Abstract
As the material defect might be included in the present FCD (spheroidal graphite cast iron) mono-block piston, material defect should be taken into account for designing the piston. If this defect could be removed by the HIP (Hot Isostatic Pressing) processing, the optimal design could be performed on condition of non-defect. Namely, it enables to design a lower weight and higher power engine. In this research, we have at first confirmed whether the defect is able to be eliminated by performing HIP processing to the specimen in which defects existed. Then, we have confirmed the influence of HIP processing on the strength by comparing with the specimen of healthy part. Consequently, it turned out that the defect can be eliminated when the defect locates at the inside of material. Although the cavity is eliminated in the crushed part of shrinkage cavity, the flake of the graphite remained there. Though the tensile strength can be improved considerably by eliminating the defect, it can not be improved up to the strength of a non-defect part due to the influence of the flake of graphite.
