Nissan Motor Company Limited

Nippon Light Metal Company, Ltd.

Hideo Yoshioka

Kiyoshi Takagi

Akio Hashimoto

Yujiro Ohara

Sanji Kitaoka

Yoji Namekawa

Ken Kanasashi

Makoto Oiyama

A method of producing a disc of an automotive road wheel by using an aluminum alloy as a material. The producing method comprising the following steps: (1) casting a disc material including an annular spoke section which has a ridge and is formed with a depression, the depression defined by a bottom wall; and (2) forging the disc material to obtain the forged disc by applying a processing degree of not less than 15% to the bottom wall of the spoke section and by applying a stress of not less than 50 MPa to the ridge of the spoke section.

Method of producing a forging

An aluminum alloy for forging comprising from 2.0 to 3.3% by weight of Si, from 0.2 to 0.6% by weight of Mg, from 0.01 to 0.1% by weight of Ti, from 0.0001 to 0.01% by weight of B, up to 0.15% by weight of Fe, one element or at least two elements selected from the group consisting of 0.001 to 0.01% by weight of Na, 0.001 to 0.05% by weight of Sr, 0.05 to 0.15% by weight of Sb and 0.0005 to 0.01% by weight of Ca, up to 0.001% by weight of P, the P/Ca weight ratio being up to 1.0, and the remainder Al, eutectic Si contained in the cast structure of said aluminum alloy having an average particle size of up to 20 .mu.m.

Aluminum alloy for forging, process for casting the same and process for

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Miura, Japan

Hideo Yoshioka