Investment precision casting method capable of reducing wax pattern deformation

Abstract

The invention provides a precision investment casting method capable of reducing wax pattern deformation, and belongs to the technical field of titanium alloy precision casting. The problems of how to reduce the deformation of the wax mould and ensure the precision and the consistency of the wax mould are solved. According to the method, before the wax mold is taken out of the mold, the mold and the wax mold are subjected to low-temperature treatment, the internal stress of the wax mold is gradually released, deformation of the wax mold in the taking-out process can be remarkably reduced, and the quality and size precision of a final casting are improved. The method is suitable for wax molds in conventional shapes, is also suitable for wax molds in complex shapes and fine structures, and has high universality.

Description

Technical Field

[0001] The invention belongs to the technical field of titanium alloy precision casting, and in particular relates to a precision investment casting method for reducing wax mold deformation. Background Art

[0002] In the investment casting process, the wax pattern is formed by injecting liquid wax into the mold and cooling it to solidify. However, when the wax pattern is removed from the mold, it often deforms, affecting the accuracy and quality of the final casting.

[0003] At present, the commonly used methods to improve the deformation of wax molds are to optimize the mold design and adjust the cooling rate of the wax mold. However, the optimization of mold design requires a lot of experiments and adjustments, which is long and costly. In addition, the effect on wax molds with complex shapes is limited, and the adjustment of cooling rate is easily restricted by environmental and equipment conditions. Therefore, there is an urgent need for a method to effectively reduce the deformation of wax molds and ensure the accuracy and consistency of wax molds. Summary of the invention

[0004] In view of this, in order to solve the problem of how to reduce the deformation of the wax model and ensure the accuracy and consistency of the wax model, the present invention proposes a method for reducing the deformation of the wax model by investment casting. The method can significantly reduce the deformation of the wax model during the removal process and improve the quality and dimensional accuracy of the final casting by performing low temperature treatment on the mold and the wax model before the wax model is removed from the mold, gradually releasing the internal stress of the wax model. This method is suitable for the production of wax models of various complex shapes and has broad application prospects.

[0005] To achieve the above object, the present invention adopts the following technical solution: a method for investment casting to reduce the deformation of wax mold, specifically comprising the following steps:

[0006] Step 1: After the wax is injected into the mold and cooled and solidified, the mold and the wax pattern are subjected to low temperature treatment as a whole to reduce the internal stress of the wax pattern;

[0007] Step 2: After low temperature treatment, the mold is heated to create a slight thermal expansion difference between the mold and the wax pattern, reducing the adhesion between the wax pattern and the mold.

[0008] Furthermore, the low temperature treatment is: putting the mold and the solidified wax mold into a freezing device, controlling the temperature between -10°C and -20°C, and keeping it for 30 minutes.

[0009] Furthermore, the cryogenic treatment controls the temperature at -18°C and is divided into two stages: the first stage is maintained at -18°C for 15 minutes, and the second stage is maintained at -12°C for 15 minutes.

[0010] Furthermore, the heating treatment is as follows: taking out the mold from the freezing device, heating it to between 20-25°C at a heating rate of 1-2°C / min, and maintaining it for 10 minutes.

[0011] Furthermore, step 3: removal and post-processing: After the wax model is carefully removed, it is left to stand at room temperature to ensure that its internal stress is further released and the stability of the final shape is ensured.

[0012] Compared with the prior art, the investment casting method for reducing wax mold deformation according to the present invention has the following beneficial effects:

[0013] 1. Staged control of low temperature treatment: Through two stages of low temperature treatment, the internal stress of the wax model is gradually released to avoid stress concentration caused by sudden temperature changes and ensure the stability of the wax model;

[0014] 2. Temperature difference guides demoulding: by heating the mold to produce a small thermal expansion difference between the mold and the wax mold, the adhesion between the wax mold and the mold is reduced, and the demoulding process is smoother;

[0015] 3. Applicable to wax models with complex shapes: The method is applicable to wax models with conventional shapes, and is also applicable to wax models with complex shapes and fine structures, and has strong universality. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention will be described clearly and completely below. It should be noted that the embodiments and features in the embodiments of the present invention can be combined with each other without conflict, and the described embodiments are only part of the embodiments of the present invention, not all of them.

[0017] A method of investment casting that reduces deformation of wax patterns by subjecting the mold and wax pattern to specific treatments before the wax pattern is removed from the mold, thereby reducing deformation and ensuring the accuracy and consistency of the wax pattern.

[0018] The method of the present invention comprises the following steps:

[0019] Step 1: After the wax is injected into the mold and cooled and solidified, the mold and wax pattern are subjected to low temperature treatment as a whole to reduce the internal stress of the wax pattern.

[0020] Step 2: After low temperature treatment, heat the mold to a moderate temperature to create a slight thermal expansion difference between the mold and the wax pattern, reducing the adhesion between the wax pattern and the mold.

[0021] The method of the present invention can significantly reduce the deformation of the wax mold during the removal process, and improve the quality and consistency of the final casting.

[0022] Example 1

[0023] A method for reducing deformation of a wax pattern in investment casting comprises the following steps:

[0024] 1. Wax mold cooling and solidification: Inject liquid wax into the pre-designed mold and wait for it to cool and solidify.

[0025] 2. Low temperature treatment: Place the mold and the cured wax model in a freezing device, control the temperature between -10℃ and -20℃, and keep it for 30 minutes to eliminate the internal stress of the wax model.

[0026] 3. Heating treatment: Take the mold out of the freezer and heat it to 20-25°C for 10 minutes to create a slight thermal expansion difference between the mold and the wax pattern.

[0027] Through the above steps, the deformation of the wax mold during the removal process can be effectively reduced and the quality of the final casting can be improved.

[0028] Example 2

[0029] In the production of complex castings, an improved investment casting method, taking SL430 filled wax as an example, is used to reduce the deformation of the wax pattern, including the following steps:

[0030] 1. Wax injection and curing: Inject liquid wax into the pre-designed mold and wait for it to cool and solidify.

[0031] 2. Staged low temperature treatment: Put the mold and the cured SL430 wax pattern into a freezer, control the temperature at -18℃, and treat it in two stages. The first stage is kept at -18℃ for 15 minutes, and the second stage is kept at -12℃ for 15 minutes. This staged treatment helps to gradually release the internal stress of the wax pattern.

[0032] 3. Precise temperature control and heating: Take the mold out of the freezer and heat it to 20-25°C at a heating rate of 1-2°C / min and keep it for 10 minutes. Precise temperature control and gradual heating can help prevent changes in internal stress caused by rapid temperature changes.

[0033] 4. Removal and post-processing: After the wax model is carefully removed, it can be left to stand at room temperature to ensure that its internal stress is further released and the stability of the final shape is ensured.

[0034] Through the above implementation, the stress distribution and shape stability of the wax pattern can be more carefully controlled, deformation can be significantly reduced, and the overall quality of investment casting can be improved. At the same time, the method of the present invention is simple to operate, scientific and reasonable, has a wide range of applications, and has high use value.

[0035] The embodiments of the present invention disclosed above are only used to help illustrate the present invention. The embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. According to the content of this specification, many modifications and changes can be made. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well.

Claims

1. A method for reducing the deformation of wax molds, characterized in that: The specific steps include: Step 1: After the wax is injected into the mold and cooled and solidified, the mold and the wax pattern are subjected to low temperature treatment as a whole to reduce the internal stress of the wax pattern; Step 2: After low temperature treatment, the mold is heated to create a slight thermal expansion difference between the mold and the wax pattern, reducing the adhesion between the wax pattern and the mold.

2. The method for reducing wax pattern deformation according to claim 1, characterized in that: Low temperature treatment is as follows: the mold and the solidified wax mold are placed in a freezing device, the temperature is controlled between -10°C and -20°C, and maintained for 30 minutes.

3. The method for reducing wax pattern deformation according to claim 2, characterized in that: The low temperature treatment controlled the temperature at -18℃ and was divided into two stages: the first stage was kept at -18℃ for 15 minutes, and the second stage was kept at -12℃ for 15 minutes.

4. The method for reducing wax pattern deformation according to claim 2, characterized in that: The heating treatment is as follows: take out the mold from the freezing device, heat it to between 20-25°C at a heating rate of 1-2°C / min, and keep it for 10 minutes.

5. The method for investment casting with reduced wax pattern deformation according to claim 1, characterized in that: Step 3: Removal and post-processing: After carefully removing the wax model, let it stand at room temperature to ensure that its internal stress is further released and the stability of the final shape is ensured.