Patent ID: 7341648

Claim:
A method for coating a steel or cast iron piston ring for internal combustion engines with an anti-abrasion or anti-corrosion coating on at least a working surface of the piston ring, comprising the following steps: a) bringing a first piston ring to a predetermined diameter or creating a predetermined gap in the first piston ring by applying a pre-stress to the first piston ring that equals the stress on the first piston ring that occurs in an installed state of the piston ring; b) carrying out an ion coating process on the first piston ring using predetermined coating parameters; c) measuring an inherent coating stress of the coating applied in step b); d) applying a tensile or pressure pre-stress to a second uncoated piston ring, said tensile or pressure pre-stress equivalent to the inherent coating stress measured in step c); and e) coating the second piston ring using the coating parameters used in step b).