The top rings and conformable oil rings are made from heat treated Nodular iron being known for its high tensile strength for heavy duty applications . This material is suited for rings which are subjected to heavy thermal loads & high dynamic stresses. These rings have high resistance againstbending, wear and breakage.
For high RPM automobile application the top rings are made from high alloyed steel and the oil rings from profiled steel wire.
Wear resistance coatings as chrome plating and molybdenum spray are being used for enhancing the life and working conditions of Piston Rings. The chrome plating is done as overlay and inlaid. The plasma Molybdenum Spray is done for nodular iron rings as inlaid coating. For some specific applications molybdenum coating and copper coating on periphery by thermal spray is also applied.
Manganese phosphate, a chemical etching of the surface and tin plating are two types of surface treatment to assist initial run-in of the ring and also provide protection from the rust.
The range of engines/machines/equipments/compressors for which LPR piston rings
are suitable as service/replacement part