| 摘要 |
PURPOSE:To shorten the time for quenching and secure the cylindricity at the time of honing by applying dense laser quenching to that portion of boss surface which should need light abrasion resistance, and a coarse laser quenching to the other portion situated belows. CONSTITUTION:A laser beam irradiating device 3 is to apply laser quenching to the surface of the bore 2 of cylinder block 1 made of stratified graphite cast iron. At this time, that portion 12 of bore surface from around upper dead point of the piston to a certain point downward which should need high abrasion resistance shall be quenched densely, while the other portion situated belows be quenched coarsely. Thereby the quenching time can be shortened, as well as the cylindricity of the bore be finished uniformly by increasing the grinding resistance with lower part of the bore so that the following honing will result in the same ground amount throughout the bore. |
