Cylindrical Pin Embossment on A5083 Aluminum Alloy Substrate Fabricated by Friction Stir Forming

2017 ◽  
Vol 730 ◽  
pp. 253-258 ◽  
Author(s):  
Takahiro Ohashi ◽  
Hamed Mofidi Tabatabaei ◽  
Tadashi Nishihara

This paper reports friction-stir forming (FSF) of cylindrical pin embossments on JIS A5083 aluminum alloy medium gauge plate. A substrate material was put on an emboss die and conducted friction stirring on its back surface. The die has 1mm diameter and 0.5mm deep fine holes at 1.5mm pitch on its top, and the material successfully filled them due to high pressure and heat caused by friction stirring. Three tools having different shoulder diameter were utilized to investigate the deformable area with a single pass. As a consequence, faster spindle speed, slower tool feed rate, and larger tool shoulder contribute to a wider range of completely formed pins. Extrusion of the material to the die cavity seemed to be mostly limited under the area of the shoulder. The ratios of the band width of the complete pins to the shoulder diameter were increased with the larger diameter of the shoulder of the FSF tool. Therefore, a larger shoulder was more effective for wide-range embossing with a single pass. In addition, we evaluated the shape of formed pins with a non-contact 3D measurement system. Accuracy of the height of the completely formed pins was within ±0.013mm, which was comparable with machining.

2016 ◽  
Vol 725 ◽  
pp. 665-670 ◽  
Author(s):  
Takahiro Ohashi ◽  
Jia Zhao Chen ◽  
Tadashi Nishihara ◽  
Hamed Mofidi Tabatabaei

Friction-stir-forming (FSF) of gear-racks of JIS A5083 aluminum alloy is reported in this paper. We put a material plate on a gear-rack die and conducted friction stirring on its back surface. The material deformed and precisely filled the fine cavity of the die due to high pressure and heat caused by friction stirring. This study investigates the forming conditions and the corresponding results, including the material fill ratio in the tooth. It is thought that the deformation volume of the material is key for the fill ratio, and the shoulder diameter of the tool in a single-pass process or the path area in a multi-pass process affects it as well.


2019 ◽  
Vol 803 ◽  
pp. 50-54
Author(s):  
Takahiro Ohashi ◽  
Kento Okuda ◽  
Hamed Mofidi Tabatabaei ◽  
Tadashi Nishihara

This paper provides a framework for the transcription of the surface of a mirror-finished die onto a metal plate by friction stir forming (FSF). In FSF, a material is put on a die, then friction stirring was conducted on its back surface for the transcription of the profile of the die onto the material. In this paper, a mirror-polished die of JIS SUS304 stainless steel with surface roughness Sz 0.014 mm and a probe-less friction-stirring tool in 18 mm shoulder diameter were employed for the experiment. A5083P-O aluminum plates, 3 mm thick, were utilized as base metals for the transcription. The authors varied tool spindle speed and tool feed rate to evaluate the forming results. Consequently, a mirror-finished surface under the friction-stirring tool was successfully transferred from the die to the aluminum alloy plate. The roughness of the base metal before processing was Sz 0.022 mm and that of the processed metal was Sz 0.012–0.016 mm. Higher spindle speed and faster feed rate resulted in a smoother surface; it is thought that high spindle speed and faster feed rate should be effective for higher contact pressure between a die and a material.


2017 ◽  
Vol 751 ◽  
pp. 186-191 ◽  
Author(s):  
Takahiro Ohashi ◽  
Hamed Mofidi Tabatabaei ◽  
Tadashi Nishihara

This paper proposes a new joining approach for dissimilar materials, called ‘the fastenerless-riveting,’ employing the friction stir forming (FSF). The FSF is a friction stir process invented by Nishihara in 2002. In FSF, a substrate material was put on a die firstly. Next, friction stirring was conducted on the back surface of the material. The material then deformed and precisely filled the cavity of the die due to high pressure and heat caused by the friction stirring. The authors utilized the FSF approach to generate rivet like joints as followings. First, a substrate which is capable for friction stirring, i.e. an aluminum alloy plate, was put on a dissimilar material plate having holes, i.e. a steel plate. The authors call the former ‘the host member,’ the latter ‘a joined member.’ These members were put on a die having the cavity to fabricate the head of the rivet-like structure. Then FSF was conducted to form the stems and heads of the structure. Joint members are able to be stacked within the forming limit. In the study, the authors firstly conducted the proof of the concept (PoC) tests to generate rivet-like structure between steel and aluminum alloy plate and between CFRP and aluminum alloy plate, then investigated the forming conditions, i.e. tool feed rate, tool pass and the corresponding results, including the volume of the generated stem and head of the individual rivet-like structure. 3mm-thick A5083P-O aluminum alloy plates was utilized as the host member, and a 0.7mm-thick SPCE steel plate and a 0.8mm-thick CFRP plate as the joined members.


2014 ◽  
Vol 984-985 ◽  
pp. 586-591 ◽  
Author(s):  
R. Ashok Kumar ◽  
M.R. Thansekhar

— For fabricating light weight structures, it requires high strength-to weight ratio. AA6061 aluminium alloy is widely used in the fabrication of light weight structures. A356 aluminium alloy has wide spread application in aerospace industries. Friction stir welding is solid state joining process which is conducting for joining similar and dissimilar materials. The friction stir welding parameters play an important role for deciding the strength of welded joints. In this investigation, A356 and AA6061 alloys were friction stir welded by varying triangular, square, hexagonal pin profiles of tool keeping the remaining parameters same and AA6061 alloys were friction stir welded by varying tool shoulder diameter as 12mm,15mm,18mm without changing other parameters. Tensile properties of each joint have been analyzed microscopically. From the experimental results, it is observed that hexagonal pin profiled tool and 15mm shoulder diameter tool provides higher tensile properties when compared to other tools.


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.


Author(s):  
Rajat Gupta ◽  
Kamal Kumar ◽  
Neeraj Sharma

This chapter presents the friction stir welding (FSW) of aluminum alloy AA-5083-O using vertical milling machine. In present FSW experimentation, effects of different process parameter namely tool rotation speed, welding speed, tool geometry, and tool shoulder diameter have been determined on welding quality of two pieces of AA-5083-O using response surface methodology (RSM). The optimal sets of process parameters have been determined for weld quality characteristics namely tensile strength (UTS) and percentage elongation (%EL). In present experimentations, a specially designed tool made of high carbon steel with different shoulder diameters (15mm, 17.5mm, and 20 mm) having constant pin length (6 mm) were used for FSW of two pieces of aluminum alloy. The ANOVA and pooled ANOVA were used to study the effect of FSW parameters on UTS and %EL. Multi response optimization has been carried out using desirability function in conjunction with RSM to obtain the optimal setting of process parameters for higher UTS and lower %EL.


2019 ◽  
Vol 813 ◽  
pp. 404-410
Author(s):  
Hardik Vyas ◽  
Kush P. Mehta

In the present investigation, friction stir processing (FSP) is carried out with multi pass processing having 100 % overlap zone on the workpiece material of aluminum alloy 6061 with constant FSP parameters and varying multi pass processing conditions. Novel processing concept of multi pass FSP was performed with different rotation directions (such as clock wise and anti-clock wise directions) and processing directions (such as forward, reverse and revert directions). Surface inspection, macrographs and microstructures of the processed regions are evaluated and compared with each other. Multi-pass FSP with 100 % overlapping of two passes caused intense dynamic recrystallization and resulted in reduced grain size. Hardness of processed zone was found increased in case of two pass FSP. Minimum tensile strength was reported with double sided FSP compare to single pass and two pass FSPs. No major variations in tensile strength were reported in case of single pass and two pass FSPs.


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