Preparation method of large-diameter round TB9 titanium alloy wire for blind rivets

Abstract

The present application relates to core-pulling rivet titanium alloy wire processing technical field, specifically to a kind of preparation method of TB9 titanium alloy large disc round wire for core-pulling rivet.The method first obtains the TB9 titanium alloy ingot with a diameter of 500-700mm, then the TB9 titanium alloy ingot is forged into a bar blank with a diameter of 290-310mm at 1100-1200 ℃, then the TB9 titanium alloy bar blank is rough forged into a bar blank with a diameter of 130-150mm at 1000-1100 ℃, then the TB9 titanium alloy bar blank is precision forged into a bar blank with a diameter of 95-105mm at 850-950 ℃, then the TB9 titanium alloy bar blank is continuously rolled at 780-900 ℃, and then quenched after rolling, to obtain a large disc round wire blank with a diameter of 7.5-15mm, then room temperature drawing, then high-temperature solid solution, then room temperature drawing again, then peeling, polishing and coating treatment.At this time, the alloy cross-section structure is fine and uniform equiaxed structure, the longitudinal section structure is elongated fibrous structure, and after aging treatment, it meets the mechanical property requirements of AMS4957F for TB9 titanium alloy wire.

Description

Technical Field

[0001] This invention relates to the field of titanium alloy wire processing technology for blind rivets, specifically a method for preparing TB9 titanium alloy large-coil round wire for blind rivets. Background Technology

[0002] Titanium alloy bulge-type blind rivets are mainly used for single-sided connections of composite materials. They possess excellent performance characteristics, primarily reflected in their light weight, high specific strength, corrosion resistance, preload capability, locking mechanism, fatigue resistance, lightning protection, and sealing properties. They also solve problems inherent in composite materials such as potential compatibility, installation damage, and low pull-out strength. Titanium alloy blind rivets are mainly used in composite material structural connections in aircraft fairings, elevators, ailerons, wingtips, fuselage rear ends, leading and trailing edges, cargo hold floors, landing gear doors, passenger / crew doors, and cabin doors, with large quantities used per aircraft.

[0003] TB9 alloy is a high-strength metastable β-titanium alloy. With appropriate heat treatment, its room temperature tensile strength can exceed 1500 MPa, and it also possesses good corrosion resistance, hardenability, and room temperature deformation capability. TB9 alloy also exhibits excellent shear and fatigue properties, making it an ideal material for producing high-strength titanium alloy blind rivet core rods. Currently, most domestic TB9 titanium alloy wire used for blind rivet core rods is produced using small-batch processing, primarily through transverse rolling mills. The finished products are mainly small-weight coils (less than 30 kg) and straight bars, making it difficult to guarantee product quality consistency. This results in significant fluctuations in the mechanical properties of the prepared blind rivet core rods, and the inability to ensure product quality stability.

[0004] Therefore, researching the preparation process of large single-coil TB9 titanium alloy wire (specifications Φ2~15mm, single coil weight ≥100kg) and preparing high-quality, highly uniform large single-coil TB9 titanium alloy wire is of great engineering significance. Summary of the Invention

[0005] Based on this, it is necessary to address the above-mentioned technical problems. The purpose of this invention is to provide a method for preparing TB9 titanium alloy large-coil round wire for blind rivets. The TB9 titanium alloy wire prepared by this method has a fine and uniform microstructure, good consistency, high strength, good plasticity, and good surface quality and dimensional tolerance.

[0006] The technical solution of this invention is:

[0007] A method for preparing TB9 titanium alloy large-coil round wire for blind rivets, the specific steps of which are as follows:

[0008] Step 1: Prepare the ingot: Take a TB9 titanium alloy ingot with a diameter of 500-700mm. The composition of the TB9 titanium alloy ingot by weight percentage is as follows: Al 3.00-4.00%, V 7.50-8.50%, Cr 5.50-6.50%, Mo 3.50-4.50%, Zr 3.50-4.50%, Fe≤0.30%, O≤0.14%, C≤0.05%, N≤0.03%, H≤0.03%, Y≤0.005%, total impurity elements≤0.40%, balance is Ti;

[0009] Step 2, billet forging: Heat the furnace to 850-950℃ for ingot loading, raise the temperature to 1100-1200℃, hold for 2-3 hours, and then draw the billet on the forging machine. The diameter of the billet after drawing is 290-310mm, and the total deformation is 70-80%. Surface defects are then repaired.

[0010] Step 3, rough forging: Heat the furnace to 800-900℃ and load the billet into the furnace. Raise the temperature to 1000-1100℃ and hold for 2-3 hours. After taking it out of the furnace, draw it on the forging machine. The diameter of the billet after drawing is 130-150mm and the total deformation is 70-90%. The rough forged billet is obtained and the surface defects are repaired.

[0011] Step 4, precision forging: Heat the furnace to 700-800℃ and load the billet into the furnace. Raise the temperature to 850-950℃ and hold for 2-3 hours. After taking it out of the furnace, draw it on the precision forging machine. The diameter of the billet after drawing is 95-105mm and the total deformation is 40-60%. The precision forged billet is obtained and the surface defects are repaired.

[0012] Step 5, continuous rolling: The precision-forged bar billet is heated to 840-920℃ using electromagnetic induction heating and held for 5-10 minutes. Then it is rolled in a continuous rolling mill and water-cooled to room temperature. The diameter of the rolled wire rod billet is 7.5-15mm.

[0013] Step 6, Drawing: The rolled wire blank is drawn at room temperature, with a deformation of 5-20% per drawing pass;

[0014] Step 7, Solution treatment: The drawn wire is subjected to high-temperature solution treatment at a temperature of 750-880℃ for 30-120 minutes, followed by water cooling to room temperature;

[0015] Step 8, drawing: The solution-treated wire is drawn at room temperature, with a deformation of 5-20% per drawing pass and a total deformation of 20-35%.

[0016] Step 9, Peeling: Peel the drawn filament using a die, with a peeling amount of more than 0.5mm.

[0017] Step 10, Polishing: Polish the stripped filaments. After polishing, the surface roughness Ra of the filaments should be ≤1.2μm and the out-of-roundness should be ≤0.01mm.

[0018] Step 11: Coating treatment: Apply a coating to the polished wire material with a coating thickness of 1-15 μm.

[0019] The preferred method for preparing TB9 titanium alloy large-coil round wire for blind rivets is as follows: In step one, the ingot preparation process involves mixing and pressing sponge titanium, aluminum briquettes, aluminum-vanadium master alloy, molybdenum-vanadium-aluminum-titanium master alloy, pure chromium particles, sponge zirconium, iron powder, and titanium dioxide into an electrode. This electrode undergoes at least three vacuum arc melting processes to obtain a TB9 titanium alloy cylindrical ingot with a diameter of 550–650 mm and an alloy phase transformation point of 750 ± 10 °C. Preferably, the Al content is controlled at 3.25–3.75 wt%, V content at 7.75–8.25 wt%, Cr content at 5.75–6.25 wt%, Mo content at 3.75–4.25 wt%, Zr content at 3.75–4.25 wt%, Fe content at 0.08–0.20 wt%, and O content at 0.06–0.12 wt%.

[0020] The preferred method for preparing TB9 titanium alloy large-coil round wire for blind rivets is as follows: in step two, the forging is free forging, the holding temperature is 1125-1175℃, and the total deformation is 72-78%.

[0021] The preferred method for preparing TB9 titanium alloy large-coil round wire for blind rivets is as follows: in step three, the rough forging is free forging, the holding temperature is 1025-1075℃, and the total deformation is 75-85%.

[0022] The preferred method for preparing TB9 titanium alloy large-coil round wire for blind rivets is as follows: in step four, the precision forging temperature is 875-925℃, the total deformation is 45-55%, the cut length is 4500-5500mm, and the weight is 150-250kg.

[0023] In the preferred method for preparing TB9 titanium alloy large coiled wire for blind rivets, in step five, the continuous rolling temperature is 860-900℃, the total deformation is greater than or equal to 97%, the cooling method after rolling is water cooling to room temperature, and the weight of the coiled wire blank after rolling is 150-250kg.

[0024] In the preferred embodiment of the method for preparing TB9 titanium alloy large-coil round wire for blind rivets, the deformation amount of each drawing pass in step six is ​​5-15%.

[0025] In the preferred embodiment of the method for preparing TB9 titanium alloy large-coil round wire for blind rivets, step seven involves a solution treatment temperature of 770–820°C and a holding time of 60–120 min.

[0026] In the preferred embodiment of the method for preparing TB9 titanium alloy large-coil round wire for blind rivets, in step eight, the deformation amount of each drawing pass is 5-15%, and the total deformation amount is 20-30%.

[0027] In the preferred embodiment of the method for preparing TB9 titanium alloy large-coil round wire for blind rivets, in step eleven, a coating made of a mixture of MoS2 and graphite is used to coat the surface of the wire. The TB9 titanium alloy wire obtained after coating weighs 150-250 kg and has a diameter of 2.5-12.5 mm.

[0028] The design concept of this invention is:

[0029] The method of this invention first obtains a TB9 titanium alloy ingot with a diameter of 500-700 mm, then forges the TB9 titanium alloy ingot at 1100-1200℃ into a bar billet with a diameter of 290-310 mm, then rough forges the TB9 titanium alloy bar billet at 1000-1100℃ into a bar billet with a diameter of 130-150 mm, then finish forges the TB9 titanium alloy bar billet at 850-950℃ into a bar billet with a diameter of 95-105 mm, then continuously rolls the TB9 titanium alloy bar billet at 780-900℃, and then quenches it to obtain a large coiled wire billet with a diameter of 7.5-15 mm, then draws it at room temperature, then performs high-temperature solution treatment, then draws it again at room temperature, and then peels, polishes, and coats it. Thus, through the overall technical solution of the present invention, the cross-sectional structure of the alloy is fine and uniform equiaxed β-grain structure, the longitudinal section structure is elongated fibrous structure, the surface is in a lubricated coating state, the wire coil weight is greater than 100kg, and after aging treatment, it has excellent strength and plasticity, meeting the requirements of TB9 titanium alloy material for blind rivets.

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

[0031] (1) In terms of composition design, the Al content is controlled at 3.25-3.75wt%, the V content at 7.75-8.25wt%, the Cr content at 5.75-6.25wt%, the Mo content at 3.75-4.25wt%, the Zr content at 3.75-4.25wt%, the Fe content at 0.08-0.20wt%, and the O content at 0.06-0.12wt%. The phase transformation point is controlled at 750±10℃, which can effectively improve the strength of the solution-aged TB9 titanium alloy and also has good plasticity.

[0032] (2) The total deformation of continuous rolling in this invention is greater than or equal to 97%, the continuous rolling temperature is controlled, the continuous rolling large deformation mode is used, and the microstructure of TB9 titanium alloy after rolling is a fine and uniform equiaxed β grain structure.

[0033] (3) The present invention can obtain TB9 titanium alloy wire for blind rivets with uniform microstructure, excellent surface quality and excellent dimensional tolerance through continuous rolling, room temperature drawing and peeling process. Attached Figure Description

[0034] Figure 1 This is a micrograph of the cross-section of a TB9 titanium alloy wire with a diameter of φ6mm obtained in Example 1.

[0035] Figure 2 This is a micrograph of the longitudinal section of a TB9 titanium alloy wire with a diameter of φ6mm obtained in Example 1. Detailed Implementation

[0036] In its specific implementation, this invention provides a method for preparing high-quality microstructured TB9 titanium alloy large single-weight circular wire for blind rivets, which is carried out according to the following steps:

[0037] Step 1: Ingot preparation: Sponge titanium, aluminum granules, aluminum-vanadium master alloy, molybdenum-vanadium-aluminum-titanium master alloy, pure chromium particles, sponge zirconium, iron powder and titanium dioxide are mixed and pressed into electrodes. After no less than 3 vacuum self-consuming arc melting processes, a cylindrical ingot of TB9 titanium alloy with a diameter of 500-700 mm (preferably 550-650 mm) is obtained.

[0038] The TB9 titanium alloy ingot is composed of the following elements by weight percentage: Al 3.00–4.00% (preferably 3.25–3.75%), V 7.50–8.50% (preferably 7.75–8.25%), Cr 5.50–6.50% (preferably 5.75–6.25%), Mo 3.50–4.50% (preferably 3.75–4.25%), Zr 3.50~4.50% (preferably 3.75~4.25%), Fe≤0.30% (preferably 0.08~0.20%), O≤0.14% (preferably 0.06~0.12%), C≤0.05%, N≤0.03%, H≤0.03%, Y≤0.005%, total impurity elements≤0.40%, balance is Ti (alloy phase transformation point is 750±10℃);

[0039] Step 2, Billet Forging: Heat the box-type industrial resistance furnace to 850-950℃ and load it into the furnace. Raise the temperature to 1100-1200℃ (holding temperature is 350-450℃ above the phase transformation point, preferably 1125-1175℃), and hold for 2-3 hours. After taking it out of the furnace, draw it on a free forging machine. The diameter of the billet after drawing is 290-310mm, and the total deformation is 70-80% (preferably 72-78%). Grind the surface defects.

[0040] Step 3, rough forging: Heat the furnace to 800-900℃ and load the billet into the furnace. Raise the temperature to 1000-1100℃ (holding temperature is 250-350℃ above the phase transformation point, preferably 1025-1075℃), hold for 2-3 hours, remove from the furnace and elongate on a free forging machine. The diameter of the elongated billet is 130-150mm, the total deformation is 70-90% (preferably 75-85%), and the weight is 150-250kg, to obtain the rough forged billet. Grind the surface defects.

[0041] Step 4, Precision Forging: The box-type industrial resistance furnace is heated to 700-800℃ and the billet is loaded into the furnace. The temperature is then raised to 850-950℃ (the holding temperature is 100-200℃ above the phase transformation point, preferably 875-925℃), and the holding time is 2-3 hours. After being taken out of the furnace, the billet is drawn on a precision forging machine. The diameter of the drawn billet is 95-105mm, and the total deformation is 40-60% (preferably 45-55%). The billet is cut into lengths of about 4500-5500mm and weighs 150-250kg to obtain a precision forged billet. Surface defects are then repaired.

[0042] Step 5, Continuous rolling: The precision-forged billet is heated to 840-920℃ using electromagnetic induction heating (the holding temperature is 90-170℃ above the phase transformation point, preferably 860-900℃), and the holding time is 5-10 minutes. Then it is rolled in a continuous rolling mill and water-cooled to room temperature. The weight of the rolled wire rod is 150-250 kg, the diameter is 7.5-15 mm, and the total rolling deformation is greater than or equal to 97%.

[0043] Step 6, drawing: The rolled wire blank is drawn at room temperature, and the deformation amount of each drawing pass is 5-20% (preferably 5-15%).

[0044] Step 7, Solution treatment: The drawn wire is subjected to high-temperature solution treatment for 30-120 minutes (preferably 60-120 minutes), with a solution temperature of 750-880℃ (the heat preservation temperature is 0℃-130℃ above the phase transformation point, preferably 770-820℃), and then cooled to room temperature with water.

[0045] Step 8: Drawing: The solution-treated wire is drawn at room temperature. The deformation per drawing pass is 5-20% (preferably 5-15%), and the total deformation is 20-35% (preferably 20-30%).

[0046] Step 9, Peeling: Use a mold to peel the annealed wire, with a peeling amount of more than 0.5mm;

[0047] Step 10, Polishing: Polish the stripped filaments. After polishing, the surface roughness Ra of the filaments should be ≤1.2μm and the out-of-roundness should be ≤0.01mm.

[0048] Step 11: Coating treatment: Coating treatment is performed on the polished wire. The coating thickness is 1-15μm. The resulting TB9 titanium alloy wire weighs 150-250kg and has a diameter of 2.5-12.5mm.

[0049] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments.

[0050] Example 1

[0051] In this embodiment, a method for preparing TB9 titanium alloy large-coil round wire for blind rivets includes the following steps:

[0052] Step 1: Sponge titanium, aluminum briquettes, aluminum-vanadium master alloy, molybdenum-vanadium-aluminum-titanium master alloy, pure chromium particles, sponge zirconium, iron powder, and titanium dioxide are mixed and pressed into 26 electrodes weighing 100 kg each. After three vacuum arc melting processes, a 2600 kg TB9 titanium alloy ingot is obtained, with an ingot size of approximately φ600 mm × 1900 mm. The composition of the TB9 titanium alloy ingot is as follows (wt%): Al 3.48, V 8.06, Cr 5.92, Mo 4.06, Zr 3.85, Fe 0.13, O 0.082, C 0.010, N 0.0084, H 0.016, with the balance being Ti (alloy phase transformation point 750℃).

[0053] Step 2: Billet forging. The box-type industrial resistance furnace is heated to 900℃ and loaded into the furnace. The temperature is then raised to 1150℃ and held at 400℃ above the phase transformation point for 3 hours. After being taken out of the furnace, the billet is drawn on a free forging machine (such as a 10MN high-speed hydraulic forging machine). The diameter of the billet after drawing is φ300mm, and the forging deformation is 75%. Surface defects are then ground until the surface is bright (without cracks and oxide scale).

[0054] Step 3: Rough forging. Heat the box-type industrial resistance furnace to 850℃ and load it into the furnace. Raise the temperature to 1050℃ and hold it at 300℃ above the phase transformation point for 2.5 hours. After removing it from the furnace, draw it on a free forging machine. The diameter of the drawn billet is 140mm. Cut it into a length of about 2800mm. The rough forging deformation is 78% and the weight is 205kg. Grind the surface defects until the surface is bright (without cracks and oxide scale).

[0055] Step 4: Precision forging. Heat the box-type industrial resistance furnace to 750℃ and load the billet into the furnace. Raise the temperature to 920℃ and hold at 170℃ above the phase transformation point for 2.5 hours. After removing the billet from the furnace, draw it out on a precision forging machine. The diameter of the billet after drawing is 100mm, the precision forging deformation is 50%, and the length is about 5300mm with a weight of 200kg. Grind the surface to remove defects until the surface is bright (without cracks and oxide scale).

[0056] Step 5: Continuous rolling. The precision-forged bar billet is heated to 880℃ using induction heating, and the holding temperature is 130℃ above the phase transformation point for 5 minutes. Then it is rolled in the continuous rolling mill and water-cooled to room temperature. The weight of the rolled coiled wire billet is 196kg, the diameter is 10mm, and the rolling deformation is 99%.

[0057] Step 6: Drawing. The rolled wire blank is drawn five times at room temperature. The diameter after drawing is φ7.5mm. The deformation of each drawing is about 10%, and the total deformation is 43.75%.

[0058] Step 7: Solution treatment. The drawn filament is solution treated at 780°C, with the holding temperature being 30°C above the phase change point and the holding time being 120 minutes. Then, it is water-cooled to room temperature.

[0059] Step 8: Drawing. The solution-treated wire is drawn twice at room temperature. The diameter after drawing is φ6.5mm. The deformation of each drawing is about 10%, and the total deformation is 25%.

[0060] Step 9: Peeling. Peel the drawn filament to obtain a filament with a diameter of φ6mm and a peeling amount of 0.5mm.

[0061] Step 10: Polishing. After polishing, the surface roughness Ra of the wire is 0.8μm, and the out-of-roundness is 0.001mm.

[0062] Step 11: Coating treatment. The polished filament is coated with a coating made of a mixture of MoS2 and graphite, with a coating thickness of 6 μm. By weight percentage, the coating composition in this embodiment is as follows: MoS2 30%, graphite 40%, and the remainder is resin binder.

[0063] like Figure 1 The image shows a cross-sectional microstructure of a 6mm diameter TB9 titanium alloy wire, which consists of fine and uniform equiaxed β grains.

[0064] like Figure 2 The image shows a cross-sectional microstructure of a 6mm diameter TB9 titanium alloy wire, which consists of elongated β grains.

[0065] Example 2

[0066] In this embodiment, a method for preparing TB9 titanium alloy large-coil round wire for blind rivets includes the following steps:

[0067] Step 1: Sponge titanium, aluminum briquettes, aluminum-vanadium master alloy, molybdenum-vanadium-aluminum-titanium master alloy, pure chromium particles, sponge zirconium, iron powder, and titanium dioxide are mixed and pressed into 26 electrodes weighing 100 kg each. After three vacuum arc melting processes, a 2600 kg TB9 titanium alloy ingot is obtained, with an ingot size of approximately φ600 mm × 1900 mm. The composition of the TB9 titanium alloy ingot is as follows (wt%): Al 3.44, V 8.02, Cr 6.04, Mo 4.08, Zr 3.85, Fe 0.08, O 0.079, C 0.0092, N 0.0073, H 0.008, with the balance being Ti (alloy phase transformation point 750℃).

[0068] Step 2: Billet forging. The box-type industrial resistance furnace is heated to 900℃ and loaded into the furnace. The temperature is then raised to 1150℃ and held at 400℃ above the phase transformation point for 3 hours. After being taken out of the furnace, the billet is drawn on a free forging machine (such as a 10MN high-speed hydraulic forging machine). The diameter of the billet after drawing is φ300mm, and the forging deformation is 75%. Surface defects are then ground until the surface is bright (without cracks and oxide scale).

[0069] Step 3: Rough forging. Heat the box-type industrial resistance furnace to 850℃ and load it into the furnace. Raise the temperature to 1050℃ and hold it at 300℃ above the phase transformation point for 2.5 hours. After removing it from the furnace, draw it on a free forging machine. The diameter of the drawn billet is 140mm. Cut it into a length of about 2800mm. The rough forging deformation is 78% and the weight is 205kg. Grind the surface defects until the surface is bright (without cracks and oxide scale).

[0070] Step 4: Precision forging. Heat the box-type industrial resistance furnace to 750℃ and load it into the furnace. Raise the temperature to 890℃ and hold it at 140℃ above the phase transformation point for 2.5 hours. After removing it from the furnace, draw it on a precision forging machine. The diameter of the billet after drawing is 100mm, the precision forging deformation is 50%, and the length is about 5300mm with a weight of 200kg. Grind the surface defects until the surface is bright (without cracks and oxide scale).

[0071] Step 5: Continuous rolling. The precision-forged bar billet is heated to 880℃ using induction heating, and the holding temperature is 130℃ above the phase transformation point for 5 minutes. Then it is rolled in the continuous rolling mill and water-cooled to room temperature. The weight of the rolled coiled wire billet is 196kg, the diameter is 10mm, and the rolling deformation is 99%.

[0072] Step 6: Drawing. The rolled wire blank is drawn five times at room temperature. The diameter after drawing is φ7.5mm. The deformation of each drawing is about 10%, and the total deformation is 43.75%.

[0073] Step 7: Solution treatment. The drawn filament is solution treated at 780°C, with the holding temperature being 30°C above the phase change point and the holding time being 120 minutes. Then, it is water-cooled to room temperature.

[0074] Step 8: Drawing. The solution-treated wire is drawn twice at room temperature. The diameter after drawing is φ6.5mm. The deformation of each drawing is about 10%, and the total deformation is 25%.

[0075] Step 9: Peeling. Peel the drawn filament to obtain a filament with a diameter of φ6mm and a peeling amount of 0.5mm.

[0076] Step 10: Polishing. After polishing, the surface roughness Ra of the wire is 0.8μm, and the out-of-roundness is 0.001mm.

[0077] Step 11: Coating treatment. The polished filament is coated with a coating made of a mixture of MoS2 and graphite, with a coating thickness of 6 μm. By weight percentage, the coating composition in this embodiment is as follows: MoS2 30%, graphite 40%, and the remainder is resin binder.

[0078] The AMS4957F standard specifies the mechanical properties of TB9 titanium alloy wire as follows: after aging at 482–566℃ for 6–10 hours, the tensile strength should be 1276–1413 MPa, the elongation should be greater than 10%, and the reduction of area should be greater than 20%. The TB9 titanium alloy wires obtained in Examples 1 and 2 were subjected to aging heat treatment at 550℃ / 10h / AC (air cooling to room temperature). Referring to the national standard GB / T 228.1-2021 "Metallic Materials—Tensive Testing—Part 1: Tests at Room Temperature," the mechanical properties of the TB9 titanium alloys obtained after aging in Examples 1 and 2 were measured, and the test results are shown in Table 1.

[0079] Table 1

[0080]

[0081] As shown in Table 1, the mechanical properties after aging in Examples 1 and 2 exhibit yield strengths of 1174–1201 MPa, tensile strengths of 1291–1317 MPa, elongation of 16.5–17.5%, and reduction of area of ​​33–39%. Therefore, the mechanical properties after aging in Examples 1 and 2 meet the performance requirements of TB9 titanium alloy as specified in AMS4957F.

[0082] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A method for preparing TB9 titanium alloy large-coil round wire for blind rivets, characterized in that, The specific steps are as follows: Step 1: Prepare the ingot: Take a TB9 titanium alloy ingot with a diameter of 500-700 mm. The composition of the TB9 titanium alloy ingot by weight percentage is as follows: Al 3.25-3.75%, V 7.75-8.25%, Cr 5.75-6.25%, Mo 3.75-4.25%, Zr 3.75-4.25%, Fe 0.08-0.20%, O 0.06-0.12%, C≤0.05%, N≤0.03%, H≤0.03%, Y≤0.005%, total impurity elements ≤0.40%, balance is Ti, and the alloy phase transformation point is 750±10℃. Step 2, billet forging: Heat the furnace to 850-950℃ for ingot loading, raise the temperature to 1100-1200℃, hold for 2-3 hours, and then draw the billet on the forging machine. The diameter of the billet after drawing is 290-310 mm, and the total deformation is 70-80%. Surface defects are then repaired. Step 3, rough forging: Heat the furnace to 800-900℃ and load the billet into the furnace. Raise the temperature to 1000-1100℃ and hold for 2-3 hours. After taking it out of the furnace, draw it on the forging machine. The diameter of the billet after drawing is 130-150 mm and the total deformation is 70-90%. The rough forged billet is obtained and the surface defects are repaired. Step 4, precision forging: Heat the furnace to 700-800℃ and load the billet into the furnace. Raise the temperature to 850-950℃ and hold for 2-3 hours. After taking it out of the furnace, draw it on the precision forging machine. The diameter of the billet after drawing is 95-105 mm and the total deformation is 40-60%. The precision forged billet is obtained and the surface defects are repaired. Step 5, continuous rolling: The precision forged bar billet is heated to 840-920℃ using electromagnetic induction heating and held for 5-10 minutes. Then it is rolled in a continuous rolling mill and water-cooled to room temperature. The diameter of the rolled wire rod billet is 7.5-15 mm. Step 6, Drawing: The rolled wire blank is drawn at room temperature, with a deformation of 5-20% per drawing pass; Step 7, Solution treatment: The drawn wire is subjected to high-temperature solution treatment at a temperature of 750-780℃ for 30-120 minutes, followed by water cooling to room temperature; Step 8: Drawing: The solution-treated wire is drawn at room temperature, with a deformation of 5-20% per drawing pass and a total deformation of 20-35%. Step 9, Peeling: Peel the drawn filament using a die, with a peeling amount of more than 0.5 mm. Step 10, Polishing: Polish the stripped filaments. After polishing, the surface roughness Ra of the filaments should be ≤1.2 μm and the out-of-roundness should be ≤0.01 mm. Step 11: Coating treatment: Apply a coating to the polished wire material with a coating thickness of 1–15 μm.

2. The preparation method according to claim 1, characterized in that, In step one, the process of preparing the ingot is as follows: sponge titanium, aluminum granules, aluminum-vanadium master alloy, molybdenum-vanadium-aluminum-titanium master alloy, pure chromium particles, sponge zirconium, iron powder and titanium dioxide are mixed and pressed into electrodes, and after no less than 3 vacuum self-consuming arc meltings, a cylindrical ingot of TB9 titanium alloy with a diameter of 550-650 mm is obtained.

3. The preparation method according to claim 1, characterized in that, In step two, the billet forging is free forging, the holding temperature is 1125-1175℃, and the total deformation is 72-78%.

4. The preparation method according to claim 1, characterized in that, In step three, the rough forging is free forging, the holding temperature is 1025-1075℃, and the total deformation is 75-85%.

5. The preparation method according to claim 1, characterized in that, In step four, the precision forging temperature is 875–925℃, the total deformation is 45–55%, the cut length is 4500–5500 mm, and the weight is 150–250 kg.

6. The preparation method according to claim 1, characterized in that, In step five, the continuous rolling temperature is 860-900℃, the total deformation is greater than or equal to 97%, the cooling method after rolling is water cooling to room temperature, and the weight of the rolled coiled wire blank is 150-250kg.

7. The preparation method according to claim 1, characterized in that, In step six, the deformation amount for each drawing pass is 5-15%.

8. The preparation method according to claim 1, characterized in that, In step eight, the deformation amount for each drawing pass is 5-15%, and the total deformation amount is 20-30%.

9. The preparation method according to claim 1, characterized in that, In step eleven, a coating made of a mixture of MoS2 and graphite is used to coat the surface of the wire. The TB9 titanium alloy wire obtained after coating weighs 150-250 kg and has a diameter of 2.5-12.5 mm.

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