Piston rings are normally manufactured
from cast iron, conforming to SAE J929 specifications.
The material is specially alloyed to provide the best combination
of wear characteristics, temperature stability and impact
strength for most standard hydraulic applications.
Many alternate materials which can be machined to solve
unique or more difficult sealing applications. These materials
include nodular iron, bronze alloys, and stainless steel.
All ferrous rings have Manganese
Phosphate applied as the standard protective coating per SAE
AMS2481.0 thermal coatings and platings designed to improve
lubricity or to increase wear resistance for sealing applications
Z-LOK Piston Rings are manufactured from 11/2”
O.D. to 301/2” all other ring designs are available from 1/2” O.D.
to 301/2” O.D. for diameters greater than 301/2”, please
contact your nearest Zatkoff location.
Drawing shows a typical hydraulic cylinder
equipped with piston rings. Designing with 3 Z-LOK Piston
Rings ensures long term sealing performance because
foreign particles which are often present in a cylinder tend to
accumulate in the outboard grooves, and adversely influence
the outer side face seal surfaces of the outboard rings.
These foreign particles are effectively trapped in the outboard
grooves and will not migrate inward to lessen the sealing
performance of the center ring. Undercutting the outboard
lands of the piston approximately 1/16” radially, as shown, is
helpful in eliminating scoring when contaminated operating