| 摘要 |
PROBLEM TO BE SOLVED: To reduce the diameters of metal particles in a micro metal structure of a forged wheel. SOLUTION: In a step of integrally forge-forming a vehicle wheel by hot forging while using a columnar billet of a light alloy as a starting material, the average height of a work after a first forging is set to be low, the forging ratio to the height of the billet is made at least≥3.5 to reduce the diameters of metal particles, the average diameters of metal particles in a spoke part are made≤9μm, and the average particle diameters in an inner rim are made≤20μm by hot spinning. A designed pattern, which is formed on a wheel disk after the first forging, is set to be a gently convexed rib, and the average height of the work is set to be low, so that extension and spread of the starting material is easily carried out. In the first forging, the whole amount of the billet is allotted according to the amounts required for each part of the disk and a rim preparatory member. COPYRIGHT: (C)2010,JPO&INPIT
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