ISO/TR 6624-2:1988

Internal combustion engines — Piston rings — Part 2: Half keystone rings

This Technical Report specifies the essential dimensional features of HK- and HKB-half keystone ring types with narrow ring width. Dimension tables 6 and 7 allow for the use of cast iron (table 6) or steel (table 7). The requirements of this Technical Report apply to half keystone rings for reciprocating internal combustion piston engines, up to and including 70 mm diameter for cast iron rings and up to and including 100 mm diameter for steel. –