| 摘要 |
1,139,168. Piston rings. GOETZEWERKE FRIEDRICH GOETZE A.G. 21 Dec., 1967 [22 Dec., 1966], No. 58186/67. Heading F2T. To promote running-in of a piston ring 1 coated on its running surface with chromium, the chromium layer 3 is softened, e.g. by means of a welding torch, in a zone or zones 4 occupying only part of the axial length of the ring. The softened zone may be a narrow continuous peripheral band (5, Figs. 3 and 4, not shown). |
