Water-based cleaning process before vacuum heat treatment of metallic materials

Abstract

The application discloses a water-based cleaning process before vacuum heat treatment of metal materials and relates to the technical field of pretreatment before heat treatment of metal materials. The process comprises five steps of pretreatment, water-based cleaning, ultrasonic rinsing, water cutting treatment and vacuum hot air drying. The FS-2 water-based cleaning agent is adopted for austenitic stainless steel (0Cr18Ni9), titanium alloy (Ti-6Al-4V) and nickel-based high-temperature alloy (GH3536), a multi-tank ultrasonic cleaning system is matched, the cleaning temperature is controlled to be 50-60 DEG C, the ultrasonic frequency is 28 kHz, and deionized water with a resistivity of greater than or equal to 15 M omega. cm is used for rinsing. The process is environmentally friendly, has no heavy metal residue, is non-flammable and non-explosive, the surface cleanliness of the parts after cleaning reaches F9 / 1.0, the surface is good in gloss and the grains are uniform after subsequent heat treatment, there is almost no oxidation and decarburization, and the microhardness is better than that of the traditional cleaning process.

Description

Technical Field

[0001] This invention relates to the field of pretreatment technology for heat treatment of metallic materials, specifically a water-based cleaning process for pre-vacuum heat treatment of metallic materials. Background Technology

[0002] Vacuum heat treatment, capable of achieving oxidation-free, decarburization-free, and carburization-free processing of metal workpieces, is widely used in the heat treatment of high-strength, high-precision aerospace components and other products. It demands extremely high surface cleanliness before parts enter the furnace. Traditional cleaning methods mainly include organic solvent cleaning and acid pickling: Organic solvent cleaning utilizes the "like dissolves like" principle to remove organic contaminants. While it offers high cleanliness and fast drying, it suffers from flammability, explosiveness, significant health hazards, high cost, and poor cleaning effect on ionic contaminants. Acid pickling removes oxide scale through chemical reactions. While it has strong rust removal capabilities, it easily leads to over-corrosion and dimensional inconsistencies in parts, and can also cause hydrogen embrittlement. Furthermore, waste acid treatment is difficult and poses significant environmental pressures. With increasingly stringent environmental requirements and the diversification and complexity of metal materials, traditional cleaning methods are no longer sufficient to meet the sustainable development needs of modern manufacturing. Therefore, we propose a water-based cleaning process for metallic materials before vacuum heat treatment. Summary of the Invention

[0003] The purpose of this invention is to provide a water-based cleaning process for metal materials before vacuum heat treatment, which solves the problems mentioned in the background art.

[0004] To achieve the above objectives, the present invention provides the following technical solution: a water-based cleaning process for metal materials before vacuum heat treatment, comprising the following steps: Step 1, Pre-treatment: High-pressure water jet technology is used to perform preliminary cleaning on the surface of the metal material to remove most of the oxides and adhering substances; the metal material is austenitic stainless steel, titanium alloy or nickel-based high-temperature alloy; Step 2, Water-based cleaning: Place the pretreated metal material into the cleaning tank of the multi-tank ultrasonic cleaning system, add water-based cleaning agent, control the cleaning temperature at 50-60℃, the ultrasonic frequency at 28kHz, and the cleaning time at 10min. During the cleaning process, maintain the overflow circulation filtration of the cleaning agent with a filtration accuracy of 50μm. Step 3, Ultrasonic rinsing: Transfer the water-based cleaned metal material to the rinsing tank and use deionized water for ultrasonic rinsing. Control the rinsing temperature at 50-60℃, the ultrasonic frequency at 28kHz, and the rinsing time at 10min. During the rinsing process, maintain the overflow circulation filtration of deionized water with a filtration accuracy of 50μm and a deionized water resistivity ≥15MΩ·cm. Step 4, Water Cutting Treatment: Compressed air is used to perform water cutting treatment on the rinsed metal material for 2 minutes; Step 5, Vacuum hot air drying: Place the cut metal material into a vacuum drying oven, control the drying temperature at 50-60℃, and dry for 10 minutes to ensure that the metal material is completely dry and free of moisture residue.

[0005] In a preferred embodiment of the present invention, the water-based cleaning agent is FS-2 multifunctional high-efficiency water-based cleaning agent, which is a light yellow transparent liquid with a density of 1.1-1.2 g / cm³ at 25°C, a pH value of 12-13 for a 5% aqueous solution, and is free of heavy metals and halogens.

[0006] In a preferred embodiment of the present invention, the multi-tank ultrasonic cleaning system is equipped with heating and stirring functions, and has a total power of 130kw.

[0007] In a preferred embodiment of the present invention, the metal material in step one has a sheet structure with dimensions of 30mm × 30mm × 2mm.

[0008] In a preferred embodiment of the present invention, when the surface of the metal material is highly contaminated, the cleaning time is extended or the concentration of the water-based cleaning agent is increased in step two.

[0009] In a preferred embodiment of the present invention, the water-based cleaning agent is composed of surfactants, chelating agents and additives, and removes pollutants through the synergistic effects of wetting, penetration, emulsification and dispersion.

[0010] In a preferred embodiment of the present invention, the cleaned metal material, after vacuum heat treatment, has a surface cleanliness level of not less than F9 / 1.0.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention uses a water-based cleaning agent as the core cleaning medium. It is non-flammable and non-explosive, with no heavy metal or halogen residues, and is highly environmentally friendly and safe. It solves the safety hazards of traditional organic solvent cleaning and the environmental pollution problems of acid washing. Through the complete process design of "pretreatment-water-based cleaning-ultrasonic rinsing-water cutting-vacuum hot air drying" and precise process parameter control, it can effectively remove oil, particulate contaminants and oxide scale from metal surfaces. The surface cleanliness level of the cleaned parts can reach F9 / 1.0, which is significantly better than traditional organic solvent cleaning and pickling processes. The cleaning process does not corrode the metal substrate, avoiding the loss of alloy elements and hydrogen embrittlement risks caused by acid pickling. It ensures the microhardness of the parts after subsequent vacuum heat treatment, making the hardness of materials such as 0Cr18Ni9, Ti-6Al-4V, and GH3536 after heat treatment superior to parts treated by traditional cleaning methods. In addition, the surface has good gloss, no oxidation and decarburization, and uniform grains. Attached Figure Description

[0012] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments with reference to the accompanying drawings: Figure 1 This is a flow chart of a water-based cleaning process for metal materials before vacuum heat treatment according to the present invention. Detailed Implementation

[0013] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below in conjunction with specific embodiments.

[0014] like Figure 1 As shown, a water-based cleaning process for pre-vacuum heat treatment of metal materials is presented. This process is designed for commonly used metal materials in vacuum heat treatment, such as austenitic stainless steel (0Cr18Ni9), titanium alloy (Ti-6Al-4V), and nickel-based high-temperature alloy (GH3536). It achieves efficient cleaning through standardized procedures and precise parameter control.

[0015] Equipment and reagents Cleaning equipment: A multi-tank ultrasonic cleaning system is adopted, which is equipped with heating, stirring and overflow circulation filtration functions, with a total power of 130kw. It can accurately control the cleaning temperature, time and ultrasonic parameters; a vacuum drying oven is provided for the final drying treatment of samples; a deionized water preparation system ensures that the resistivity of the rinsing water is ≥15MΩ·cm.

[0016] Cleaning reagent: FS-2 multifunctional high-efficiency water-based cleaning agent is selected. It is a light yellow transparent liquid with a density of 1.1-1.2 g / cm³ at 25℃. The pH value of a 5% aqueous solution is 12-13. It is composed of surfactants, chelating agents and additives, and does not contain heavy metals or halogens, meeting environmental protection requirements.

[0017] Implementation steps Preprocessing High-pressure water jet technology is used to initially rinse the sample surface. The water pressure is controlled at 0.8-1.2 MPa and the rinsing time is 30-60 seconds. The main purpose is to remove surface dust, large pieces of attached material and some loose oxide scale, so as to reduce the processing burden of subsequent cleaning steps.

[0018] Water-based cleaning Place the pretreated samples evenly into the cleaning tank of the multi-tank ultrasonic cleaning system, ensuring the samples are completely immersed in FS-2 water-based cleaning agent. Set the cleaning parameters: temperature 55℃ (within the 50-60℃ range), ultrasonic frequency 28kHz, cleaning time 10min; during the cleaning process, maintain overflow circulation filtration of the cleaning agent with a filtration accuracy of 50μm to promptly remove contaminants stripped from the cleaning solution and avoid secondary contamination. For samples with a high degree of surface contamination, the cleaning time can be extended to 12-15min, or the cleaning agent concentration can be appropriately increased (by 10%-20% from the original concentration).

[0019] Ultrasonic rinsing After water-based cleaning, the sample was quickly transferred to a rinsing tank and filled with deionized water (resistivity ≥15MΩ·cm) treated by a deionized water preparation system. The rinsing parameters were set as follows: temperature 55℃, ultrasonic frequency 28kHz, rinsing time 10min. During rinsing, the deionized water was continuously circulated and filtered with a filtration accuracy of 50μm to ensure thorough removal of residual cleaning agent from the sample surface.

[0020] Water cutting treatment Turn on the compressed air system to remove water from the rinsed sample. The compressed air pressure is controlled at 0.4-0.6 MPa and the treatment time is 2 minutes. The airflow quickly removes most of the water adhering to the sample surface, laying the foundation for the subsequent drying process.

[0021] Vacuum hot air drying Place the dehydrated sample into a vacuum drying oven, close the oven door, start the equipment, set the drying temperature to 55℃, and the drying time to 10 minutes, ensuring the sample is completely dry with no moisture residue. After drying, wait for the oven temperature to drop to room temperature before removing the sample to avoid surface oxidation caused by contact with air at high temperatures.

[0022] III. Performance Testing and Results Surface condition inspection The samples treated by this process have a uniform surface gloss, no oil stains, gray-black marks, corrosion layering, or obvious water stains. After subsequent vacuum heat treatment with the corresponding process, the 0Cr18Ni9 and GH3536 samples show almost no oxidation and decarburization on the surface, and the grains are uniform. The thickness of the oxidation and decarburization layer of the Ti-6Al-4V sample is significantly lower than that of the acid-washed group.

[0023] Cleanliness test Cleanliness testing was conducted according to AETF 5.2B standards. The results showed that the surface cleanliness level of the 0Cr18Ni9 and Ti-6Al-4V samples reached F9 / 1.0, and the cleanliness level of the GH3536 sample was F9 / 1.0. The contaminant content per unit area was significantly lower than that of traditional acetone / ethanol cleaning and acid washing processes.

[0024] Microhardness testing The heat-treated samples were tested for HV0.5 hardness using a FALCON500G2 microhardness tester. The results are as follows: the average hardness of the 0Cr18Ni9 sample was 160 HV0.5, the average hardness of the Ti-6Al-4V sample was 313.5 HV0.5, and the average hardness of the GH3536 sample was 243 HV0.5. All of these results are better than the hardness of the samples treated with the traditional cleaning process, which verifies the protective effect of this process on the metal matrix and the effect on improving the quality of heat treatment.

[0025] This implementation method, through standardized processes and precise parameter control, fully leverages the environmental advantages and cleaning efficiency of water-based cleaning. It is suitable for automated batch cleaning of related metal materials before vacuum heat treatment in the aerospace, medical, and energy fields, and can effectively ensure the surface quality and performance of subsequent heat-treated products.

[0026] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

[0027] 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 water-based cleaning process for metallic materials before vacuum heat treatment, characterized in that: Includes the following steps: Step 1, Pre-treatment: High-pressure water jet technology is used to perform preliminary cleaning on the surface of the metal material to remove most of the oxides and adhering substances; the metal material is austenitic stainless steel, titanium alloy or nickel-based high-temperature alloy; Step 2, Water-based cleaning: Place the pretreated metal material into the cleaning tank of the multi-tank ultrasonic cleaning system, add water-based cleaning agent, control the cleaning temperature at 50-60℃, the ultrasonic frequency at 28kHz, and the cleaning time at 10min. During the cleaning process, maintain the overflow circulation filtration of the cleaning agent with a filtration accuracy of 50μm. Step 3, Ultrasonic rinsing: Transfer the water-based cleaned metal material to the rinsing tank and use deionized water for ultrasonic rinsing. Control the rinsing temperature at 50-60℃, the ultrasonic frequency at 28kHz, and the rinsing time at 10min. During the rinsing process, maintain the overflow circulation filtration of deionized water with a filtration accuracy of 50μm and a deionized water resistivity ≥15MΩ·cm. Step 4, Water Cutting Treatment: Compressed air is used to perform water cutting treatment on the rinsed metal material for 2 minutes; Step 5, Vacuum hot air drying: Place the cut metal material into a vacuum drying oven, control the drying temperature at 50-60℃, and dry for 10 minutes to ensure that the metal material is completely dry and free of moisture residue.

2. The water-based cleaning process for metal materials before vacuum heat treatment according to claim 1, characterized in that: The water-based cleaning agent is FS-2 multifunctional high-efficiency water-based cleaning agent, which is a light yellow transparent liquid with a density of 1.1-1.2 g / cm³ at 25°C. The pH value of a 5% aqueous solution is 12-13, and it does not contain heavy metals or halogens.

3. The water-based cleaning process for metal materials before vacuum heat treatment according to claim 1, characterized in that: The multi-tank ultrasonic cleaning system is equipped with heating and stirring functions, with a total power of 130kw.

4. The water-based cleaning process for metal materials before vacuum heat treatment according to claim 1, characterized in that: The metal material mentioned in step one has a sheet-like structure with dimensions of 30mm × 30mm × 2mm.

5. The water-based cleaning process for metal materials before vacuum heat treatment according to claim 1, characterized in that: When the surface of the metal material is highly contaminated, the cleaning time should be extended or the concentration of the water-based cleaning agent should be increased in step two.

6. The water-based cleaning process for metal materials before vacuum heat treatment according to claim 1, characterized in that: The water-based cleaning agent is composed of surfactants, chelating agents, and additives, and removes pollutants through the synergistic effects of wetting, penetration, emulsification, and dispersion.

7. The water-based cleaning process for metal materials before vacuum heat treatment according to claim 1, characterized in that: After cleaning, the surface cleanliness level of the metal material is not lower than F9 / 1.0 after vacuum heat treatment.

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