A method for preparing alpha-type titanium strip based on super large cumulative deformation and direct rolling without heating

Abstract

The application provides a method for preparing alpha-type titanium strip based on super-large cumulative deformation and fire-free straight rolling, and relates to the technical field of strip processing. The method detects the two-end tolerance and mechanical property of a wedge-shaped base material with a specification of 3.0 mm, presets and calculates parameters corresponding to the thickness interval of the base material and the finished strip, then divides the cumulative deformation of the to-be-rolled base material into three continuously executed stages, respectively configures different relevant strategies in different stages, finally takes the thickness, shape and edge defect state as closed-loop control targets, and adjusts the tension, friction / lubrication, temperature control and roll shape parameters in combination, so that the to-be-rolled base material is directly rolled from 3.0 mm to 0.5 mm in the same continuous cold rolling process without setting intermediate annealing. The application can effectively realize the efficient preparation of plate-strip fire-free straight rolling, fill the technical bottlenecks of edge wave, local buckling and edge defect and the like which are prone to occur in cold rolling with super-large cumulative deformation, and improve the process repeatability and subsequent forming consistency.

Description

Technical Field

[0001] This invention relates to the field of strip processing technology, and in particular to a method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling. Background Technology

[0002] In recent years, titanium and titanium alloys have been widely used in aerospace and military fields due to their low density, high specific strength, excellent corrosion resistance, and good biocompatibility. With the upgrading of consumption and the development of high-end manufacturing, the application of titanium materials in the civilian sector has been continuously expanding, especially in areas such as home kitchenware, thermal insulation containers, decorative panels, sports equipment, and lightweight structural components. Industrial pure titanium strips with a thickness of approximately 0.5 mm are gradually becoming the mainstream material specification. In the civilian sector, titanium strips of this thickness are typically used for stamped parts, deep-drawn shells, decorative panels, and structural supports. These strips must possess good formability and meet surface decoration requirements, such as forming a uniform "ice flower" texture after stamping. Simultaneously, the material must have stable yield strength, tensile strength, and high elongation to adapt to complex cold-forming processes.

[0003] Because industrial pure titanium is a hexagonal close-packed material, its slip system for plastic deformation at room temperature is limited, easily forming a distinct texture during cold rolling. This leads to strong anisotropy, making it prone to work hardening, strain concentration, and sheet instability. Furthermore, under the combined effects of multi-pass rolling, friction traction, and tension coupling, the edge regions are more susceptible to instability, and cracking or uneven springback is likely during stamping. In current industrial production, multi-pass rolling with intermediate annealing is typically used to restore plasticity and control sheet shape. However, intermediate annealing significantly increases process length and energy consumption, introduces risks of surface oxidation / contamination, prolongs cycle time, and has high energy consumption, hindering large-scale production. Even with intermediate annealing, issues such as edge wedge fluctuations and sheet asymmetry may still occur with wedge-shaped incoming materials or edge-wavy sensitive specifications.

[0004] In Chinese invention patent CN103706636A, the inventor proposed using a 20-roll high-rigidity rolling mill to cold roll multiple passes and stages to achieve the target thickness. The semi-finished strip is then subjected to annealing, shot blasting, pickling, and other reprocessing in a continuous annealing furnace to finally produce finished titanium strip. Although the strip preparation method given in this patent is feasible, the key problem is that the preparation process from base material to finished product is lengthy and inefficient. The cold rolling process requires intermediate annealing and the deformation is less than 80%, resulting in high energy consumption, making it unsuitable for strip rolling preparation.

[0005] Chinese invention patent CN112122382B discloses a preparation process for a wide and ultra-thin cold-rolled titanium strip coil. Its preparation method is basically the same as the technical process path involved in patent CN103706636A. Both require intermediate annealing for hardening and elimination. This fully demonstrates that the existing preparation process is difficult to achieve the purpose of direct rolling, which greatly increases production costs and energy consumption.

[0006] In summary, how to balance ultra-large cumulative reduction, sheet shape stability and edge waviness suppression, and ensure process repeatability in a single-stand 20-roll reversible cold rolling process without introducing intermediate annealing has become an urgent technical problem to be solved, which is also the problem that this invention aims to overcome. Summary of the Invention

[0007] To overcome the technical barriers in the existing technology for preparing wedge-shaped wide titanium strips, this invention provides a method for preparing α-type titanium strips based on ultra-large cumulative deformation and fireless direct rolling. The technical solution is as follows:

[0008] A method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling, the method comprising: S1. The tolerance and mechanical properties of the two ends of the wedge-shaped substrate with a specification of 3.0mm are tested. The thickness difference is analyzed in relation to the elastic stage, plastic stage and strengthening stage of the material. The tension, boundary lubrication and temperature control parameters corresponding to the thickness range of the substrate and the finished strip are preset, and the cold rolling deformation corresponding to the thickness range of the substrate and the finished strip is calculated. S2. The wedge-shaped substrate in S1 is rolled in the same continuous cold rolling process without intermediate annealing using a 20-roll multi-roll mill, so that the rolled strip is directly rolled from 3.0 mm to 0.5 mm, and a finished α-type titanium coil strip with a target thickness of 0.5 mm is obtained.

[0009] The wedge-shaped substrate is TA series α type industrial pure titanium strip, and the grain size of the hot-rolled slab is controlled at level 5 with HRC≤51; the wedge height difference of the wedge-shaped substrate is ≤0.05mm, and the incoming material width is 650mm.

[0010] In S1, the cold rolling deformation is Hh / H, where H is the thickness before rolling and h is the thickness after rolling. Here, it is expressed as the cold rolling deformation amount per pass.

[0011] Specifically, S2 refers to: S21. The cumulative deformation in the cold rolling process is divided into three continuously executed stages: the initial plasticity establishment stage A, the stable deformation transfer stage B, and the final size / shape convergence stage C. Differentiated pass reduction strategies, tension strategies, lubrication and cooling strategies, and shape control strategies are configured for each stage. The inlet tension, outlet tension, and the variation law of inlet tension and outlet tension with the rolling process are set according to actual requirements at each stage. At the same time, the lubrication supply method is set. S22. Obtain the temperature rise value of the rolled strip before and after the mill stand, and construct the temperature rise characterization quantity I(T)=T out -T in , among which, T out T is the temperature of the rolled strip when it exits the mill stand. in The temperature of the rolled strip when it enters the mill stand; When T out If I(T) exceeds the preset upper limit of the corresponding stage, adjust the rolling speed, tension, lubrication / cooling supply and pass reduction strategy according to the actual situation to keep the strip within the preset process temperature rise window in each stage, so as to maintain the hardening continuity of dislocation evolution during deformation and reduce edge crack sensitivity. S23. Obtain the wedge shape characterization quantity W in the width direction of the rolled strip. Adjust the shape of the roll system by controlling the strip shape adjustment actuator of the 20-roll cold rolling mill through ASU. Implement stress transmission control in the edge area of ​​the strip that is different from that in the middle area to suppress edge cracks, edge waves and local buckling instability. S24. Using thickness, shape, and edge defect status as closed-loop control targets, and through joint adjustment of tension, friction / lubrication, temperature control, and roller shape parameters, a finished coil with a target thickness of 0.5 mm is obtained.

[0012] The wedge shape characteristic W in S23 is obtained through at least one of the following methods: Lateral scanning of inlet thickness, lateral scanning of outlet thickness, inversion estimation based on plate shape signal and lateral roll response, or model prediction based on historical incoming material data.

[0013] The plate shape control actuator in S23 only includes the transverse roller and the ASU automatic plate shape control unit, and can still complete the plate shape closed-loop control without relying on the partition spray or partition lubrication device. The closed-loop control in S24 includes identifying the wedge shape (obtained by a thickness gauge) and incorporating the wedge compensation amount (the thickness difference after identification) into the target settings of the transverse roller and ASU.

[0014] The three consecutively executed stages are divided according to the total deformation and the amount of reduction per pass. The first pass is the initial plasticity establishment stage A, the plate shape convergence stage is the terminal size / plate shape convergence stage C, and the remaining passes are the stable deformation transmission stage B. The initial plasticity establishment stage A: ensures stable rolling bite and uniform deformation on both sides; stable deformation transmission stage B: a coordinated strategy of reduction-tension-speed-temperature control with reduction as the priority; final size / shape convergence stage C: a control path with dimensional accuracy and surface feedback as the priority.

[0015] The deformation of the rolled strip is ≥20% in the initial plasticity establishment stage A; 15~25% in the stable deformation transmission stage B; and 8~10% in the final size / shape convergence stage C.

[0016] The tension strategy is a gradient tension strategy, based on the hard strip yield strength σ. 0.2 Dimensionless settings are used as a benchmark, and the equivalent tensile stress corresponding to the inlet tension and / or outlet tension is (0.05–0.5)·σ. 0.2 And decrease it step by step along the rolling process; The gradient tension strategy has a tension value range of 200~40kN, and the value decreases from high to low for each pass.

[0017] The temperature rise characterization quantity I(T) in S22 is maintained within the range of 10℃~60℃ or T out Maintain the temperature within the range of 40℃ to 120℃; The lubrication / cooling supply intensity is set by one or more of flow rate, concentration, temperature, and injection pressure, and is within T... out If I(T) exceeds the upper limit, increase the cooling supply intensity and / or reduce the rolling speed; The lubricating medium is an emulsion, with the emulsion temperature controlled at 30~40℃, the concentration at 3~9%, and the injection pressure at 2~10 bar.

[0018] The rolling speed is 10~100m / min, and the rolling T... out The process is divided into three stages: A, B, and C. The initial plasticity establishment stage A has a T value of... out ≤35℃; T of stable deformation transfer stage B out ≤100℃; T of terminal size / plate shape convergence stage C out ≤40℃, ensuring the continuity of temperature and dislocation initiation and evolution transmission on the roll / surface during the rolling process.

[0019] The transverse roll control is a staged roll control: in the stable deformation transmission stage B, the goal is to suppress plate shape divergence, and in the terminal size / plate shape convergence stage C, the goal is to reduce edge waviness. The ASU automatic shape control unit outputs the roller system adjustment amount based on the shape index, pass information, direction information, and the position of the transverse roll, so as to suppress the mid-wave in the pressing-dominant mode.

[0020] S2 further includes online or quasi-online monitoring of key state quantities in the rolling process. The key state quantities include at least two or more of the following: rolling force, rolling force fluctuation, tension, tension fluctuation, temperature characterization quantity, and plate shape index. Based on this, the stage strategy is adaptively switched or modified.

[0021] After completing a cumulative cold rolling deformation of 3.0 mm to 0.5 mm, the S2 cold rolling process does not perform intermediate annealing and allows for the selection of whether to perform a finished product annealing process depending on the end use.

[0022] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following: The above method, through a coordinated control mechanism of cold rolling deformation path, tension gradient, friction distribution, and thermo-mechanical coupling, solves the problems of current cumulative deformation requiring intermediate annealing and re-rolling, plate hardening instability, edge crack initiation, and cumbersome preparation processes. Compared with traditional processes, this method can effectively achieve efficient preparation of plate-strip without heat, obtain excellent plate shape accuracy, grain size, and mechanical properties, fill the technical bottlenecks of edge waviness, local buckling, and edge defects that are prone to occur in cold rolling with ultra-large cumulative deformation, and improve process repeatability and consistency of subsequent forming.

[0023] This invention achieves a stable cumulative reduction of 0.5mm from 3.0mm to 0.5mm in α-type industrial pure titanium strip using a single-stand 20-roll reversible cold rolling process without intermediate annealing. This significantly shortens the process flow, reduces energy consumption and production cycle, and minimizes the risk of surface oxidation / contamination caused by intermediate annealing. Through staged deformation path and terminal convergence control, thickness, strip shape, and edge waviness defects can converge synergistically, reducing the risk of downtime and scrap due to edge waviness, local buckling instability, and strip shape asymmetry, thereby improving yield and process stability. Furthermore, it constructs a process temperature rise characterization based solely on the inlet / outlet strip temperature and implements closed-loop control. The ring-linkage adjustment enables stable control of the thermo-mechanical coupling state even without zoned spraying and multi-point temperature measurement, improving the robustness and repeatability of the process to incoming material wedge fluctuations and environmental fluctuations. For 650mm wedge-shaped incoming materials, the wedge degree is introduced into the plate shape target and the width extension difference is converged by transverse roller + ASU and reversible reversal compensation, which significantly improves the edge wave-dominant defect. This invention is applicable to both TA1 and TA2, which helps to form a more uniform deformation energy storage distribution, which is beneficial to obtain a more consistent recrystallization response in subsequent finished product annealing, thereby improving the uniformity of the microstructure after annealing, the stability of stamping, and the consistency of surface ice flower performance.

[0024] This invention effectively solves the technical bottlenecks of current cumulative deformation requiring intermediate annealing and re-rolling, plate hardening instability, edge crack initiation, and cumbersome preparation processes. It greatly reduces production costs, improves production efficiency, reduces the cumbersome process of leapfrog preparation between raw materials and finished products, breaks the domestic industrial gap, enables independent supply of key materials, and has positive significance for promoting the development of key technology industries in my country. It can be widely used in deep drawing processing and other fields. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a flowchart of a method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling, provided by an embodiment of the present invention. Detailed Implementation

[0027] The technical solution of the present invention will now be described with reference to the accompanying drawings.

[0028] In embodiments of the present invention, words such as "exemplarily," "for example," etc., are used to indicate that something is an example, illustration, or description. Any embodiment or design described as "exemplary" in the present invention should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of the word "exemplary" is intended to present the concept in a concrete manner. Furthermore, in embodiments of the present invention, the meaning expressed by "and / or" can be both, or either one.

[0029] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.

[0030] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0031] This invention provides a method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling. For example... Figure 1 The flowchart shown illustrates a method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling. This method may include the following steps:

[0032] S1. Test the tolerance and mechanical properties of the two ends of the wedge-shaped substrate with a specification of 3.0mm. Preset the tension, boundary lubrication and temperature control parameters corresponding to the thickness range of the substrate and the finished strip, and calculate the cold rolling deformation corresponding to the thickness range of the substrate and the finished strip. S2. The wedge-shaped substrate in S1 is rolled in the same continuous cold rolling process without intermediate annealing using a 20-roll multi-roll mill, so that the rolled strip is directly rolled from 3.0 mm to 0.5 mm, and a finished α-type titanium coil strip with a target thickness of 0.5 mm is obtained.

[0033] Specifically, S2 refers to: S21. Divide the cumulative deformation in the cold rolling process into three continuously executed stages: the initial plasticity establishment stage A, the stable deformation transfer stage B, and the final size / shape convergence stage C. Configure differentiated pass reduction strategies, tension strategies, lubrication and cooling strategies, and shape control strategies in different stages. Set the inlet tension, outlet tension, and their variation with the rolling process according to actual requirements in different stages, and set the lubrication supply method at the same time. S22. Obtain the temperature rise value of the rolled strip before and after the stand, and construct the temperature rise characterization quantity I(T)=T out -T in , among which, T out T is the temperature of the rolled strip when it exits the mill stand. in The temperature of the rolled strip when it enters the stand; When T out If I(T) exceeds the preset upper limit of the corresponding stage, adjust the rolling speed, tension, lubrication / cooling supply and pass reduction strategy according to the actual situation to keep the strip within the preset process temperature rise window in each stage, so as to maintain the hardening continuity of dislocation evolution during deformation and reduce edge crack sensitivity. S23. Obtain the wedge shape characterization quantity W in the width direction of the rolled strip. Adjust the shape of the roll system by controlling the strip shape adjustment actuator of the 20-roll cold rolling mill through ASU. Implement stress transmission control in the edge area of ​​the strip that is different from that in the middle area to suppress edge cracks, edge waves and local buckling instability. S24. Using thickness, shape, and edge defect status as closed-loop control targets, and through joint adjustment of tension, friction / lubrication, temperature control, and roller shape parameters, a finished coil with a target thickness of 0.5 mm is obtained.

[0034] The following description, in conjunction with specific embodiments, illustrates this point.

[0035] Example 1 Taking a TA2 wedge-shaped hot-rolled titanium plate with a width of 650mm and a thickness of 3.0mm as an example, the specific process for preparing α-type titanium strip by fireless direct rolling is as follows: S1. The tolerance and mechanical properties of the TA2 wedge-shaped hot-rolled titanium sheet with a width of 650mm and a thickness of 3.0mm were tested at both ends. The thickness difference was analyzed in relation to the elastic stage, plastic stage and strengthening stage of the material. The grain size of the substrate was grade 5 and the HRC was 50. The height difference between the two sides was 0.04mm. The cold rolling deformation, tension, boundary lubrication and temperature control parameters corresponding to the thickness range of the substrate and the finished strip were preset and calculated, as shown in Table 1. S2. The cumulative deformation of cold rolling is divided into three consecutive stages: the initial plasticity establishment stage A, the stable deformation transfer stage B, and the final size / shape convergence stage C. Different pass reduction strategies, tension strategies, lubrication and cooling strategies, and shape control strategies are adopted in different stages. The rolling schedule is 1 rolling pass and 9 passes. The deformation of the initial plasticity establishment stage A is 22%; the deformation of the stable deformation transfer stage B is 18%; and the deformation of the final size / shape convergence stage C is 8%. The rolling speed is set according to the deformation zones A, B, and C, which are 30, 80, and 15 m / min, respectively, and the rolling force is 50~200T.

[0036] S3. Set the inlet tension and outlet tension for each stage. The equivalent tensile stress corresponding to the inlet tension and / or outlet tension is (0.05–0.5)·σ. 0.2 The tension value is set for each pass: 200~40kN. At the same time, the lubrication supply method is set, and the lubrication and friction state are set in the width direction of the strip. The lubricating medium is emulsion. The lubrication / cooling supply intensity is set by various parameters such as flow rate, concentration, temperature and injection pressure. The emulsion temperature is controlled at 36℃, the concentration is 6%, and the injection pressure is 5 bar.

[0037] S4. Obtain the temperature rise values ​​of the rolled strip in the mill front and back or roll gap areas at different deformation zones. By adjusting the rolling speed, tension, lubrication / cooling supply, and pass reduction strategy, keep the strip within the preset process temperature rise window at each stage. The preset range for the temperature rise characteristic of the rolling process is: I(T) = T out -T in Maintain within the range of 10°C to 60°C and / or T out Maintain within the range of 40℃ to 120℃, and at T out If I(T) exceeds the upper limit, increase the cooling supply intensity and / or decrease the rolling speed, rolling T out The rolling speed or friction coefficient is set in three stages: A, B, and C. The temperature of stage A is ≤35℃; the temperature of stage B is ≤100℃; the temperature of stage C is ≤25℃; and the strip temperature of the first to ninth passes is 25℃~70℃.

[0038] S5. Online or quasi-online monitoring of key state quantities in the rolling process, taking thickness, plate shape and edge defect status as closed-loop control targets, and adjusting multiple parameters such as rolling force, rolling force fluctuation, tension, tension fluctuation and temperature through joint adjustment, and adaptively switching or correcting stage strategies accordingly.

[0039] S6. The wedge shape characteristic W is obtained by transverse scanning of the thickness at the inlet and outlet, based on the shape signal acquisition, and by adjusting the shape control actuator of the 20-roll cold rolling mill controlled by ASU+ transverse rolls to adjust the roll system shape, shape accuracy, and edge. In the stable deformation transmission stage, the goal is to suppress the shape divergence, and in the final shape accuracy convergence stage, the goal is to reduce edge waviness, so as to obtain a finished coil strip with a target thickness of 0.5mm.

[0040] The parameters listed above, such as speed, tension, emulsion temperature / concentration / pressure, and stage reduction rate, are recommended windows under the constraints of the closed-loop control rules described in this invention. They can be slightly adjusted according to the strength of the incoming material, thickness tolerance, and plate shape, but should meet the following requirements: stage A / stage C has a lower upper limit for temperature rise and priority is given to plate shape convergence; stage B allows for a higher temperature rise and prioritizes thinning and stabilization.

[0041] The relevant rolling process parameters are shown in Table 1.

[0042] Table 1 Rolling procedure parameters in Example 1 Example 2 Taking a TA1 wedge-shaped hot-rolled titanium plate with a width of 615mm and a thickness of 3.0mm as an example, the specific process for preparing α-type titanium strip by fireless direct rolling is as follows: S1. The tolerance and mechanical properties of the TA1 wedge-shaped hot-rolled titanium sheet with a width of 615mm and a thickness of 3.0mm were tested at both ends. The thickness difference was analyzed in relation to the elastic stage, plastic stage and strengthening stage of the material. The grain size of the substrate was grade 5 and the HRC was 48. The height difference between the two sides was 0.05mm. The cold rolling deformation, tension, boundary lubrication and temperature control parameters corresponding to the thickness range of the substrate and the finished strip were preset and calculated, as shown in Table 2. S2. The cumulative deformation of cold rolling is divided into three consecutive stages: the initial plasticity establishment stage A, the stable deformation transfer stage B, and the final size / shape convergence stage C. Different pass reduction strategies, tension strategies, lubrication and cooling strategies, and shape control strategies are adopted in different stages. The rolling schedule is 1 rolling pass and 11 passes. The deformation of the initial plasticity establishment stage A is 22%; the deformation of the stable deformation transfer stage B is 18%; and the deformation of the final size / shape convergence stage C is 8%. The rolling speed is set according to the deformation zones A, B, and C, which are 30, 80, and 15 m / min, respectively, and the rolling force is 60~200T.

[0043] S3. Set the inlet tension and outlet tension at each stage. The equivalent tensile stress corresponding to the inlet tension and / or outlet tension is (0.05–0.5)·σ. 0.2 The tension value is set according to each pass: 200~40kN. At the same time, the lubrication supply method is set, and the lubrication and friction state are set in the width direction of the strip. The lubricating medium is emulsion. The lubrication / cooling supply intensity is set by various parameters such as flow rate, concentration, temperature and injection pressure. The emulsion temperature is controlled at 38℃, the concentration is 4.38%, and the injection pressure is 7 bar.

[0044] S4. Obtain the temperature rise values ​​of the rolled strip in the mill front and back or roll gap areas at different deformation zones. By adjusting the rolling speed, tension, lubrication / cooling supply, and pass reduction strategy, keep the strip within the preset process temperature rise window at each stage. The preset range for the temperature rise characteristic of the rolling process is: I(T) = T out -T in Maintain within the range of 10°C to 60°C and / or T out Maintain within the range of 40℃ to 120℃, and at T out If I(T) exceeds the upper limit, increase the cooling supply intensity and / or decrease the rolling speed, rolling T out The rolling speed or friction coefficient is set in three stages: A, B, and C. The temperature of stage A is ≤35℃; the temperature of stage B is ≤100℃; the temperature of stage C is ≤25℃, and the strip temperature of the first to 11th passes is 25℃~83℃.

[0045] S5. Online or quasi-online monitoring of key state quantities in the rolling process, taking thickness, plate shape and edge defect status as closed-loop control targets, and adjusting multiple parameters such as rolling force, rolling force fluctuation, tension, tension fluctuation and temperature through joint adjustment, and adaptively switching or correcting stage strategies accordingly.

[0046] S6. The wedge shape characteristic W is obtained by transverse scanning of the thickness at the inlet and outlet, based on the shape signal acquisition, and by adjusting the shape control actuator of the 20-roll cold rolling mill controlled by ASU+ transverse rolls to adjust the roll system shape, shape accuracy, and edge. In the stable deformation transmission stage, the goal is to suppress the shape divergence, and in the final shape accuracy convergence stage, the goal is to reduce edge waviness, so as to obtain a finished coil with a target thickness of 0.498mm.

[0047] The relevant rolling process parameters are shown in Table 2.

[0048] Table 2 Rolling process parameters in Example 2 The innovativeness of the method of this invention is reflected in the following: (0) The method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling described in this invention adopts a staged stable rolling path without intermediate annealing under 20-roll multi-roll reversible cold rolling conditions. The cumulative deformation from 3.0 mm to 0.5 mm is designed according to the stages of "initial plasticity establishment - stable deformation transmission - terminal size / strip shape convergence". Differentiated reduction, tension, speed and temperature synergistic control strategies are configured for different stages. The problem of strip shape divergence and edge wave growth during ultra-large cumulative reduction is solved from the mechanism level. It breaks through the traditional deformation amount within 80% and intermediate annealing treatment, solves the cumbersome long-sequence preparation process of rolling, significantly improves the size and shape accuracy, appearance quality and yield of wedge-shaped wide titanium strip, and reduces its production cost.

[0049] (1) Utilizing the inlet / outlet strip temperature T in T out A process temperature rise characterization quantity I(T) is constructed and used as a closed-loop feedback quantity to adjust the rolling speed, tension distribution, reduction rate and overall lubrication / cooling supply intensity. In the absence of multi-point temperature measurement, roll gap temperature measurement or zoned spraying hardware, the thermo-mechanical coupling state is controllable and repeatable, ensuring the plastic continuity and stability of strip during the process of no intermediate annealing and ultra-large cumulative deformation.

[0050] (2) Adopting a wedge-edge coupling plate shape closed loop: the integrated convergence of the lateral roll + ASU + reversible reversing compensation is used to address the plate shape asymmetry risk caused by wide wedge material and reversible reciprocating rolling. The wedge degree characterization quantity is introduced into the plate shape target setting. The wedge compensation and width extension difference convergence are realized through the transverse lateral roll and ASU automatic plate shape control unit. A forward / reverse stroke direction compensation quantity library is established and called after reversing, thereby upgrading edge wave suppression from empirical adjustment to a closed-loop and reproducible control chain, which significantly reduces edge wave dominant defects and local buckling instability.

[0051] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling, characterized in that, The method includes: S1. Test the tolerance and mechanical properties of the two ends of the wedge-shaped substrate with a specification of 3.0mm. Preset the tension, boundary lubrication and temperature control parameters corresponding to the thickness range of the substrate and the finished strip, and calculate the cold rolling deformation corresponding to the thickness range of the substrate and the finished strip. S2. The wedge-shaped substrate in S1 is rolled in the same continuous cold rolling process without intermediate annealing through a 20-roll multi-roll mill, so that the rolled strip is rolled directly from 3.0 mm to 0.5 mm, and a finished α-type titanium coil strip with a target thickness of 0.5 mm is obtained. Specifically, S2 refers to: S21. Divide the cumulative deformation in the cold rolling process into three continuously executed stages: the initial plasticity establishment stage A, the stable deformation transfer stage B, and the final size / shape convergence stage C. Configure differentiated pass reduction strategies, tension strategies, lubrication and cooling strategies, and shape control strategies in different stages. Set the inlet tension, outlet tension, and the variation law of inlet tension and outlet tension with the rolling process in different stages. At the same time, set the lubrication supply method. S22. Obtain the temperature rise value of the rolled strip before and after the mill stand, and construct the temperature rise characterization quantity I(T)=T out T in , among which, T out T is the temperature of the rolled strip when it exits the mill stand. in The temperature of the rolled strip when it enters the mill stand; When T out If I(T) exceeds the preset upper limit of the corresponding stage, adjust the rolling speed, tension, lubrication / cooling supply and pass reduction strategy according to the actual situation to keep the strip within the preset process temperature rise window in each stage, so as to maintain the hardening continuity of dislocation evolution during deformation and reduce edge crack sensitivity. S23. Obtain the wedge shape characterization quantity W in the width direction of the rolled strip. Adjust the shape of the roll system by controlling the strip shape adjustment actuator of the 20-roll cold rolling mill through ASU. Implement stress transmission control in the edge area of ​​the strip that is different from that in the middle area to suppress edge cracks, edge waves and local buckling instability. S24. Using thickness, shape, and edge defect status as closed-loop control targets, and through joint adjustment of tension, friction / lubrication, temperature control, and roller shape parameters, a finished coil with a target thickness of 0.5 mm is obtained.

2. The method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling according to claim 1, characterized in that, The wedge-shaped substrate is TA series α-type industrial pure titanium strip, and the grain size of the hot-rolled slab is controlled at level 5 with HRC≤51; the wedge height difference of the wedge-shaped substrate is ≤0.05mm.

3. The method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling according to claim 1, characterized in that, The wedge shape characteristic W in S23 is obtained through at least one of the following methods: Lateral scanning of inlet thickness, lateral scanning of outlet thickness, inversion estimation based on plate shape signal and lateral roll response, or model prediction based on historical incoming material data.

4. The method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling according to claim 1, characterized in that, The plate shape control actuator in S23 includes only the transverse roller and the ASU automatic plate shape control unit; The closed-loop control in S24 includes identifying the wedge shape and incorporating the wedge compensation amount into the target settings of the transverse roller and the ASU.

5. The method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling according to claim 1, characterized in that, The three consecutively executed stages are divided according to the total deformation and the amount of reduction per pass. The first pass is the initial plasticity establishment stage A, the plate shape convergence stage is the terminal size / plate shape convergence stage C, and the remaining passes are the stable deformation transmission stage B. The deformation of rolled strip is ≥20% in the initial plasticity establishment stage A; 15~25% in the stable deformation transmission stage B; and 8~10% in the final size / shape convergence stage C.

6. The method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling according to claim 1, characterized in that, The tension strategy is a gradient tension strategy, based on the hard strip yield strength σ. 0.2 Dimensionless settings are used as a benchmark, and the equivalent tensile stress corresponding to the inlet tension and / or outlet tension is (0.05–0.5)·σ. 0.2 And decrease it step by step along the rolling process; The gradient tension strategy has a tension value range of 200~40kN, and the value decreases sequentially from high to low for each pass.

7. The method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling according to claim 1, characterized in that, The temperature rise characterization quantity I(T) in S22 is maintained within the range of 10℃~60℃ or T out Maintain the temperature within the range of 40℃ to 120℃; The lubrication / cooling supply intensity is set by one or more of flow rate, concentration, temperature, and injection pressure, and is within T... out If I(T) exceeds the upper limit, increase the cooling supply intensity and / or reduce the rolling speed; The lubricating medium is an emulsion, with the emulsion temperature controlled at 30~40℃, the concentration at 3~9%, and the injection pressure at 2~10 bar.

8. The method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling according to claim 1, characterized in that, The rolling speed is 10~100m / min, and the rolling T... out The process is divided into three stages: A, B, and C. The initial plasticity establishment stage A has a T value of... out ≤35℃; T of stable deformation transfer stage B out ≤100℃; T of terminal size / plate shape convergence stage C out ≤40℃, ensuring the continuity of temperature and dislocation initiation and evolution transmission on the roll / surface during the rolling process.

9. The method for preparing α-type titanium strip based on ultra-large cumulative deformation and fireless direct rolling according to claim 4, characterized in that, The transverse roller is controlled in stages: in the stable deformation transmission stage B, the goal is to suppress the divergence of the plate shape, and in the terminal size / plate shape convergence stage C, the goal is to reduce the edge waviness. The ASU automatic shape control unit outputs the roller system adjustment amount based on the shape index, pass information, direction information, and the position of the transverse roll, so as to suppress the mid-wave in the pressing-dominant mode.

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