Historical
ISO 6623:2004
Internal combustion engines - Piston rings - Scraper rings made of cast iron
ISO 6623:2004 specifies the essential dimensional features of scraper rings made of cast iron, types N, NM, E and EM, having diameters of from 30 mm up to and including 200 mm, used in reciprocating internal combustion engines. It is also applicable to piston rings of compressors working under similar conditions.
International Organization for Standardization [iso]