The cylinder liner is an important component of a diesel engine. The quality of the cylinder liner, especially its wear resistance, will directly affect the performance and economic efficiency of the diesel engine. Therefore, the cylinder liner has very high technical requirements.

The main requirements for the material of the cylinder liner are: sufficient strength, good wear resistance, heat resistance, density, and corrosion resistance, etc. Among them, wear resistance is an important characteristic of a high-quality cylinder liner. When the wear resistance is poor, the wear will intensify, and the tightness of the fit between the cylinder liner and the piston ring will deteriorate, thereby causing air leakage, making the engine difficult to start and reducing power. When the wear is too severe, it will aggravate the wear of the piston ring groove, and even cause the piston ring to break; or whenever the direction of the piston's movement changes, knocking will occur.

Domestic and foreign researchers have conducted a large amount of research to improve the wear resistance of the cylinder liner. Different materials such as chromium-molybdenum copper cast iron, high phosphorus cast iron, nickel-chromium cast iron, boron cast iron, vanadium-titanium cast iron, and niobium cast iron have been developed as alloy cast iron cylinder liners. Surface strengthening methods can also be used to improve the wear resistance of the cylinder liner. Processes such as surface quenching, chrome plating, nitriding treatment, and extrusion of silicon carbide can all achieve certain effects to a varying extent, thereby greatly improving the wear resistance of the cylinder liner. For example, the cylinder liners of large low-speed diesel engines produced abroad have a wear amount of only 0.013mm/1000h. The wear resistance of the cylinder liners of domestic marine main engines has also achieved good results: for a medium-speed diesel engine cylinder liner, the average wear rate of 4500-6500h is 0.0017mm/1000h; for the low-speed diesel engine cylinder liner of an oil tanker main engine, the wear amount does not exceed 0.02mm/1000h.

The force acting on the cylinder liner during use is very complex. The tensile strength of the material generally should be Rm ≥ 250MPa, and the Brinell hardness should be 180-248HBW. For large marine main engine cylinder liners, the tensile strength of the upper body Rm should be 215-245MPa, and the Brinell hardness should be 180-230HBW. There are many types of cylinder liner materials, and countries should select them based on their own resource conditions and the types, uses, and operating conditions of the engines. Currently, the following are commonly used types.

1. Alloy series based on vanadium 

2. Boron cast iron 

3. Chromium-molybdenum copper cast iron 

4. Nickel-chromium cast iron 

5. High-strength ductile iron 

6. Mottled cast iron 

(The text is from the internet. If there is any infringement, please contact us to delete it.)