A repair wax for investment casting of superalloys

Abstract

The application provides a repairing wax for high-temperature alloy investment casting, which comprises 60-95 parts of microcrystalline wax and 5-40 parts of beeswax in terms of mass fraction. The repairing wax designed by the application will not chemically react with the part wax mold and the shell material during use. After the wax part is repaired, the repairing part is tightly combined and is not easy to fall off. Furthermore, the surface defects such as pores, depressions and pockmarks on the wax part can be effectively eliminated after reasonable repairing by corresponding tools. The surface smoothness of the repaired wax part can meet the process requirements, and the qualified rate of the wax part is obviously improved.

Description

Technical Field

[0001] This invention belongs to the field of investment casting wax patterns and relates to repair wax technology, specifically a repair wax for high-temperature alloy investment casting. Background Technology

[0002] In the aerospace industry, high-temperature alloys occupy an important position due to their excellent high-temperature strength, high-temperature stability, weldability, machinability, and corrosion resistance. With the continuous increase in the strength requirements of high-temperature alloys, complex-shaped products have encountered a series of problems during processing, such as the difficulty in hot forging, welding, and especially cutting. This has led to the research and development of a series of near-net-shape forming technologies, among which investment casting, which has high production flexibility and strong adaptability, is widely favored.

[0003] In recent years, with the rapid development of investment casting technology, casting precision has evolved from allowance to zero, casting microstructure from arbitrary crystallization (equiaxed crystals) to controlled crystallization (directional columnar crystals, single crystals, fine grains), and casting structure from solid planar surfaces to complex hollow cavities. The dimensional accuracy and surface finish requirements for investment castings used in aerospace applications are significantly higher than those of other casting methods, typically exceeding them by 1-2 grades. Therefore, the mold materials used in investment casting require high-quality materials with good thermal stability, high strength, good fluidity, and low expansion and shrinkage.

[0004] Currently, mold materials can be classified into wax-based mold materials, resin-based mold materials, plastic mold materials, filling mold materials, and water-soluble mold materials according to the composition of the base material. When these mold materials are used and formed in the wax pattern by a wax injection machine, surface defects such as micropores, surface shrinkage, and rough pitting may occur. In order to ensure the surface quality of subsequent metal castings, it is necessary to repair and improve them with repair wax during the wax casting stage. At present, most manufacturers make their own repair wax according to their own environment and wax casting characteristics. There are few commercial repair waxes on the market that can meet the requirements of various manufacturers. Summary of the Invention

[0005] The purpose of this invention is to design a repair wax for high-temperature alloy investment casting. When used, it will not chemically react with the wax model and shell material of the part. After the wax part is repaired, the repaired part is tightly bonded and not easy to fall off. Furthermore, after proper repair with appropriate tools, surface defects such as pores, depressions, and pits on the wax part can be effectively eliminated. The surface smoothness of the repaired wax part can meet the process requirements, and the wax part qualification rate is significantly improved.

[0006] The technical solution to achieve the purpose of the invention is as follows: a repair wax for high-temperature alloy investment casting, comprising 60 to 95 parts by mass of microcrystalline wax and 5 to 40 parts by mass of beeswax.

[0007] Furthermore, the repair wax, by weight fraction, includes 75-90 parts microcrystalline wax and 10-25 parts beeswax.

[0008] Preferably, the repair wax comprises, by weight fraction, 87 parts microcrystalline wax and 13 parts beeswax.

[0009] In one embodiment, the microcrystalline wax includes 80# microcrystalline wax and 85# microcrystalline wax.

[0010] In an improved embodiment, the amount of 80# microcrystalline wax in the above-mentioned microcrystalline wax is less than the amount of 85# microcrystalline wax.

[0011] Preferably, in the above-mentioned microcrystalline wax, 33 to 53 parts of 80# microcrystalline wax and 33 to 60 parts of 85# microcrystalline wax are present.

[0012] Even better, of the above-mentioned microcrystalline waxes, 40 parts are 80# microcrystalline wax and 47 parts are 85# microcrystalline wax.

[0013] Compared with the prior art, the beneficial effects of the present invention are that the repair wax designed in this invention has the following advantages:

[0014] 1. It will not chemically react with the wax model of the parts or the shell material during use;

[0015] 2. After wax repair, the repaired area adheres tightly and is not easily detached;

[0016] 3. After proper repair with appropriate tools, surface defects such as pores, dents, and pits on the wax parts can be effectively eliminated, ensuring that the surface finish of the wax parts meets the process requirements and significantly improving the pass rate of the wax parts. Detailed Implementation

[0017] The present invention will be further described below with reference to specific embodiments, and the advantages and features of the present invention will become clearer as a result. However, these embodiments are merely exemplary and do not constitute any limitation on the scope of the present invention. Those skilled in the art should understand that modifications or substitutions can be made to the details and form of the technical solutions of the present invention without departing from the spirit and scope of the present invention, but all such modifications and substitutions fall within the protection scope of the present invention.

[0018] This specific embodiment discloses a repair wax for high-temperature alloy investment casting, which, by mass parts, includes 60 to 95 parts of microcrystalline wax and 5 to 40 parts of beeswax.

[0019] Beeswax, also known as yellow wax or honey wax, is a fatty substance secreted by four pairs of wax glands on the abdomen of worker bees of appropriate age in a bee colony. Its melting point varies between 62 and 67°C depending on the source and processing method.

[0020] In one embodiment of the above-mentioned repair wax, the repair wax comprises, by mass fraction, 75 to 90 parts of microcrystalline wax and 10 to 25 parts of beeswax.

[0021] In a preferred embodiment of the above-mentioned repair wax, the repair wax comprises, by mass fraction, 87 parts of microcrystalline wax and 13 parts of beeswax.

[0022] Microcrystalline wax is a refined synthetic wax with near-microcrystalline properties. It features good gloss, high melting point, and light color. Its structure is compact, firm yet smooth, allowing it to be mixed with various natural waxes. It can also increase the melting point of low-density waxes and improve the performance of coarse waxes. Its melting point ranges from 60 to 95℃, and it includes 70#, 80#, 85#, and 90# microcrystalline waxes. Specifically, 80# microcrystalline wax has a melting point of 60℃, conforming to SH / T 0013-2008; 85# microcrystalline wax has a melting point of 85℃, conforming to SH / T 0013-2008; 75# microcrystalline wax has a melting point of 90℃, conforming to SH / T 0013-2008; and 90# microcrystalline wax has a melting point of 95℃, conforming to SH / T 0013-2008.

[0023] In one embodiment of the above-mentioned microcrystalline wax, the microcrystalline wax used to prepare the repair wax is 80# microcrystalline wax or 85# microcrystalline wax.

[0024] In an improved embodiment of the above-mentioned microcrystalline wax, the amount of 80# microcrystalline wax is less than the amount of 85# microcrystalline wax. Preferably, the amount of 80# microcrystalline wax in the microcrystalline wax is 33-53 parts and the amount of 85# microcrystalline wax is 33-60 parts; more preferably, the amount of 80# microcrystalline wax is 40 parts and the amount of 85# microcrystalline wax is 47 parts.

[0025] The following specific examples illustrate the repair wax described above:

[0026] Example 1: The repair wax is calculated by weight fraction, including 44KG of 75# microcrystalline wax, 26KG of 95# microcrystalline wax, and 10KG of beeswax.

[0027] Example 2: The repair wax is calculated by weight fraction, including 40KG of 85# microcrystalline wax, 23KG of 70# microcrystalline wax, and 37KG of beeswax.

[0028] Example 3: Repair wax is calculated by weight fraction, including 50KG of 90# microcrystalline wax, 35KG of 85# microcrystalline wax, and 15KG of beeswax.

[0029] Example 4: The repair wax is calculated by weight fraction, including 40KG of 85# microcrystalline wax, 23KG of 80# microcrystalline wax, and 37KG of beeswax.

[0030] Example 5: The repair wax is calculated by weight fraction, including 43KG of 85# microcrystalline wax, 39KG of 80# microcrystalline wax, and 18KG of beeswax.

[0031] Example 6: The repair wax is calculated by weight fraction, including 40KG of 80# microcrystalline wax, 47KG of 85# microcrystalline wax, and 13KG of beeswax.

[0032] In Examples 1 to 6 above, the preparation method of the repair wax is as follows: heat No. 1 microcrystalline wax and No. 2 microcrystalline wax (No. 1 microcrystalline wax refers to microcrystalline wax with a higher melting point and No. 2 microcrystalline wax refers to microcrystalline wax with a lower melting point) to about 120-150°C, and after they are fully melted, stir them thoroughly and evenly. When the temperature drops to about 100°C, add beeswax and stir. After stirring thoroughly and evenly, add petroleum jelly and continue to stir evenly. After cooling and standing, it can be shaped.

[0033] The shrinkage rate of the repair waxes prepared in Examples 1 to 6 above was tested, and the test results are shown in the table below:

[0034] The method for measuring the shrinkage rate of repair wax is as follows: after melting the repair wax, let it stand until it becomes a semi-solid state, then pour it into the material cylinder of a 4B27-1016 semi-automatic wax pressing machine. Select a cube or cuboid mold, press in the wax material, and cool it at room temperature for 12 hours or more. Compare the changes in the same space size before and after the wax model cools, and calculate the shrinkage rate.

[0035]

[0036]

[0037] Analysis: As shown in the table above, the shrinkage rate of the repair waxes provided in Examples 1 to 6 is all below 1.6%, which is better than the shrinkage rate of existing repair wax formulations (≤2%). In particular, the melting point and shrinkage properties of the repair wax provided in Example 6 are better than those of other examples.

[0038] The repair wax provided in this specific embodiment will not chemically react with the wax mold and shell material of the parts during use; after the wax parts are repaired, the repaired parts are tightly bonded and not easy to fall off; after the wax parts are properly repaired with the appropriate tools, surface defects such as air holes, depressions, and pits on the wax parts can be effectively eliminated, so that the surface smoothness of the wax parts can meet the process requirements and the wax parts qualification rate is significantly improved.

[0039] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

[0040] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A repair wax for high-temperature alloy investment casting, characterized in that, It is used to repair and eliminate surface defects on waxed parts, including pores, dents and pits. The repair wax, by weight, includes 75 to 90 parts of microcrystalline wax and 10 to 25 parts of beeswax. The microcrystalline wax includes 33-53 parts of 80# microcrystalline wax and 33-60 parts of 85# microcrystalline wax, wherein the number of parts of 80# microcrystalline wax is less than the number of parts of 85# microcrystalline wax.

2. The repair wax according to claim 1, characterized in that: The repair wax, by weight fraction, comprises 87 parts microcrystalline wax and 13 parts beeswax.

3. The repair wax according to claim 1 or 2, characterized in that: The microcrystalline wax consists of 40 parts of 80# microcrystalline wax and 47 parts of 85# microcrystalline wax.

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