| 摘要 |
PURPOSE:To provide a working method for obtaining an internal combustion engine piston having a grooved portion with same widths at upper and lower steps between the piston body and the grooved portion wherein a step is first formed by cutting on grooved portion substance molded integrally with the piston body and then the piston body is profield and the grooved portion substance is cut to form an annular groove therein. |
