Friction Stir Forming of Aluminum Alloy Gear-Racks

2016 ◽  
Vol 725 ◽  
pp. 665-670 ◽  
Author(s):  
Takahiro Ohashi ◽  
Jia Zhao Chen ◽  
Tadashi Nishihara ◽  
Hamed Mofidi Tabatabaei
Keyword(s):  
High Pressure ◽  
Aluminum Alloy ◽  
Back Surface ◽  
Fill Ratio ◽  
Friction Stir ◽  
Single Pass ◽  
Shoulder Diameter ◽  
Gear Rack

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.

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
Keyword(s):  
Aluminum Alloy ◽  
Substrate Material ◽  
Back Surface ◽  
3D Measurement ◽  
Friction Stir ◽  
Single Pass ◽  
Tool Shoulder ◽  
Shoulder Diameter ◽  
Wide Range ◽  
3D Measurement System

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.

Surface Smoothing of A5083 Aluminum Alloy Plate by Friction Stir Forming

2019 ◽  
Vol 803 ◽  
pp. 50-54
Author(s):  
Takahiro Ohashi ◽  
Kento Okuda ◽  
Hamed Mofidi Tabatabaei ◽  
Tadashi Nishihara
Keyword(s):  
Aluminum Alloy ◽  
Feed Rate ◽  
Metal Plate ◽  
Spindle Speed ◽  
Back Surface ◽  
Alloy Plate ◽  
Friction Stir ◽  
Shoulder Diameter ◽  
Aluminum Alloy Plate ◽  
Aluminum Plates

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.

Friction Stir Forming of Aluminum Alloy Gear-Racks with Semi-Closed Dies

2020 ◽  
Vol 977 ◽  
pp. 50-56
Author(s):  
Takahiro Ohashi ◽  
Hamed Mofidi Tabatabaei ◽  
Tetta Ikeya ◽  
Tadashi Nishihara
Keyword(s):  
Aluminum Alloy ◽  
Frictional Heat ◽  
Fill Ratio ◽  
Mechanical Joining ◽  
Friction Stir ◽  
Die Structure ◽  
Internal Forces ◽  
Net Shape Forming ◽  
The Difference ◽  
Gear Rack

This paper reports friction-stir forming (FSF) of gear-racks of JIS A5083 aluminum alloy with semi-closed dies. FSF is a modified friction-stir process suggested by Nishihara in 2002. The process generates frictional heat and internal forces, enabling massive deformation of the material. It has been successfully utilized for mechanical joining and microforming, but seems to offer an opportunity for net-shape forming of bulk products as well. We put a material in a semi-closed gear-rack die and conducted friction stirring on its top surface. The material deformed and filled the 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. We also investigated the difference between this method and open-type FSF that had been conducted with an open-die structure.

Observation of Material Flow in Friction Stir Forming for A5083 Aluminum Alloy Gear-Rack

2017 ◽  
Vol 889 ◽  
pp. 113-118 ◽  
Author(s):  
Takahiro Ohashi ◽  
Hamed Mofidi Tabatabaei ◽  
Tadashi Nishihara
Keyword(s):  
Aluminum Alloy ◽  
Cross Section ◽  
Cross Sections ◽  
Material Flow ◽  
Transverse Direction ◽  
Back Surface ◽  
Friction Stir ◽  
Net Shape Forming ◽  
Material Forming ◽  
Gear Rack

This paper reports observation of material flow in friction-stir forming of aluminum alloy gear racks. Friction-stir forming was newly developed by Nishihara and is dedicated for material forming. In the process, a material plate is placed on the die and friction stirring is conducted on its back surface. The material deforms due to high pressure and heat caused by the friction-stir process and deforms precisely to the shape of the die. The process has mainly been studied for microforming and mechanical jointing; however it was successfully utilized for net-shape forming of A5083 aluminum alloy gear racks. The authors observed the appearance of products, change of mark-off lines on its surface, and deformation of its longitudinal cross section by photo-processing. In addition, we evaluated the distribution of hardness in transverse cross sections of a product tooth. As a result, it was observed that the material did not flow in the transverse direction of the cavity of the gear-rack die, though more material filled at the retreating side than at the advancing side. The material filled the tooth-cavity mostly before passage of the tool probe over the tooth.

Effect of Multi Pass Friction Stir Processing on Surface Modification and Properties of Aluminum Alloy 6061

2019 ◽  
Vol 813 ◽  
pp. 404-410
Author(s):  
Hardik Vyas ◽  
Kush P. Mehta
Keyword(s):  
Tensile Strength ◽  
Aluminum Alloy ◽  
Friction Stir Processing ◽  
Processing Conditions ◽  
Workpiece Material ◽  
Friction Stir ◽  
Single Pass ◽  
Aluminum Alloy 6061 ◽  
Novel Processing ◽  
Alloy 6061

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.

Microstructure and Joint Strength of Similar- and Dissimilar Lap Joints Fabricated by Several Advanced Solid-State Welding Methods

2010 ◽  
Vol 654-656 ◽  
pp. 596-601 ◽  
Author(s):  
Shinji Kumai ◽  
Mitsuhiro Watanabe ◽  
Keyan Feng
Keyword(s):  
Aluminum Alloy ◽  
Solid State ◽  
High Speed ◽  
Joint Strength ◽  
Lap Joints ◽  
Back Surface ◽  
Magnetic Pulse ◽  
Oblique Collision ◽  
Friction Stir ◽  
Steel Sheets

Both similar- and dissimilar metal joints, which are difficult to be welded by using ordinary fusion welding methods, were successfully obtained by using several advanced high-speed solid-state joining methods. (1) Al/Al, Cu/Cu, Al/Fe(Steel), Al/Cu, Al/Ni, Cu/Ni and Al/Bulk metallic glass lap joints were magnetic pulse welded by means of mutual high-speed oblique collision of metal sheets at a high speed of about 500m/s. (2) 2xxx aluminum alloy pins were stud-welded to 5xxx alloy aluminum sheets and several kinds of plated steel sheets at a high speed by using a specially designed discharge circuit. The welding was achieved within a few milliseconds without producing any weld marks on the back surface of the plate. (3) 6022 aluminum alloy sheets were friction stir spot welded to steel sheets and various kinds of galvanized and aluminum-plated steel sheets. The welding was achieved within a few seconds. For those joints, joint strength and characteristic joint interface morphology were investigated.

Friction Stir Forming of A5083 Aluminum Alloy Gear-Racks with WC Particles Embedded in Tooth Surface

2016 ◽  
Vol 723 ◽  
pp. 148-153 ◽  
Author(s):  
Takahiro Ohashi ◽  
Hamed Mofidi Tabatabaei ◽  
Tetta Ikeya ◽  
Tadashi Nishihara
Keyword(s):  
Aluminum Alloy ◽  
Particle Density ◽  
Rear Surface ◽  
Tooth Surface ◽  
Back Surface ◽  
Forming Process ◽  
Alloy Matrix ◽  
Alloy Plate ◽  
Friction Stir ◽  
The Matrix

This paper proposes a new forming process for gear racks featuring a tooth-surface stiffening layer. The proposed process is as follows. First, a JIS A5083P aluminum alloy plate on which a surface modifier of WC particles and vaseline paste had been applied was put on a gear-rack die. Next, friction stirring was conducted on the back surface of the plate. The material then deformed and precisely filled the cavity of the die. WC particles were embedded into the surface of the aluminum alloy matrix due to high pressure and heat caused by friction stirring. The forming conditions and the corresponding results, including the distribution of WC perticles on the tooth surface, are investigated in the study. WC particles were embedded near the surface mechanically, and only a very few particles were observed inside the matrix. With an undefill condition, WC particles are concentrated on the rear surface of the tooth, which contacts the tail side of the die. In contrast, No significant particle density differences were observed among the profile of teeth with a fully filled condition in the die cavity.

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