DD 209:1992

This standard DD 209:1992 Piston rings up to 200 mm diameter for reciprocating internal combustion engines: specification for half keystone rings is classified in these ICS categories:

• 43.060.10 Engine block and internal components

This Technical Report specifies the essential dimensional features of HK- and HKB-half keystone rings with narrow ring width types.

Dimension Table 6 and Table 7 allow for the use of cast iron (Table 6) or steel (Table 7). Since the modulus of elasticity of steel rings is higher than that of cast iron rings, the fluctuation in the surface pressure will become greater if the free gap is set as the reference for forces. Therefore forces are set using the surface pressure as the reference, in order to minimize the effect of the fluctuation.

The requirements of this Technical Report apply to half keystone rings of 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.