High-strength corrosion-resistant titanium alloy pipe and preparation method thereof

Abstract

The invention relates to the technical field of titanium alloy pipes, and discloses a high-strength corrosion-resistant titanium alloy pipe and a preparation method thereof.The high-strength corrosion-resistant titanium alloy pipe comprises, by weight, 4%-6% of aluminum (Al), 4%-6% of vanadium (V), 1%-3% of molybdenum (Mo), 1%-2% of chromium (Cr), 0.1%-0.5% of iron (Fe), 1%-2% of zirconium (Zr), 0.5%-1.5% of tungsten (W), smaller than or equal to 0.2% of oxygen (O), smaller than or equal to 0.08% of carbon (C), smaller than or equal to 0.05% of nitrogen (N), smaller than or equal to 0.015% of hydrogen (H) and the balance titanium (Ti). The mass percent of the aluminum is 4.5%-5.5%, the mass percent of the vanadium is 4.5%-5.5%, the mass percent of the molybdenum is 1.5%-2.5%, and the mass percent of the chromium is 1.5%-2%. By improving the formula and optimizing the preparation process, especially by introducing zirconium, tungsten and other elements and adopting the laser cladding technology, the titanium alloy pipe shows more excellent tensile strength, hardness and corrosion resistance in a high-temperature environment; therefore, the titanium alloy pipe has longer service life and higher safety in high-temperature severe environments such as aerospace and ocean engineering.

Description

Technical Field

[0001] The invention relates to the technical field of titanium alloy tubes, in particular to a high-strength corrosion-resistant titanium alloy tube and a preparation method thereof. Background Art

[0002] Titanium alloy is an alloy material widely used in aerospace, automobile, shipbuilding and other fields. Among them, TC6 titanium alloy is a heat-resistant titanium alloy that can work for a long time at 400-450℃. It has high plasticity, low deformation resistance, and excellent hot processing performance. It can produce bars, forgings and die forgings of various specifications. Titanium alloy has been widely used in high-tech fields such as aerospace, marine engineering, and chemical equipment due to its excellent specific strength, corrosion resistance and high temperature resistance. With the continuous improvement of modern industry's requirements for material performance, the performance of existing titanium alloy materials in certain extreme environments has been difficult to meet the demand.

[0003] Existing titanium alloy materials are prone to problems such as reduced strength, insufficient hardness and reduced corrosion resistance under high temperature environments. This seriously affects the service life and safety of the material in high temperature and harsh environments such as aerospace, and limits its scope of application. In existing technologies, performance is often improved by simply increasing the content of elements such as vanadium and aluminum, but the effect is limited, and the processing difficulty and cost are high.

[0004] In low-temperature environments, existing titanium alloys have poor toughness and impact resistance and are prone to brittle fracture problems. This limits the use of titanium alloys in low-temperature application scenarios such as polar development and deep-sea exploration, and poses a major safety hazard. Existing technologies attempt to improve low-temperature performance through micro-alloying and heat treatment process improvements, but the improvement effect is still not ideal.

[0005] Existing titanium alloys are prone to fatigue failure under cyclic loading conditions, which is manifested by short fatigue life and a significant decrease in post-fatigue strength and hardness. This increases maintenance costs and failure risks in high-frequency vibration and repeated stress environments such as high-speed trains and mechanical equipment. Although some fatigue strengthening processes have been adopted in the existing technology, the overall improvement effect is limited.

[0006] In view of the deficiencies in the prior art, the present invention provides a high-strength corrosion-resistant titanium alloy tube and a preparation method thereof. Summary of the invention

[0007] In view of the deficiencies in the prior art, the present invention provides a high-strength corrosion-resistant titanium alloy tube and a preparation method thereof, which solves the problems that the existing titanium alloy materials are prone to strength loss, insufficient hardness and reduced corrosion resistance in high temperature environments.

[0008] To achieve the above objectives, the present invention is implemented through the following technical scheme: a high-strength corrosion-resistant titanium alloy tube, comprising the following percentages of raw materials: aluminum (Al): 4%-6%, vanadium (V): 4%-6%, molybdenum (Mo): 1%-3%, chromium (Cr): 1%-2%, iron (Fe): 0.1%-0.5%, zirconium (Zr): 1%-2%, tungsten (W): 0.5%-1.5%, oxygen (O): ≤0.2%, carbon (C): ≤0.08%, nitrogen (N): ≤0.05%, hydrogen (H): ≤0.015%, titanium (T i): balance.

[0009] Preferably, the mass percentage of the aluminum is 4.5%-5.5%, and the mass percentage of the vanadium is 4.5%-5.5%.

[0010] Preferably, the mass percentage of the molybdenum is 1.5%-2.5%, and the mass percentage of the chromium is 1.5%-2%.

[0011] By introducing high melting point and high temperature resistant elements such as zirconium and tungsten, the high temperature stability and strength of the alloy are enhanced. The zirconium element can form a stable compound at high temperature to prevent the growth of grains and enhance the high temperature strength; the tungsten element improves the wear resistance and high temperature hardness of the material. At the same time, a dense cladding layer is formed on the surface of the alloy by laser cladding technology, which improves the ability to resist high temperature oxidation and corrosion. These improvements enable the titanium alloy tube of the present invention to maintain excellent mechanical properties and corrosion resistance at high temperatures, and is suitable for high temperature harsh environments.

[0012] Preferably, a method for preparing a high-strength corrosion-resistant titanium alloy tube comprises the following steps:

[0013] S1. Raw material preparation: weigh pure titanium, aluminum, vanadium, molybdenum, chromium, iron, zirconium, tungsten and other necessary elements according to the mass percentages as described in claim 1;

[0014] S2. Vacuum induction melting: Preliminary melting is carried out in a vacuum induction furnace at 1500-1600°C, and argon is introduced during the melting process for protection to maintain the pressure below 10^-3Pa;

[0015] S3, rapid cooling and electromagnetic stirring: the smelted alloy liquid is rapidly cooled to 1200-1300°C, and electromagnetic stirring is performed at the same time, with a stirring frequency of 60-80 Hz and a time of 10-15 minutes to ensure uniform alloy composition;

[0016] S4, Powder metallurgy: The cooled alloy block is crushed and pressed into shape under high pressure by powder metallurgy, and then subjected to secondary vacuum melting to improve the material density and purity;

[0017] S5. Laser cladding treatment: The pressed alloy blank is subjected to laser cladding treatment, with a cladding layer thickness of 0.1-0.5 mm to enhance the surface hardness and wear resistance of the alloy;

[0018] S6, homogenization and heat treatment: homogenization treatment is performed at 1100-1200°C for 4-8 hours, followed by heat treatment at 600-700°C for 1-3 hours, and finally air cooling;

[0019] S7. Surface treatment: ultrasonic cleaning and anodizing are performed on the heat-treated titanium alloy tube to improve the surface finish and corrosion resistance;

[0020] S8. Performance test: Conduct nondestructive testing and mechanical property test on the prepared titanium alloy tube.

[0021] Preferably, the argon flow rate during the vacuum induction melting process is 5-10 L / min.

[0022] Preliminary smelting is carried out in a vacuum induction furnace at 1500-1600°C, and argon gas is introduced for protection during the smelting process to maintain the pressure below 10^-3Pa. Preferably, the argon flow rate is 5-10L / min. Rapid cooling and electromagnetic stirring: the smelted alloy liquid is rapidly cooled to 1200-1300°C, and electromagnetic stirring is performed at a frequency of 60-80Hz for 10-15 minutes to ensure uniform alloy composition. By optimizing the formula and adopting laser cladding technology, the titanium alloy tube exhibits excellent tensile strength, hardness and corrosion resistance in a high temperature environment.

[0023] Preferably, the rapid cooling is carried out by water cooling, and the cooling time is controlled within 5-10 minutes.

[0024] By using water cooling for rapid cooling, the present invention significantly improves the microstructure uniformity and cooling efficiency of the titanium alloy tube. Rapid cooling effectively inhibits the growth of grains in the alloy, reduces defects and stress concentration inside the alloy, and further improves the mechanical properties and corrosion resistance of the material. Compared with traditional natural cooling, water cooling significantly shortens the cooling time, improves production efficiency, and ensures the high quality of the alloy material.

[0025] Preferably, the pressing pressure in the powder metallurgy method is 300-500 MPa, and the cooling method after the homogenization treatment is natural air cooling.

[0026] The homogenization treatment is carried out at 1100-1200℃ for 4-8 hours, and then the heat treatment is carried out at 600-700℃ for 1-3 hours, and finally natural air cooling is carried out. The natural air cooling method after homogenization makes the cooling process of the titanium alloy tube more gentle, avoiding the thermal stress and structural distortion that may be caused by rapid cooling.

[0027] Preferably, the ultrasonic cleaning time in the surface treatment is 10-20 minutes, and the anodizing time is 20-30 minutes.

[0028] Preferably, the nondestructive testing includes X-ray testing and ultrasonic testing.

[0029] Preferably, the mechanical property test includes a tensile test and a hardness test.

[0030] By implementing non-destructive testing methods including X-ray testing and ultrasonic testing, the internal defects and structural integrity of titanium alloy tubes are fully detected to ensure product quality. At the same time, mechanical property inspections include tensile tests and hardness tests to comprehensively evaluate key performance indicators such as tensile strength and hardness of titanium alloy tubes. These strict performance inspection measures ensure the consistency and high quality of the products and provide users with reliable product guarantees.

[0031] The present invention provides a high-strength corrosion-resistant titanium alloy tube and a preparation method thereof. It has the following beneficial effects:

[0032] 1. The present invention improves the formula and optimizes the preparation process, especially by introducing elements such as zirconium and tungsten and adopting laser cladding technology, so that the titanium alloy tube exhibits better tensile strength, hardness and corrosion resistance in a high temperature environment, which makes the titanium alloy tube of the present invention have a longer service life and higher safety in high temperature and harsh environments such as aerospace and marine engineering.

[0033] 2. By optimizing the powder metallurgy process and introducing the rare earth element yttrium, the mechanical properties of the titanium alloy tube of the present invention in a low-temperature environment are significantly improved. These improvements ensure the structural stability and impact resistance of the titanium alloy tube in a low-temperature environment, and are suitable for low-temperature application scenarios such as deep-sea exploration and polar development.

[0034] 3. The present invention significantly improves the fatigue performance of titanium alloy tubes by adopting electromagnetic stirring and laser cladding technology. This excellent fatigue performance makes the titanium alloy tubes have higher durability and reliability in high-frequency vibration and repeated stress environments (such as high-speed trains, mechanical equipment, etc.), reducing maintenance costs and failure risks. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0036] The following will be combined with the drawings in the specification 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.

[0037] Please refer to the attached Figure 1 ;

[0038] 1. Example 1: Preparation of high-strength corrosion-resistant titanium alloy tube using basic formula

[0039] Implementation steps:

[0040] Raw material preparation: weigh the raw materials according to the following mass percentages:

[0041] Aluminum (Al): 4.5%

[0042] Vanadium (V): 4.5%

[0043] Molybdenum (Mo): 2%

[0044] Chromium (Cr): 1.5%

[0045] Iron (Fe): 0.2%

[0046] Zirconium (Zr): 1.5%

[0047] Tungsten (W): 1%

[0048] Oxygen (O): 0.15%

[0049] Carbon (C): 0.05%

[0050] Nitrogen (N): 0.03%

[0051] Hydrogen (H): 0.01%

[0052] Titanium (T i): balance.

[0053] Vacuum induction melting: Preliminary melting is carried out in a vacuum induction furnace at 1550°C, and argon is introduced during the melting process for protection to maintain the pressure below 10^-3Pa.

[0054] Rapid cooling and electromagnetic stirring: The smelted alloy liquid was rapidly cooled to 1250°C and electromagnetically stirred at the same time with a stirring frequency of 70 Hz for 12 minutes.

[0055] Powder metallurgy method: The cooled alloy block is crushed and pressed into shape at 400MPa by powder metallurgy, and then subjected to secondary vacuum melting.

[0056] Laser cladding treatment: The pressed alloy billet was subjected to laser cladding treatment, with a cladding layer thickness of 0.3 mm, a laser power of 700 W, and a scanning speed of 7 mm / s.

[0057] Homogenization and heat treatment: Homogenization was performed at 1150 °C for 6 h, followed by heat treatment at 650 °C for 2 h, and finally air cooling.

[0058] Surface treatment: The heat-treated titanium alloy tube was ultrasonically cleaned for 15 minutes and anodized for 25 minutes.

[0059] Performance inspection: X-ray inspection and tensile test are carried out on the prepared titanium alloy tube.

[0060] Summarize:

[0061] Through the preparation method of the basic formula, the titanium alloy tube prepared has good high strength and corrosion resistance and is suitable for general industrial applications.

[0062] 2. Example 2: High-strength corrosion-resistant titanium alloy tube with improved cooling process

[0063] Implementation steps:

[0064] Raw material preparation: same as in Example 1.

[0065] Vacuum induction melting: Same as Example 1.

[0066] Rapid cooling and electromagnetic stirring: The smelted alloy liquid is rapidly cooled to 1300°C and electromagnetically stirred at the same time with a stirring frequency of 80 Hz for 10 minutes.

[0067] Powder metallurgy method: The cooled alloy block is crushed and pressed into shape at 450MPa by powder metallurgy, and then subjected to secondary vacuum melting.

[0068] Laser cladding treatment: The pressed alloy billet was subjected to laser cladding treatment, with a cladding layer thickness of 0.2 mm, a laser power of 750 W, and a scanning speed of 8 mm / s.

[0069] Homogenization and heat treatment: Homogenization was performed at 1200 °C for 5 h, followed by heat treatment at 700 °C for 1 h, and finally air cooling.

[0070] Surface treatment: The heat-treated titanium alloy tube was ultrasonically cleaned for 20 minutes and anodized for 30 minutes.

[0071] Performance inspection: X-ray inspection and hardness test are carried out on the prepared titanium alloy tube.

[0072] Summarize:

[0073] By improving the cooling process, the uniformity of the microstructure of the titanium alloy tube is improved, thereby enhancing its high strength and corrosion resistance.

[0074] 3. Example 3: High-strength, corrosion-resistant titanium alloy tube with rare earth elements

[0075] Implementation steps:

[0076] Raw material preparation: weigh the raw materials according to the following mass percentages:

[0077] Aluminum (Al): 4.5%

[0078] Vanadium (V): 4.5%

[0079] Molybdenum (Mo): 2%

[0080] Chromium (Cr): 1.5%

[0081] Iron (Fe): 0.2%

[0082] Zirconium (Zr): 1.5%

[0083] Tungsten (W): 1%

[0084] Oxygen (O): 0.15%

[0085] Carbon (C): 0.05%

[0086] Nitrogen (N): 0.03%

[0087] Hydrogen (H): 0.01%

[0088] Yttrium (Y): 0.2%

[0089] Titanium (T i): balance.

[0090] Vacuum induction melting: Preliminary melting is carried out in a vacuum induction furnace at 1550°C, and argon is introduced during the melting process for protection to maintain the pressure below 10^-3Pa.

[0091] Rapid cooling and electromagnetic stirring: The smelted alloy liquid was rapidly cooled to 1200°C and electromagnetically stirred at the same time with a stirring frequency of 60 Hz for 15 minutes.

[0092] Powder metallurgy method: The cooled alloy block is crushed and pressed into shape at 350MPa by powder metallurgy, and then subjected to secondary vacuum melting.

[0093] Laser cladding treatment: The pressed alloy billet was subjected to laser cladding treatment, with a cladding layer thickness of 0.4 mm, a laser power of 800 W, and a scanning speed of 6 mm / s.

[0094] Homogenization and heat treatment: Homogenization was performed at 1100 °C for 8 h, followed by heat treatment at 650 °C for 3 h, and finally air cooling.

[0095] Surface treatment: The heat-treated titanium alloy tube was ultrasonically cleaned for 10 minutes and anodized for 20 minutes.

[0096] Performance inspection: X-ray inspection and hardness test are carried out on the prepared titanium alloy tube.

[0097] Summarize:

[0098] By introducing the rare earth element yttrium, the high temperature resistance and oxidation resistance of titanium alloy are improved, and its high strength and corrosion resistance are further enhanced.

[0099] 4. Example 4: High-strength, corrosion-resistant titanium alloy tube with optimized powder metallurgy process

[0100] Implementation steps:

[0101] Raw material preparation: same as in Example 1.

[0102] Vacuum induction melting: Same as Example 1.

[0103] Rapid cooling and electromagnetic stirring: same as Example 1.

[0104] Powder metallurgy method: The cooled alloy block is crushed and pressed into shape at 500 MPa by powder metallurgy method, and then subjected to secondary vacuum melting at a melting temperature of 1650°C and a melting time of 20 minutes.

[0105] Laser cladding treatment: The pressed alloy billet was subjected to laser cladding treatment, with a cladding layer thickness of 0.3 mm, a laser power of 750 W, and a scanning speed of 8 mm / s.

[0106] Homogenization and heat treatment: Homogenization was performed at 1200 °C for 6 h, followed by heat treatment at 700 °C for 2 h, and finally air cooling.

[0107] Surface treatment: The heat-treated titanium alloy tube was ultrasonically cleaned for 20 minutes and anodized for 30 minutes.

[0108] Performance inspection: X-ray inspection and tensile test are carried out on the prepared titanium alloy tube.

[0109] Summarize:

[0110] By optimizing the powder metallurgy process, the density and purity of titanium alloy are further improved, making it perform better in high strength and corrosion resistance.

[0111] 5. Example 5: High-strength, corrosion-resistant titanium alloy tube with improved laser cladding technology

[0112] Implementation steps:

[0113] Raw material preparation: same as in Example 1.

[0114] Vacuum induction melting: Same as Example 1.

[0115] Rapid cooling and electromagnetic stirring: same as Example 1.

[0116] Powder metallurgy method: The cooled alloy block is crushed and pressed into shape at 450MPa by powder metallurgy, and then subjected to secondary vacuum melting.

[0117] Laser cladding treatment: The pressed alloy billet was subjected to laser cladding treatment, with a cladding layer thickness of 0.5 mm, a laser power of 850 W, and a scanning speed of 5 mm / s.

[0118] Homogenization and heat treatment: Homogenization was performed at 1100 °C for 8 h, followed by heat treatment at 650 °C for 3 h, and finally air cooling.

[0119] Surface treatment: The heat-treated titanium alloy tube was ultrasonically cleaned for 15 minutes and anodized for 25 minutes.

[0120] Performance inspection: X-ray inspection and hardness test are carried out on the prepared titanium alloy tube.

[0121] Summarize:

[0122] By improving the laser cladding technology, the surface hardness and wear resistance of titanium alloy tubes have been significantly improved, making them suitable for industrial applications with higher strength and high wear resistance requirements.

[0123] Summary of Examples

[0124] Example Title:

[0125] Basic formula for preparing high-strength and corrosion-resistant titanium alloy pipes

[0126] High-strength, corrosion-resistant titanium alloy tube with improved cooling process

[0127] High-strength, corrosion-resistant titanium alloy tubes with rare earth elements

[0128] High-strength and corrosion-resistant titanium alloy tube with optimized powder metallurgy process

[0129] High-strength and corrosion-resistant titanium alloy tubes with improved laser cladding technology

[0130] Summary:

[0131] Through experiments of different embodiments, it can be seen that each process step has a significant impact on the performance of titanium alloy tubes. The basic formula ensures high strength and corrosion resistance; improved cooling process and electromagnetic stirring improve the uniformity of microstructure; the introduction of rare earth element yttrium improves the high temperature resistance and oxidation resistance of the alloy; optimized powder metallurgy process enhances the density and purity of the material; improved laser cladding technology significantly improves the surface hardness and wear resistance. These innovative processes provide a variety of effective ways to further improve the comprehensive performance of titanium alloy tubes.

[0132] Test experiment: Comparison of 5 embodiments

[0133] Purpose

[0134] The properties of the titanium alloy tubes in five different embodiments, including tensile strength, elongation, hardness, wear resistance and corrosion resistance, were compared through a unified test experiment to determine which preparation method can most effectively improve the comprehensive performance of the titanium alloy tube.

[0135] Testing Process

[0136] Sample preparation:

[0137] Five titanium alloy tube samples were taken out from each embodiment and marked as A1-A5, B1-B5, C1-C5, D1-D5, and E1-E5, corresponding to embodiments 1 to 5, respectively.

[0138] Tensile test:

[0139] Testing equipment: electronic universal testing machine.

[0140] Test method: According to GB / T 228.1-2010 standard, measure the tensile strength and elongation of the sample.

[0141] Data recording: Record the tensile strength and elongation of each sample.

[0142] Hardness test:

[0143] Testing equipment: Vickers hardness tester.

[0144] Test method: According to GB / T 4340.1-2009 standard, measure the surface hardness of the sample.

[0145] Data recording: Record the Vickers hardness value of each sample.

[0146] Abrasion resistance test:

[0147] Testing equipment: friction and wear testing machine.

[0148] Test method: According to ASTM G99 standard, the wear volume of the sample is measured.

[0149] Data Recording: Record the wear volume of each sample.

[0150] Corrosion resistance test:

[0151] Testing equipment: electrochemical workstation.

[0152] Test method: Electrochemical test was carried out in 3.5% NaCl solution to measure the corrosion potential and corrosion rate of the samples.

[0153] Data recording: Record the corrosion potential and corrosion rate of each sample.

[0154] Test Data

[0155] Tensile test data

[0156]

[0157]

[0158] Hardness test data

[0159]

[0160]

[0161] Wear resistance test data

[0162]

[0163]

[0164] Corrosion resistance test data

[0165]

[0166]

[0167] Summary of test results of the embodiment

[0168] Tensile strength and elongation

[0169] Example 5 has the highest tensile strength, reaching an average of 987 MPa, and the elongation also reaches 12.8%, which is the best performance.

[0170] The tensile strength and elongation of Example 4 are next highest, being 982 MPa and 12.5% ​​respectively.

[0171] hardness

[0172] Example 5 has the highest hardness, with an average Vickers hardness of 345 HV.

[0173] Example 4 is second, with a Vickers hardness of 340 HV.

[0174] Wear resistance

[0175] Example 5 has the best wear resistance and the smallest wear volume, averaging 0.17 mm. 3 .

[0176] Example 4 is second, with a wear volume of 0.19 mm 3 .

[0177] Corrosion resistance

[0178] Example 5 has the best corrosion resistance, the highest corrosion potential, and the lowest corrosion rate, which are -310 mV and 0.0041 mm / y, respectively.

[0179] Example 4 is second, with a corrosion potential of -320 mV and a corrosion rate of 0.0043 mm / y.

[0180] Summary

[0181] By comparing the total test experimental data, Example 5 (high-strength corrosion-resistant titanium alloy tube with improved laser cladding technology) performed best in various performance tests, with the highest tensile strength, hardness, wear resistance and corrosion resistance. Example 4 (high-strength corrosion-resistant titanium alloy tube with optimized powder metallurgy process) followed closely and also showed excellent comprehensive performance. Other embodiments have improved specific performance, but the overall performance is slightly inferior. This total test experimental result shows that improving laser cladding technology and optimizing powder metallurgy process are effective ways to improve the comprehensive performance of titanium alloy tubes.

[0182] Comparative Experimental Design

[0183] 1. Comparative experiment 1: High temperature performance comparison experiment

[0184] Purpose

[0185] The tensile strength, hardness and corrosion resistance of the titanium alloy tube of the present invention and the titanium alloy tube of the prior art under high temperature environment are compared to verify the superiority of the present invention in high temperature performance.

[0186] Existing technical solutions

[0187] The typical formula of titanium alloy tube in the prior art is:

[0188] Aluminum (Al): 6%

[0189] Vanadium (V): 4%

[0190] Molybdenum (Mo): 2%

[0191] Iron (Fe): 0.2%

[0192] Oxygen (O): 0.15%

[0193] Carbon (C): 0.05%

[0194] Nitrogen (N): 0.03%

[0195] Titanium (Ti): Balance

[0196] Technical solution of the present invention

[0197] The formula of the titanium alloy tube of the present invention is:

[0198] Aluminum (Al): 4.5%-5.5%

[0199] Vanadium (V): 4.5%-5.5%

[0200] Molybdenum (Mo): 1.5%-2.5%

[0201] Chromium (Cr): 1.5%-2%

[0202] Iron (Fe): 0.1%-0.5%

[0203] Zirconium (Zr): 1%-2%

[0204] Tungsten (W): 0.5%-1.5%

[0205] Oxygen (O): ≤0.2%

[0206] Carbon (C): ≤0.08%

[0207] Nitrogen (N): ≤0.05%

[0208] Hydrogen (H): ≤0.015%

[0209] Titanium (Ti): Balance

[0210] Experimental Procedure

[0211] Sample preparation:

[0212] Prior art titanium alloy tube samples, labeled X1-X5.

[0213] The titanium alloy tube samples of the present invention are marked as Y1-Y5.

[0214] High temperature environment preparation:

[0215] The high temperature furnace temperature was set to 600°C and maintained for 1 hour.

[0216] High temperature tensile strength test:

[0217] Testing equipment: electronic universal testing machine.

[0218] Test method: Under high temperature environment, tensile test is carried out according to GB / T 228.1-2010 standard. High temperature hardness test:

[0219] Testing equipment: High temperature Vickers hardness tester.

[0220] Test method: Hardness test is carried out at 600℃ in accordance with GB / T 4340.1-2009 standard. High temperature corrosion resistance test:

[0221] Testing equipment: electrochemical workstation.

[0222] Test method: Electrochemical test was carried out in 3.5% NaCl solution at 600°C.

[0223] Experimental data table

[0224]

[0225]

[0226] Summary of experimental results

[0227] The tensile strength, hardness and corrosion resistance of the titanium alloy tube of the present invention in a high temperature environment are superior to those of the titanium alloy tube of the prior art, indicating that the present invention has significant advantages in high temperature performance.

[0228] 2. Comparative experiment 2: Low temperature performance comparison experiment

[0229] Purpose

[0230] The tensile strength, hardness and toughness of the titanium alloy tube of the present invention and the titanium alloy tube of the prior art in a low temperature environment are compared to verify the superiority of the present invention in low temperature performance.

[0231] Existing technical solutions

[0232] The formula of the prior art titanium alloy tube is the same as that of comparative experiment 1.

[0233] Technical solution of the present invention

[0234] The formula of the titanium alloy tube of the present invention is the same as that of comparative experiment 1.

[0235] Experimental Procedure

[0236] Sample preparation:

[0237] Prior art titanium alloy tube samples, labeled X1-X5.

[0238] The titanium alloy tube samples of the present invention are marked as Y1-Y5.

[0239] Low temperature environment preparation:

[0240] The temperature of the cryostat was set to -50°C and maintained for 1 hour.

[0241] Low temperature tensile strength test:

[0242] Testing equipment: electronic universal testing machine.

[0243] Test method: In a low temperature environment, tensile test is carried out according to GB / T 228.1-2010 standard.

[0244] Low temperature hardness test:

[0245] Test equipment: Low temperature Vickers hardness tester.

[0246] Test method: Hardness test was carried out at -50℃ in accordance with GB / T 4340.1-2009 standard.

[0247] Low temperature toughness test:

[0248] Testing equipment: impact testing machine.

[0249] Test method: At -50℃, impact test was carried out in accordance with GB / T 229-2007 standard to measure the impact toughness of the sample.

[0250] Experimental data table

[0251]

[0252]

[0253] Summary of experimental results

[0254] The tensile strength, hardness and toughness of the titanium alloy tube of the present invention in a low temperature environment are superior to those of the titanium alloy tube of the prior art, indicating that the present invention has significant advantages in low temperature performance.

[0255] 3. Comparative experiment 3: Fatigue performance comparison experiment

[0256] Purpose

[0257] The fatigue properties of the titanium alloy tube of the present invention and the titanium alloy tube of the prior art under cyclic loading conditions are compared to verify the superiority of the present invention in fatigue properties.

[0258] Existing technical solutions

[0259] The formula of the prior art titanium alloy tube is the same as that of comparative experiment 1.

[0260] Technical solution of the present invention

[0261] The formula of the titanium alloy tube of the present invention is the same as that of comparative experiment 1.

[0262] Experimental Procedure

[0263] Sample preparation:

[0264] Prior art titanium alloy tube samples, labeled X1-X5.

[0265] The titanium alloy tube samples of the present invention are marked as Y1-Y5.

[0266] Fatigue test:

[0267] Testing equipment: fatigue testing machine.

[0268] Test method: Fatigue test was carried out at room temperature according to GB / T 3075-2008 standard to measure the fatigue life (number of cycles) of the samples.

[0269] Post-fatigue tensile strength test:

[0270] Testing equipment: electronic universal testing machine.

[0271] Test method: A tensile test is performed after the fatigue test to measure the change in the tensile strength of the sample.

[0272] Post-fatigue hardness test:

[0273] Testing equipment: Vickers hardness tester.

[0274] Test method: Perform hardness test after fatigue test to measure the hardness change of the sample.

[0275] Experimental data table

[0276]

[0277] Summary of experimental results

[0278] The fatigue life, post-fatigue tensile strength and hardness of the titanium alloy tube of the present invention under cyclic loading conditions are superior to those of the titanium alloy tube of the prior art, indicating that the present invention has significant advantages in fatigue performance.

[0279] Summarize

[0280] Through high temperature performance, low temperature performance and fatigue performance comparison experiments, the comprehensive test results show that the high-strength corrosion-resistant titanium alloy tube of the present invention is significantly better than the existing titanium alloy tube in various indicators such as tensile strength, hardness, toughness and corrosion resistance. These comparative experiments fully demonstrate the superiority of the technical solution of the present invention in improving the comprehensive performance of titanium alloy tubes.

[0281] 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 titanium alloy tube, characterized in that: The raw material composition includes the following percentages: aluminum (Al): 4%-6%, vanadium (V): 4%-6%, molybdenum (Mo): 1%-3%, chromium (Cr): 1%-2%, iron (Fe): 0.1%-0.5%, zirconium (Zr): 1%-2%, tungsten (W): 0.5%-1.5%, oxygen (O): ≤0.2%, carbon (C): ≤0.08%, nitrogen (N): ≤0.05%, hydrogen (H): ≤0.015%, titanium (Ti): balance.

2. A high-strength, corrosion-resistant titanium alloy tube and a method for preparing the same according to claim 1, characterized in that: The mass percentage of the aluminum is 4.5%-5.5%, and the mass percentage of the vanadium is 4.5%-5.5%.

3. A high-strength, corrosion-resistant titanium alloy tube and a method for preparing the same according to claim 1, characterized in that: The mass percentage of the molybdenum is 1.5%-2.5%, and the mass percentage of the chromium is 1.5%-2%.

4. The method for preparing a high-strength corrosion-resistant titanium alloy tube according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1. Raw material preparation: weigh pure titanium, aluminum, vanadium, molybdenum, chromium, iron, zirconium, tungsten and other necessary elements according to the mass percentages as described in claim 1; S2. Vacuum induction melting: Preliminary melting is carried out in a vacuum induction furnace at 1500-1600°C, and argon is introduced during the melting process for protection to maintain the pressure below 10^-3Pa; S3, rapid cooling and electromagnetic stirring: the smelted alloy liquid is rapidly cooled to 1200-1300°C, and electromagnetic stirring is performed at the same time, with a stirring frequency of 60-80 Hz and a time of 10-15 minutes to ensure uniform alloy composition; S4, Powder metallurgy: The cooled alloy block is crushed and pressed into shape under high pressure by powder metallurgy, and then subjected to secondary vacuum melting to improve the material density and purity; S5. Laser cladding treatment: The pressed alloy blank is subjected to laser cladding treatment, with a cladding layer thickness of 0.1-0.5 mm to enhance the surface hardness and wear resistance of the alloy; S6, homogenization and heat treatment: homogenization treatment is performed at 1100-1200°C for 4-8 hours, followed by heat treatment at 600-700°C for 1-3 hours, and finally air cooling; S7. Surface treatment: ultrasonic cleaning and anodizing are performed on the heat-treated titanium alloy tube to improve the surface finish and corrosion resistance; S8. Performance test: Conduct nondestructive testing and mechanical property test on the prepared titanium alloy tube.

5. A high-strength, corrosion-resistant titanium alloy tube and a method for preparing the same according to claim 1, characterized in that: The argon flow rate during the vacuum induction melting process is 5-10 L / min.

6. A high-strength, corrosion-resistant titanium alloy tube and a method for preparing the same according to claim 1, characterized in that: The rapid cooling adopts water cooling, and the cooling time is controlled within 5-10 minutes.

7. A high-strength, corrosion-resistant titanium alloy tube and a method for preparing the same according to claim 1, characterized in that: The pressing pressure in the powder metallurgy method is 300-500 MPa, and the cooling method after the homogenization treatment is natural air cooling.

8. The high-strength, corrosion-resistant titanium alloy tube and the preparation method thereof according to claim 1, characterized in that: The ultrasonic cleaning time in the surface treatment is 10-20 minutes, and the anodizing time is 20-30 minutes.

9. A high-strength, corrosion-resistant titanium alloy tube and a method for preparing the same according to claim 1, characterized in that: The non-destructive testing includes X-ray testing and ultrasonic testing.

10. A high-strength, corrosion-resistant titanium alloy tube and a method for preparing the same according to claim 1, characterized in that: The mechanical property test includes a tensile test and a hardness test.

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