PURPOSE: To increase the lifetime of a wheel made of Al-Mg series alloy and making its rim lightweight and in small wall thickness by forming a facial layer having a compressive residual stress in a specified value over the surface of the well radius part of the outside circumferential surface of rim by means of shotpeening.
CONSTITUTION: In a wheel made of Al alloy, bead seat radius parts 1, 1' and well radius parts 2, 2' are provided recessedly at the outside circumferential surface (tire fitting surface) consisting of a ductile material, and a disc B of Al-Mg series alloy having a hub mounting surface 4 is welded or jointed by any other appropriate means with the inside of a rim A made of Al-Mg series alloy provided protrudingly with flanges 3, 3' on both side edges. Therein a shot-peening layer is formed on the well radius parts 2, 2' and the bead seat radius parts 1, 1' at the outside circumferential surface of the rim A, in particular on the former, and thereby a compressive residual stress is given to the part concerned. That is, a compressive residual stress of 2-15kg/mm2 remains on the surface layer of the part provided with a shot-peening layer. This prolongs the radial load lifetime as a wheel 2-3 times, and the rim A can be made lightweight and in small wall thickness.
AKIYAMA KAZUMITSU
WATANABE KATSUMI
OKITA TOMIHARU
| JPS5289557A | 1977-07-27 |