Composite mold shell preparation method for reducing recrystallization tendency of high-temperature single-crystal alloy casting

A technology of superalloy and recrystallization, which is applied in the field of shell preparation of investment casting superalloy castings for investment casting, can solve the problems of difficulty in eliminating residual stress in casting, and achieves elimination of recrystallization defects, reduction of residual stress, and improvement of residual stress. concessional effect

Active Publication Date: 2017-10-13
INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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  • Abstract
  • Description
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Problems solved by technology

[0013] The application of the above methods can reduce the recrystallization of castings to a certain extent, but so far the real so

Method used

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  • Composite mold shell preparation method for reducing recrystallization tendency of high-temperature single-crystal alloy casting
  • Composite mold shell preparation method for reducing recrystallization tendency of high-temperature single-crystal alloy casting

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Embodiment

[0045] In the present embodiment, the method for inhibiting recrystallization of the directionally solidified superalloy casting (the alloy grade of this embodiment: DD407) adopts the following steps in sequence:

[0046] (1) Coating preparation

[0047] a) Preparation of surface coating: first pour quantitative silica sol into the paint bucket, then add wetting agent and defoamer each accounting for 0.3vol.% of silica sol, and start the mixer at the same time, while stirring, slowly add 3 Fused corundum powder twice the weight of silica sol, after stirring for 48 hours, adjust the viscosity by adding distilled water for about 30-35 seconds.

[0048] b) Preparation of the transition layer coating: first pour a certain amount of silica sol into the paint bucket, start the mixer at the same time, slowly add fused corundum powder 2 times the weight of the silica sol while stirring, after stirring for 48 hours, add distilled water Adjust the viscosity for about 20-22 seconds.

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Abstract

The invention belongs to the casting field, relates to a composite mold shell preparation method for reducing the recrystallization tendency of a high-temperature single-crystal alloy casting. The preparation method is suitable for preparing a shell of the investment precision casting high-temperature alloy casting for investment casting. The preparation method comprises the following steps: pressing a wax mold; preparing a surface layer coating, a transition layer coating, a middle layer coating and a back layer coating; sequentially immersing the wax mold into the coatings, scattering corresponding sand and preparing a shell model after the wax mold is dried; dewaxing the shell model; and roasting the shell model. According to the technical scheme, the defects of poor deformability and collapsibility of an existing shell are overcome, after a composite mold shell is used as a mold shell of the investment precision casting, the casting residual stress of the shrinkage blocking area of the high-temperature single-crystal alloy casting is remarkably reduced, and therefore the casting recrystallization defect caused by subsequent heat treatment is eliminated, the single crystal integrity of a casting blank is ensured, and the qualification rate of the casting is remarkably improved.

Description

technical field [0001] The invention belongs to the field of casting, and relates to a method for preparing a composite mold shell for reducing the recrystallization tendency of a high-temperature alloy single crystal casting, which is suitable for the mold shell preparation of an investment precision casting high-temperature alloy casting for investment casting. Background technique [0002] Since the 1990s, almost all advanced aero-engines have used single crystal high-temperature alloy castings, such as: engines with a thrust-to-weight ratio of 10 F119, F120, GE90, EJ200, M88-2, P2000, etc. High strength is an important feature of the silica sol shell for directional solidification, which often leads to poor yield and collapse of the shell. In addition, since the thermal expansion coefficient of the casting alloy is much greater than that of the ceramic shell, the solidification and shrinkage of the casting must be hindered by the ceramic shell, which leads to plastic def...

Claims

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Application Information

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IPC IPC(8): B22C9/04B22C3/00B22D27/04C30B11/00
CPCB22C3/00B22C9/043B22D27/045C30B11/00
Inventor 张炫王志辉林泉洪张朝威金涛
Owner INST OF METAL RESEARCH - CHINESE ACAD OF SCI
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