PURPOSE: To eliminate internal defect of a cast material and substantially improve its creep strength in such a way that, when cast material having pores inside is treated by hydrostatic pressure at high temperature and at high pressure (HIP treatment), liquid phase are allowed to occur in each grain boundary by raising the temperature of the cast material until it causes initial fusion.
CONSTITUTION: Where an HIP treatment is applied to an Ni, Co, Fe or another metal- base alloy, liquid phase is allowed to occure in each grain boundary of said alloy to unify the liquid phase containing internal porous parts with said liquid phase due to the load of the gas pressure, by making the HIP treatment temperature somewhat higher than that usually employed and treating it at a temperature which is high enought to cause the initial difusion. The cast material has now been closely packed and reproduced as a cast mateial having a good metal texture. Different from a close packing by virtue of a mere diffusion unification, the closely packed cast material according to the above method will not be accompanied by sliding movements between crystalline grains even in an subsequent application at a high temperature and will exhibit a far-improved creep strength as the cast material has been closely packed in a fused state.
TATENO TSUNEO
AOTA KENICHI
| JPS5114131A | 1976-02-04 |