A method for preparing TA1 and TA2 tapes

Abstract

This invention discloses a method for preparing TA1 and TA2 strips, belonging to the field of titanium alloy technology. Through low-cost pre-deformation, a certain amount of deformation storage energy is accumulated after surface rolling, allowing subsequent heating to form a surface recrystallization structure. The fine-grained surface region enhances oxidation resistance and reduces the depth of the hard α layer. After heating in a furnace, the oxide layer thickness is controlled to be less than 80 μm, while simultaneously improving the synergistic deformation capability between the hard oxide layer and the substrate during rolling. Finally, wide hot-rolled titanium coils with a width of 1700–2200 mm, a thickness of 3–10 mm, and good surface quality are obtained. This method solves the technical problems of numerous surface defects and poor microstructure uniformity after rolling TA1 and TA2 smelted in an EB furnace.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy technology and relates to a production method for hot rolling of TA1 and TA2 slabs smelted in an EB furnace, specifically a method for preparing TA1 and TA2 coils. Background Technology

[0002] Titanium alloys possess excellent properties such as low density, high specific strength, and good corrosion resistance, making them an important structural material widely used in aerospace, chemical, shipbuilding, automotive, weaponry, sports, and medical fields. However, the large-scale application of titanium and its alloys is limited by problems such as numerous surface defects, small single-roll width, low roll weight, and high smelting and processing costs.

[0003] Titanium alloy coils produced by co-rolling titanium and steel can improve the utilization rate of the rolling line and increase enterprise profits. During the heating process of titanium alloy slabs in the heating furnace, a mixed atmosphere of blast furnace or converter gas and natural gas is used for heating. However, titanium has poor thermal conductivity, resulting in long heating times and severe surface oxidation of the titanium slabs in the steel mill's heating furnace. The intense surface reaction and the thick oxygen-rich embrittlement layer on the surface lead to severe cracking during subsequent rolling. When pure titanium is heated in the temperature range of 300℃ to 1100℃, it undergoes varying degrees of surface oxidation; within this temperature range, the degree of oxidation gradually intensifies with increasing temperature. At lower temperatures between 300℃ and 500℃, the weight gain of pure titanium samples is approximately 0.32% to 0.34%. When the temperature is below 500℃, the properties of pure titanium are relatively stable, and oxygen continuously diffuses into the titanium lattice and reacts with the titanium matrix, generating a large amount of TiO2 oxide on the titanium surface. When the temperature rises to 700℃ to 900℃, the oxidation weight gain increases significantly. As the temperature continues to rise, the oxygen penetration rate accelerates. Combined with the heating during rolling, the oxygen penetration layer depth can reach more than 200μm, causing the surface of pure titanium to be exposed again with a fresh surface, thus forming a cyclic layered peeling phenomenon.

[0004] The hot rolling temperature of titanium and titanium alloys is generally lower than the α→β transformation temperature. For example, the rolling temperature of TA1 is 870℃~910℃. During the heating process of titanium at medium and low temperatures, as the temperature rises, the film structure is composed of titanium oxide with different degrees of density. The oxide film increases in weight, but it is a dense layer with protective properties. When the temperature exceeds 800℃, the oxide film will gradually penetrate into the matrix, and the oxide film will crack and no longer be dense. In the hot continuous rolling process, in order to ensure the plasticity of the titanium billet, descaling water is basically not used. This inevitably leads to the hard oxide scale on the surface being pressed into the matrix, causing surface defects and affecting the surface quality of the titanium coil. When TA1 and TA2 titanium billets are heated to a rolling temperature of 870℃~910℃, the surface oxidation products are mainly TiO2 with varying degrees of density. In addition, the titanium slabs melted in the EB furnace have relatively coarse grains, with sizes reaching the millimeter level. At the same time, since they have not undergone VAR casting and forging, their slab density is relatively low. Relatively speaking, their oxidation resistance is different from that of slabs forged by VAR. The stress generated by the difference between the coefficient of thermal expansion of the surface oxidation products and the matrix can easily lead to oxide film peeling and microcracks forming during subsequent rolling, resulting in poor surface quality and severe edge cracks in the hot-rolled coils. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention utilizes a slab to form a dense oxide film on its surface at temperatures below 800°C, followed by surface rolling using gradient heating to prepare a surface deformation layer. Through low-cost pre-deformation, a certain amount of deformation storage energy is accumulated after surface rolling, allowing subsequent heating to form a surface recrystallization structure. The fine-grained surface region enhances oxidation resistance and reduces the depth of the hard α-layer. Compared to conventional titanium slabs, the oxide layer thickness is controlled to less than 80 μm after furnace heating, while simultaneously improving the synergistic deformation capability between the hard oxide layer and the substrate during rolling, thus improving surface quality. To achieve this method, a series of key parameters, including the pre-deformation method of the titanium slab, heating regime, and rolling deformation amount, were proposed. Ultimately, wide-width hot-rolled titanium coils with a width of 1700–2200 mm, a thickness of 3–10 mm, and excellent surface quality are produced, significantly improving product quality, reducing costs, increasing yield, and demonstrating good economic benefits.

[0006] To achieve the above-mentioned objectives, this invention provides a method for preparing TA1 and TA2 coils, the process flow of which includes: ingot smelting—slab preparation—slab pre-deformation—slab rolling—coiling—annealing—performance testing; the preparation method includes the following steps:

[0007] S1 Ingot Melting

[0008] Using sponge titanium, vanadium-aluminum alloy, and other raw materials, TA1 and TA2 titanium alloy ingots are smelted in a vacuum electron beam cold hearth furnace (EB furnace). The alloy element range of the ingots conforms to the GB / T 3620.1-2016 standard for titanium and titanium alloy grades and chemical composition. The ingots are smelted into billets with a thickness of (240-330 mm) × a width of (1500-2000 mm) × L mm. After grinding, the billets are used as slabs to be rolled.

[0009] S2 slab grinding

[0010] The slab is milled on all six sides to a thickness of 10–20 mm. Along the length, the four long sides are chamfered to 40–60 mm, and along the width, the four wide sides are chamfered to 50–80 mm. Due to the presence of numerous surface impurities, insufficient milling depth cannot remove them, while excessive milling depth results in metal loss and affects the yield. Therefore, a milling thickness of 10–20 mm is preferred.

[0011] Along the length direction, the four long sides are chamfered by 40-60mm. If the chamfer is too large, it will affect the yield. If the chamfer is too small, the temperature will drop too quickly during rolling, which will easily cause corner cracks and affect the edge quality.

[0012] In the width direction, the four wide edges should be chamfered by 50-80mm. If the chamfer is too large, it will affect the yield; if the chamfer is too small, it will be difficult for the rolled part to bite in.

[0013] S3 slab pre-deformation

[0014] ① The slab to be rolled is surface-polished to remove the oxide layer until bright metal is exposed, with a surface roughness Ra < 3.2μm. After polishing, it is loaded into the furnace and rapidly moved by a walking beam to a temperature zone of 700℃~800℃, held for 30~60 minutes, and then pre-deformed after being removed from the furnace. The EB furnace melts TA1 and TA2 slabs at a relatively high temperature and cools slowly, resulting in relatively coarse original grains. Rapid heating will not change their microstructure or cause mixed grains.

[0015] ② The slab heating must ensure that the temperature difference between the upper and lower surfaces is less than 10°C. To ensure uniform heating of the upper and lower surfaces, rotate 90° after loading into the furnace, that is, the contact position of the walking beam is in the thickness direction.

[0016] ③ After holding the heat for 30-60 minutes, rotate 90° and feed the material for rolling after removing it from the furnace.

[0017] ④ After feeding and centering, the material undergoes pre-deformation rolling via a four-roll mill. The work roll length is greater than 2000mm, the work roll diameter is 350-600mm, the work roll angular velocity during rolling is 0.8-6 rad / s, the deformation per pass is 5-30mm, and 4-6 passes of pre-deformation are performed. Larger roll diameters provide higher rigidity and uniform hardness distribution, reducing surface defects such as cracks and spalling during rolling, thus improving the surface finish and smoothness of the rolled material. Larger roll diameters lead to an increased deformation zone length, resulting in greater width expansion. Considering the difficulty of workpiece biting and deformation efficiency, a work roll diameter of 350-600mm is preferred for pre-deformation. Faster rolling rates result in greater deformation resistance, while slower rolling rates lead to faster temperature drop, also causing greater deformation resistance and increased rolling difficulty. Therefore, a work roll angular velocity of 0.8-6 rad / s is suitable during rolling, and preferably, to improve the surface rolling effect, a work roll angular velocity of 6 rad / s in the final pass is more appropriate. Titanium billets have short heating times, and only the surface layer undergoes plastic deformation after heating. The reduction per pass is 5–20 mm, with 2–6 pre-deformation passes. Insufficient reduction fails to create a deformable layer, while excessive reduction results in high deformation resistance and rolling difficulties. EB billets typically have centimeter-level grain sizes, with many having 20–50 mm grain sizes in the two-dimensional direction. Therefore, the reduction is controlled at 5–10 mm per pass, with 2–6 pre-deformation passes and a cumulative reduction of 60 mm.

[0018] By pre-deforming at low cost, a certain amount of stored energy is accumulated after the surface layer is rolled, so that the surface structure recrystallizes during subsequent heating. The fine grain region of the surface layer is used to improve the oxidation resistance, reduce the diffusion depth of the hard α layer, and improve the synergistic deformation ability of the surface oxide layer and the matrix during the rolling of the finished product, thereby improving the surface quality.

[0019] S4 slab heating

[0020] The pre-deformed slab is sent to a heating furnace for heating and rolling. The slab, already at a certain temperature, passes through the first and second heating zones of the furnace before being held in a soaking zone at 870℃~910℃ for 90~120 minutes. The total furnace time is less than 300 minutes, with the soaking time in the heating zone less than 180 minutes. After the soaking period, the slab is removed from the furnace for further rolling. In the first heating zone, the temperature is raised from room temperature to 550℃ using a walking beam, controlling the heating temperature range, and the heating time is less than 60 minutes. In the second heating zone, the temperature is raised from 550℃ to 700~800℃ using a walking beam, controlling the heating temperature range, and the heating time is 100~120 minutes. This segmented heating method avoids overheating of the surface layer, preventing uneven microstructure, and controls the total reheat time, avoiding severe surface oxygen absorption due to prolonged heating.

[0021] The temperature range of the secondary heating zone of the slab is equal to the pre-treatment temperature of the pre-deformed slab, which allows for pre-deformed slab heating during normal titanium plate and coil production, thereby improving production efficiency.

[0022] S5 black leather roll rolling: includes rough rolling, finish rolling and slow cooling processes.

[0023] The slab is rolled into hot-rolled coils with a thickness of 3-12mm and a width of 1700-2200mm by a 2050mm continuous rolling mill.

[0024] Rough rolling: The slab is rolled to a thickness of 40-60 mm by a rough rolling mill.

[0025] Finishing Rolling: After the slab is rolled to a thickness of 40-60mm on the roughing mill, it is rolled to a thickness of 3-10mm on the finishing mill. The entry temperature of the finishing mill is <820℃, and the final rolling temperature is >720℃. The threading speed is 1.5-2.5m / s. TA1 and TA2 have good high-temperature plasticity, and slow threading can avoid tail swing and ensure the straightness of the coil. Controlling the entry temperature of the finishing mill to less than 820℃ is because when the finishing mill is rolled at high speed, it is necessary to avoid the adiabatic temperature rise caused by strain rate sensitivity, which can lead to β phase transformation. After the phase transformation, Widmanstätten structure is easily formed during the subsequent cooling process, which will deteriorate the mechanical properties of the titanium alloy coil. After the final rolling, it passes through a laminar flow cooling line, which is relatively long and has a large temperature drop. A final rolling temperature <720℃ is not conducive to coiling.

[0026] Slow cooling: After precision rolling, the coil is rolled at a temperature of 550℃~600℃. After rolling, it is moved to a slow cooling zone for stacking and cooling at a temperature of 550℃ for 12~16 hours. After the holding period, it is removed from the furnace and air-cooled. Slow cooling in the slow cooling pit helps reduce residual stress and facilitates subsequent uncoiling.

[0027] S6 Black Leather Roll Continuous Annealing

[0028] After hot rolling, the coiled strip is cooled and then continuously annealed at a temperature of 760℃~840℃. Titanium has a thermal conductivity λ=15.24W / (m·K), approximately 1 / 4 that of nickel, 1 / 5 that of iron, and 1 / 14 that of aluminum. The thermal conductivity of various titanium alloys is about 50% lower than that of titanium. Therefore, it is necessary to strictly control the heating rate to ensure uniform heat transfer and sufficient holding time. The continuous annealing line has a uniform temperature zone length of 50m and a travel speed of 2~5m / min, ensuring a holding time ≥10min.

[0029] Furthermore, the performance of the TA1 and TA2 titanium alloy coils prepared by the above method was tested: After annealing, tensile test specimens were prepared and tested according to GB / T 228.1-2021. The room temperature mechanical properties of TA1: R... m ≥240MPa, 140MPa≤R p0.2 ≤310MPa, A≥30%; TA2: R m ≥400MPa, 275MPa≤R p0.2≤450MPa, A≥25%, conforming to the mechanical property requirements of GB / T 3621-2022 for titanium and titanium alloy plates.

[0030] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0031] This invention addresses the bottleneck problem of numerous surface defects and poor microstructure uniformity after TA1 and TA2 are produced by EB furnace melting and rolling. It comprehensively controls the preparation process of TA1 and TA2 titanium coils from the aspects of titanium billet preparation, heating, rolling and heat treatment, which greatly improves the product quality of titanium coils.

[0032] A surface deformation layer is prepared by forming a dense oxide film on the surface of a slab at temperatures below 800℃ and then performing surface rolling using gradient heating. Through low-cost pre-deformation, a certain amount of deformation storage energy is accumulated after surface rolling, allowing subsequent heating to form a surface recrystallization structure. The fine-grained region of the surface layer enhances oxidation resistance and reduces the depth of the hard α-layer. Compared to conventional titanium slabs, the oxide layer thickness is controlled to less than 80 μm after furnace heating, while simultaneously improving the synergistic deformation ability between the hard oxide layer and the substrate during rolling, thus improving surface quality. To achieve this method, a series of key parameters, including the pre-deformation method of the titanium slab, heating regime, and rolling deformation amount, were proposed. The final product is a wide-width hot-rolled titanium coil with a width of 1700–2200 mm, a thickness of 3–10 mm, and excellent surface quality. This significantly improves product quality, reduces costs, increases yield, and yields good economic benefits. Attached Figure Description

[0033] Figure 1 The metallographic structure of TA1 slab sample 1 prepared in Example 1 is shown.

[0034] Figure 2 This is a diagram showing the oxygen permeation layer depth of TA1 slab sample 2 obtained in Example 1;

[0035] Figure 3 The image shows the metallographic structure of the TA1 tape finished product sample 3 prepared in Example 1. Detailed Implementation

[0036] The present invention will be further described below with reference to specific embodiments, but this does not limit the invention in any way. To avoid redundancy, unless otherwise specified, the raw materials used in the following embodiments are all commercially available products, and the methods used are all conventional methods unless otherwise specified.

[0037] A method for preparing TA1 and TA2 tapes includes the following steps:

[0038] S1 Ingot Smelting: Using sponge titanium and vanadium-aluminum alloy as raw materials, TA1 and TA2 titanium alloy ingots with a thickness of (240-330 mm) × width of (1500-2000 mm) × L mm are smelted in a vacuum electron beam cold hearth furnace.

[0039] S2 slab grinding: Slab grinding treatment, six-sided milling with a thickness of 10-20mm; in the length direction, the four long sides are chamfered by 40-60mm; in the width direction, the four wide sides are chamfered by 50-80mm.

[0040] S3 slab pre-deformation: The slab to be rolled is surface-polished to expose bright metal with a surface roughness Ra of less than 3.2μm; after polishing, it is loaded into the furnace and rotated 90° after loading; it is then rapidly moved by a walking beam to the 700℃~800℃ temperature zone and held for 30~60min; after exiting the furnace, it is rotated 90° and fed for pre-deformation rolling.

[0041] S4 slab heating: The pre-deformed slab is sent to the heating furnace for heating and rolling. After passing through the first heating zone and the second heating zone of the heating furnace, the slab is held in the soaking zone at 870℃~910℃ for 90~120min. The total time in the furnace is less than 300min, the time in the heating zone is less than 180min, and the slab is taken out of the furnace for rolling after the holding period.

[0042] S5 black sheet rolling: including roughing, finishing and slow cooling processes, the slab is rolled into hot rolled sheet coils with a thickness of 3 to 12 mm and a width of 1700 to 2200 mm by a 2050 mm continuous rolling mill.

[0043] S6 Black Strip Continuous Annealing: After hot rolling, the strip is cooled and then continuously annealed at an annealing temperature of 760℃~840℃; the continuous annealing line has a uniform temperature zone length of 50m, a travel speed of 2~5m / min, and a holding time of ≥10min.

[0044] Any aspects not described in the following embodiments are the same as those described in the specific embodiments above.

[0045] Example 1

[0046] A method for preparing TA1 tape, the specific process flow is as follows:

[0047] S1 Ingot Melting

[0048] A method for preparing titanium alloy coils involves using sponge titanium, vanadium-aluminum alloy, etc., as raw materials, and melting them into TA1 ingots through a vacuum electron beam cold hearth furnace (EB furnace). The element range of the ingots conforms to the GB / T 3620.1-2016 standard for titanium and titanium alloy grades and chemical composition. The slabs are then melted into 240mm thick × 1500mm wide × 6500mm slabs.

[0049] S2 slab preparation

[0050] Slab finishing: Milling 10mm thickness on all six sides;

[0051] Along the length direction, the four long sides are chamfered by 40mm;

[0052] In the width direction, the four wide edges are chamfered by 50mm.

[0053] S3 slab pre-deformation

[0054] (1) Grind the surface of the slab to be rolled until it is exposed to a fresh metallic color and the surface roughness Ra = 3.0 μm. After grinding, load it into the furnace and move it quickly by the walking beam to the 700℃ temperature zone for 60 min. After being taken out of the furnace, it is pre-deformed.

[0055] (2) After the slab is loaded into the furnace, rotate it 90° to stand the titanium billet upright.

[0056] (3) After the heat preservation is completed, rotate 90° and feed the material for rolling.

[0057] (4) After feeding and centering, the material is pre-deformed through a four-roll mill. The length of the work roll is 2000mm and the diameter of the work roll is 350mm. The pre-deformation is carried out in 6 passes. The angular velocity of the work roll in the first 5 passes is 0.8rad / s and the deformation amount per pass is 5mm. The angular velocity of the work roll in the 6th pass is 6rad / s and the deformation amount per pass is 5mm. The cumulative deformation amount is 30mm.

[0058] By pre-deforming at low cost, a certain amount of deformation layer strain is accumulated after the surface layer is rolled, so that subsequent heating can form a fine-grained surface structure.

[0059] S4 slab heating

[0060] The pre-deformed slab is sent to a heating furnace for heating and rolling. The slab, already at a certain temperature, passes through the first and second heating zones of the furnace before being held in a 910°C soaking zone for 90 minutes. The total furnace time is 270 minutes, with 180 minutes spent in the heating zones. After the soaking period, the slab is removed from the furnace for further rolling. In the first heating zone, the temperature is raised from room temperature to 550°C using a walking beam, controlling the heating temperature zone, and the heating time is 60 minutes. In the second heating zone, the temperature is raised from 550°C to 800°C using a walking beam, controlling the heating temperature zone, and the heating time is 120 minutes. The slab tail is cut off and sampled for testing; the surface metallographic structure is shown below. Figure 1 Oxygen layer depth see Figure 2 The oxygen penetration depth is approximately 50 μm.

[0061] S5 black leather roll rolling

[0062] The slab is rolled into a hot-rolled coil with a thickness of 3mm and a width of 1700mm using a 2050mm continuous rolling mill. After the slab is rolled to a thickness of 40mm using a roughing mill, it is rolled to a thickness of 3mm using a finishing mill. The finishing mill inlet temperature is 800℃, the strip threading speed is 1.5m / s, and TA1 has good high-temperature plasticity. Slow strip threading can avoid tail swing and ensure the straightness of the coil. The finishing mill inlet temperature is controlled to be less than 820℃, and the final rolling temperature is 730℃.

[0063] After finishing rolling, the coil is coiled at 600℃, then moved to a slow cooling zone for further cooling at 600℃ for 12 hours. After the holding period, the coil is removed from the furnace and air-cooled. Slow cooling in the slow cooling pit helps reduce residual stress and facilitates subsequent uncoiling.

[0064] S6 Black Leather Roll Continuous Annealing

[0065] After hot rolling, the coil is cooled and then continuously annealed at a temperature of 840℃. The continuous annealing line has a uniform temperature zone length of 50m, a travel speed of 2m / min, and a holding time of 25min.

[0066] S7 Performance Testing

[0067] After annealing, TA1 tape was prepared and tested for tensile strength according to GB / T228.1-2021. The room temperature mechanical properties R... p0.2 For 210MPa, R m The strength is 320 MPa, and the alumina is 42%, which meets the mechanical property requirements of GB / T3621-2023 for titanium and titanium alloy plates. The average grain size grade is 5.5. Metallographic photographs of the finished sample are shown below. Figure 3 As shown, its size is uniform.

[0068] Example 2

[0069] A method for preparing TA2 tape, the specific process flow is as follows:

[0070] S1 Ingot Melting

[0071] A method for preparing titanium alloy coils involves using sponge titanium, vanadium-aluminum alloy, etc., as raw materials, and melting them into TA2 ingots through a vacuum electron beam cold hearth furnace (EB furnace). The element range of the ingots conforms to the GB / T 3620.1-2016 standard for titanium and titanium alloy grades and chemical composition. The slabs are then melted into slabs with a thickness of 330mm, a width of 2000mm, and a height of 7200mm.

[0072] S2 slab grinding

[0073] Slab finishing: Milling 20mm thickness on all six sides;

[0074] Along the length direction, the four long sides are chamfered by 40mm;

[0075] In the width direction, the four wide edges are chamfered by 50mm.

[0076] S3 slab pre-deformation

[0077] (1) Grind the surface of the slab to be rolled until it is exposed to a fresh metallic color. The surface roughness Ra = 2.8 μm. After grinding, load it into the furnace and move it quickly by the walking beam to the 800℃ temperature zone. Hold it for 60 minutes and then remove it from the furnace for pre-deformation.

[0078] (2) After the slab is loaded into the furnace, rotate it 90° to stand the titanium billet upright.

[0079] (3) After the heat preservation is completed, rotate 90° and feed the material for rolling.

[0080] (4) After feeding and centering, the material is pre-deformed through a four-roll mill. The length of the work roll is 2000mm and the diameter of the work roll is 600mm. The pre-deformation is carried out in 4 passes. The angular velocity of the work roll in the first 3 passes is 0.8rad / s and the deformation amount per pass is 10mm. The angular velocity of the work roll in the 4th pass is 6rad / s and the deformation amount per pass is 10mm. The cumulative deformation amount is 40mm.

[0081] By pre-deforming at low cost, a certain amount of deformation layer strain is accumulated after the surface layer is rolled, so that subsequent heating can form a fine-grained surface structure.

[0082] S4 slab heating

[0083] The pre-deformed slab is sent to a heating furnace for heating and rolling. The slab, already at a certain temperature, passes through the first and second heating zones of the furnace before being held in a soaking zone at 870°C for 120 minutes. The total furnace time is 300 minutes, including 120 minutes in the heating zones. After the soaking period, the slab is removed from the furnace for further rolling. In the first heating zone, the slab is moved from room temperature to 550°C using a walking beam to control the heating temperature, and the heating time is 60 minutes. In the second heating zone, the slab is moved from 550°C to 700°C using a walking beam to control the heating temperature, and the heating time is 120 minutes.

[0084] S5 black leather roll rolling

[0085] The slab is rolled into a hot-rolled coil with a thickness of 12mm and a width of 2200mm using a 2050mm continuous rolling mill. After the slab is rolled to a thickness of 60mm by a roughing mill, it is rolled to 12mm by a finishing mill. The finishing mill inlet temperature is 780℃, the strip threading speed is 2.5m / s, and TA2 has good high-temperature plasticity. Slow strip threading can avoid tail swing and ensure the straightness of the coil. The finishing mill inlet temperature is controlled to be less than 800℃, and the final rolling temperature is 700℃.

[0086] After finishing rolling, the coils are coiled at 550℃. After coiling, they are moved to a slow cooling zone for further cooling at 550℃ for 12 hours. After the holding period, they are removed from the furnace and air-cooled. Slow cooling in the slow cooling pit helps reduce residual stress and facilitates subsequent uncoiling.

[0087] S6 Black Leather Roll Continuous Annealing

[0088] After hot rolling, the coil is cooled and then continuously annealed at a temperature of 760℃. The continuous annealing line has a uniform temperature zone length of 50m, a travel speed of 2m / min, and a holding time of 25min.

[0089] S7 Performance Testing

[0090] After annealing, TA2 tape was used to prepare and test tensile specimens according to GB / T228.1-2021. The room temperature mechanical properties R... p0.2 360MPa, R m The strength is 460 MPa, and the alumina is 35%, which meets the mechanical property requirements of GB / T 3621-2022 for titanium and titanium alloy plates.

[0091] For anyone skilled in the art, many possible variations and modifications can be made to the technical solutions of this invention, or equivalent embodiments can be modified based on the disclosed technical content, without departing from the scope of the technical solutions of this invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this invention without departing from the content of the technical solutions of this invention should still fall within the protection scope of the technical solutions of this invention.

Claims

1. A method for preparing TA1 or TA2 tape, characterized in that, The preparation method includes the following steps: S1 Ingot Smelting: Using sponge titanium and vanadium-aluminum alloy as raw materials, TA1 and TA2 titanium alloy ingots with a thickness of (240~330 mm) × width of (1500~2000 mm) × L mm are smelted in a vacuum electron beam cold hearth furnace. S2 slab grinding: Slab grinding treatment, six-sided milling with a thickness of 10~20 mm; in the length direction, the four long sides are chamfered by 40~60 mm; in the width direction, the four wide sides are chamfered by 50~80 mm. S3 slab pre-deformation: The slab to be rolled is surface-polished to expose bright metal, and the surface roughness Ra is less than 3.2 μm; After grinding, the slab is loaded into the furnace and rotated 90°. It is then moved by the walking beam to the 700℃~800℃ temperature zone and held for 30~60 min. After exiting the furnace, it is rotated 90° and fed for pre-deformation rolling. During rolling, the working roll angular speed is 0.8~6 rad / s, the deformation per pass is 5~10 mm, and 4~6 passes of pre-deformation are performed. S4 slab heating: The pre-deformed slab is sent to the heating furnace for heating and rolling. After passing through the first heating zone and the second heating zone of the heating furnace, the slab is held in the soaking zone at 870℃~910℃ for 90~120 min; the total time in the furnace is less than or equal to 300 min, the time in the heating zone is less than or equal to 180 min, and the slab is taken out of the furnace for rolling after the holding period. S5 black sheet rolling: including roughing, finishing and slow cooling processes, the slab is rolled into hot-rolled sheet coils with a thickness of 3~12 mm and a width of 1700~2200 mm by a 2050 mm continuous rolling mill. S6 Black Strip Continuous Annealing: After hot rolling, the strip is cooled and then continuously annealed at an annealing temperature of 760℃~840℃; the continuous annealing line has a uniform temperature zone length of 50 m, a travel speed of 2~5 m / min, and a holding time of ≥10 min.

2. The preparation method according to claim 1, characterized in that, The pre-deformation rolling in step S3 includes: after feeding and centering, pre-deformation rolling is carried out through a four-roll mill, with the length of the work roll body being greater than 2000 mm and the diameter of the work roll being 350~600 mm.

3. The preparation method according to claim 1, characterized in that, In step S4, the first heating zone is heated from room temperature to 550°C, and the billet is fed by moving the stepping beam, controlling the heating time of the heating zone to be 60 min; the second heating zone is heated from 550°C to 700~800°C, and the billet is fed by moving the stepping beam, controlling the heating time of the heating zone to be 100~120 min.

4. The preparation method according to claim 1, characterized in that, Step S5 describes rough rolling: the slab is rolled to a thickness of 40~60 mm by a rough rolling mill.

5. The preparation method according to claim 1, characterized in that, In step S5, the entry temperature of the finishing mill is less than 820℃, and the threading speed is 1.5~2.5 m / s. After finishing milling, the strip is coiled at a temperature of 550℃~600℃. After coiling, the strip is moved into a slow cooling zone for stacking and cooling at a temperature of 550℃ for 12~16 h.

Images