Directional solidification method capable of eliminating freckles in castings

A directional solidification and casting technology, applied in the direction of self-solidification, chemical instruments and methods, crystal growth, etc., can solve the problems of concave solidification interface, low temperature gradient, etc., to improve the temperature gradient, wide material sources, and eliminate freckles. Effect

Inactive Publication Date: 2018-02-06
NORTHWESTERN POLYTECHNICAL UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] In order to solve the problem of freckles due to the low temperature gradient of the cross-sectional mutation region and the concave solidification interface during the directional solidification process of the existing cross-sectional mutation casting, the present invention proposes a directional solidification method that can eliminate the freckles in the casting

Method used

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  • Directional solidification method capable of eliminating freckles in castings
  • Directional solidification method capable of eliminating freckles in castings
  • Directional solidification method capable of eliminating freckles in castings

Examples

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Effect test

Embodiment 1

[0037] This embodiment is applied to the directional solidification process of a casting 1 with a sudden cross-section, such as figure 1 Shown. The size of the small section of the casting with abrupt cross-section is 4mm×20mm×100mm, the size of the large section of the casting is 40mm×20mm×25mm, and the material is CMSX-4 superalloy; the specific steps are as follows:

[0038] Step 1. Determine the temperature gradient distribution and solidification interface shape during the directional solidification of the casting. Use ProCAST software to numerically simulate the directional solidification process of casting 1 according to conventional methods, and perform post-processing to obtain figure 1 The temperature gradient distribution and solidification interface shape of the cross-sectional sudden change area shown in A are as follows figure 2 (A) and Figure 4 (A) Shown.

[0039] Step 2. Determine the shape, size and placement of the graphite block. According to the principle of...

Embodiment 2

[0052] This embodiment is applied to the directional solidification of a casting 1 with a sudden cross-section, such as figure 1 Shown. The size of the small section of the casting with abrupt cross-section is 4mm×20mm×100mm, the size of the large section of the casting is 40mm×20mm×50mm, and the material is DZ411 superalloy; the specific steps are as follows:

[0053] Step 1. Determine the temperature gradient distribution and solidification interface shape during the directional solidification of the casting. Use ProCAST software to numerically simulate the directional solidification process of casting 1 according to conventional methods, and perform post-processing to obtain figure 1 The temperature gradient distribution and solidification interface shape of the cross-sectional sudden change area shown in A are as follows image 3 (A) and Figure 5 (A) Shown.

[0054] Step 2. Determine the shape, size and placement of the graphite block. According to the principle of improvin...

Embodiment 3

[0067] This embodiment is applied to the directional solidification process of a casting 1 with a sudden cross-section, such as figure 1 Shown. The size of the small section of the casting with abrupt cross-section is 4mm×20mm×100mm, and the size of the large section of the casting is 40mm×20mm×25mm, and the material is DZ125 superalloy; the specific steps are as follows:

[0068] Step 1. Determine the temperature gradient distribution and solidification interface shape during the directional solidification of the casting. Use ProCAST software to numerically simulate the directional solidification process of casting 1 according to conventional methods, and perform post-processing to obtain figure 1 The temperature gradient distribution and the solidification interface shape of the cross-sectional mutation area shown in A.

[0069] Step 2. Determine the shape, size and placement of the graphite block. According to the principle of improving the cooling conditions of the cross-sec...

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Abstract

The invention provides a directional solidification method capable of eliminating spots in a casting. The purpose of eliminating the spots is achieved by replacing part of a mold case in a cross-sectional abrupt change area with a graphite block with a certain shape and size, having an excellent heat conducting property. The temperature gradient of the cross-sectional abrupt change area of the casting is improved, and a solidification interface tends to be horizontal, so that an arborescent structure is possible to be refined, flowing resistance increases, and the tendency that segregation melt partially clusters decreases. Therefore, the spot forming tendency decreases. The graphite block is placed at the bottom of a platform in the cross-sectional abrupt change area of the cross-sectional abrupt change casting, the temperature gradient of the cross-sectional abrupt change area of the casting is improved, the solidification interface tends to be horizontal, and spot defects are eliminated. The directional solidification method has the characteristics of simple and feasible application and implementation, wide sources of materials and low cost.

Description

Technical field [0001] The invention belongs to the field of directional solidification of nickel-based superalloys, in particular to a directional solidification method capable of eliminating freckles on the surface of blade castings that can eliminate abrupt changes in cross-section. Background technique [0002] Because the size and quality of gas turbine turbine blades are much larger than aero engine blades. Therefore, the commonly used high-speed solidification method (HRS method), which eliminates the lateral grain boundaries and obtains oriented crystals or single crystals, directional solidification technology, due to insufficient cooling capacity and other reasons, causes the occurrence of casting defects such as freckles to increase. Freckle defects are a kind of macro segregation, composed of shrinkage, eutectic, broken dendritic arms, etc., which reduce the high temperature mechanical properties of the blade. [0003] It is generally believed that the formation of fre...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22D27/04C30B11/00C30B29/52
CPCB22D27/045C30B11/00C30B29/52
Inventor 李秋东沈军秦岭
Owner NORTHWESTERN POLYTECHNICAL UNIV
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