Method for detecting blue corrosion defects of titanium alloy workpiece

Abstract

The invention relates to the technical field of part defect detection, in particular to a titanium alloy workpiece blue corrosion defect detection method which comprises the following steps: S1, oil removal: carrying out oil removal and cleaning on the surface of a titanium alloy product; s2, corrosion is conducted, specifically, the titanium alloy product is immersed in a corrosion tank solution to be corroded, and deionized water washing is conducted after corrosion is completed; s3, anodizing is conducted, specifically, the titanium alloy workpiece subjected to deionized water washing after corrosion is anodized, and deionized water washing is conducted after anodizing is completed; s4, developing: putting the anodized titanium alloy workpiece subjected to water washing into the corrosion tank solution in the step S2, taking out the workpiece after the surface of the workpiece shows uniform light blue to light blue gray, and carrying out deionized water washing; and S5, inspection. Compared with existing blue corrosion, the method is short in technological process, convenient to operate, short in production cycle and stable in process, production and processing can be completed only through four solution tanks, and the corrosion inspection efficiency and quality can be greatly improved.

Description

Technical Field

[0001] The invention relates to the technical field of parts defect detection, in particular to a method for blue corrosion defect detection of titanium alloy parts. Background Art

[0002] The density of titanium is 4.5 g / cm 3 , between aluminum 2.7g / cm 3 and iron 7.6g / cm 3 The density of titanium is between 200 and 210, but its specific strength is higher than that of aluminum and iron, its operating temperature is wider, and its heat resistance and corrosion resistance are better. Therefore, titanium and its alloys are widely used in structural materials in the aerospace industry.

[0003] The macro defect inspection of titanium alloy parts mainly adopts the gray corrosion method of nitric acid / hydrofluoric acid system. After corrosion, the surface of the parts presents a certain gray scale. According to the gray color difference of the surface of the parts, the defects such as folding, overheating, corrosion, etc. generated during the processing can be identified. The main disadvantage of this method is that after the corrosion inspection, the color change difference at the defect is not clearly exposed, the contrast is small, and the types of defects are few, which is easy to cause misjudgment or misjudgment. In addition, this method can only be performed on semi-finished parts, and the parts need to be reprocessed later, which may cause new machining defects, resulting in missed defects.

[0004] Anodizing of titanium alloy surfaces is more used for corrosion protection and wear resistance, but is less used in corrosion inspection. Even if it is used, the processing flow is relatively complicated and cumbersome. The general processing flow is: degreasing → hot water washing → cold water washing → pre-corrosion → cold water washing → activation → cold water washing → anodizing → cold water washing → development → cold water washing → hot water washing → drying. The production cycle is long, the cost is high, and the process application is difficult. Summary of the invention

[0005] The main purpose of the present invention is to provide a method for inspecting blue corrosion defects of titanium alloy parts, aiming to solve the above technical problems.

[0006] To achieve the above object, the present invention provides a method for inspecting blue corrosion defects of titanium alloy parts, comprising the following steps:

[0007] S1. Degreasing: Degreasing and cleaning the surface of titanium alloy products;

[0008] S2. Corrosion: Immerse the titanium alloy product in a corrosion tank for corrosion, and then wash with deionized water after the corrosion is completed;

[0009] S3, anodizing: anodizing the titanium alloy parts that have been washed with deionized water after corrosion, and then washing with deionized water after anodizing;

[0010] S4, development: placing the anodized and water-washed titanium alloy workpiece in the etching bath of step S2, and taking it out and washing it with deionized water when the surface of the workpiece shows a uniform light blue to light blue-gray color;

[0011] S5. Inspection.

[0012] Preferably, in step S1, when degreasing, clean absorbent cotton is dipped in analytically pure acetone to degrease and clean the surface of the titanium alloy product, and then the product is air-dried for 1 to 5 minutes.

[0013] Preferably, in step S2, during the corrosion, the titanium alloy product after degreasing and drying is immersed in a corrosion tank liquid at a temperature of 15 to 35° C. for 0.5 to 3 minutes for corrosion, and after the corrosion is completed, it is placed in a deionized water washing solution at room temperature for 0.5 to 1 minute for water washing.

[0014] Preferably, in step S2, when performing the etching, the etching bath liquid composition used is:

[0015] HNO3: 280~380g / L;

[0016] HF: 12-22 g / L;

[0017] Dissolved titanium: 0.3~6g / L;

[0018] The balance is H2O.

[0019] Preferably, in step S3, during anodizing, the titanium alloy workpiece that has been deionized and washed with water after corrosion is hung on a conductive fixture, and then the whole is completely immersed in an anodizing solution with a pH of 8 to 9 and a temperature of 20 to 40°C for 30±5s, and then placed in a deionized water washing solution at room temperature for 0.5 to 1min for washing.

[0020] Preferably, in step S3, during anodization, the voltage is set to 30±1V; the composition of the anodizing bath solution is: Na3PO4·12H2O: 90-142 g / L, with the remainder being H2O.

[0021] Preferably, in step S4, during development, the titanium alloy workpiece that has been washed after anodization is placed in the corrosion tank solution of step S2 for 0.5 to 1 min; after being taken out, it is washed with deionized water twice, the first time is washed with deionized water at room temperature, and the second time is washed with hot water.

[0022] Preferably, in step S4, the two deionized water washes are respectively: the titanium alloy workpiece is placed in a deionized water washing solution at room temperature for 0.5 to 1 min for water washing, and then placed in deionized water at a temperature of 60 to 90° C. for 0.5 to 1 min to complete hot water washing.

[0023] Due to the adoption of the above technical solution, the beneficial effects of the present invention are as follows:

[0024] Compared with the prior art, the method for inspecting defects of titanium alloy parts by blue corrosion provided by the present invention is based on the slight removal of the anodized film layer of the titanium alloy, so as to achieve the effect of revealing corrosion defects. Compared with the separate gray corrosion nitric acid / hydrofluoric acid system, the defects are more clearly revealed, the defect identification is more accurate, and the types of defects that can be revealed are more numerous. Compared with the existing blue corrosion, this method has a short process flow, is easy to operate, requires only 4 solution tanks to complete the production and processing, has a short production cycle, and a stable process, which can greatly improve the efficiency and quality of corrosion inspection. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the structures shown in these drawings without paying creative work.

[0026] Figure 1 A schematic diagram of four tanks used in the method provided by the present invention;

[0027] Figure 2 This is an abnormal display diagram of a blue corrosion inspection workpiece prepared by the method provided by the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] Embodiment 1:

[0030] A method for inspecting blue corrosion defects of titanium alloy parts comprises the following steps:

[0031] S1. Degreasing: Use clean absorbent cotton to dip analytically pure acetone to degrease and clean the surface of the titanium alloy product, and then dry it in air for 1 minute;

[0032] S2. Corrosion: Immerse the degreased and air-dried titanium alloy product in a corrosion solution at a temperature of 15°C for 0.5 min, and then wash it with a deionized water solution at room temperature for 0.5 min. The corrosion tank solution composition is: HNO3: 280g / L; HF: 12g / L; dissolved titanium: 0.3g / L; the remainder is H2O.

[0033] S3. Anodizing: After the corrosion, the titanium alloy parts that have been washed with deionized water are hung on a conductive fixture, and then completely immersed in an anodizing solution with a pH of 8 and a temperature of 20°C for 25 seconds, and then placed in a deionized water washing solution at room temperature for 0.5 minutes for washing, wherein the voltage is set to 30±1V, and the composition of the anodizing tank solution is: Na3PO4·12H2O: 90g / L, and the balance is: H2O. After anodizing, the surface of the product appears blue.

[0034] S4, development: place the anodized and washed titanium alloy workpiece in the corrosion tank solution of step S2 for 0.5 min. When the surface of the workpiece shows a uniform light blue to light blue-gray color, take it out and place it in a deionized water solution at room temperature for 0.5 min for water washing, and finally place it in deionized water at a temperature of 60°C for 0.5 min to complete hot water washing.

[0035] S5. Inspection.

[0036] The titanium alloy prepared according to the above scheme has a uniform light blue to light blue-gray surface, while the color of the defective area is obviously different from the color of the normal area matrix, and the defects of the workpiece can be judged based on the color difference.

[0037] Embodiment 2:

[0038] A method for inspecting blue corrosion defects of titanium alloy parts comprises the following steps:

[0039] S1. Degreasing: Use clean absorbent cotton to dip analytically pure acetone to degrease and clean the surface of the titanium alloy product, and then air dry it for 2.5 minutes;

[0040] S2. Corrosion: Immerse the degreased and air-dried titanium alloy product in a corrosion solution at 25°C for 2 minutes, and then wash it with a deionized water solution at room temperature for 0.7 minutes. The corrosion tank solution contains: HNO3: 330 g / L; HF: 17 g / L; dissolved titanium: 3.3 g / L; and the remainder is H2O.

[0041] S3, anodizing: the titanium alloy parts that have been deionized after corrosion are hung on a conductive fixture, and then completely immersed in an anodizing solution with a pH of 8.5 and a temperature of 30°C for 30 seconds, and then placed in a deionized water washing solution at room temperature for 0.7 minutes for water washing, wherein the voltage is set to 30±1V, and the composition of the anodizing bath is: Na3PO4·12H2O: 120g / L, and the balance is H2O. After anodizing, the surface of the product appears blue.

[0042] S4 Development: Place the anodized and washed titanium alloy workpiece in the corrosion tank solution of step S2 for 0.7 minutes. When the surface of the workpiece presents a uniform light blue to light blue-gray color, take it out and place it in a deionized water solution at room temperature for 0.7 minutes for water washing, and finally place it in deionized water at a temperature of 75°C for 0.7 minutes to complete hot water washing.

[0043] S5. Inspection.

[0044] The titanium alloy prepared according to the above scheme has a uniform light blue to light blue-gray surface, while the color of the defective area is obviously different from the color of the normal area matrix, and the defects of the workpiece can be judged based on the color difference.

[0045] Embodiment 3:

[0046] A method for inspecting blue corrosion defects of titanium alloy parts comprises the following steps:

[0047] S1. Degreasing: Use clean absorbent cotton to dip analytically pure acetone to degrease and clean the surface of the titanium alloy product, and then dry it in air for 5 minutes;

[0048] S2. Corrosion: Immerse the degreased and air-dried titanium alloy product in a corrosion solution at 35°C for 3 minutes, and then wash it with a deionized water solution at room temperature for 1 minute. The corrosion tank solution contains: HNO3: 380g / L; HF: 22g / L; dissolved titanium: 6g / L; and the remainder is H2O.

[0049] S3. Anodizing: After the corrosion, the titanium alloy parts that have been washed with deionized water are hung on a conductive fixture, and then completely immersed in an anodizing solution with a pH of 9 and a temperature of 40°C for 35 seconds, and then placed in a deionized water washing solution at room temperature for 1 minute for washing, wherein the voltage is set to 30±1V, and the composition of the anodizing tank solution is: Na3PO4·12H2O: 142g / L, and the balance is H2O. After anodizing, the surface of the product appears blue.

[0050] S4, development: the titanium alloy workpiece after anodization and water washing is placed in the corrosion tank solution of step S2 for 1 minute. When the surface of the workpiece shows a uniform light blue to light blue-gray color, it can be taken out and placed in a deionized water washing solution at room temperature for 1 minute for water washing, and finally placed in deionized water at a temperature of 90°C for 1 minute to complete hot water washing.

[0051] S5. Inspection.

[0052] The titanium alloy prepared according to the above scheme has a uniform light blue to light blue-gray surface, while the color of the defective area is obviously different from the color of the normal area matrix, and the defects of the workpiece can be judged based on the color difference.

[0053] In the present invention, the process flow mainly includes: degreasing → corrosion → deionized water washing → anodizing → deionized water washing → developing → deionized water washing → hot water washing → inspection. Compared with the traditional process, the process is greatly simplified.

[0054] Combination Figure 1 As shown, in the present invention, only four solution tanks are needed to complete the production process. The first solution tank is an etching / developing tank, which contains etching tank solution. The second solution tank is a deionized water washing tank at room temperature. The third solution tank is an anodizing tank. The fourth solution tank is a deionized water washing tank at 60-90°C.

[0055] By adopting the method provided by the present invention, the surface of the parts presents a uniform light blue to light blue-gray color, and the appearance of defects such as cracks, folds, segregation, overburning and inclusions is greatly different from that of the normal matrix in terms of state and color, and the surface defect types of titanium alloy parts can be clearly and accurately identified. In the process flow, the etching and development are both nitric acid / hydrofluoric acid systems, and the processing conditions and solution composition parameters are consistent, so a processing tank can be shared, the production space occupies a small area, the process is short, the processing process is stable, the efficiency is high, and it is suitable for batch-scale processing and production.

[0056] Combination Figure 2 As shown, the color development of the defective area is obviously different from that of the normal area matrix, and the defects of the workpiece can be judged based on the color development difference.

[0057] The above description is only a preferred embodiment of the present invention, and does not limit the patent scope of the present invention. All equivalent structural changes made by using the contents of the present invention specification and drawings under the inventive concept of the present invention, or directly / indirectly applied in other related technical fields are included in the patent protection scope of the present invention.

Claims

1. A method for inspecting blue corrosion defects of titanium alloy parts, characterized in that: The following steps are involved: S1. Degreasing: Degreasing and cleaning the surface of titanium alloy products; S2, corrosion: immerse the titanium alloy product in the corrosion tank liquid for corrosion, and wash with deionized water after the corrosion is completed; S3, anodizing: anodizing the titanium alloy parts that have been washed with deionized water after corrosion, and then washing with deionized water after anodizing; S4, development: placing the anodized and water-washed titanium alloy workpiece in the etching bath of step S2, and taking it out and washing it with deionized water when the surface of the workpiece shows a uniform light blue to light blue-gray color; S5. Inspection.

2. A method for inspecting defects of titanium alloy parts by blue corrosion as claimed in claim 1, characterized in that: In the step S1, when degreasing, clean absorbent cotton is dipped in analytically pure acetone to degrease and clean the surface of the titanium alloy product, and then the product is air-dried for 1 to 5 minutes.

3. A method for inspecting defects of titanium alloy parts by blue corrosion as claimed in claim 1, characterized in that: In step S2, during the corrosion process, the titanium alloy product after degreasing and drying is immersed in a corrosion tank liquid at a temperature of 15 to 35° C. for 0.5 to 3 minutes for corrosion, and then placed in a deionized water washing solution at room temperature for 0.5 to 1 minute for water washing after the corrosion is completed.

4. A method for inspecting defects of titanium alloy parts by blue corrosion as claimed in claim 1, characterized in that: In step S2, when etching is performed, the etching bath liquid composition used is: HNO3: 280~380g / L; HF: 12-22 g / L; Dissolved titanium: 0.3~6g / L; The balance is H2O.

5. The method for blue corrosion inspection of titanium alloy parts as claimed in claim 1, characterized in that: In step S3, during anodization, the titanium alloy workpiece that has been deionized and washed with water after corrosion is hung on a conductive fixture, and then the whole is completely immersed in an anodizing solution with a pH of 8 to 9 and a temperature of 20 to 40°C for 30±5s, and then placed in a deionized water washing solution at room temperature for 0.5 to 1min for water washing.

6. A method for inspecting defects of titanium alloy parts by blue corrosion as claimed in claim 5, characterized in that: In step S3, during anodization, the voltage is set to 30±1V; the composition of the anodizing bath solution is: Na3PO4·12H2O: 90-142 g / L, with the remainder being H2O.

7. A method for inspecting defects of titanium alloy parts by blue corrosion as claimed in claim 1, characterized in that: In step S4, during development, the anodized and water-washed titanium alloy workpiece is placed in the corrosion tank solution of step S2 for 0.5 to 1 minute; after being taken out, it is washed with deionized water twice, the first time is washed with deionized water at room temperature, and the second time is washed with hot water.

8. A method for inspecting defects of titanium alloy parts by blue corrosion as claimed in claim 7, characterized in that: In step S4, the two deionized water washings are respectively: the titanium alloy workpiece is placed in a deionized water washing solution at room temperature for 0.5 to 1 min for washing, and then placed in deionized water at a temperature of 60 to 90° C. for 0.5 to 1 min to complete hot water washing.

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