Piston Rings-Materials

There are various materials for piston rings, when selecting the material of piston rings, consideration should be given to its use conditions, performance requirements and other factors.


Generally speaking, the material of the piston ring should meet the following requirements:


·  Enough mechanical hardness in high temperature

·  Wear resistance and low friction coefficient

·  Easy to processing and running


Below are some common materials we usually do for production

Ductile Cast Iron - KV1, GGG50, QT


Chemical Composition


C% Si% Mn% S% Cr% P% Mg%
3.5-4.0 2.1-2.9 0.2-0.5 ≤0.05 ≤0.2 ≤0.3 ≤0.1


Mechanical properties


Hardness: HRB 104-112 (HB270-260)
Modulus: ≥150000 N/mm2
Bending strength: ≥1300 N/ mm²

Vermicular Cast Iron - RuT



Chemical Composition(%)



C% Si% Mn% Cr% Cu%
3.4-3.8 2.3-2.8 0.4-0.6 0.18-0.30 0.6-0.8
Mg% Mo% Ni% P% S%
0.15-0.25 0.2-0.35 0.28-0.4 <0.07 ≤0.05


Mechanical properties


Hardness: HRB 102-112
Modulus: 120000-150000 N/mm²
Bending strength: ≥600 N/mm²

Bronze - CuSn10 & CuAl10Ni


Bronze is a softer material, and less brittle than Iron, has high temperature corrosion resistance and oxidation resistance.


Its ability to effectively co-deposit on the mating surface results in lower friction.

Steel - 55CrSi


The strong heat resistance of steel material can better control the tension of the piston ring and prevent deformation. It is also a good material for surface treatment, which is easy to reduce friction and prolong the service life of the piston ring.

Alloy Cast Iron - STD, GG25, HT


Chemical Composition(%)


C% Si% Mn% Cr% Cu%
3.0-3.8 2.3-3.0 0.5-0.9 0.2-0.45 0.3-0.5
V% Mo% P% S%  
0.12-0.2 0.2-0.45 0.3-0.6 ≤0.12  


Mechanical properties


Hardness: HRB 95-105 (HB204-257)
Modulus: 95000-115000 N/mm²
Bending strength: ≥350 N/mm²