Ti-based flux-cored wire for laser brazing of titanium alloy sheet, preparation method and application thereof

Abstract

The application discloses a Ti-based medicine core wire material suitable for laser brazing of titanium alloy sheet, which comprises a medicine core and an outer skin, wherein the medicine core elements are prepared according to atomic percentage, and the atomic percentage of the medicine core elements comprises Zr: 20%-45%, Cu: 20%, Ni: 20%, and Cr: 15%-40%, and the total atomic percentage is 100%; the outer skin is a TA1 belt, and the composition of the TA1 belt is H: 0.015%, O: 0.18%, N: 0.05%, C: 0.26%, Fe: 0.2%, and Ti is the balance. The Ti-based medicine core wire material brazing filler metal is suitable for laser brazing connection of the titanium alloy sheet, a solution method for solving the cracking and even scrapping of the connection part of the titanium alloy sheet component in the aerospace field under complex working conditions for a long time is provided, and a preparation method of the Ti-based medicine core wire material brazing filler metal foil is also provided.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of brazing materials, and particularly relates to a Ti-based flux-cored wire suitable for laser brazing of titanium alloy thin plates and a preparation method thereof, and also relates to application of the Ti-based flux-cored wire. BACKGROUND

[0002] Titanium alloy plates are often used in the manufacture of aerospace, medical devices, chemical equipment, high-end sports equipment and other equipment due to their excellent strength, corrosion resistance and lightweight properties.

[0003] Due to limitations of their own structures and material properties, some titanium alloy thin plate components are difficult to manufacture integrally and can only be manufactured by segmental processing and assembly, such as aircraft fuselage skins, chemical reaction kettle walls and other complex equipment. In order to ensure that these components do not deform or loosen during use, welding, a permanent connection method, is used. At present, the welding methods suitable for titanium alloy thin plates include gas metal arc welding (MAG welding), tungsten inert gas arc welding (TIG welding) and plasma welding. Compared with the foregoing welding methods, laser brazing for welding titanium alloy thin plates has the following advantages: (1) intermetallic compound formation is greatly reduced, (2) heat and welding thermal cycle control is facilitated, and (3) precise control of the melting position can be achieved.

[0004] Traditional Ti-based filler metals have the advantages of high strength of welded joints and excellent corrosion resistance in laser brazing of titanium alloy thin plates. However, they often face problems such as low joint strength, easy production of welding defects and high production cost. SUMMARY

[0005] The first object of the present application is to provide a Ti-based flux-cored wire suitable for laser brazing of titanium alloy thin plates, which solves the problems of low joint strength and easy production of welding defects after brazing of the existing Ti-based flux-cored wire filler metal.

[0006] The second object of the present application is to provide a preparation method of the Ti-based flux-cored wire suitable for laser brazing of titanium alloy thin plates.

[0007] The third object of the present application is to provide application of the Ti-based flux-cored wire.

[0008] The first technical solution of the present application is: a Ti-based flux-cored wire suitable for laser brazing of titanium alloy sheet, comprising a core and a sheath, wherein the core comprises Zr: 20-45%, Cu: 20%, Ni: 20%, and Cr: 15-40% by atomic percentage, and the total of the above atomic percentages is 100%; the sheath is a TA1 tape, and the sheath comprises H: 0.015%, O: 0.18%, N: 0.05%, C: 0.26%, Fe: 0.2%, and the balance of Ti by mass percentage.

[0009] The functions of each element of the Ti-based flux-cored wire brazing filler metal are as follows:

[0010] Ti: can provide excellent high-temperature resistance and chemical stability, and help to form good metallurgical bonding with the TC4 titanium alloy base body, thereby enhancing the strength and corrosion resistance of the brazed joint.

[0011] Zr: Zr is a neutral element of Ti alloy, and can form infinite solid solution with each other (can form continuous solid solution with α-Ti and β-Ti), has solid solution strengthening effect on Ti, and the high-temperature strengthening effect is particularly obvious, and will not form brittle intermetallic compound with Ti. Zr can also improve the creep resistance of TC4 and increase the strength of the alloy without significantly reducing the plasticity of the titanium alloy.

[0012] Cu / Ni: Cu and Ni are both β-Ti stabilizers, have similar atomic sizes and structures, and can form infinite solid solution with each other. Cu, Ni and Ti can form eutectic structure, effectively reduce the melting point of Ti alloy, and also can improve the fluidity of molten Ti-based brazing filler metal and the filling capacity, which is beneficial to the brazing.

[0013] Cr: Cr can improve the corrosion resistance of the brazing filler metal, especially in an environment containing corrosive medium, the protective film formed by Cr in the brazing filler metal can prevent the corrosive medium from eroding the weld, thereby prolonging the service life of the weld.

[0014] The second technical solution of the present application is: a preparation method of a Ti-based flux-cored wire suitable for laser brazing of titanium alloy sheet, and the specific operation steps are as follows:

[0015] Step 1: first clean the TA1 tape with a mixture of acetone and NaOH, then rinse with clean water, and finally ultrasonic clean with ethanol to obtain clean TA1 tape;

[0016] Step 2: prepare the wire core according to the atomic percentage, the core comprises Zr: 20-45%, Cu: 20%, Ni: 20%, and Cr: 15-40% by atomic percentage, convert the atomic percentage to mass percentage, and then weigh each raw material powder according to the mass percentage;

[0017] Step 3: the raw material powders prepared in step 2 are mixed and dried, and then the dried raw material powders are put into a mixer for dry mixing, and the powder is fully mixed to obtain the core powder;

[0018] Step 4: the uniformly mixed core powder obtained in step 3 is wrapped in a TA1 tape through a core wire making machine, and a forming machine is used to close the TA1 tape to obtain a 2.1mm diameter wire semi-finished product;

[0019] Step 5: the 2.1mm diameter wire semi-finished product obtained in step 4 is subjected to a multi-pass cold-drawing reducing-diameter drawing die to obtain a 1.18mm diameter Ti-based core wire filler material;

[0020] Step 6: the oil stains on the wire filler material are wiped off with a cotton cloth dipped in anhydrous ethanol, and finally the wire is straightened, coiled into a disc, and sealed and packaged by a wire drawing machine.

[0021] The application also has the characteristics that,

[0022] In step 1, the mass fraction of NaOH in the mixed solution of NaOH and acetone is 25%, and the mass fraction of acetone is 75%; the ultrasonic cleaning in step 1 is 2-3min, and the frequency is 25-30kHz.

[0023] In step 2, the particle size of each raw material powder is not greater than 200μm.

[0024] The drying temperature in step 3 is 15℃, and the time is 30min.

[0025] In step 5, the specific process of the multi-pass cold-drawing reducing-diameter drawing die is as follows: sequentially passing through drawing dies with diameters of 1.9mm, 1.7mm, 1.5mm and 1.42mm.

[0026] The third technical scheme adopted by the application is the application of the Ti-based core wire filler material, and the specific operation steps are as follows:

[0027] The assembled TC4 titanium alloy to be welded is firmly assembled with a clamp, the Ti-based core wire filler material is placed on the weld to be welded, the laser power is set to 600W, the laser energy density range is 100-200J / mm 3 , the scanning speed is 450mm / s, argon gas is continuously supplied during the laser brazing process, and the laser brazing is completed in an argon gas environment with a gas flow of 10L / min.

[0028] The application has the beneficial effects that,

[0029] (1) The Ti-based core-in-sheath wire filler material designed in the application is used for laser brazing of titanium alloy thin plates, and has good weldability, and the brazed joint obtained is beautiful in appearance, free of welding defects such as pores, inclusions, oxidation and cracks, and has high strength, and is suitable for welded structures that bear certain load.

[0030] (2) The Ti-based core-in-sheath wire filler material designed in the application is used for laser brazing of titanium alloy thin plates, and the brazed joint obtained has uniform hardness distribution, and excellent shear tensile property and corrosion resistance.

[0031] (3) The Ti-based core-in-sheath wire filler material designed in the application has high economy, and has low requirement on equipment, and can achieve simple process and good operability, and is suitable for mass production. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 is a high-magnification metallographic microstructure diagram of a TC4 brazed joint prepared by the embodiment 4 of the application.

[0033] Figure 2 is a low-magnification metallographic microstructure diagram of a TC4 brazed joint prepared by the embodiment 4 of the application.

[0034] Figure 3 is a tensile strength and shear strength diagram of brazed joints in the embodiments 1 to 6 of the application with the change of Zr element in the brazing paste. DETAILED DESCRIPTION

[0035] The application will be described in detail below in combination with the drawings and specific embodiments.

[0036] The application is suitable for a Ti-based core-in-sheath wire for laser brazing of titanium alloy thin plates, and the wire includes a core and a sheath, wherein the core includes, in atomic percentage, Zr: 20% to 45%, Cu: 20%, Ni: 20%, and Cr: 15% to 40%; the total of the above atomic percentages is 100%, and the sheath is a TA1 tape; the sheath includes, in mass percentage, H: 0.015%, O: 0.18%, N: 0.05%, C: 0.26%, Fe: 0.2%, and the balance of Ti.

[0037] Embodiment 1

[0038] The application further provides a preparation method of the Ti-based core-in-sheath wire filler material for laser brazing of titanium alloy thin plates, and the specific steps are as follows:

[0039] Step 1: first clean the TA1 tape with a mixed solution of acetone and NaOH, then rinse with clean water, and finally ultrasonically clean with ethanol to obtain a clean TA1 tape;

[0040] Step 2: The wire core is prepared according to the atomic percentage, and the total atomic percentage is 100%, wherein Zr: 20%, Cu: 20%, Ni: 20%, and Cr: 40%. The atomic percentage is converted into mass percentage, Zr: 28.74%, Cu: 20.01%, Ni: 18.48%, and Cr: 32.77%. Then, the raw material powders are weighed according to the mass percentage;

[0041] Step 3: The mixed powder prepared in step 2 is dried at a temperature of 15 DEG C for 30 min, and then the dried raw material powder is put into a mixer for dry mixing until the powder is fully mixed, thereby obtaining the core powder;

[0042] Step 4: The uniformly mixed core powder obtained in step 3 is wrapped in a TA1 tape by a core wire making machine, and a forming machine is used to close the TA1 tape, thereby obtaining a semi-finished product of a wire with a diameter of 2.1 mm;

[0043] Step 5: The core wire brazing filler alloy precursor obtained in step 4 is subjected to multi-pass cold-drawing reduction drawing dies, thereby obtaining a wire brazing filler alloy with a diameter of 1.18 mm;

[0044] Step 6: The oil stains on the welding wire are wiped with cotton cloth dipped in anhydrous ethanol, and finally the wire is straightened, coiled into a disc, and sealed and packaged by a wire drawing machine.

[0045] The laser brazing process of the TC4 titanium alloy in Example 1 is as follows: the assembled TC4 titanium alloy to be welded is firmly assembled by a clamp, the Ti-based core wire brazing filler alloy prepared in step 6 is placed on the weld to be welded, the laser power is set to 600 W, the laser energy density is in the range of 100-200 J / mm 3 , the scanning speed is 450 mm / s, argon gas is continuously supplied during the laser brazing process to prevent oxidation during welding, and the laser brazing is completed in an argon gas environment with a gas flow of 5-10 L / min. The Ti-based core wire brazing filler alloy is used to braze the TC4 titanium alloy, and the weld is formed with good appearance and without defects such as pores, inclusions, cracks, and oxidation. In the performance test of the obtained brazed joint, the maximum hardness can reach 400 HV 0.5 , the tensile strength is 190 MPa, and the shear strength is 340 MPa, and the performance is excellent, meeting the use requirements.

[0046] Example 2

[0047] The application provides a preparation method of a Ti-based core wire brazing filler alloy for laser brazing of a titanium alloy sheet, and the specific steps are as follows:

[0048] Step 1: The TA1 tape is first cleaned with a mixed solution of acetone and NaOH, then rinsed with clean water, and finally ultrasonically cleaned with ethanol to obtain a clean TA1 tape;

[0049] Step 2: The core of the wire is prepared according to the atomic percentage, and the total atomic percentage is 100%, wherein Zr: 25%, Cu: 20%, Ni: 20%, and Cr: 35%. The atomic percentage is converted into mass percentage Zr: 34.85%, Cu: 19.42%, Ni: 17.93%, and Cr: 27.80%, and then each raw material powder is weighed according to the mass percentage;

[0050] Step 3: The mixed powder prepared in Step 2 is dried at a temperature of 15℃ for 30 minutes, and then the dried raw material powder is put into a mixer for dry mixing until the powder is fully mixed, thereby obtaining the core powder;

[0051] Step 4: The uniformly mixed core powder obtained in Step 3 is wrapped in a TA1 tape by a core wire making machine, and a forming machine is used to close the TA1 tape, thereby obtaining a semi-finished product of a wire with a diameter of 2.1mm;

[0052] Step 5: The core wire brazing filler alloy precursor with a diameter of 2.1mm obtained in Step 4 is subjected to multi-pass cold-drawing reduction drawing dies, thereby obtaining a wire brazing filler alloy with a diameter of 1.18mm;

[0053] Step 6: The oil stains on the welding wire are wiped off with a cotton cloth dipped in anhydrous ethanol, and finally the wire is straightened, coiled into a disc, and sealed and packaged by a wire drawing machine.

[0054] The laser brazing process of the TC4 titanium alloy in Example 2 is as follows: the assembled TC4 titanium alloy to be welded is firmly assembled with a clamp, the Ti-based core wire brazing filler alloy prepared in Step 6 is placed on the weld to be welded, the laser power is set to 600W, the laser energy density is in the range of 100-200J / mm 3 , the scanning speed is 450mm / s, argon gas is continuously supplied during the laser brazing process to prevent oxidation during welding, and the laser brazing is completed in an argon gas environment with a gas flow of 5-10L / min. The Ti-based core wire brazing filler alloy is used to braze the TC4 titanium alloy, and the weld is formed with an attractive appearance and without defects such as pores, inclusions, cracks, and oxidation. In the performance test of the obtained brazed joint, the maximum hardness is up to 423HV 0.5 , the tensile strength is 206MPa, and the shear strength is 374MPa, and the performance is excellent, meeting the use requirements.

[0055] Example 3

[0056] Step 1: The TA1 tape is first cleaned with a mixed solution of acetone and NaOH, then rinsed with water, and finally ultrasonically cleaned with ethanol to obtain a clean TA1 tape;

[0057] In step 1, the mass fraction of NaOH in the mixture of NaOH and acetone used is 25%, and the mass fraction of acetone is 75%. Ultrasonic cleaning is performed for 2-3 min at a frequency of 25-30 kHz.

[0058] In step 2, the atomic percentage of the wire core is prepared, and the total atomic percentage is 100%, in which Zr: 30%, Cu: 20%, Ni: 20%, and Cr: 20%. The atomic percentage is converted into mass percentage Zr: 43.98%, Cu: 20.43%, Ni: 18.87%, and Cr: 16.72%, and then each raw material powder is weighed according to the mass percentage.

[0059] In step 2, the particle size of each raw material powder is not greater than 200 μm.

[0060] In step 3, the mixed powder prepared in step 2 is dried at a drying temperature of 15°C for 30 min, and then the dried raw material powder is put into a mixer for dry mixing until the powder is fully mixed, thereby obtaining the core powder.

[0061] In step 4, the uniformly mixed core powder obtained in step 3 is wrapped in a TA1 tape by a core wire making machine, and a forming machine is used to close the TA1 tape, thereby obtaining a semi-finished product of a wire with a diameter of 2.1 mm.

[0062] In step 5, the core wire brazing filler alloy precursor obtained in step 4 is subjected to multi-pass cold-drawing reduction drawing dies, thereby obtaining a wire brazing filler alloy with a diameter of 1.18 mm.

[0063] In step 5, the specific process of the multi-pass cold-drawing reduction drawing die is as follows: the drawing die with a diameter of 1.9 mm, 1.7 mm, 1.5 mm, and 1.42 mm is passed in sequence.

[0064] In step 6, the oil stains on the welding wire are wiped with cotton cloth dipped in anhydrous ethanol, and finally the wire is straightened, coiled into a disc, and sealed and packaged by a wire drawing machine.

[0065] In example 3, the laser brazing process of TC4 titanium alloy is as follows: the assembled TC4 titanium alloy to be welded is firmly assembled by a clamp, the Ti-based core wire brazing filler alloy prepared in step 6 is placed on the weld to be welded, the laser power is set to 600 W, the laser energy density is in the range of 100-200 J / mm 3 , the scanning speed is 450 mm / s, argon gas is continuously supplied during the laser brazing process to prevent oxidation, and the laser brazing is completed in an argon gas environment with a gas flow of 10 L / min. The Ti-based core wire brazing filler alloy is used to braze TC4 titanium alloy, and the weld is formed in an attractive manner without defects such as pores, inclusions, cracks, and oxidation. In the performance test of the obtained brazed joint, the maximum hardness can reach 452 HV 0.5 .The tensile strength is 246 MPa, the shear strength is 429 MPa, and the performance is excellent, meeting the use requirements.

[0066] Example 4

[0067] Step 1: First, clean the TA1 strip with a mixture of acetone and NaOH, then rinse with water, and finally ultrasonic cleaning with ethanol to obtain a clean TA1 strip;

[0068] In step 1, the mass fraction of NaOH in the mixture of NaOH and acetone is 25%, and the mass fraction of acetone is 75%. Ultrasonic cleaning for 2-3 min, frequency 25-30 kHz.

[0069] Step 2: Prepare the wire core according to the atomic percentage, the total atomic percentage is 100%, among which Zr: 35%, Cu: 20%, Ni: 20%, Cr: 20%. Convert the atomic percentage to mass percentage Zr: 47.82%, Cu: 19.03%, Ni: 17.57%, Cr: 15.58%, and then weigh each raw material powder according to the mass percentage;

[0070] In step 2, the particle size of each raw material powder is not greater than 200 μm.

[0071] Step 3: Dry the mixed powder prepared in step 2 at a drying temperature of 15°C for 30 minutes, and then put the dried raw material powder into a mixer for dry mixing. After the powder is fully mixed, the core powder is obtained;

[0072] Step 4: Wrap the uniformly mixed core powder obtained in step 3 in the TA1 strip through the core wire manufacturing machine, and use the forming machine to close the TA1 strip to obtain a diameter of 2.1 mm wire semi-finished product;

[0073] Step 5: The diameter of the core wire brazing filler alloy precursor obtained in step 4 is 2.1 mm, and the multi-pass cold-drawing reducing die is used to obtain a diameter of 1.18 mm of the wire brazing filler alloy;

[0074] In step 5, the specific process of the multi-pass cold-drawing reducing die is as follows: pass through the drawing dies with diameters of 1.9 mm, 1.7 mm, 1.5 mm, and 1.42 mm in sequence.

[0075] Step 6: Wipe the oil stains on the welding wire with cotton cloth dipped in anhydrous ethanol, and finally use the wire drawing machine to straighten, disc, and seal the wire.

[0076] The laser brazing process of the TC4 titanium alloy in Example 4 is as follows: the assembled TC4 titanium alloy to be welded is firmly assembled with a clamp, the Ti-based flux-cored wire filler metal prepared in step 6 is placed on the weld to be welded, the laser power is set to 600 W, the laser energy density is in the range of 200 J / mm 3 , the scanning speed is 450 mm / s, argon is continuously supplied during the laser brazing process to prevent oxidation during welding, and the laser brazing is completed in an argon environment with a gas flow of 10 L / min. The Ti-based flux-cored wire filler metal is used to braze the TC4 titanium alloy, and the weld is formed with good appearance and without defects such as pores, inclusions, cracks, and oxidation. The obtained brazed joint is observed by metallographic structure observation (as shown in Figures 1-2 ), and the brazed joint has a clear layered structure and can be divided into three parts: acicular zone, diffusion reaction zone, and central eutectic residual zone. The weld is well combined with the TC4 substrate. In the performance test of the obtained brazed joint, the maximum hardness is 500 HV 0.5 , the tensile strength is 310 MPa, and the shear strength is 485 MPa, with excellent performance and meeting the use requirements.

[0077] Example 5

[0078] Step 1: First, clean the TA1 tape with a mixture of acetone and NaOH, then rinse with water, and finally ultrasonic clean with ethanol to obtain clean TA1 tape;

[0079] In step 1, the mass fraction of NaOH in the mixture of NaOH and acetone is 25%, and the mass fraction of acetone is 75%. Ultrasonic cleaning for 2-3 min, frequency 25-30 kHz.

[0080] Step 2: Prepare the flux-cored wire according to the atomic percentage, the total atomic percentage is 100%, among which Zr: 40%, Cu: 20%, Ni: 20%, Cr: 20%. Convert the atomic percentage to mass percentage Zr: 51.16%, Cu: 17.82%, Ni: 16.45%, Cr: 14.58%, and then weigh each raw material powder according to the mass percentage;

[0081] In step 2, the particle size of each raw material powder is not greater than 200 μm.

[0082] Step 3: Dry the mixed powder prepared in step 2 at a drying temperature of 15℃ for 30 min, then put the dried raw material powder into a mixer for dry mixing, and the flux-cored powder is obtained after the powder is fully mixed;

[0083] Step 4: Wrap the uniformly mixed flux-cored powder obtained in step 3 in the TA1 tape through a flux-cored wire making machine, and close the TA1 tape with a forming machine to obtain a 2.1 mm diameter semi-finished product of the wire;

[0084] Step 5: The diameter 2.1mm core wire filler metal precursor obtained in step 4 is subjected to multi-pass cold-drawing reduction drawing dies to obtain a diameter 1.18mm wire filler metal;

[0085] In step 5, the specific process of the multi-pass cold-drawing reduction drawing dies is: sequentially passing through drawing dies with diameters of 1.9mm, 1.7mm, 1.5mm, and 1.42mm.

[0086] Step 6: The oil stains on the welding wire are wiped with cotton cloth dipped with anhydrous ethanol, and finally the wire is straightened, coiled into a disc, and sealed packaged by the wire drawing machine.

[0087] The laser brazing process of the TC4 titanium alloy in Example 5 is: the assembled TC4 titanium alloy to be welded is firmly assembled with a clamp, the Ti-based core wire filler metal prepared in step 6 is placed on the weld to be welded, the laser power is set to 600W, the laser energy density range is 200J / mm 3 , the scanning speed is 450mm / s, argon gas is continuously supplied during the laser brazing process to prevent oxidation during welding, and the laser brazing is completed in an argon gas environment with a gas flow of 10L / min. Using the Ti-based core wire filler metal to braze the TC4 titanium alloy, the weld is formed with good appearance, and there are no defects such as pores, inclusions, cracks, and oxidation, and the weld is well combined with the TC4 base. In the performance test of the obtained brazed joint, the maximum hardness can reach 482HV 0.5 , the tensile strength is 293MPa, and the shear strength is 464MPa, and each performance is excellent, meeting the use requirements.

[0088] Example 6

[0089] Step 1: First, clean the TA1 strip with a mixed solution of acetone and NaOH, then rinse with water, and finally ultrasonic clean with ethanol to obtain a clean TA1 strip;

[0090] In step 1, the mass fraction of NaOH in the mixed solution of NaOH and acetone is 25%, and the mass fraction of acetone is 75%. Ultrasonic cleaning for 2-3min, frequency 25-30kHz.

[0091] Step 2: Prepare the wire core according to the atomic percentage, the total atomic percentage is 100%, among which Zr: 45%, Cu: 20%, Ni: 20%, Cr: 15%. Convert the atomic percentage to mass percentage Zr: 56.00%, Cu: 17.43%, Ni: 15.99%, Cr: 10.67%, and then weigh each raw powder according to the mass percentage;

[0092] In step 2, the particle size of each raw powder is not greater than 200μm.

[0093] Step 3: The mixed powder prepared in step 2 is dried at a temperature of 15℃ for 30 min, and then the dried powder is put into a mixer for dry mixing, to obtain the core powder;

[0094] Step 4: The uniformly mixed core powder prepared in step 3 is wrapped in a TA1 tape by a core wire making machine, and the TA1 tape is closed by a forming machine to obtain a semi-finished product of a wire with a diameter of 2.1 mm;

[0095] Step 5: The core wire brazing filler prepared in step 4 is subjected to multi-pass cold-drawing reduction drawing dies to obtain a brazing filler wire with a diameter of 1.18 mm;

[0096] In step 5, the specific process of the multi-pass cold-drawing reduction drawing dies is as follows: the wire is sequentially passed through drawing dies with diameters of 1.9 mm, 1.7 mm, 1.5 mm and 1.42 mm.

[0097] Step 6: The oil stains on the wire are wiped off with a cotton cloth dipped in anhydrous ethanol, and then the wire is straightened, coiled into a disc and sealed for packaging by a wire drawing machine.

[0098] In example 6, the laser brazing process of the TC4 titanium alloy is as follows: the assembled TC4 titanium alloy to be welded is firmly assembled by a clamp, the Ti-based core wire brazing filler prepared in step 6 is placed on the weld to be welded, the laser power is set to 600 W, the laser energy density is in the range of 100 J / mm 3 , the scanning speed is 450 mm / s, argon gas is continuously supplied during the laser brazing process to prevent oxidation, and the laser brazing is completed in an argon gas environment with a gas flow of 10 L / min. The Ti-based core wire brazing filler is used to braze the TC4 titanium alloy, and the weld is formed with good appearance and without defects such as pores, inclusions, cracks and oxidation. The weld is well combined with the TC4 substrate. In the performance test of the obtained brazed joint, the maximum hardness is 448 HV 0.5 , the tensile strength is 263 MPa, and the shear strength is 410 MPa, and the performances are excellent, meeting the use requirements.

Claims

1. A Ti-based flux-cored wire for laser brazing of titanium alloy sheet, characterized by, The wire includes a core and a sheath, wherein the core includes, in atomic percentage, Zr: 20-45%, Cu: 20%, Ni: 20%, and Cr: 15-40%; the sum of the above atomic percentages is 100%, and the sheath is a TA1 tape.

2. The Ti-based flux cored wire for laser brazing of titanium alloy sheet according to claim 1, characterized in that, The sheath includes, in mass percentage, H: 0.015%, O: 0.18%, N: 0.05%, C: 0.26%, Fe: 0.2%, and the balance being Ti.

3. A method for preparing a Ti-based flux-cored wire for laser brazing of titanium alloy sheet, characterized by, The specific operation steps are as follows: Step 1: first clean the TA1 tape with a mixed solution of acetone and NaOH, then rinse with clean water, and finally ultrasonic clean with ethanol to obtain a clean TA1 tape; Step 2: prepare the core of the wire according to atomic percentage, the core includes, in atomic percentage, Zr: 20-45%, Cu: 20%, Ni: 20%, and Cr: 15-40%, weigh each raw material powder after converting the atomic percentage to mass percentage; Step 3: mix and dry the raw material powder prepared in step 2, then put the dried raw material powder into a mixer for dry mixing, and obtain the core powder after the powder is fully mixed; Step 4: wrap the TA1 tape with the core powder obtained in step 3 through a core welding wire making machine, and close the TA1 tape with a forming machine to obtain a wire semi-finished product with a diameter of 2.1 mm; Step 5: perform multi-pass cold-drawing reduction drawing die on the wire semi-finished product with a diameter of 2.1 mm obtained in step 4 to obtain a Ti-based core wire solder with a diameter of 1.18 mm; Step 6: wipe the oil stains on the wire solder with cotton soaked in anhydrous ethanol, and finally straighten, disc, and seal the wire through a wire drawing machine.

4. The method of producing a Ti-based flux cored wire for laser brazing of a titanium alloy sheet according to claim 3, characterized in that, In step 1, the mass fraction of NaOH in the mixed solution of NaOH and acetone is 25%, and the mass fraction of acetone is 75%; the ultrasonic cleaning in step 1 is 2-3 min, and the frequency is 25-30 kHz.

5. The method of producing a Ti-based flux cored wire for laser brazing of a titanium alloy sheet according to claim 3, characterized in that, In step 2, the particle size of each raw material powder is not greater than 200 μm.

6. The method of producing a Ti-based flux cored wire for laser brazing of a titanium alloy sheet according to claim 3, characterized in that, The drying temperature in step 3 is 15°C, and the time is 30 min.

7. The method of producing a Ti-based flux cored wire for laser brazing of a titanium alloy sheet according to claim 3, characterized in that, In step 5, the specific process of the multi-pass cold-drawing reduction drawing die is as follows: pass through the drawing dies with diameters of 1.9 mm, 1.7 mm, 1.5 mm, and 1.42 mm in sequence.

8. Use of a Ti-based drug core wire, characterized in that The titanium alloy sheet laser brazing is suitable, and specific operation steps are as follows: the assembled TC4 titanium alloy to be welded is assembled firmly with a clamp, Ti-based flux-cored wire brazing filler is placed on the weld to be welded, laser power is set to 600W, laser energy density range is 100-200J / mm 3 , scanning speed is 450mm / s, argon is continuously supplied during laser brazing, and laser brazing is completed in an argon environment with a gas flow of 10L / min.

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