A high-strength corrosion-resistant forged flange manufacturing process

Abstract

The invention relates to the technical field of flange manufacturing, and discloses a high-strength corrosion-resistant forged flange manufacturing process, comprising: a working platform placed on the ground, a mold for forming a sleeper is provided on the top of the working platform; a dragging device is installed on the top of the working platform, and the bottom of the dragging device moves on the working platform through a track and a guide wheel, so that the dragging device can pass a steel wire rope into a track mold; a cleaning mechanism is installed between the dragging device and the mold, and the cleaning device removes concrete blocks on the surface of the mold through the movement of the dragging device; a transmission member is installed between the guide wheel of the dragging device and the cleaning mechanism; the present invention can knock and drop concrete attached to the mold through the cleaning mechanism, and through the linkage of the transmission member, it is convenient to remove the attachments on the inner wall of the mold, reduce the labor intensity of personnel, have a high efficiency in removing concrete, reduce the standing time of personnel, and reduce the safety hazards of personnel.

Description

Technical Field

[0001] The invention relates to the technical field of flange manufacturing, and in particular to a high-strength corrosion-resistant forged flange manufacturing process. Background Art

[0002] With the rapid development of modern industry, especially in the fields of marine engineering, petrochemical industry and nuclear industry, the performance requirements for high-pressure pipeline connectors are getting higher and higher. Although traditional forged flanges meet the basic connection requirements to a certain extent, under extreme environments such as high temperature, high pressure, and highly corrosive media, the performance of traditional flanges is often difficult to meet expectations, and they are prone to leakage, corrosion and other problems, which seriously affect the safe operation and service life of the equipment.

[0003] Traditional forged flanges are mostly made of ordinary carbon steel or low alloy steel, which are prone to performance degradation in high temperature, high pressure and corrosive environments, resulting in reduced strength, poor corrosion resistance and other problems. In some special applications, such as seawater corrosion in marine engineering and acid and alkali corrosion in petrochemicals, the corrosion resistance of traditional materials cannot meet the requirements of long-term use.

[0004] Traditional forging processes usually use simple preheating, forging and quenching treatments, lacking fine control over the internal stress and organizational structure of the material, resulting in unstable mechanical properties of the flange. The lack of effective surface treatment technology, such as chemical nickel plating, nano-ceramic coating, etc., makes the flange surface susceptible to corrosion and wear, affecting the service life. Traditional surface treatment methods such as galvanizing and painting can improve corrosion resistance to a certain extent, but the protective layer is easy to fall off and has poor durability. The lack of advanced surface modification technology has resulted in the surface performance not being able to reach the optimal state. Summary of the invention

[0005] The object of the present invention is to provide a high-strength corrosion-resistant forged flange manufacturing process to solve the problems raised in the above background technology.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] A high-strength corrosion-resistant forged flange manufacturing process comprises the following steps:

[0008] S1. Preheat the metal material to 900°C to 1100°C at a preheating rate of 10°C / min to 20°C / min;

[0009] S2. The preheated metal material is subjected to high-pressure forging at a pressure of 200 MPa to 250 MPa, and the forging die is coated with graphite, and the flange body, the annular sealing reinforcement, and the reinforcement ribs are forged;

[0010] S3. The formed forgings are quenched under a nitrogen protective atmosphere at a quenching temperature of 900°C and a holding time of 2 hours. During the quenching process, nitrogen is introduced at a nitrogen flow rate of 10 L / min to 20 L / min, and the purity of the nitrogen is not less than 99.99%;

[0011] S4, performing low-temperature tempering treatment at a temperature of 250° C. to 300° C. for 2 to 3 hours, and before the low-temperature tempering treatment, a surface polishing treatment is also included, using a grinding wheel with a particle size of 1000 mesh for polishing;

[0012] S5, a through-going mounting slot hole is drilled on the front end surface where the flange body formed in S4 is located;

[0013] S6. Perform multi-layer chemical nickel plating on the tempered forging to form a multi-layer chemical nickel plating layer, each layer having a thickness of 5 μm to 10 μm and a total thickness of 20 μm to 40 μm, and ultrasonic cleaning is performed between each layer of nickel plating, the temperature of the chemical plating solution is 85° C. to 95° C., and the pH value is 4.5 to 5.5;

[0014] S7. After the multi-layer chemical nickel plating treatment, the forged part is sprayed with a nano-ceramic coating to form an outer protective coating, the coating thickness is 1 μm to 5 μm, and the coating material is titanium dioxide or aluminum oxide;

[0015] And the forged flange has the following performance indicators:

[0016] The tensile strength is not less than 1000MPa;

[0017] Yield strength is not less than 850MPa;

[0018] The fracture toughness KIC value is not less than 100MPa·m^0.5;

[0019] The corrosion rate after immersion in 3.5% NaCl solution for 24 hours does not exceed 0.1mm / year;

[0020] The surface roughness Ra value does not exceed 0.8μm.

[0021] Furthermore: the nano ceramic coating is subjected to ultraviolet curing treatment during spraying;

[0022] The nano-ceramic coating was sprayed at a temperature of 0–25°C and a relative humidity of 30–55%.

[0023] Furthermore: the multi-layer chemical nickel plating is preceded by an anodic oxidation treatment to form a dense oxide film.

[0024] Furthermore: the low temperature tempering treatment is followed by surface nitriding treatment.

[0025] Furthermore: the nano ceramic coating is sprayed by a sol-gel method, the coating spraying speed is 10 μm / min to 20 μm / min, and the spraying distance is 10 cm to 20 cm.

[0026] Furthermore: the surface is polished before the low-temperature tempering treatment, using a grinding wheel with a particle size of 1000 mesh for polishing.

[0027] Furthermore: the low temperature tempering treatment also includes a magnetron sputtering treatment.

[0028] Furthermore: the metal material is selected from high alloy steel and stainless steel containing 15% to 20% chromium and 8% to 12% nickel.

[0029] Furthermore: the nano ceramic coating is treated by plasma enhanced chemical vapor deposition after spraying.

[0030] Furthermore: the specific method of drilling the installation slot hole includes: starting the drilling machine, setting the rotation speed and feed speed; slowly feeding the drill bit to the surface of the flange body and starting drilling; during the drilling process, synchronously controlling the flow of the coolant to ensure smooth drilling.

[0031] The present invention has at least the following beneficial effects:

[0032] (1) This solution effectively reduces the residual stress inside the material and improves the plasticity and toughness of the material by optimizing the preheating conditions and high-pressure forging parameters. After quenching, low-temperature tempering is performed to further refine the grain structure of the material and improve the tensile strength and yield strength. The tensile strength of the flange in the embodiment can reach more than 1000MPa, and the yield strength can reach more than 850MPa, which is significantly better than the traditional flange.

[0033] (2) This solution forms a dense nickel coating through multi-layer chemical nickel plating, which significantly improves the corrosion resistance of the flange. The corrosion rate of the flange in the embodiment does not exceed 0.1mm / year after being immersed in a 3.5% NaCl solution for 24 hours, which is much lower than the corrosion rate of the traditional flange. The nano-ceramic coating spraying further enhances the corrosion resistance of the surface, especially after UV curing and plasma enhanced chemical vapor deposition treatment, the adhesion and density of the coating are significantly improved, further extending the service life of the flange.

[0034] (3) This solution performs surface polishing before low-temperature tempering, and uses a grinding wheel with a particle size of 1000 to polish the surface, which significantly reduces the surface roughness and improves the surface finish. The surface roughness Ra value of the flange in the embodiment does not exceed 0.8μm, and the surface quality is excellent. After low-temperature tempering, the surface is nitrided or magnetron sputtered to further improve the surface hardness and wear resistance, so that the flange is not easy to wear during long-term use and maintains good performance.

[0035] (4) The manufacturing process of this solution not only improves the mechanical properties and corrosion resistance of the flange, but also achieves significant improvements in fracture toughness and surface quality. The flange fracture toughness KIC value in the embodiment can reach more than 100MPa·m^0.5, which is much higher than the fracture toughness of traditional flanges. By optimizing each process step, the high performance of the flange in extreme environments is achieved, which is suitable for high-pressure pipeline connectors in the fields of marine engineering, petrochemical industry and nuclear industry, ensuring the safety and reliability of the equipment. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0037] Figure 1 It is a structural schematic diagram of the flange body of the present invention;

[0038] Figure 2 This is a schematic structural diagram of the flange body end surface of the present invention in a state where no holes are drilled;

[0039] Figure 3 This is a schematic diagram of the structure of the flange body end face of the present invention in a drilling state;

[0040] Figure 4 It is a schematic diagram of the process flow of the present invention.

[0041] Explanation of the reference numerals: 1. flange body; 101. multi-layer chemical nickel plating layer; 102. outer protective coating; 2. annular sealing reinforcement; 3. mounting slot; 4. reinforcement rib. DETAILED DESCRIPTION

[0042] 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.

[0043] Example 1

[0044] See also Figure 1-Figure 2 , Figure 4 The present invention provides a technical solution: a high-strength corrosion-resistant forged flange manufacturing process, which aims to provide a high-pressure pipeline connector that can withstand extreme environments, and is particularly suitable for fields such as marine engineering, petrochemicals, and nuclear industries. The process can significantly improve the mechanical properties and corrosion resistance of the flange, ensuring its reliability and safety under harsh working conditions. The specific implementation steps of the process are as follows:

[0045] S1: Preheating

[0046] First, high alloy steel containing 15% to 20% chromium and 8% to 12% nickel is selected as the raw material. The metal material is placed in a preheating furnace and heated to 900°C to 1100°C, preferably 950°C to 1050°C, at a rate of 10°C / min to 20°C / min. This step helps to reduce the internal stress of the metal and improve the plasticity and toughness of the material.

[0047] S2: High pressure forging

[0048] After preheating, when the metal material reaches the preset temperature, it is quickly transferred to the forging die that has been preheated to the same temperature. A layer of graphite coating is applied to the inner and outer surfaces of the die to improve demoulding performance. The metal material is forged using a hydraulic press at a pressure of 230 MPa, and a flange blank including a flange body 1, an annular sealing reinforcement 2, and a reinforcement rib 4 is formed in one go.

[0049] S3: Quenching treatment

[0050] After forging, the forged parts are immediately placed in a quenching furnace under nitrogen protection atmosphere, the temperature is set to 900℃, and the temperature is kept for 2 hours. The nitrogen flow rate is controlled at 10L / min to 20L / min, and the nitrogen purity is not less than 99.99%. Quenching treatment can significantly improve the hardness and strength of the material.

[0051] S4: Low temperature tempering and surface treatment

[0052] Finally, the forged parts sprayed with nano-ceramic coating are subjected to low-temperature tempering treatment, with the temperature set at 250°C to 300°C and kept warm for 2 to 3 hours. Before low-temperature tempering, the surface is polished with a grinding wheel with a grit size of 1000 to obtain a smoother surface. After low-temperature tempering, the surface can also be nitrided to further improve the surface hardness and corrosion resistance. In order to further improve the surface hardness and wear resistance, magnetron sputtering treatment can be performed after low-temperature tempering.

[0053] S5: A through-hole installation slot 3 (such as Figure 3 As shown in the figure, the specific method of penetrating the installation slot hole includes: starting the drilling machine, setting the rotation speed and feed speed; slowly feeding the drill bit to the surface of the flange body and starting drilling; during the drilling process, synchronously controlling the flow of the coolant to ensure smooth drilling.

[0054] S6: Multi-layer chemical nickel plating

[0055] After the quenched flange is ultrasonically cleaned to remove surface impurities, it is placed in a chemical nickel plating solution for treatment. The thickness of each nickel plating layer is 5μm to 10μm, and the total thickness is 20μm to 40μm.

[0056] The temperature of the chemical plating solution is controlled at 85℃ to 95℃, and the pH value is maintained at 4.5 to 5.5. Ultrasonic cleaning is performed after each layer of nickel plating to remove surface residues and ensure uniform plating.

[0057] S7: Nano ceramic coating spraying

[0058] After the chemical nickel plating treatment, the flange is evenly sprayed with a layer of nano titanium dioxide coating with a thickness of about 3 μm as an outer protective coating 102 by a spray gun in a clean and dry state to enhance the corrosion resistance and wear resistance of the flange surface. The coating material can be titanium dioxide or aluminum oxide, and the coating thickness is 1 μm to 5 μm. The coating spraying adopts the sol-gel method, the spraying speed is 10 μm / min to 20 μm / min, and the spraying distance is 10 cm to 20 cm.

[0059] After spraying, UV curing is carried out. When the nano-ceramic coating is sprayed, the temperature is 0–25°C and the relative humidity is 30–55%. In this temperature range, the adhesion of the coating is usually good. Lower temperatures may cause the coating to cure more slowly, but at appropriate humidity, the coating can still effectively adhere to the substrate. At a humidity of 30–55%, the drying and curing process of the coating is relatively stable, which helps to form a uniform coating. To improve the adhesion and durability of the coating. In addition, plasma enhanced chemical vapor deposition (PECVD) treatment can also be carried out to further improve the density and corrosion resistance of the coating.

[0060] Example 2

[0061] The present invention provides a technical solution: a high-strength corrosion-resistant forged flange manufacturing process, the specific implementation steps of the process are as follows:

[0062] Material selection: High alloy steel containing 18% chromium and 10% nickel.

[0063] Preheating conditions: Place the high alloy steel material in an electric heating furnace and heat it to 1000°C at a rate of 15°C / min. The preheating time is about 1 hour.

[0064] High-pressure forging: After preheating, when the metal material reaches the preset temperature, it is quickly transferred to the forging die that has been preheated to the same temperature. A layer of graphite coating is applied to the inner and outer surfaces of the die to improve demolding performance. The metal material is forged using a hydraulic press at a pressure of 230MPa for 1 minute, and a flange blank including the flange body 1, the annular sealing reinforcement 2 and the reinforcement rib 4 is formed in one go.

[0065] Quenching treatment: the forgings are quickly transferred to a quenching furnace with a nitrogen protective atmosphere, the temperature is set to 900°C, kept warm for 2 hours, the nitrogen flow rate is 15L / min, and the nitrogen purity is 99.99%.

[0066] Low temperature tempering: The forged parts sprayed with nano ceramic coating are subjected to low temperature tempering treatment, the temperature is set to 280℃, and the temperature is kept for 2.5 hours. Before low temperature tempering, the surface is polished with a grinding wheel with a grit size of 1000 mesh to obtain a smoother surface. After low temperature tempering, the surface is nitrided to further improve the surface hardness and corrosion resistance.

[0067] A penetrating mounting slot hole 3 is drilled through the front end surface of the formed flange body 1 .

[0068] Multi-layer chemical nickel plating: After the quenched flange is ultrasonically cleaned to remove surface impurities, it is placed in a chemical nickel plating solution for treatment. The solution temperature is maintained at 90°C, the pH value is adjusted to 5.0, and the plating is continued until a multi-layer chemical nickel plating layer 101 with a thickness of 8μm per layer and a total thickness of 32μm is formed. Ultrasonic cleaning is required again after each layer of nickel plating to ensure the quality of the plating.

[0069] Nano ceramic coating spraying: After the chemical nickel plating is completed, a layer of nano titanium dioxide coating with a thickness of about 3μm is evenly sprayed as an outer protective coating 102 by a spray gun in a clean and dry state to enhance the corrosion resistance and wear resistance of the flange surface. The coating spraying adopts the sol-gel method, the spraying speed is 15μm / min, and the spraying distance is 15cm. After the spraying is completed, UV curing treatment is carried out to improve the adhesion and durability of the coating.

[0070] Example 3

[0071] The present invention provides a technical solution: a high-strength corrosion-resistant forged flange manufacturing process, the specific implementation steps of the process are as follows:

[0072] Material selection: High alloy steel containing 16% chromium and 9% nickel.

[0073] Preheating conditions: Place the high alloy steel material in an electric heating furnace and heat it to 950°C at a rate of 12°C / min. The preheating time is about 1 hour.

[0074] High-pressure forging: When the metal material reaches the preset temperature, it is quickly transferred to a forging die that has been preheated to the same temperature. A layer of graphite coating is applied to the inner and outer surfaces of the die to improve demolding performance. The metal material is forged using a hydraulic press at a pressure of 220 MPa for 1 minute, and a flange blank including a flange body 1, an annular sealing reinforcement 2, and a reinforcement rib 4 is formed in one go.

[0075] Quenching treatment: the forgings are quickly transferred to a quenching furnace with a nitrogen protective atmosphere, the temperature is set to 900°C, kept warm for 2 hours, the nitrogen flow rate is 12L / min, and the nitrogen purity is 99.99%.

[0076] Low temperature tempering: The forged parts sprayed with nano ceramic coating are subjected to low temperature tempering treatment, the temperature is set to 260℃, and the temperature is kept for 2 hours. Before low temperature tempering, the surface is polished with a grinding wheel with a particle size of 1000 mesh. After low temperature tempering, magnetron sputtering treatment is performed to further improve the surface hardness and wear resistance.

[0077] A penetrating mounting slot hole 3 is drilled through the front end surface of the formed flange body 1 .

[0078] Multi-layer chemical nickel plating: After the quenched flange is cleaned with ultrasonic waves to remove surface impurities, it is placed in a chemical nickel plating solution for treatment. The solution temperature is maintained at 88°C, the pH value is adjusted to 4.8, and the plating is continued until a multi-layer chemical nickel plating layer 101 with a thickness of 6μm per layer and a total thickness of 24μm is formed. After each layer of nickel plating, ultrasonic cleaning is required again to ensure the quality of the plating layer.

[0079] Nano ceramic coating spraying: After the chemical nickel plating is completed, the flange is evenly sprayed with a layer of nano titanium dioxide coating with a thickness of about 4μm as an outer protective coating 102 through a spray gun in a clean and dry state to enhance the corrosion resistance and wear resistance of the flange surface. The spraying speed is 18μm / min and the spraying distance is 12cm. After the spraying is completed, ultraviolet curing is carried out.

[0080] Example 4

[0081] The present invention provides a technical solution: a high-strength corrosion-resistant forged flange manufacturing process, the specific implementation steps of the process are as follows:

[0082] Material choice: High alloy steel containing 17% chromium and 11% nickel.

[0083] Preheating conditions: Place the high alloy steel material in an electric heating furnace and heat it to 1050°C at a rate of 18°C / min. The preheating time is about 1 hour.

[0084] High-pressure forging: When the metal material reaches the preset temperature, it is quickly transferred to a forging die that has been preheated to the same temperature. A layer of graphite coating is applied to the inner and outer surfaces of the die to improve demoulding performance. The metal material is forged using a hydraulic press at a pressure of 240 MPa for 1 minute, and a flange blank including a flange body 1, an annular sealing reinforcement 2, and a reinforcement rib 4 is formed in one go.

[0085] Quenching treatment: the forgings are quickly transferred to a quenching furnace with a nitrogen protective atmosphere, the temperature is set to 900°C, kept warm for 2 hours, the nitrogen flow rate is 18L / min, and the nitrogen purity is 99.99%.

[0086] A penetrating mounting slot hole 3 is drilled through the front end surface of the formed flange body 1 .

[0087] Multi-layer chemical nickel plating: After the quenched flange is ultrasonically cleaned to remove surface impurities, it is placed in a chemical nickel plating solution for treatment. The solution temperature is maintained at 92°C, the pH value is adjusted to 5.2, and the plating is continued until a multi-layer chemical nickel plating layer 101 with a thickness of 10 μm per layer and a total thickness of 40 μm is formed. Ultrasonic cleaning is required again after each layer of nickel plating to ensure the quality of the plating.

[0088] Nano ceramic coating spraying: After the chemical nickel plating is completed, a layer of nano titanium dioxide coating with a thickness of about 5 μm is evenly sprayed as an outer protective coating 102 by a spray gun in a clean and dry state to enhance the corrosion resistance and wear resistance of the flange surface. The coating spraying adopts the sol-gel method, the spraying speed is 12 μm / min, and the spraying distance is 18 cm. After the spraying is completed, ultraviolet curing treatment is carried out.

[0089] Low temperature tempering: The forged parts sprayed with nano ceramic coating are subjected to low temperature tempering treatment, the temperature is set to 270℃, and the temperature is kept for 3 hours. Before low temperature tempering, the surface is polished with a grinding wheel with a particle size of 1000 mesh. After low temperature tempering, the surface is nitrided.

[0090] Example 5

[0091] The present invention provides a technical solution: a high-strength corrosion-resistant forged flange manufacturing process, the specific implementation steps of the process are as follows:

[0092] Material choice: High alloy steel containing 19% chromium and 12% nickel.

[0093] Preheating conditions: Place the high alloy steel material in an electric heating furnace and heat it to 1020°C at a rate of 16°C / min. The preheating time is about 1 hour.

[0094] High-pressure forging: When the metal material reaches the preset temperature, it is quickly transferred to a forging die that has been preheated to the same temperature. A layer of graphite coating is applied to the inner and outer surfaces of the die to improve demoulding performance. The metal material is forged using a hydraulic press at a pressure of 235 MPa for 1 minute, and a flange blank including a flange body 1, an annular sealing reinforcement 2, and a reinforcement rib 4 is formed in one go.

[0095] Quenching treatment: the forgings are quickly transferred to a quenching furnace with a nitrogen protective atmosphere, the temperature is set to 900°C, kept warm for 2 hours, the nitrogen flow rate is 16L / min, and the nitrogen purity is 99.99%.

[0096] A penetrating mounting slot hole 3 is drilled through the front end surface of the formed flange body 1 .

[0097] Multi-layer chemical nickel plating: After the quenched flange is cleaned with ultrasonic waves to remove surface impurities, it is placed in a chemical nickel plating solution for treatment. The solution temperature is maintained at 95°C, the pH value is adjusted to 5.0, and the plating is continued until a multi-layer chemical nickel plating layer 101 with a thickness of 7 μm per layer and a total thickness of 28 μm is formed. After each layer of nickel plating, ultrasonic cleaning is required again to ensure the quality of the plating layer.

[0098] Nano ceramic coating spraying: After the chemical nickel plating is completed, a layer of nano titanium dioxide coating with a thickness of about 2 μm is evenly sprayed as an outer protective coating 102 by a spray gun in a clean and dry state to enhance the corrosion resistance and wear resistance of the flange surface. The coating spraying adopts the sol-gel method, the spraying speed is 10 μm / min, and the spraying distance is 20 cm. After the spraying is completed, ultraviolet curing treatment is carried out.

[0099] Low temperature tempering: The forged parts sprayed with nano ceramic coating are subjected to low temperature tempering treatment, the temperature is set to 290℃, and the temperature is kept for 2.5 hours. Before low temperature tempering, the surface is polished with a grinding wheel with a particle size of 1000 mesh. After low temperature tempering, magnetron sputtering treatment is performed.

[0100] Comparative Example 1

[0101] This comparative example provides a technical solution: a high-strength corrosion-resistant forged flange manufacturing process, and the specific implementation steps of the process are as follows:

[0102] Material selection: ordinary carbon steel.

[0103] Preheating conditions: Place the ordinary carbon steel material in an electric heating furnace and heat it to 900°C at a rate of 10°C / min. The preheating time is about 1.5 hours.

[0104] High-pressure forging: The preheated material was immediately transferred to a forging die without graphite coating, and a pressure of 200 MPa was applied for forging, which was maintained for 1 minute.

[0105] Quenching treatment: the forgings are quickly transferred to a quenching furnace with a nitrogen protective atmosphere, the temperature is set to 900°C, kept warm for 2 hours, the nitrogen flow rate is 10L / min, and the nitrogen purity is 99.99%.

[0106] Low temperature tempering: The forgings were subjected to low temperature tempering treatment, the temperature was set to 250°C, and the temperature was kept for 2 hours. No surface polishing or surface nitriding treatment was performed.

[0107] A penetrating mounting slot hole 3 is drilled through the front end surface of the formed flange body 1 .

[0108] Multi-layer chemical nickel plating: After tempering, the forged parts are subjected to multi-layer chemical nickel plating in a chemical nickel plating tank. The thickness of each layer is 5μm, and the total thickness is 20μm. The temperature of the chemical plating solution is 85℃ and the pH value is 4.5. Ultrasonic cleaning is performed after each layer of nickel plating.

[0109] Nano ceramic coating spraying: After multi-layer chemical nickel plating, the forged parts are sprayed with nano ceramic coating. The coating material is titanium dioxide with a thickness of 1μm. The coating spraying is prepared by sol-gel method, the spraying speed is 10μm / min, and the spraying distance is 10cm. No UV curing treatment is performed.

[0110] Comparative Example 2

[0111] This comparative example provides a technical solution: a high-strength corrosion-resistant forged flange manufacturing process, and the specific implementation steps of the process are as follows:

[0112] Material selection: High alloy steel containing 15% chromium and 8% nickel.

[0113] Preheating conditions: Place the high alloy steel material in an electric heating furnace and heat it to 900°C at a rate of 10°C / min. The preheating time is about 1.5 hours.

[0114] High-pressure forging: The preheated material was immediately transferred to a forging die without graphite coating, and a pressure of 200 MPa was applied for forging, which was maintained for 1 minute.

[0115] Quenching treatment: the forgings are quickly transferred to a quenching furnace with a nitrogen protective atmosphere, the temperature is set to 900°C, kept warm for 2 hours, the nitrogen flow rate is 10L / min, and the nitrogen purity is 99.99%.

[0116] Low temperature tempering: The forgings were subjected to low temperature tempering treatment, the temperature was set to 250°C, and the temperature was kept for 2 hours. No surface polishing treatment or surface nitriding treatment was performed.

[0117] Multi-layer chemical nickel plating: After tempering, the forged parts are subjected to multi-layer chemical nickel plating in a chemical nickel plating tank. The thickness of each layer is 5μm, and the total thickness is 20μm. The temperature of the chemical plating solution is 85℃ and the pH value is 4.5. Ultrasonic cleaning is performed after each layer of nickel plating.

[0118] Nano ceramic coating spraying: After multi-layer chemical nickel plating, the forged parts are sprayed with nano ceramic coating. The coating material is titanium dioxide with a thickness of 1μm. The coating spraying is prepared by sol-gel method, the spraying speed is 10μm / min, the spraying distance is 10cm, and no UV curing treatment is performed.

[0119] Table 1 is a performance comparison of Examples 1-5 and Comparative Examples

[0120]

[0121] In summary, the results of the embodiments and comparative examples show that the high-strength corrosion-resistant forged flange manufacturing process provided by the present invention can significantly improve the mechanical properties and corrosion resistance of the flange. In particular, by optimizing the preheating conditions, high-pressure forging parameters, quenching treatment, multi-layer chemical nickel plating, nano-ceramic coating spraying, and low-temperature tempering, the performance of the final product is far superior to that of ordinary carbon steel and high-alloy steel that has not been optimized.

[0122] These improvement measures not only improve the tensile strength, yield strength and fracture toughness of the flange, but also significantly reduce the corrosion rate and improve the surface quality, making it more suitable for application in extreme environments. Specifically, the flange in the embodiment is significantly better than the flange in the comparative example in terms of tensile strength, yield strength, fracture toughness and corrosion resistance, indicating that the process of the present invention has significant technical advantages.

[0123] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-strength corrosion-resistant forged flange manufacturing process, characterized in that: The following steps are involved: S1. Preheat the metal material to 900°C to 1100°C at a preheating rate of 10°C / min to 20°C / min; S2, performing high-pressure forging on the preheated metal material at a pressure of 200 MPa to 250 MPa, and using a graphite coating on the forging die, and forging to form a flange body (1), an annular sealing reinforcement (2), and a reinforcement rib (4); S3. The formed forgings are quenched under a nitrogen protective atmosphere at a quenching temperature of 900°C and a holding time of 2 hours. During the quenching process, nitrogen is introduced at a nitrogen flow rate of 10 L / min to 20 L / min, and the purity of the nitrogen is not less than 99.99%; S4, performing low-temperature tempering treatment at a temperature of 250° C. to 300° C. for 2 to 3 hours, and before the low-temperature tempering treatment, a surface polishing treatment is also included, using a grinding wheel with a particle size of 1000 mesh for polishing; S5, a mounting slot hole (3) is drilled through the front end surface of the flange body (1) formed in S4; S6. Perform multi-layer chemical nickel plating on the tempered forging to form a multi-layer chemical nickel plating layer, each layer having a thickness of 5 μm to 10 μm and a total thickness of 20 μm to 40 μm, and ultrasonic cleaning is performed between each layer of nickel plating, the temperature of the chemical plating solution is 85° C. to 95° C., and the pH value is 4.5 to 5.5; S7. After the multi-layer chemical nickel plating treatment, the forged part is sprayed with a nano-ceramic coating to form an outer protective coating, the coating thickness is 1 μm to 5 μm, and the coating material is titanium dioxide or aluminum oxide; And the forged flange has the following performance indicators: The tensile strength is not less than 1000MPa; Yield strength is not less than 850MPa; The fracture toughness KIC value is not less than 100MPa·m^0.5; The corrosion rate after immersion in 3.5% NaCl solution for 24 hours does not exceed 0.1mm / year; The surface roughness Ra value does not exceed 0.8μm.

2. A high-strength corrosion-resistant forged flange manufacturing process according to claim 1, characterized in that: The nano ceramic coating is subjected to ultraviolet curing treatment during spraying; The nano-ceramic coating was sprayed at a temperature of 0–25°C and a relative humidity of 30–55%.

3. A high-strength corrosion-resistant forged flange manufacturing process according to claim 2, characterized in that: The multi-layer chemical nickel plating is preceded by an anodic oxidation treatment to form a dense oxide film.

4. A high-strength corrosion-resistant forged flange manufacturing process according to claim 3, characterized in that: The low temperature tempering treatment is followed by surface nitriding treatment.

5. The high-strength corrosion-resistant forged flange manufacturing process according to claim 1 is characterized in that: The nano ceramic coating is sprayed by a sol-gel method, the coating spraying speed is 10 μm / min to 20 μm / min, and the spraying distance is 10 cm to 20 cm.

6. A high-strength corrosion-resistant forged flange manufacturing process according to claim 1, characterized in that: The surface is polished before the low-temperature tempering treatment, using a grinding wheel with a particle size of 1000 meshes for polishing.

7. The high-strength corrosion-resistant forged flange manufacturing process according to claim 5 is characterized in that: The low temperature tempering treatment further includes a magnetron sputtering treatment.

8. A high-strength corrosion-resistant forged flange manufacturing process according to claim 7, characterized in that: The metal material is selected from high alloy steel and stainless steel containing 15% to 20% chromium and 8% to 12% nickel.

9. The high-strength corrosion-resistant forged flange manufacturing process according to claim 1 is characterized in that: The nano ceramic coating is sprayed and then treated by plasma enhanced chemical vapor deposition.

10. The high-strength corrosion-resistant forged flange manufacturing process according to claim 1, characterized in that: The specific method for drilling the installation slot hole (3) includes: starting the drilling machine, setting the rotation speed and feed speed; slowly feeding the drill bit to the surface of the flange body (1) to start drilling; during the drilling process, synchronously controlling the flow rate of the coolant to ensure smooth drilling.

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