A wear-resistant and corrosion-resistant high-strength titanium alloy slotted screen and a preparation method thereof

Abstract

The present application relates to the field of wear-resistant and corrosion-resistant high-speed rotating screen, in particular to a wear-resistant and corrosion-resistant high-strength titanium alloy slit screen and a preparation method thereof. First, high-strength beta titanium alloy plate material with excellent cold workability and welding performance is selected as raw material, and the screen meeting the size requirements is prepared through laser cutting, cold roll forming and laser welding, and then aging treatment is carried out to meet the performance requirements. Then, the rough inner wall of the laser cutting gap is treated by electrolytic polishing process, so that the roughness is within 0.8 μm. Subsequently, the plate material with slits is rolled into the designed screen shape by using a plate rolling machine, and the both sides are welded by laser, thereby completing the manufacture of the screen shape. Finally, the milling machine is used to process the outside of the screen to have a gradient step profile, so as to reduce the filtrate passing path. The slit screen prepared by the method has high structural strength and rigidity, small running noise, excellent corrosion resistance and wear resistance, and can meet the solid-liquid screening requirements in harsh environment.

Description

Technical Field

[0001] This invention relates to the field of wear-resistant, corrosion-resistant, and high-speed rotating screens, specifically to a wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen and its preparation method. Background Technology

[0002] In the preparation of potash fertilizer, centrifuge scrapers and screens are often used to separate substances such as potassium chloride and sodium chloride. However, the operating environment is high temperature, high brine salt, or slightly acidic, causing the screens to be subjected to high chloride ion corrosion and erosion by salt residue particles for a long time. This leads to the rapid failure of commonly used traditional duplex stainless steel Johnson screens, resulting in frequent replacements and seriously affecting the production efficiency of potash fertilizer. Therefore, it is necessary to design a new type of screen structure to address the harsh operating conditions of salt residue centrifuges. This new structure should improve the wear resistance and corrosion resistance of the screen while ensuring its performance, thereby extending its service life.

[0003] Traditional Johnson screens are made of shaped wires resist-welded into cylindrical or conical shapes, such as... Figure 1 As shown, wedge wires 1 are placed side by side on support ribs 2, with support rib spacing 3 between support ribs 2 and wedge wire spacing 4 between adjacent wedge wires 1. The wedge wires 1 are connected to each other only by welding points, and the resistance welding points have low strength and are prone to tearing. Summary of the Invention

[0004] The purpose of this invention is to provide a wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen and its preparation method. The slotted screen has high structural strength and rigidity, low operating noise, and excellent corrosion resistance and wear resistance, which can meet the solid-liquid screening requirements of harsh environments.

[0005] The technical solution of this invention is:

[0006] A wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen has the following chemical composition and mass percentage: Al 2.5-3.5%, V 14.0-16.0%, Cr 2.5-3.5%, Sn 2.5-3.5%, O 0.09-0.13%, C ≤0.02%, H ≤0.03%, N ≤0.03%, with the balance being Ti, and the titanium alloy is in a solid solution state.

[0007] The preparation method of the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen includes the following steps:

[0008] (1) Material selection

[0009] Solid solution β titanium alloy sheet is selected as raw material, and the cold rolling deformation can reach more than 90%. The thickness of the titanium alloy sheet is 3-6 mm.

[0010] (2) Processing of strip screen slots

[0011] Laser cutting is used to process strip slits under nitrogen protection. The laser power is 8000-12000W, the spot diameter is 0.1-0.3mm, and the processing speed is 800-2000mm / min. The width of the strip slit is 0.2-0.35mm±0.01, and the length of the strip slit is 50-100mm.

[0012] (3) Electrolytic polishing of screen gaps

[0013] (4) Board leveling

[0014] (5) Roll forming

[0015] (6) Laser sealing

[0016] (7) Timeliness processing

[0017] The titanium alloy screen is subjected to low-temperature aging treatment at 480℃±10℃ for 15~20h, and then hot straightened by molding to make the overall tensile strength of the titanium alloy screen reach more than 1240MPa and the shape is fixed.

[0018] (8) Finishing.

[0019] In the preparation method of the wear-resistant and corrosion-resistant high-strength titanium alloy slotted screen, step (3) uses a DC pulse plasma electrolytic polishing device with a power of 150-170kW and a voltage of 380V, and a salt solution as the main electrolyte to reduce the roughness of its inner pores to below 0.8μm.

[0020] In the preparation method of the wear-resistant and corrosion-resistant high-strength titanium alloy slotted screen, in step (4), the plate after laser cutting or wire cutting will be deformed. It is rough leveled with a 40-ton press, and the unevenness is less than 20mm / m. Then, it is fine leveled with a 25-ton small press, and the flatness is less than 10mm / m.

[0021] In the preparation method of the wear-resistant and corrosion-resistant high-strength titanium alloy slotted screen, in step (5), the qualified titanium alloy slotted material is pre-bent, centered, rolled into a circle, and straightened by a plate rolling machine to finally achieve the designed shape.

[0022] The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen described herein, wherein the titanium alloy slotted screen is designed in the shape of a cylindrical or conical screen.

[0023] The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen, wherein when the titanium alloy slotted screen is designed as a conical screen, with the small end of the cone as the origin, each slot within 250mm of the cone has a length of 50mm and a width of 0.35mm; and between 250mm and 650mm from the small end of the cone, each slot has a length of 100mm and a width of 0.25mm.

[0024] In the preparation method of the wear-resistant and corrosion-resistant high-strength titanium alloy slotted screen, in step (6), the cylindrical or conical screen that meets the design shape requirements is subjected to double-sided sealing welding. The laser welding current is 3000-5000W and the welding speed is 900-1100mm / min to achieve single-sided welding and double-sided forming.

[0025] In the preparation method of the wear-resistant and corrosion-resistant high-strength titanium alloy slotted screen, in step (8), the outermost side of the titanium alloy slotted screen is machined with a milling machine to make the filtration area retain a width of 1-3mm, forming a contour with gradient steps, so as to further improve the filtration effect of the screen.

[0026] The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen involves using a milling machine to process an annular groove with a thickness of 2mm on the outermost side of the cylindrical or conical screen, with a spacing of 200mm between adjacent grooves, and a reinforcing rib with a width of 5mm formed between adjacent grooves.

[0027] The design concept of this invention is:

[0028] like Figures 2-3 As shown, during the process of cutting slits in the integral plate of the present invention, a laser beam 5 is set above the plate 7, and the slits 8 are processed on the plate 7 through the focal point 6 of the laser beam 5. The present invention uses integral titanium alloy plate to cut slits to prepare a centrifuge screen with both high wear resistance and high corrosion resistance, thereby improving its service life, reducing the number of downtimes of the salt slag centrifuge, and improving the production efficiency and output of the salt slag centrifuge.

[0029] This invention selects a solution-treated β-titanium alloy sheet of suitable thickness as raw material. Laser cutting is used to process strip-shaped slits, ensuring the width of the slits is 0.18–0.35 mm and the length is 50–100 mm. Electrolytic polishing is employed to treat the rough inner wall of the laser-cut slits. After laser cutting, the burrs inside the slits are smoothed using electrolytic polishing, ensuring a surface roughness within 0.8 μm to reduce liquid phase viscosity. Then, a plate rolling machine is used for cold forming to roll the slit sheet into the designed screen shape (e.g., cylindrical or conical cylinder), and laser welding is used for double-sided sealing, thus completing the screen shape manufacturing. After the screen is formed, an aging treatment is performed to precipitate secondary phases inside the β-titanium alloy, increasing its strength to over 1240 MPa and improving the overall wear resistance of the screen. To ensure the smooth passage of filtrate while maintaining sufficient rigidity of the screen, a milling machine is used to machine the outer side of the screen. Gradient step grooves are then machined on the outer side of the cylindrical or conical cylinder to give it a stepped profile, thereby reducing the path of the filtrate.

[0030] The advantages and beneficial effects of this invention are:

[0031] 1. This invention first utilizes the excellent resistance of titanium alloy to chloride ion corrosion to solve the serious corrosion problem in salt slag centrifuges; secondly, given the low wear resistance of titanium alloy, solution aging treatment is used to improve the alloy strength and thus improve the wear resistance of the screen, thereby extending the service life of the salt slag centrifuge screen.

[0032] 2. This invention uses solution-treated β-titanium alloy as raw material. Taking advantage of its relatively low strength and cold-forming ability, the finished screen mesh can be produced by cold rolling. Subsequent aging treatment improves the screen mesh strength, thereby enhancing its wear resistance.

[0033] 3. This invention employs a novel laser-cut strip-slit roll plate integral forming process, enhancing the structural strength and rigidity of the screen while improving wear resistance and ensuring stable operation after installation. In contrast, traditional Johnson screens are formed by resistance welding of shaped wires, resulting in low strength at the weld joints, making them prone to tearing during use. The tips of the shaped wires are also easily worn, and the screens experience significant vibration during operation, impacting the equipment's lifespan. Attached Figure Description

[0034] Figure 1 This is a schematic diagram of a traditional Johnson screen. In the diagram, 1 is a wedge wire, 2 is a support rib, 3 is a support rib spacer, and 4 is a wedge wire spacer.

[0035] Figures 2-3 This is a schematic diagram of the cut seams in the overall sheet metal of the present invention. Wherein, Figure 2 For the processing, Figure 3 This is after processing. In the image, 5 represents the laser beam, 6 the focal point, 7 the sheet material, and 8 the seams.

[0036] Figures 4-5 This is a diagram of a gradient grooved screen. In the diagram, 9 is a conical screen, 10 is a reinforcing rib, and 11 is a groove. Detailed Implementation

[0037] To make the purpose, technical solution and effects of this application clearer and more explicit, the following describes this application in further detail with reference to the accompanying drawings and embodiments.

[0038] Example

[0039] This embodiment proposes a wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen and its preparation method, including the following steps:

[0040] (1) Material selection. High-strength β-titanium alloy sheet with a thickness of 4mm was selected as raw material. After solution treatment, it was heated at 780℃, held for 30 minutes and then air-cooled to room temperature. The tensile strength of the material was 768MPa and the elongation was 23%, which met the requirements for cold forming (Table 1).

[0041] The chemical composition and mass percentage of the high-strength β-titanium alloy sheet are as follows: Al 2.7%, V 15.4%, Cr 3.1%, Sn 2.6%, O 0.12%, C 0.005%, H 0.02%, N 0.01%, with the balance being Ti.

[0042] This alloy has excellent cold forming properties, with a cold rolling deformation of over 90%, and can form moderately complex sheet metal parts at room temperature, ensuring rigidity and tear resistance.

[0043] (2) Design the mesh slots: with the small end of the cone as the origin, each slot within 250mm of the cone is 50mm long and 0.35mm wide; between 250mm and 650mm from the small end of the cone, each slot is 100mm long and 0.25mm wide.

[0044] (3) Processing of strip screen slots. For example... Figures 2-3 As shown, laser cutting is used with nitrogen protection. The laser power is 10000W. When the gap width is 0.35mm, the spot diameter is 0.3mm. When the gap width is 0.25mm, the spot diameter is 0.25mm. The processing speed is 1000mm / min.

[0045] (4) Electrolytic polishing of sieve gaps. A commercially available SFM 20D-T DC pulse plasma electrolytic polishing equipment was used for electrolytic polishing. The power was 160kW and the voltage was 380V. The main electrolyte was SFE01A salt solution (the electrolytic polishing equipment and electrolyte were manufactured by Nanjing Shangji Additive Manufacturing Research Institute Co., Ltd.), which reduced the roughness of the inner pores to below 0.8μm.

[0046] (5) Plate leveling. The plates will be deformed after laser cutting or wire cutting. Use a 40-ton press for rough leveling, with an unevenness of less than 20mm / m. Then use a 25-ton small press for fine leveling, with a flatness of less than 10mm / m.

[0047] (6) Plate rolling. The qualified titanium alloy slotted screen plate is pre-bent, centered, rolled into a circle, and straightened by a plate rolling machine to finally achieve a conical shape.

[0048] (7) Laser sealing. The conical screen is sealed on both sides using a laser welding current of 4000W and a welding speed of 1000mm / min to achieve single-sided welding and double-sided forming.

[0049] (8) Aging treatment. It is preferred to use low temperature aging treatment at 480℃ for 16h and hot straightening with a pressing mold to make the overall tensile strength of the titanium alloy screen reach 1303MPa and the shape fixed (Table 1).

[0050] (9) Finishing. For example... Figures 4-5 As shown, an annular groove 11 with a thickness of 2mm is machined on the outermost side of the conical screen 9 using a milling machine. The distance between adjacent grooves is 200mm, and a reinforcing rib 10 is formed in the middle of adjacent grooves 11 as a reserved sheet metal with a width of 5mm. Finally, a contour with gradient steps is formed to further improve the filtration effect of the screen.

[0051]

[0052] The results show that this invention uses high-strength β-titanium alloy plates with excellent cold working and welding properties as raw materials. Screens meeting dimensional requirements are prepared through laser cutting, cold rolling, and laser welding. Subsequent aging treatment increases the tensile strength of the screens to over 1240 MPa, meeting performance requirements and exhibiting the following characteristics:

[0053] 1. This invention uses high-strength β-titanium alloy sheet as raw material and forms an integral plate by laser cutting of slots. The slot size is controllable, and the roughness inside can be treated by electrolytic polishing. At the same time, the integral plate can resist centrifugal force and the impact force of materials, which greatly improves the strength and rigidity of the screen.

[0054] 2. In order to meet the screening efficiency requirements, the present invention reduces the filtrate passage path by processing a concave groove, thereby improving wear resistance and increasing the filtrate throughput.

[0055] The above description is merely an embodiment of this application and does not limit the scope of protection of this application. Any equivalent structural or procedural transformations made based on the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the scope of protection of this application.

Claims

1. A method for preparing a wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen, characterized in that, The chemical composition and mass percentage of this titanium alloy slotted screen are as follows: Al 2.5~3.5%, V 14.0~16.0%, Cr 2.5~3.5%, Sn 2.5~3.5%, O 0.09~0.13%, C ≤0.02%, H ≤0.03%, N ≤0.03%, with the balance being Ti; The preparation method of the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen includes the following steps: (1) Material selection Solid solution β titanium alloy sheet is selected as raw material, and the cold rolling deformation can reach more than 90%. The thickness of the titanium alloy sheet is 3~6mm. (2) Processing of strip screen slots Laser cutting is used to process strip slits under nitrogen protection. The laser power is 8000~12000W, the spot diameter is 0.1~0.3mm, and the processing speed is 800~2000mm / min. The width of the strip slit is 0.2~0.35mm with an error within ±0.01, and the length of the strip slit is 50~100mm. (3) Electrolytic polishing of screen gaps (4) Board leveling (5) Roll forming (6) Laser sealing (7) Timeliness processing The titanium alloy screen is subjected to low-temperature aging treatment at 480℃±10℃ for 15~20h, followed by hot straightening with a mold, so that the overall tensile strength of the titanium alloy screen reaches more than 1240MPa and the shape is fixed. (8) Finishing.

2. The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen according to claim 1, characterized in that, In step (3), a DC pulse plasma electropolishing device with a power of 150~170kW and a voltage of 380V is used, with salt solution as the main electrolyte, to reduce the roughness of its inner pores to below 0.8μm.

3. The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen according to claim 1, characterized in that, In step (4), the plate material after laser cutting or wire cutting will be deformed. A 40-ton press is used for rough leveling, and the flatness is less than 20mm / m. Then a 25-ton small press is used for fine leveling, and the flatness is less than 10mm / m.

4. The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen according to claim 1, characterized in that, In step (5), the qualified titanium alloy strip material is pre-bent, centered, rolled into a circle, and straightened through a plate rolling machine to finally achieve the designed shape.

5. The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen according to claim 4, characterized in that, Titanium alloy slotted screens are designed in cylindrical or conical shapes.

6. The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen according to claim 5, characterized in that, When the titanium alloy slotted screen is designed as a conical screen, with the small end of the cone as the origin, each slot within 250mm of the cone has a length of 50mm and a width of 0.35mm; between 250mm and 650mm from the small end of the cone, each slot has a length of 100mm and a width of 0.25mm.

7. The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen according to claim 1, characterized in that, In step (6), double-sided sealing is performed using a cylindrical or conical screen that meets the design shape requirements. The laser welding current is 3000~5000W and the welding speed is 900~1100mm / min, achieving single-sided welding and double-sided forming.

8. The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen according to claim 1 or 5, characterized in that, In step (8), the outermost part of the titanium alloy slotted screen is machined with a milling machine to make the filtration area retain a width of 1~3mm, forming a contour with gradient steps, so as to further improve the filtration effect of the screen.

9. The method for preparing the wear-resistant, corrosion-resistant, high-strength titanium alloy slotted screen according to claim 8, characterized in that, A 2mm thick annular groove is machined on the outermost side of the cylindrical or conical screen using a milling machine. The distance between adjacent grooves is 200mm, and a 5mm wide reinforcing rib is formed between adjacent grooves.

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