The effects of alloying elements and cooling rates during solidification on the microstructure and mechanical properties of P-contained C/V graphite cast irons.

초록

Fecently, it has become of importance to reduce the oil consumption and to improve the engine performance in the design of marine diesel engines, of which chlinder liners are usually made with flake graphite cast irons. As one of the most effective measures for this is to increase the conbustion pressure, the requiements for the materil strength of the cylinder liners have been increased. Cylinder liner materials represent a compromise between the wear properties cyclically appled. By modifying the graphite morpholoy of the cast iron from flake to compacted- vemicular type, the tensile, elongation and impact properties of the cast irons can be improved witout loss in thermal conductivety, damping capacity and machinability, and the metallographic constituents of the cast iron have been shown to be of prime importance in controlling the wear properties. Therefore, in th production process of high strength, highly eear resistant compacted vermicular graphite cast irons with a reduced magnesium treatment method, control of processing variables and combination of alloying elements to obtain a desired graphite structure and matrix structure are very important. In this study, the influence of alloying elements and cooling rates during solidification on the formation of phosphide eutectics, and on the mechanical properties of CV grphite cast irons containing copper, tin, molybdenum for producing pearlitic matrix, and also containing phosphorus and boron for increasing wear resistancem were investigated.