Preparation technique for thin-walled silica-based ceramic mold core

Abstract

The invention discloses a preparation technique for a thin-walled silica-based ceramic mold core. The core material of the ceramic mold core comprises 70-85% of quartz glass powder and 15-30% of M75 Mullite powders; a plasticizer comprises 97% of white paraffin wax and 3% of polyethylene; the pressing process parameters of the ceramic mold core are as follows: the mould preheating temperature is 30-45 DEG C, the slurry temperature is 95-110 DEG C, the pressing casting pressure is 2.0-3.0 Mpa, and the dwell time is 15-20 s; the sintering process parameters of the ceramic mold core are as follows: heat preserving at 200 DEG C for 4 h, heat preserving at 400 DEG C for 4 h, heat preserving at 600 DEG C for 1 h, heat preserving at 900 DEG C for 1 h, and heat preserving with the final sintering temperature of 1150-1160 DEG C for 4 h; after sintering, adopting an ethyl silicate enhancer for high-temperature reinforcement, and adopting epoxy resin, polyamide resin and acetone to prepare a low-temperature enhancer according to a certain proportion for low-temperature reinforcement; finally carrying out roasting. According to the ceramic mold core prepared by adopting the preparation technique, the yield can reach over 85%, and the broken core rate in the casting process is lower than 8%; the ceramic mold core is low in shrinking percentage, good in room-temperature or high-temperature strength, high in size accuracy, free of deformation in the casting process and easy in depoling, and can satisfy the casting requirements of thin-walled casting pieces with complex canals.

Description

technical field [0001] The invention relates to investment precision casting, in particular to a preparation process for a thin-walled silicon-based ceramic core for investment casting hollow castings of aero-engines. Background technique [0002] In recent years, countries around the world are continuously improving the comprehensive performance of aero-engines, especially improving the temperature-bearing capacity of blades. Therefore, continuous improvement of blade cooling structure and cooling performance has become the goal pursued by the design and manufacture of turbine blades. [0003] At present, ceramic cores are widely used in investment casting of aero-engine castings to form intricate inner cavity structures of castings. With the continuous improvement of engine technology, the cooling structure of air-cooled blades (currently mainly directional, single crystal superalloy blades) is more complex, and the wall is thinner (for example, the thickness of the exhau...

AI Technical Summary

Problems solved by technology

Using the conventional ceramic core preparation process to manufacture this kind of thin-walled ceramic core with complex structure, there are technical problems such as insufficient core pressure, prone to compression cracks and sintering cracks, resulting in a very low pass rate of the ceramic core, generally not more than 40 %; and this type of core is prone to broken cores during the pouring process, and the casting waste caused by broken cores accounts for more than 60% of the total waste

Obviously, the conventional ceramic core preparation process can no longer meet the process requirements for preparing such complex-structured thin-walled ceramic cores.

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