Preparation method of shell with long and thin blades of investment casting aero-engine

Abstract

The invention discloses a preparation method of a shell with long and thin blades of an investment casting aero-engine. The preparation method comprises the following steps: mixing 5%-10% of cobaltous oxide powder and 90%-95% of electric smelting diamantane, roasting at 1200 DEG C-1350 DEG C, cooling to room temperature, and grinding so as to prepare a nucleating agent; preparing a mixed powder material from the nucleating agent and diamantane powder, adding silica sol into the mixed powder material so as to prepare slurry, coating the first layer of the shell with the slurry, coating the second layer to the eighth layer of the shell with the slurry prepared from the diamantane powder and silica sol, carrying out sand-lining on the first and second layers with No.80-No.100 emery, carrying out sand-lining on the third and fourth layers with No.46-No.60 emery, and carrying out sand-lining on the fifth-eighth layers with No.16-No.25 emery. Compared with a traditional shell preparation method, the shell prepared by the method disclosed by the invention is compact and smooth in surface; the long and thin blades of the aero-engine, which are prepared from the shell, are smooth in surface, and are refined in crystal grain, and can reach the technique requirements.

Description

technical field [0001] The invention relates to investment casting, in particular to a method for preparing a mold shell of thin and slender blades of an investment casting aero-engine. Background technique [0002] With the continuous development of aero-engine manufacturing technology, the working blades of low-pressure turbines are developing in the direction of longer, thinner and thinner. For this type of blade, the blade length can reach 200mm, the chord width is about 25mm, the maximum thickness of the blade body is about 3mm, and the thickness of the inlet and exhaust edges is about 0.5mm. Grain refinement, the grain diameter is required to be no more than 3mm. The shell preparation method for investment casting such thin and slender blades is closely related to blade grain refinement. [0003] The length of the traditional low-pressure turbine working blade is about 100mm, the chord is about 60-70mm, the maximum thickness of the blade body is 5-6mm, and the thickn...

AI Technical Summary

Problems solved by technology

[0003] The length of the traditional low-pressure turbine working blade is about 100mm, the chord is about 60-70mm, the maximum thickness of the blade body is 5-6mm, and the thickness of the intake and exhaust edges is about 2-3mm. Usually, it is a blade with a margin, such as investment casting with a margin The traditional shell preparation method of the blade does not pay attention to the grain refinement problem. The thin and slender low-pressure turbine working blade adopts this traditional shell preparation method, and there are point-shaped metallurgical defects on the surface of the blade, which cannot meet the technical requirements for grain refinement.