Grain size corrosion method for nickel-based single crystal alloy blade casting
By using a gradient-controlled etching solution formula and stirring device, the problems of uneven and low-efficiency etching of nickel-based single crystal blades were solved, achieving efficient and clear etching of nickel-based single crystal blades and meeting the rapid testing requirements of high-temperature components.
Patent Information
- Application Number
- CN202511644108.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-11-11
- Publication Date
- 2026-02-13
AI Technical Summary
Existing methods for grain size etching of nickel-based single crystal blades suffer from problems such as low efficiency, uneven etching, and significant environmental hazards, making it difficult to meet the rapid testing needs of high-temperature components.
The etching solution formula employs gradient constant temperature control, including a combination of FeCl3, HCl and ethylene glycol, combined with a stirring device, to achieve an etching process of 30℃~50℃, shortening the etching time and avoiding excessive dissolution of grains.
It achieves clear exposure of grain boundaries, improves detection efficiency, reduces production costs, avoids the defects of traditional etching processes, and meets the requirements of high-efficiency, clear, and low-cost etching.
Smart Images
Figure CN121521587A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal material microstructure analysis technology, specifically relating to a grain size corrosion method for nickel-based single crystal alloy blade castings. Background Technology
[0002] Nickel-based single-crystal blades are core high-temperature components in high-end equipment such as aero-engines and gas turbines. They operate for extended periods in extreme high-temperature environments exceeding 1000°C. The integrity of their internal structure, particularly the integrity of the single-crystal structure, directly determines the engine's thrust-to-weight ratio, efficiency, reliability, and service life. Therefore, rapid and accurate testing of single-crystal integrity is an indispensable step in the research, development, manufacturing, and quality control of blades. Before this testing, appropriate etching treatment must be performed to clearly expose the macroscopic grain boundaries for observation and evaluation under a metallographic microscope.
[0003] Currently, before conducting single-crystal integrity testing on this type of blade, it is usually necessary to perform grain size etching on the sample to expose the grain boundaries. Existing techniques for grain size etching of nickel-based single-crystal blades mainly fall into the following categories, but each has significant limitations.
[0004] While traditional corrosion solutions based on hydrofluoric acid have some effectiveness, hydrofluoric acid is highly toxic and environmentally hazardous. Its use, storage, and waste disposal pose significant environmental risks and compliance costs, which seriously contradict the "green, safe, and sustainable development" concept advocated by the global manufacturing industry.
[0005] Etching systems composed of various inorganic acids (such as hydrochloric acid, nitric acid, and sulfuric acid) can theoretically achieve targeted etching of grain boundaries by precisely controlling the concentration of each component. However, in practical applications, achieving sufficient grain boundary contrast often requires a long etching time, resulting in low overall process efficiency.
[0006] In addition, organic etching systems have been tried in Europe and other places as an alternative. However, such systems have not yet been successfully applied in China, and in actual operation, they generally suffer from insufficient grain boundary contrast, resulting in unsatisfactory etching effects and affecting the accuracy of subsequent grain boundary interpretation.
[0007] Therefore, there is an urgent need for a new corrosion technology to meet the requirements of "high efficiency, high clarity, and low composition" in research and production. Summary of the Invention
[0008] To address the shortcomings of existing technologies and improve the research and production efficiency of nickel-based single-crystal alloy blade castings, this study optimizes the etching solution formula and process, employs gradient isothermal control, and achieves clear grain boundary exposure at 30℃~50℃ while avoiding excessive grain dissolution caused by excessive etching. This solves the problems of blurred grain boundaries and uneven etching caused by traditional etching processes, shortens the single etching time, improves detection efficiency, and provides a reliable grain size etching technology for the quality control of aero-engine blades.
[0009] A method for grain size etching of nickel-based single-crystal alloy blade castings, specifically including the following steps:
[0010] The surface of the nickel-based single crystal alloy blade casting is sandblasted and polished to remove non-metallic residues and feeding structures and core supports that affect corrosion.
[0011] The treated blade castings are placed in a single layer in a special corrosion mesh tank and immersed in a constant-temperature corrosion solution for corrosion. The corrosion solution is then heated, and the stirring device of the corrosion tank is started to stir it. Once the set temperature is reached, the corrosion continues.
[0012] After corrosion is stopped, immediately immerse the corrosion-specific mesh tank containing the blades in the neutralizing solution, and at the same time start the stirring device of the corrosion tank to stir.
[0013] After neutralization, the special corrosion mesh tank containing the blades is immersed in a flowing clean water tank to remove the neutralization liquid residue, thus obtaining the corroded blade casting.
[0014] in:
[0015] The composition of the corrosion solution is: FeCl3 300±5g / L, HCl 170±2g / L, ethylene glycol 45±2vol%, and the balance is deionized water.
[0016] The constant temperature of the etchant is 40±2℃, and the etching time for the blade casting is 2min~3min.
[0017] The heating rate of the etchant is 5℃ / min, and the etchant is heated to the set temperature of 50±2℃.
[0018] The corrosion time of the blade casting in the heated corrosive solution is 1 min to 1.5 min.
[0019] The neutralizing solution is a 1 mol / L NaOH solution.
[0020] The temperature of the neutralizing solution is 25℃~30℃, and the neutralization time is 3min~5min.
[0021] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0022] The etching method of this invention can achieve clear exposure of grain boundaries while avoiding excessive grain dissolution caused by excessive etching. This solves the problems of blurred grain boundaries and uneven etching caused by traditional etching processes, shortens the single etching time, improves detection efficiency, and reduces research and production costs. Attached Figure Description
[0023] Figure 1 Macroscopic effect diagram of single crystals and impurities in the blade after corrosion in Example 1 of this invention;
[0024] Figure 2 Fluorescence examination pattern in Example 1 of this invention;
[0025] Figure 3 Macroscopic effect diagram of the single crystal of the blade after corrosion in Embodiment 2 of the present invention. Detailed Implementation
[0026] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples.
[0027] A method for grain size etching of nickel-based single-crystal alloy blade castings, specifically including the following steps:
[0028] The surface of the nickel-based single crystal alloy blade casting is sandblasted and polished to remove non-metallic residues and feeding structures and core supports that affect corrosion.
[0029] The treated blade castings were placed in a single layer in a special etching tank and immersed in an etching solution at a constant temperature of 40±2℃ for 2-3 minutes. The etching solution was then heated to the set temperature of 50±2℃ at a rate of 5℃ / min. Simultaneously, the etching tank's agitator was activated to stir the solution. After reaching the set temperature, etching continued for 1-1.5 minutes. The etching solution consisted of: FeCl3 300±5 g / L, HCl 170±2 g / L, ethylene glycol 45±2 vol%, and the remainder being deionized water.
[0030] After corrosion is stopped, the corrosion-specific mesh tank containing the blades is immediately immersed in the neutralization solution, which is a 1 mol / L NaOH solution. The temperature of the neutralization solution is 25℃~30℃, and the neutralization time is 3min~5min. At the same time, the stirring device of the corrosion tank is started to stir.
[0031] After neutralization, the special corrosion mesh tank containing the blades is immersed in a flowing clean water tank to remove the neutralization liquid residue, thus obtaining the corroded blade casting.
[0032] Example 1
[0033] A method for grain size etching of nickel-based single-crystal alloy blade castings, specifically including the following steps:
[0034] The surface of a DD5 single-crystal alloy low-vortex blade casting was sandblasted and polished to remove non-metallic residues and feeding structures and core supports that affect corrosion.
[0035] The treated blade castings were placed in a single layer in a special etching tank and immersed in an etching solution at a constant temperature of 40°C for 3 minutes. The etching solution was then heated to a set temperature of 50°C at a rate of 5°C / min. Simultaneously, the stirring device in the etching tank was activated to agitate the solution. After reaching the set temperature, etching continued for 1 minute. The etching solution consisted of: FeCl3 300g / L, HCl 170g / L, ethylene glycol 45vol%, and the remainder being deionized water.
[0036] After corrosion is stopped, the corrosion-specific mesh tank containing the blades is immediately immersed in the neutralization solution, which is a 1 mol / L NaOH solution at a temperature of 25°C for 3 minutes. At the same time, the stirring device of the corrosion tank is started to stir.
[0037] After neutralization, the etching mesh containing the blades is immersed in a flowing clean water tank to remove any neutralization residue, resulting in the etched blade casting. Macroscopic images of the single crystals and impurities in the etched blade are shown below. Figure 1 As shown, the fluorescence examination image is as follows. Figure 2 As shown.
[0038] Example 2
[0039] A method for grain size etching of nickel-based single-crystal alloy blade castings, specifically including the following steps:
[0040] The surface of a DD6 single crystal alloy low vortex blade casting was sandblasted and polished to remove non-metallic residues and feeding structures and core supports that affect corrosion.
[0041] The treated blade castings were placed in a single layer in a special etching tank and immersed in an etching solution at a constant temperature of 40°C for 2 minutes. The etching solution was then heated to a set temperature of 52°C at a rate of 5°C / min. Simultaneously, the stirring device in the etching tank was activated to agitate the solution. After reaching the set temperature, etching continued for 1.5 minutes. The etching solution consisted of: FeCl3 305 g / L, HCl 172 g / L, ethylene glycol 45 vol%, and the remainder being deionized water.
[0042] After corrosion is stopped, the corrosion-specific mesh tank containing the blades is immediately immersed in the neutralization solution, which is a 1 mol / L NaOH solution at a temperature of 25°C for 3 minutes. At the same time, the stirring device of the corrosion tank is started to stir.
[0043] After neutralization, the etching mesh containing the blades is immersed in a flowing clean water tank to remove any neutralization residue, resulting in the etched blade casting. A macroscopic image of the etched blade single crystal is shown below. Figure 3 As shown.
[0044] Example 3
[0045] A method for grain size etching of nickel-based single-crystal alloy blade castings, specifically including the following steps:
[0046] The surface of a DZ125 oriented columnar crystal blade simulation part was sandblasted and polished to remove non-metallic residues and feeding structures and core supports that affect corrosion from the casting surface.
[0047] The treated blade simulation parts were placed in a single layer in a special etching tank and immersed in an etching solution at a constant temperature of 42℃ for 2 minutes. The etching solution was then heated to a set temperature of 52℃ at a rate of 5℃ / min. Simultaneously, the stirring device in the etching tank was activated to agitate the solution. After reaching the set temperature, etching continued for 1.5 minutes. The etching solution consisted of: FeCl3 295g / L, HCl 170g / L, ethylene glycol 47vol%, and the remainder being deionized water.
[0048] After corrosion is stopped, the corrosion-specific mesh tank containing the blades is immediately immersed in the neutralization solution, which is a 1 mol / L NaOH solution at a temperature of 25°C for 4 minutes. At the same time, the stirring device of the corrosion tank is started to stir.
[0049] After neutralization, the special corrosion mesh tank containing the blades is immersed in a flowing clean water tank to remove the neutralization liquid residue, thus obtaining the corroded blade casting.
[0050] Example 4
[0051] A method for grain size etching of nickel-based single-crystal alloy blade castings, specifically including the following steps:
[0052] The surface of a DZ125 oriented columnar crystal blade simulation part was sandblasted and polished to remove non-metallic residues and feeding structures and core supports that affect corrosion from the casting surface.
[0053] The treated blade simulation parts were placed in a single layer in a special etching tank and immersed in an etching solution at a constant temperature of 40℃ for 2.5 minutes. The etching solution was then heated to a set temperature of 51℃ at a rate of 5℃ / min, while the stirring device in the etching tank was simultaneously activated. Etching continued for 1 minute after reaching the set temperature. The etching solution consisted of: FeCl3 295g / L, HCl 171g / L, ethylene glycol 47vol%, and the remainder being deionized water.
[0054] After corrosion is stopped, the corrosion-specific mesh tank containing the blades is immediately immersed in the neutralization solution, which is a 1 mol / L NaOH solution at a temperature of 27°C for 3 minutes. At the same time, the stirring device of the corrosion tank is started to stir.
[0055] After neutralization, the special corrosion mesh tank containing the blades is immersed in a flowing clean water tank to remove the neutralization liquid residue, thus obtaining the corroded blade casting.
[0056] Example 5
[0057] A method for grain size etching of nickel-based single-crystal alloy blade castings, specifically including the following steps:
[0058] The surface of a DD5 single-crystal alloy low-vortex blade casting was sandblasted and polished to remove non-metallic residues and feeding structures and core supports that affect corrosion.
[0059] The treated blade simulation parts were placed in a single layer in a special etching tank and immersed in an etching solution at a constant temperature of 41°C for 2 minutes. The etching solution was then heated to a set temperature of 50°C at a rate of 5°C / min. Simultaneously, the etching tank's agitator was activated to stir the solution. After reaching the set temperature, etching continued for 1.5 minutes. The etching solution consisted of: FeCl3 300 g / L, HCl 172 g / L, ethylene glycol 47 vol%, and the remainder being deionized water.
[0060] After corrosion is stopped, the corrosion-specific mesh tank containing the blades is immediately immersed in the neutralization solution, which is a 1 mol / L NaOH solution at a temperature of 28°C for 5 minutes. At the same time, the stirring device of the corrosion tank is started to stir.
[0061] After neutralization, the special corrosion mesh tank containing the blades is immersed in a flowing clean water tank to remove the neutralization liquid residue, thus obtaining the corroded blade casting.
[0062] Example 6
[0063] A method for grain size etching of nickel-based single-crystal alloy blade castings, specifically including the following steps:
[0064] The surface of a DD6 single crystal alloy low vortex blade casting was sandblasted and polished to remove non-metallic residues and feeding structures and core supports that affect corrosion.
[0065] The treated blade simulation parts were placed in a single layer in a special etching tank and immersed in an etching solution at a constant temperature of 41°C for 3 minutes. The etching solution was then heated to a set temperature of 52°C at a rate of 5°C / min. Simultaneously, the etching tank's agitator was activated to stir the solution. After reaching the set temperature, etching continued for 1.3 minutes. The etching solution consisted of: FeCl3 300 g / L, HCl 170 g / L, ethylene glycol 46 vol%, and the remainder being deionized water.
[0066] After corrosion is stopped, the corrosion-specific mesh tank containing the blades is immediately immersed in the neutralization solution, which is a 1 mol / L NaOH solution at a temperature of 26°C for 3 minutes. At the same time, the stirring device of the corrosion tank is started to stir.
[0067] After neutralization, the special corrosion mesh tank containing the blades is immersed in a flowing clean water tank to remove the neutralization liquid residue, thus obtaining the corroded blade casting.
[0068] Example 7
[0069] A method for grain size etching of nickel-based single-crystal alloy blade castings, specifically including the following steps:
[0070] The surface of a DZ125 oriented columnar crystal blade simulation part was sandblasted and polished to remove non-metallic residues and feeding structures and core supports that affect corrosion from the casting surface.
[0071] The treated blade simulation parts were placed in a single layer in a special etching tank and immersed in an etching solution at a constant temperature of 40℃ for 2.5 minutes. The etching solution was then heated to a set temperature of 51℃ at a rate of 5℃ / min, while the stirring device in the etching tank was simultaneously activated. Etching continued for 1 minute after reaching the set temperature. The etching solution consisted of: FeCl3 305g / L, HCl 168g / L, ethylene glycol 46vol%, and the remainder being deionized water.
[0072] After corrosion is stopped, the corrosion-specific mesh tank containing the blades is immediately immersed in the neutralization solution, which is a 1 mol / L NaOH solution at a temperature of 25°C for 4 minutes. At the same time, the stirring device of the corrosion tank is started to stir.
[0073] After neutralization, the special corrosion mesh tank containing the blades is immersed in a flowing clean water tank to remove the neutralization liquid residue, thus obtaining the corroded blade casting.
[0074] Example 8
[0075] A method for grain size etching of nickel-based single-crystal alloy blade castings, specifically including the following steps:
[0076] The surface of a DD5 single-crystal alloy low-vortex blade casting was sandblasted and polished to remove non-metallic residues and feeding structures and core supports that affect corrosion.
[0077] The treated blade simulation parts were placed in a single layer in a special etching tank and immersed in an etching solution at a constant temperature of 42℃ for 2 minutes. The etching solution was then heated to a set temperature of 50℃ at a rate of 5℃ / min, while the stirring device in the etching tank was simultaneously activated. Etching continued for 1.5 minutes after reaching the set temperature. The etching solution consisted of: FeCl3 295g / L, HCl 172g / L, ethylene glycol 46vol%, and the remainder being deionized water.
[0078] After corrosion is stopped, the corrosion-specific mesh tank containing the blades is immediately immersed in the neutralization solution, which is a 1 mol / L NaOH solution at a temperature of 25°C for 5 minutes. At the same time, the stirring device of the corrosion tank is started to stir.
[0079] After neutralization, the special corrosion mesh tank containing the blades is immersed in a flowing clean water tank to remove the neutralization liquid residue, thus obtaining the corroded blade casting.
[0080] The scope of protection of this invention is not limited to the embodiments described above. Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its scope and spirit. If these modifications and variations fall within the scope of this invention and its equivalents, then the intent of this invention also includes these modifications and variations.
Claims
1. A method of grain size etching of a nickel-base single crystal alloy blade casting, characterized by, Specifically comprising the following steps: Sandblasting and polishing the surface of the nickel-based single crystal alloy blade castings to remove non-metallic residues and feeding structures and core supports on the surface of the castings that affect corrosion; After the blade castings are placed in a special corrosion tank and immersed in a constant-temperature corrosion solution, the corrosion solution is heated, and the stirring device of the corrosion tank is started to stir, and the corrosion is continued until the set temperature is reached; After the corrosion is stopped, the blade-containing special corrosion tank is immediately immersed in a neutralizing solution, and the stirring device of the corrosion tank is started to stir; After the neutralization is completed, the blade-containing special corrosion tank is immersed in a flowing clean water tank to remove residual neutralizing solution, and the corroded blade castings are obtained.
2. A method of grain size etching of a nickel-based single crystal alloy blade casting according to claim 1, characterized in that, The composition of the corrosion solution is: FeCl3 300±5g / L, HCl 170±2g / L, ethylene glycol 45±2vol%, and the balance is deionized water.
3. A method of grain size etching of a nickel-based single crystal alloy blade casting according to claim 1, characterized in that, The constant-temperature temperature of the corrosion solution is 40±2℃, and the corrosion time of the blade castings is 2min~3min.
4. A method of grain size etching of a nickel-based single crystal alloy blade casting according to claim 1, characterized in that, The heating rate of the corrosion solution is 5℃ / min, and the corrosion solution is heated to a set temperature of 50±2℃.
5. A method of grain size etching of a nickel-based single crystal alloy blade casting according to claim 1, characterized in that, The corrosion time of the blade castings in the heated corrosion solution is 1min~1.5min.
6. A method of grain size etching of a nickel-based single crystal alloy blade casting according to claim 1, characterized in that, The neutralizing solution is a 1mol / L NaOH solution.
7. A method of grain size etching of a nickel-based single crystal alloy blade casting according to claim 1, characterized in that, The neutralizing solution temperature is 25℃~30℃, and the neutralization time is 3min~5min.