Abstract

In order to save weight and increase productivity, the FC subframe developed for vehicle mounting of the fuel cell system employed in the FCX Clarity fuel cell vehicle is constructed from both extruded and cut parts produced from 6000 series aluminum alloy. Friction stir welding (FSW) was used to weld the main structural parts of the subframe. FSW was applied to 12 types of lap joints and one type of butt joint. Five tools were developed for the lap joints and one tool for the butt joints. The strength of lap joints formed using FSW can be diminished by the infiltration of the material in the bottom sheet into the material in the top sheet, a phenomenon referred to as “hook.” The project discussed here clarified the mechanism of this phenomenon, and reduced its occurrence by forming grooves on the probes of the welding tools. In addition, in the case of butt welds of forms with radii, the occurrence of elongated cavity was controlled without the use of filler metal by having the center of the tool approach the thickest side of the material.The use of these methods has enabled the achievement of a 17% weight saving against a conventional subframe using stamped parts.

References

1. (1) Tokisue, H., Shinoda, T., Kumagai, M.: FSW no Jisshirei, FSW (Masatsu Kakuhan Setsugou) no Kiso to Oyo, Nikkan Kogyo Shimbun, p. 129-161 (2005) (in Japanese)
2. (2) Fujii, H.: Masatsu Kakuhan Setsugo no Genri to Tokutyo, Masatsu Kakuhan Setsugo (FSW no Subete), Sanpo Publications, p. 12-18 (2006) (in Japanese)
3. (3) Tokisue, H., Shinoda, T., Kumagai, M.: FSW no Genri to Tokutyo, FSW (Masatsu Kakuhan Setsugo) no Kiso to Oyo, Nikkan Kogyo Shimbun, p. 11-12 (2005) (in Japanese)
4. (4) Mori, H., Noda, M., Tominaga, T.: Current state on application of friction stir welding for rolling stock, Journal of Japan Institute of Light Metals, Vol. 57, No. 11, p. 506-510 (2007) (in Japanese)
5. (5) Koga, S.: Zidosya e no Spot FSW no Tekiyo, Masatsu Kakuhan Setsugo (FSW no Subete), Sanpo Publications, p. 232-235 (2006) (in Japanese)
6. (6) JIS H4100 : 2006, Aluminium and aluminium alloy extruded shape
7. (7) JIS H4000 : 2006, Aluminium and aluminium alloy sheets, strips and plates
8. (8) Fujii, H.: Masatsu Kakuhan Setsugo no Genri to Tokutyo, Masatsu Kakuhan Setsugou (FSW no Subete), Sanpo Publications, p. 22-24 (2006) (in Japanese)
9. (9) JP, 2007-268558, A (2007)

Author (organization or company)

• Tsutomu KOBAYASHI（Automobile R&D Center）
• Mitsuru SAYAMA（Automobile R&D Center）
• Takanori YAHABA（Automobile R&D Center）
• Takashi KATO（Automobile R&D Center）

Publication Information

Article of Honda R&D Technical Review Vol.21 No.1 (49 - 57)

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Citation Information