Patent ID: 9352427
Filing Date: 2016-05-31
CPC Classification: B23P,C23C,F16J,Y10T

Claim Text:
1. A method for producing a recessed steel piston ring, comprising producing a main body that has a running surface, an inner circumferential surface, a pair of flanks each transitioning into both said surfaces, a lower one of the flanks being configured to face a cylinder crankcase and an upper one of the flanks being configured to face a combustion chamber when the piston ring is installed in an internal combustion engine, and a recess on the running surface, and, in a region where the lower flank transitions into the running surface, providing a chamfer, providing the running surface and at least portions of the chamfer with at least one wear-resistant layer, the flanks not being provided with any wear-resistant layer, nitriding the inner circumferential surface and the flanks so that an annular portion of the lower flank of predetermined radial width and having no nitride layer is adjacent the chamfer, and removing at least all said at least one wear-resistant layer to such an extent that a substantially sharp, but unnitrided functional edge is created where the lower flank transitions into the running surface.