper describes the design, manufacturing and welding sequence for the aluminum alloy vacuum chamber for Taiwan Photon Source. The vacuum chamber composes of aluminum extrusion chamber of A6063 and BPM chamber of A6061 aluminum alloys. The straightness and flatness of these extrusion chambers are controlled under 0.1mm/m and 0.2mm/m, respectively. The BPM chambers are manufactured precisely in oil-free environment, which provide clean surface and a precise sealing surface after machining. All the components are assembled in pre-aligned support system through the welding process, and then the results show the straightness of < 0.15mm/m, flatness of < 0.3mm/m, and leakage rates of < 2 × 10-10 mbar‧l/sec. were achieved.


Alloy Digest ◽  
1989 ◽  
Vol 38 (5) ◽  

Abstract IncoMAP alloy Al-9052 is a high-strength, corrosion resistant aluminum alloy made by the mechanical alloying process. It is dispersion strengthened by oxides and carbides. Its density is 5% less than age hardenable aluminum alloys of comparable strength. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as fracture toughness. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Al-296. Producer or source: Inco Alloys International Inc..


Author(s):  
Vijay S Gadakh ◽  
Vishvesh J Badheka ◽  
Amrut S Mulay

The dissimilar material joining of aluminum and titanium alloys is recognized as a challenge due to the significant differences in the physical, chemical, and metallurgical properties of these alloys, where the increasing demands for high strength and lightweight alloys in aerospace, defense, and automotive industries. Joining these two alloys using the conventional fusion techniques produces commercially unacceptable sound joints due to irregular, complex weld pool shapes, cracking and low strength, high residual stresses, cracks, and microporosity, and the brittle intermetallic compounds formation leads to poor formability or inferior mechanical properties. The formation of intermetallic compounds is inevitable but it is less severe in solid-state than in the fusion welding process. Hence, this article reviews on aluminum–titanium joining using different solid-state and hybrid joining processes with emphasis on the effect of process parameters of the different processes on the weld microstructure, mechanical properties along with the type of intermetallic compounds and defects formed at the weld interface. Among the various solid-state welding processes for aluminum–titanium joining, the following grades of aluminum and titanium alloys were employed such as cp Ti, Ti6Al4V, cp Al, AA1xxx, AA 2xxx, AA5xxx, AA6xxx, AA7xxx, out of which Ti6Al4V and AA6xxx alloys are the most common combination.


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