A wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper and its preparation method

Abstract

This invention relates to the field of wear-resistant and corrosion-resistant centrifuge scrapers, specifically a wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper and its preparation method. First, a vacuum consumable arc melting method is used to generate dispersed TiB whiskers and TiC particle reinforcing phases in situ within a Ti6Al4V alloy matrix, thereby improving the wear resistance of the titanium alloy. Then, the prepared ingot is centrifugally cast into a centrifuge scraper using a vacuum investment casting method. Addressing the problem of rapid wear caused by long-term scraping of salt slag layers on the scraper blade, this invention further utilizes laser cladding technology to form a gradient in-situ generated carbide layer on the blade surface, further improving the wear resistance of the centrifuge scraper. The centrifuge spiral scraper prepared by this method can meet the requirements for conveying high-halogen salts and corrosive solid-liquid two-phase substances and can be widely used in chlor-alkali, salt production, and coal chemical industries.

Description

Technical Field

[0001] This invention relates to the field of wear-resistant and corrosion-resistant centrifuge scrapers, specifically to a wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper and its preparation method. Background Technology

[0002] In centrifuges, scrapers serve the functions of material transport and solid-liquid separation. However, when centrifuges operate at high temperatures, high halogen content, or acidic duplex materials at high speeds, traditional duplex stainless steel scrapers are prone to corrosion and accelerated wear, leading to failure. Although ceramic or carbide plates are used to improve wear resistance on the blade edges of traditional scrapers, the interface cannot achieve metallurgical bonding. Under conditions of high chloride ion concentration and high temperature, galvanic corrosion occurs, causing interface separation. This results in short service life and frequent replacements for centrifuge scrapers used in the salt industry due to the combined effects of wear, corrosion, and high temperatures, severely impacting operational efficiency. Therefore, there is an urgent need for material innovation to improve the wear and corrosion resistance of spiral scrapers, thereby extending their service life and meeting the requirements of on-site production operations. Summary of the Invention

[0003] The purpose of this invention is to provide a wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper and its preparation method.

[0004] Without altering the spiral scraper structure, this invention leverages the superior resistance of titanium alloy to chloride ion corrosion to address the severe corrosion problem in salt slag centrifuges. Secondly, it utilizes in-situ generated TiB and TiC particles, along with a surface-coated carbide ceramic layer, to enhance the wear resistance of the titanium alloy, thereby improving the wear resistance of the spiral scraper and extending its service life. The centrifuge spiral scraper prepared using this method can meet the requirements for conveying high-halogen salts and corrosive solid-liquid two-phase substances, and can be widely applied in chlor-alkali, salt production, and coal chemical industries.

[0005] The technical solution of this invention is:

[0006] A wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper, wherein the chemical composition and mass percentage of the titanium-based composite material are as follows: Al 5.9-6.4%, V 3.9-4.4%, Fe 0.15-0.22%, O 0.09-0.13%, B 0.47-3.16%, C 0.13-0.88%, H ≤0.005%, N ≤0.01%, and the balance is Ti.

[0007] The preparation method of the wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper includes the following specific steps:

[0008] (1) Preparation of titanium-based composite material ingots

[0009] Using sponge titanium, Al bean, AlV master alloy, Fe powder, TiO2 powder, and B4C powder as raw materials, the alloy composition is prepared and the titanium-based composite material ingot is obtained by vacuum arc remelting three times.

[0010] (2) Design and prepare scraper wax mold

[0011] Prepare the scraper wax mold core using 3D printing;

[0012] (3) Preparation of precision casting shell

[0013] After the wax film undergoes processes such as bonding to the gating system, applying sand, and firing the mold shell, a precision casting mold shell is formed.

[0014] (4) Centrifugal precision casting scraper

[0015] First, the prepared titanium-based composite material ingot is melted in a vacuum consumable solidification furnace. The range of the induction current is adjusted from 5000 to 30000A according to the melting rate in the furnace. After the ingot is completely melted into the induction copper crucible, the melt is centrifugally poured into the spiral scraper precision casting mold and fed back. After casting, it is slowly cooled in the vacuum chamber and the furnace temperature does not exceed 200℃.

[0016] (5) Densification treatment

[0017] The integral casting is heated to 900-1100℃ in a hot isostatic pressing furnace and held for 1-3 hours to perform hot isostatic pressing treatment, which makes the structure dense and meets the requirements of high strength and high fatigue performance.

[0018] (6) Laser cladding gradient composite material at scraper blade edge

[0019] An eight-axis linkage laser cladding equipment is used at the scraper blade edge. The scraper model, which is reverse-modeled by 3D scanning, is programmed in multiple postures offline to reasonably plan the laser cladding scanning path. Segmented gradient laser cladding of titanium-based composite materials is performed on the scraper outlet, the edge of the blade, and the upper surface of the spiral surface.

[0020] (7) Stress-relieving annealing

[0021] The prepared scraper was subjected to stress-relieving and homogenizing annealing treatment at 650-800℃ for 0.5-2 hours.

[0022] (8) Finishing

[0023] The scraper is then precision-machined according to the drawings to complete the entire scraper manufacturing process.

[0024] The method for preparing the wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper, in step (1), the mass percentage of B4C in TiAl64V is 0.6-4%.

[0025] The method for preparing the wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper involves in-situ generating dispersed TiB whiskers and TiC particle reinforcing phases in a Ti6Al4V alloy matrix. The TiB whiskers have a diameter of 1–3 μm and an aspect ratio of 1:6–1:8, while the TiC particle reinforcing phase consists of equiaxed particles with a diameter of 4–6 μm.

[0026] In the preparation method of the wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper, in step (5), the hot isostatic pressing treatment is carried out under a pressure of 100-200 MPa.

[0027] In the preparation method of the wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper, in step (6), the laser cladding powder and equipment parameters of the wear-resistant and corrosion-resistant titanium-based composite scraper are as follows: WC or TiC powder is used, and its mass percentage in Ti6Al4V powder is 40-80%. The laser cladding power is 1500-5000W, the cladding layer thickness is 3-8mm, and the segment size does not exceed 200mm.

[0028] The design concept of this invention is:

[0029] This invention employs a vacuum consumable arc melting method to incorporate a certain proportion of B4C ceramic phase into Ti6Al4V alloy raw materials. This results in the in-situ formation of dispersed TiB whiskers and TiC particle reinforcing phases within the Ti6Al4V alloy matrix, thereby improving the strength, toughness, corrosion resistance, and wear resistance of the titanium alloy. The prepared ingot is then precisely centrifuged using vacuum investment casting to obtain a titanium-based composite material precision-cast scraper. To enhance the durability of the centrifuge scraper blade, laser cladding is used on the scraper blade surface to form a gradient proportion of in-situ self-generated carbide reinforcing phases. This eliminates the macroscopic interface of traditional composite materials, resulting in a titanium-based functionally graded composite material, further improving the wear resistance of the centrifuge scraper. Finally, the scraper is precision-machined according to the drawings to meet the design requirements.

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

[0031] 1. This invention can obtain a corrosion-resistant titanium-based composite material. The corrosion resistance of the material is significantly improved compared with that of traditional duplex stainless steel scrapers, and it can meet the requirements of long-term use in weakly acidic and high-halogen salt environments.

[0032] 2. This invention can obtain a laser cladding wear-resistant titanium-based composite coating material. The wear resistance of the material is improved compared with that of Ti6Al4V and traditional duplex stainless steel scrapers. It can meet the requirements of long-term abrasive wear, and the corrosion resistance of the coating can also meet the requirements of weak acid, high temperature and high halide salt environment.

[0033] 3. This invention can obtain a wear-resistant and corrosion-resistant precision centrifugal casting scraper, and obtain a gradient segmented in-situ carbide high wear-resistant coating on the edge of the scraper blade, which can significantly improve the service life of the scraper. Attached Figure Description

[0034] Figure 1 Tensile property curves of the titanium-based composite material and TC4 titanium alloy described in the examples.

[0035] Figure 2 The wear volumes of the titanium-based composite material 1wt% B4C+TC4, laser-clad 50wt% TiC+TC4, and TC4 and 2507 duplex stainless steel described in the examples are shown under different loads. In the figures, the horizontal axis Load represents the load (N), and each group from left to right represents TC4, 2507, 1wt% B4C+TC4, and 50wt% TiC+TC4, respectively. The vertical axis Wear Volume represents the wear volume (mm). 3 ).

[0036] Figure 3 Comparison of corrosion performance of titanium-based composite material 1wt% B4C+TC4, laser cladding 50wt% TiC+TC4, TC4 and 2507 duplex stainless steel before and after corrosion.

[0037] Figure 4 Gradient cladding pattern of scraper blade.

[0038] Figure 5 Scraper on-machine test diagram. Detailed Implementation

[0039] 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.

[0040] Example:

[0041] In this embodiment, the composition of the titanium-based composite material is designed with the following mass percentages: Al 6.16%, V 4.09%, Fe 0.17%, O 0.13%, C 0.24%, B 0.83%, H 0.0005%, N 0.0078%, and the balance is Ti.

[0042] In this embodiment, the method for preparing the titanium-based composite centrifuge scraper and its blade gradient cladding layer is as follows:

[0043] (1) Using sponge titanium, Al bean, AlV master alloy, Fe powder, TiO2 powder and B4C powder as raw materials, according to the alloy composition, the titanium-based composite material ingot is obtained by vacuum self-consumption three-time melting.

[0044] In the titanium-based composite material, the mass percentage of B4C in TiAl64V is 1 wt%. In the Ti6Al4V alloy matrix, dispersed TiB whiskers and TiC particle reinforcing phases are generated in situ. The TiB whiskers have a diameter of approximately 2 μm and an aspect ratio of 1:6, while the TiC particle reinforcing phase consists of equiaxed particles with a diameter of 5 μm.

[0045] (2) The scraper wax mold core was prepared by 3D printing process.

[0046] (3) The wax film is bonded to the pouring channel, sand is applied, and the mold shell is baked to form a precision casting mold shell.

[0047] (4) First, the prepared titanium-based composite material ingot is melted in a vacuum self-consuming solidification furnace. The induction current range is adjusted from 5000 to 28000A. After the ingot is completely melted into the induction copper crucible, it is fully melted for 15 minutes and then centrifugally cast and fed back. After casting, it is slowly cooled in the vacuum chamber and the furnace temperature does not exceed 200℃.

[0048] (5) The integral casting is heated to 980°C in a hot isostatic pressing furnace, held for 2 hours, and densified under a pressure of 180MPa.

[0049] (6) TiC was selected as the source of the ceramic reinforcing phase. Laser cladding was used to achieve in-situ reaction synthesis of carbide reinforcing phases from TiC and Ti6Al4V powders. Gradient cladding was performed on the blade edge. The preferred process parameters were 4000W, speed 1500mm / min, overlap 2.4mm, single-layer thickness 0.7mm, and total thickness 5mm. The composition of each layer was continuously varied by adjusting the powder feed rate.

[0050] (7) The scraper after cladding is subjected to homogenization annealing at 750℃ / 1h and then cooled to room temperature in the furnace.

[0051] (8) Perform finishing on the scraper according to the drawings.

[0052] like Figure 1 As shown in the tensile property curves of the titanium-based composite material and TC4 titanium alloy described in the examples, the tensile strength of 1wt% B4C+TC4 is 1410MPa, while the tensile strength of TC4 is only 880MPa. Adding 1wt% of B4C increases the strength by 530MPa compared to TC4, which can significantly improve the comprehensive mechanical properties of the material.

[0053] like Figure 2As shown in the examples, the wear volumes of the titanium-based composite material 1wt% B4C+TC4, laser-clad 50wt% TiC+TC4, TC4, and 2507 duplex stainless steel under different loads reveal that the wear volume ratio of each material increases as the applied wear load increases from 4N to 16N. The wear volume of 1wt% B4C+TC4 is 58.8% lower than that of TC4, but still significantly higher than that of 2507 duplex stainless steel. Furthermore, the wear volume of laser-clad 50wt% TiC+TC4 is 138% lower than that of 2507 duplex stainless steel, indicating that the wear-resistant zone after laser cladding is higher than that of 2057 duplex stainless steel.

[0054] like Figure 3 As shown in the comparison diagram of the corrosion performance of titanium-based composite materials 1wt% B4C+TC4, laser-clad 50wt% TiC+TC4, TC4 and 2507 duplex stainless steel before and after corrosion, it can be seen that after 40 days of potassium chloride immersion corrosion, 2057 duplex stainless steel showed obvious corrosion pits, while 1wt% B4C+TC4, laser-clad 50wt% TiC+TC4 and TC4 did not show obvious corrosion. Only the edge interface of the second phase precipitated in 1wt% B4C+TC4 and laser-clad 50wt% TiC+TC4 became clearer. Therefore, it can be seen that the corrosion resistance of titanium-based composite materials is much higher than that of 2057 duplex stainless steel.

[0055] like Figures 4-5 As shown, the scraper manufactured according to the above process has passed the test and meets the functional requirements of the centrifuge. Under the condition of maximum frequency of 50HZ, it has low vibration, stable operation, and significantly improves the service life of the scraper.

[0056] The results show that the centrifuge spiral scraper prepared by the method of the present invention can meet the requirements for conveying high-halogen salts and corrosive solid-liquid two-phase substances, and is widely used in chlor-alkali, salt production, coal chemical and other fields, and has the following characteristics:

[0057] 1. The corrosion-resistant Ti6Al4V and B4C titanium-based composite material developed in this invention has better uniformity and finer reinforcing phases due to the vacuum self-consumable three-stage melting process, which can meet the requirements of long-term use in weakly acidic and high-halogen salt environments.

[0058] 2. The present invention uses laser cladding of wear-resistant titanium-based composite coating material. The innovative method of segmented stress release, coaxial powder feeding and synchronous adjustment of powder ratio results in a gradient coating with improved wear resistance compared to Ti6Al4V and the steel used in the original scraper. It can meet the requirements of long-term abrasive wear, and the coating corrosion resistance also meets the requirements of weak acid, high temperature and high halide salt environment.

[0059] 3. This invention develops a precision centrifugal casting scraper based on Ti6Al4V and B4C titanium-based composite materials and innovatively uses a high proportion of ceramic particles to form a gradient wear-resistant coating on the scraper's cutting edge. The scraper prepared by this method can meet the dual advantages of long-term use and remanufacturing repair, which can significantly improve the service life of the scraper and reduce the long-term investment cost of scraper parts, thus achieving the effect of cost reduction and efficiency improvement.

[0060] 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 and corrosion-resistant titanium-based composite centrifuge scraper, characterized in that, The chemical composition and mass percentage of the titanium-based composite material are as follows: Al 5.9~6.4%, V 3.9~4.4%, Fe 0.15~0.22%, O 0.09~0.13%, B 0.47~3.16%, C 0.13~0.88%, H ≤0.005%, N ≤0.01%, with the balance being Ti; The preparation method of the wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper includes the following specific steps: (1) Preparation of titanium-based composite material ingots Using sponge titanium, Al bean, AlV master alloy, Fe powder, TiO2 powder, and B4C powder as raw materials, the alloy composition is prepared and the titanium-based composite material ingot is obtained by vacuum arc remelting three times. (2) Design and prepare scraper wax mold Prepare the scraper wax mold core using 3D printing; (3) Preparation of precision casting shell After the wax film undergoes processes such as bonding to the gating system, applying sand, and firing the mold shell, a precision casting mold shell is formed. (4) Centrifugal precision casting scraper First, the prepared titanium-based composite material ingot is melted in a vacuum consumable solidification furnace. The range of the induction current is adjusted from 5000 to 30000A according to the melting rate in the furnace. After the ingot is completely melted into the induction copper crucible, the melt is centrifugally poured into the spiral scraper precision casting mold and fed back. After casting, it is slowly cooled in the vacuum chamber and the furnace temperature does not exceed 200℃. (5) Densification treatment The integral casting is heated to 900~1100℃ in a hot isostatic pressing furnace and held for 1~3 hours for hot isostatic pressing treatment to make the structure dense and meet the requirements of high strength and high fatigue performance. (6) Laser cladding gradient composite material on scraper blade edge An eight-axis linkage laser cladding equipment is used at the scraper blade edge. The scraper model, which is reverse-modeled by 3D scanning, is programmed in multiple postures offline to reasonably plan the laser cladding scanning path. Segmented gradient laser cladding of titanium-based composite materials is performed on the scraper outlet, the edge of the blade, and the upper surface of the spiral surface. (7) Stress-relief annealing The prepared scraper was subjected to stress-relieving and homogenizing annealing treatment at 650~800℃ for 0.5~2 hours. (8) Finishing The scraper is then precision-machined according to the drawings to complete the entire scraper manufacturing process.

2. The method for preparing the wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper according to claim 1, characterized in that, In the titanium-based composite material of step (1), the mass percentage of B4C in the Ti6Al4V alloy matrix is ​​0.6~4%.

3. The method for preparing the wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper according to claim 2, characterized in that, In situ, dispersed TiB whiskers and TiC particle reinforcement phases are generated in the Ti6Al4V alloy matrix. The TiB whiskers have a diameter of 1~3μm and an aspect ratio of 1:6~1:

8. The TiC particle reinforcement phase consists of equiaxed particles with a diameter of 4~6μm.

4. The method for preparing the wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper according to claim 1, characterized in that, In step (5), the hot isostatic pressing is carried out at a pressure of 100~200MPa.

5. The method for preparing the wear-resistant and corrosion-resistant titanium-based composite centrifuge scraper according to claim 1, characterized in that, In step (6), the laser cladding powder and equipment parameters for the wear-resistant and corrosion-resistant titanium-based composite scraper are as follows: WC or TiC powder is used, and its mass percentage in Ti6Al4V powder is 40~80%. The laser cladding power is 1500~5000W, the cladding layer thickness is 3~8mm, and the segment size does not exceed 200mm.

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