Casting Technology of Ductile Iron Cylinder Liner

As the core component of the engine, the cylinder liner has put forward higher requirements for various performances of the cylinder liner with the development of the engine technology in the direction of high speed, high power, high detonation pressure, low emissions, and high performance. In the working process of the engine, the inner wall of the cylinder liner, as the friction working surface of the reciprocating movement of the piston, needs to have high strength, high temperature resistance, friction resistance and other characteristics, so the reliability and life of the cylinder liner are crucial to the life of the engine.

Ductile iron is widely used in main engine plants for its excellent mechanical properties and cavitation resistance. However, when producing ductile iron cylinder liner by horizontal centrifugal casting process with water-cooled metal mold, it was found that white structure appeared at the wall thickness of the casting, which is called anti white casting. The anti white defect is a kind of defect hidden in the ductile iron casting. It will reduce the mechanical properties of the casting, increase the difficulty of machining the casting, reduce the tool life, and directly affect the quality and economic benefits of the casting. The formation of reverse chill is mainly related to the chemical composition segregation of ductile iron, the inoculation effect of molten iron and the cooling conditions of castings.

With the development of computer numerical simulation technology, a new way to explore the filling process and solidification law of centrifugal casting has been provided for the process designers of centrifugal casting. Although the current casting simulation software for horizontal centrifugal casting process simulation is not yet mature, and there is still a certain gap with the actual production process, it has the advantages of short development cycle, low research cost, convenient adjustment of process parameters, etc., and plays an increasingly important role in guiding the actual production and process improvement process.

The solidification process of cylinder liner casting was simulated numerically. By studying the solidification law, temperature field, solid-liquid phase distribution and other problems of the cylinder liner casting after filling, the location of the anti white mouth defect of the cylinder liner casting was determined, providing data support for process optimization and improvement.