A 3dp sand casting process suitable for complex thin-walled components of zl205a aluminum alloy

A ZL205A, thin-walled component technology, used in manufacturing tools, casting molding equipment, metal processing equipment, etc., can solve problems such as affecting dimensional tolerances, increasing sand mold gas generation, and increasing printing costs, reducing casting defects and casting quality. Excellent, improve the effect of casting quality

Active Publication Date: 2022-06-28
NORTHWESTERN POLYTECHNICAL UNIV +1
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  • Application Information

AI Technical Summary

Problems solved by technology

The strength of 3DP sand mold increases with the increase of resin content in the sand, but higher sand mold strength will lead to poor mold yield, resulting in hot cracking, stress concentration and other problems
When the resin content of the molding sand is high, it will not only increase the printing cost, but also cause the shrinkage of the sand mold, which seriously affects the dimensional tolerance; at the same time, it will increase the gas generation of the sand mold, reduce the air permeability of the mold, and cause defects such as pores and suffocation
Similarly, the thickness of the printing layer will also cause differences in the characteristics of the mold, which in turn will affect the casting quality of the casting
Most of the current 3DP sand casting research focuses on 3DP printing consumables, 3DP sand characteristics and 3DP sand casting process, but there are not many reports on the influence of 3DP sand printing parameters on the performance of cast aluminum alloy 3DP sand casting
The current research on the preparation of aluminum alloy castings with complex structures by 3DP sand molds focuses on Al-Si alloys with good casting properties such as ZL101A, and less research on Al-Cu series high-strength cast aluminum alloys such as ZL205A with poor casting properties.
The air volume and air permeability of the sand mold are the key factors that directly affect the quality of gold castings. The problems of large air volume, poor air permeability and poor yield of the 3DP sand mold will aggravate the casting defects of ZL205A alloy castings, which seriously affect the 3DP sand mold in ZL205A aluminum alloy. Popularization and Application in Casting Production of Structural Parts
At the same time, there are few studies on the related casting process of ZL205A alloy castings prepared by 3DP sand molds.

Method used

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  • A 3dp sand casting process suitable for complex thin-walled components of zl205a aluminum alloy
  • A 3dp sand casting process suitable for complex thin-walled components of zl205a aluminum alloy
  • A 3dp sand casting process suitable for complex thin-walled components of zl205a aluminum alloy

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0032] Embodiment 1, the casting of ZL205A pitch seat casting:

[0033] (a) Taking a certain type of pitching seat as an example, its structural features are complex and its size is relatively large. Its horizontal plane size is 997mm×636mm, its height is 627mm, and its mass is about 52kg. The ZL205A alloy pitching seat has a large number of variable cross-section structures, the thinnest part of which is only 6mm, and the cross-section ratio is nearly 1:15. In the vertical direction, there are two shell members with complex shapes and structures, and their cross-sectional dimensions change frequently. There is only one horizontal bracket with a minimum wall thickness of 6mm and a maximum wall thickness of 15mm between the two shell parts, and the length of the horizontal bracket is 420mm, accounting for nearly half of the overall length of the pitch seat casting, which is very prone to deformation. These structural characteristics make the pitch seat castings different from ...

Embodiment 2

[0039] Example 2, casting of ZL205A pitch frame casting:

[0040] (a) Taking a pitching frame as an example, its structural feature is a frame structure, its horizontal dimension is 415mm×286mm, its height is 156mm, and its mass is about 7.5kg. The pitch frame is a frame-shaped structure as a whole, and the outer wall as a whole presents a large area of ​​thin walls, the wall thickness is 9mm, and there are multiple reinforcing rib structures on the wall, where the wall thickness is 14mm. There are two bosses on the inner wall, where the wall thickness is 32mm. During the solidification process, the thin-walled structure may have problems such as insufficient pouring, shrinkage holes, and difficulty in feeding. The uneven thickness may cause excessive thermal stress and cracks during the cooling process of the casting. The pitch frame casting exhibits a "large size effect" during the filling process and solidification process, and cracks are prone to occur at the corners of t...

example 3

[0046] Example 3, casting of ZL205A small cabin casting:

[0047] (a) Taking a certain type of small cabin as an example, the overall dimensions of the cabin are: the diameter of the small end is 240mm, the diameter of the large end is 340mm, the height is 263mm, the minimum wall thickness is 7mm, and the mass is about 12.7kg. There are 5:1 and 3:1 variable-section structures on the inner wall bosses and wall thicknesses of the cabin. There are 6 large bosses at one end of the cabin, with a height of 40mm and a thickness of 37mm. The internal structure of the cabin is complex, and there are many There are two irregular windows, the wall thickness of the cabin is not uniform, and there are many variable-section structures. It is easy to form casting hot spots and defects in these parts with large differences in wall thickness. The multiple bosses of the casting may cause insufficient pouring during mold filling, and may also cause defects due to insufficient feeding during the ...

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Abstract

The present invention is a 3DP sand casting process suitable for ZL205A aluminum alloy complex and thin-walled components, which belongs to the technical field of 3DP sand casting technology; firstly, the casting system of the casting is designed by using three-dimensional drawing software to obtain the three-dimensional structure of the casting mold, and the 3D printing of the casting mold is obtained Slice the data; then slice the data, use silica sand with a mesh number of 70‑140, furan resin as the binder, p-toluene sulfuric acid as the catalyst, and use a 3D printer for 3DP sand printing; set the printing parameters: the printing layer thickness is 0.28mm, the resin The content is 1.5wt.%; after that, the 3DP sand mold is cleaned, dried and molded, and a layer of water-based zircon powder coating is coated on the inner wall of the 3DP sand mold, and dried at a temperature of 120-130°C for 2.5-3 Hours, cooling with the furnace; finally, smelting the ZL205A alloy, cooling to 725±5°C for casting; after the casting is solidified, clean it to get the casting. The process of the present invention reduces casting defects and improves the quality of castings through a reasonable 3DP sand mold printing process and a casting process, through dual approaches of sand mold preparation and casting process.

Description

technical field [0001] The invention belongs to the technical field of 3DP sand casting technology, in particular to a 3DP sand casting technology suitable for ZL205A aluminum alloy complex thin-walled components. Background technique [0002] ZL205A aluminum alloy is an Al-Cu series high-strength cast aluminum alloy. It has the advantages of high strength, good plasticity, high hardness and strong machinability. It is widely used in load-bearing structural parts such as aviation and aerospace vehicles. The crystallization temperature range is wide, and it solidifies in a mushy manner. The casting performance is poor, the wall thickness sensitivity is large, and the hot cracking tendency is large. The paper "Improvement of ZL205A Coated Sand Casting Molding Process" (New Technology and New Technology, No. 11, 2018, 72-75) announced that the current ZL205A alloy castings can be used in limited casting methods. Thin-walled parts are produced by gypsum type precision casting, ...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22C9/02B33Y10/00B33Y50/00
CPCB22C9/02B33Y10/00B33Y50/00
Inventor 杨光昱王春辉付锋涛阿热达克·阿力玛斯介万奇
Owner NORTHWESTERN POLYTECHNICAL UNIV
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