Titanium alloy corrosion production process

Abstract

The invention discloses a titanium alloy corrosion production process which comprises the following steps: S1, preparing a corrosion liquid in a corrosion tank for later use; s2, the titanium alloy workpiece is hoisted into a constant-temperature and constant-pressure corrosion tank to be stirred and corroded; s3, after corrosion is completed, the titanium alloy workpiece is put into a neutralizing solution to be subjected to neutralizing treatment; s4, the titanium alloy workpiece obtained after neutralization treatment is put into a cleaning tank, and hot water is added for first-time cleaning; s5, the titanium alloy workpiece cleaned with the hot water is put into an ultrasonic oil removal tank, and water is added for cleaning and oil removal; s6, the titanium alloy workpiece subjected to cleaning and oil removal is put into a passivation solution to be subjected to passivation treatment; s7, the cleaned and deoiled titanium alloy workpiece is put into a drying tank to be dried; s8, discharging the titanium alloy finished product out of the groove; and S9, recovery and cyclic utilization of the corrosive liquid. The corrosion process is accurately controlled, the product quality is improved, the pollution to the environment is reduced, and meanwhile the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the field of metal processing, and particularly to a production process for titanium alloy corrosion. Background Art

[0002] Due to its excellent properties such as high melting point, high hardness, high tensile strength, strong plasticity (characteristics change when impurities are present), non-toxicity, non-magnetism, high temperature resistance, and excellent corrosion resistance (the corrosion resistance is 15 times that of ordinary stainless steel, especially outstanding in seawater corrosion resistance), titanium alloy has been widely used in many industrial fields. In the aerospace field, titanium alloy structural parts are widely used in aeroengines. For example, on aircraft such as the Su-27, the US third-generation fighter jets F-14, F-15, and the fourth-generation fighter jet F-22, the titanium alloy usage reaches 15%-41%. In leisure sports goods, there are titanium tennis rackets, badminton rackets, golf club heads and shafts, etc. In the medical industry, due to its good biocompatibility, titanium alloy is used in human repair fields such as dentures, bones and joints.

[0003] As one of the important means of metal processing, corrosion processing technology places the workpiece in a chemical solution and uses the chemical solution to corrode and dissolve the substrate. By controlling the chemical solution and applying protective measures to the workpiece, the substrate material can be accurately removed within a predetermined range and depth. This is a process involving many local reactions such as diffusion, adsorption, chemical reaction, and electrochemical reaction. For alloy materials, due to the existence of metal potential differences inside, both chemical reaction and electrochemical reaction coexist during corrosion processing, and which one is dominant depends on the metal material composition and its content. When pure metal is corroded and processed, it is mainly a chemical reaction process, and the mechanism is the dissolution of grain boundaries and grains. Under the action of the corrosion solution, the places with wide atomic (grain) spacing dissolve rapidly until an uneven surface appears. The lattice distortion and impurity enrichment on the grain boundaries will accelerate the dissolution, which may cause pitted corrosion of the entire grain. Generally, the smaller the grain size, the lighter the grain boundary corrosion.

[0004] The current production process for titanium alloy corrosion has some deficiencies. On the one hand, during the corrosion process, the control of the corrosion rate and corrosion accuracy is not precise enough, resulting in uneven quality of the processed titanium alloy products and unable to meet the manufacturing requirements of some fields with extremely high precision requirements, such as some key components in aerospace. On the other hand, the existing process has defects in environmental protection. The corrosion solutions used often contain a large amount of substances harmful to the environment, and the waste water and waste gas discharged during the production process are likely to pollute the surrounding environment, which does not conform to the current concept of green production. At the same time, some processes have high costs. Whether it is the cost of the corrosion solution or the energy consumption cost during the production process, it limits the wide application of titanium alloy products in some cost-sensitive fields. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a titanium alloy corrosion production process to solve the problems of poor corrosion rate and precision control, poor environmental protection, and high cost in the existing process, realizing precise control of the corrosion process, improving product quality, reducing environmental pollution, and at the same time reducing production costs.

[0006] To solve the above technical problems, the solution of the present invention is: a titanium alloy corrosion production process, including the following steps:

[0007] S1. Prepare the corrosion solution and reserve it in the corrosion tank;

[0008] S2. Lift the titanium alloy workpiece into the corrosion tank with constant temperature and pressure and stir for corrosion;

[0009] S3. After the corrosion is completed, put the titanium alloy workpiece into the neutralizing solution for neutralization treatment;

[0010] S4. Put the neutralized titanium alloy workpiece into the cleaning tank and heat water for the first cleaning;

[0011] S5. Put the titanium alloy workpiece after hot water cleaning into the ultrasonic degreasing tank and add water for cleaning and degreasing;

[0012] S6. Take the titanium alloy workpiece after cleaning and degreasing and put it into the passivation solution for passivation treatment;

[0013] S7. Take the titanium alloy workpiece after cleaning and degreasing and put it into the drying tank for drying;

[0014] S8. The titanium alloy finished product exits the tank;

[0015] S9. Recycle and reuse the corrosion solution.

[0016] Preferably, in step S1, the corrosion solution is composed of hydrofluoric acid, nitric acid, and an additive. The additive is composed of an organic amine compound and a rare earth compound. The concentration of hydrofluoric acid is 5-10 ml / L, the concentration of nitric acid is 20-125 ml / L, the organic amine compound accounts for 0.5-2% of the total mass of the corrosion solution, and the rare earth compound accounts for 0.1-1% of the total mass of the corrosion solution.

[0017] Preferably, in step S2, the temperature in the corrosion tank is 25-35 °C, and the pressure is 0.1-0.3 MPa.

[0018] Preferably, in step S3, the neutralizing solution is a sodium bicarbonate solution with a mass fraction of 5%-10%, and the soaking time is 5-10 min.

[0019] Preferably, in step S4, the temperature of the hot water is 60-90 °C, and the cleaning time is 10-20 min.

[0020] Preferably, the water in step S5 is pure water, and the cleaning time is 10 - 20 min.

[0021] Preferably, the passivation solution in step S6 is chromic acid with a mass fraction of 2 - 5%, and the passivation time is 15 - 30 min.

[0022] Preferably, the temperature in the drying tank in step S7 is 85°C.

[0023] Preferably, the corrosion tank is made of duplex stainless steel.

[0024] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0025] 1. The corrosion process is precisely controlled through a constant temperature and constant pressure corrosion tank;

[0026] 2. The product quality is improved by optimizing the corrosion solution formula;

[0027] 3. The harmful corrosion solution residues on the workpiece surface are removed through the neutralizing solution and ultrasonic cleaning, enhancing environmental protection.

[0028] 4. The environmental pollution is reduced through the recovery and recycling of the corrosion solution; the production cost is reduced. Specific Embodiments

[0029] The following further illustrates the specific embodiments of the present invention in conjunction with the examples. It should be noted here that the description of these embodiments is used to help understand the present invention, but does not constitute a limitation to the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0030] A titanium alloy corrosion production process of the present invention includes the following steps:

[0031] S1. Prepare the corrosion solution and reserve it in the corrosion tank;

[0032] S2. Lift the titanium alloy workpiece into the constant temperature and constant pressure corrosion tank for stirring and corrosion;

[0033] S3. After the corrosion is completed, put the titanium alloy workpiece into the neutralizing solution for neutralization treatment;

[0034] S4. Put the neutralized titanium alloy workpiece into the cleaning tank and heat water for the first cleaning;

[0035] S5. Put the titanium alloy workpiece after hot water cleaning into the ultrasonic degreasing tank and add water for cleaning and degreasing;

[0036] S6. Take the titanium alloy workpiece after cleaning and degreasing and put it into the passivation solution for passivation treatment;

[0037] S7. Place the degreased titanium alloy workpiece in a drying tank for drying.

[0038] S8. The titanium alloy finished product is taken out of the tank.

[0039] S9. Recycling and reusing the etching solution.

[0040] Specifically, in step S1, the etching solution is composed of hydrofluoric acid, nitric acid and an additive. The additive is composed of an organic amine compound and a rare earth compound. The concentration of hydrofluoric acid is 5 - 10 ml / L, the concentration of nitric acid is 20 - 125 ml / L, the organic amine compound accounts for 0.5 - 2% of the total mass of the etching solution, and the rare earth compound accounts for 0.1 - 1% of the total mass of the etching solution.

[0041] Further, in step S2, the temperature in the etching tank is 25 - 35 °C, and the pressure is 0.1 - 0.3 MPa.

[0042] Further, in step S3, the neutralizing solution is a sodium bicarbonate solution with a mass fraction of 5% - 10%, and the soaking time is 5 - 10 min.

[0043] Further, in step S4, the temperature of the hot water is 60 - 90 °C, and the cleaning time is 10 - 20 min.

[0044] Further, the water in step S5 is pure water, and the cleaning time is 10 - 20 min.

[0045] In step S6, the passivation solution is chromic acid with a mass fraction of 2% - 5%, and the passivation time is 15 - 30 min.

[0046] Further, in step S7, the temperature in the drying tank is 85 °C.

[0047] Specifically, the etching tank is made of duplex stainless steel.

[0048] Example 1

[0049] Preparation work: Prepare titanium alloy plates with a purity of 99.5% as the workpieces to be processed, with dimensions of 100 mm × 100 mm × 5 mm. Prepare the etching solution according to the formula. Take 100 g of hydrofluoric acid with a mass fraction of 10%, 200 g of nitric acid with a mass fraction of 20%, 15 g of organic amine compound (accounting for 1.5% of the total mass of the etching solution), 8 g of rare earth compound (accounting for 0.8% of the total mass of the etching solution), and add deionized water to 1000 g.

[0050] Corrosion process: Place the titanium alloy sheet into a special corrosion tank. Turn on the precise temperature control device to maintain the temperature of the corrosion liquid at 30°C, and the pressure control system keeps the pressure in the corrosion tank at 0.2 MPa. The stirring device stirs the corrosion liquid at a speed of 100 r / min. The corrosion time is set to 30 min.

[0051] Post-treatment: After corrosion is completed, immerse the sheet in a sodium bicarbonate neutralizing solution with a concentration of 8% for 8 min, wash it with hot water (temperature 85°C, washing time 20 min), then place it in an ultrasonic cleaning device and wash it with pure water for 15 min. Finally, immerse the sheet in a passivation solution containing 3% chromic acid for 20 min.

[0052] Testing: Conduct surface quality inspection and dimensional accuracy measurement on the treated titanium alloy sheet. Observe the surface through a scanning electron microscope and find that the corrosion layer is uniform and there are no obvious defects. The dimensional accuracy measurement results show that the dimensional deviation of the sheet is within the range of ±0.05 mm, meeting the requirements of high-precision products. At the same time, recycle and treat the corrosion liquid. After filtration and distillation, the recycled corrosion liquid can be reused after its composition is adjusted through testing.

[0053] Example 2

[0054] Preparation work: Select a titanium alloy rod with a purity of 99.8%, a diameter of 20 mm, and a length of 100 mm. Prepare the corrosion liquid, including 80 g of hydrofluoric acid with a mass fraction of 8%, 150 g of nitric acid with a mass fraction of 15%, 10 g of organic amine compound (accounting for 1% of the total mass of the corrosion liquid), 5 g of rare earth compound (accounting for 0.5% of the total mass of the corrosion liquid), and add pure water to 1000 g.

[0055] Corrosion process: Place the titanium alloy rod into the corrosion tank, control the temperature of the corrosion liquid at 28°C, the pressure at 0.15 MPa, the stirring speed at 80 r / min, and the corrosion time at 25 min.

[0056] Post-treatment: Conduct neutralization (neutralizing solution concentration 6% sodium bicarbonate, soaking for 6 min), hot water washing (temperature 70°C, washing time 20 min), ultrasonic cleaning (washing with pure water for 12 min), and passivation (passivation solution containing 4% chromic acid, passivation for 25 min) in sequence.

[0057] Testing: After testing, the surface of the rod is smooth and the corrosion is uniform. Dimensional measurement shows that the diameter deviation is within ±0.03 mm. After the corrosion liquid is recycled and treated, the recovery rate reaches 85%, effectively reducing costs and environmental pollution.

[0058] The titanium alloy corrosion production process of the present invention has remarkable effects in improving product quality, enhancing environmental protection, and reducing costs, and has good application prospects.

[0059] The above embodiments have described the implementation manners of the present invention in detail, but the present invention is not limited to the described implementation manners. For those skilled in the art, without departing from the principle and spirit of the present invention, various changes, modifications, substitutions and variations made to these implementation manners still fall within the protection scope of the present invention.

Claims

1. A titanium alloy corrosion production process, characterized in that, It includes the following steps: S1. Prepare the etching solution and reserve it in the etching tank; S2. Lift the titanium alloy workpiece into the etching tank with constant temperature and pressure and stir for etching; S3. After etching, put the titanium alloy workpiece into the neutralizing solution for neutralization treatment; S4. Put the titanium alloy workpiece after neutralization treatment into the cleaning tank and heat water for the first cleaning; S5. Put the titanium alloy workpiece after hot water cleaning into the ultrasonic degreasing tank and add water for cleaning and degreasing; S6. Take the titanium alloy workpiece after cleaning and degreasing and put it into the passivation solution for passivation treatment; S7. Take the titanium alloy workpiece after cleaning and degreasing and put it into the drying tank for drying; S8. The finished titanium alloy product exits the tank; S9. Recover and recycle the etching solution.

2. The titanium alloy corrosion production process according to claim 1, characterized in that, In step S1, the etching solution is composed of hydrofluoric acid, nitric acid and additives. The additives are composed of organic amine compounds and rare earth compounds. The concentration of hydrofluoric acid is 5-10 ml / L, the concentration of nitric acid is 20-125 ml / L, the organic amine compounds account for 0.5-2% of the total mass of the etching solution, and the rare earth compounds account for 0.1-1% of the total mass of the etching solution.

3. The titanium alloy corrosion production process according to claim 1, characterized in that, In step S2, the temperature in the etching tank is 25-35 °C and the pressure is 0.1-0.3 MPa.

4. The titanium alloy corrosion production process according to claim 1, characterized in that, In step S3, the neutralizing solution is a sodium bicarbonate solution with a mass fraction of 5%-10%, and the soaking time is 5-10 min.

5. The titanium alloy corrosion production process according to claim 1, characterized in that, In step S4, the temperature of the hot water is 60-90 °C and the cleaning time is 10-20 min.

6. The titanium alloy corrosion production process according to claim 1, characterized in that, The water in step S5 is pure water and the cleaning time is 10-20 min.

7. The titanium alloy corrosion production process according to claim 1, characterized in that, In step S6, the passivation solution is chromic acid with a mass fraction of 2-5%, and the passivation time is 15-30 min.

8. The titanium alloy corrosion production process according to claim 1, characterized in that, In step S7, the temperature in the drying tank is 85 °C.

9. The titanium alloy corrosion production process according to claim 1, characterized in that, The etching tank is made of duplex stainless steel.