Development of Aluminum Cylinder Head Castings for Diesel Engines

摘要

An Al-Si-Mg-Cu alloy and its heat treatment process for the cylinder head castings of diesel engines have been developed. Developed alloy is not only superior on the mechanical strength, but also on the thermal fatigue durability comparing with the conventional aluminum casting alloys. This alloy allows increasing the engine output under the condition of higher combustion pressure. In order to improve durability of cylinder head castings, it has been studied that influences of precipitation behavior in various contents of alloy elements and heat treatment conditions. And it was founded out that precipitated phase and its microstructures influence to thermal fatigue durability. This study results in improving the both mechanical and thermal fatigue properties. In addition to optimizations of aluminum casting alloy, casting processes have been improved. Developed tilting casting process prevents generation of oxides. New cooling system of the mold contributes to increase solidification speed, and to decrease shrinkage porosities with lower riser weight.