Titanium alloy disc continuous rolling method

Abstract

This invention relates to the field of rolling technology and discloses a continuous rolling method for titanium alloy wire rods, comprising: for a roughing mill, setting multiple roughing mill pass types sequentially along the rolling direction as box-shaped passes, symmetrical hexagonal passes, and elliptical passes; for an intermediate mill, setting multiple intermediate mill pass types sequentially along the rolling direction as composite passes including elliptical and circular passes, and asymmetrical hexagonal passes; for a finishing mill, setting multiple finishing mill pass types sequentially along the rolling direction as elliptical passes and circular passes; for a sizing mill, dynamically compensating for the pass opening based on workpiece temperature and rolling speed; and for a wire rod mill, dynamically generating suitable pass parameters based on workpiece temperature, rolling speed, and workpiece diameter using a pass parameter generation model. This invention can improve dimensional accuracy, reduce defects, and refine grains, thereby enhancing the overall performance of titanium alloy wire rods.

Description

Technical Field

[0001] This invention relates to the field of rolling technology, and more specifically to a method for continuous rolling of titanium alloy discs. Background Technology

[0002] Currently, in the continuous rolling production of titanium discs, continuous rolling lines typically consist of multiple units, resulting in a complex overall structure. For these continuous rolling units, existing pass designs present numerous problems in actual production. Traditional pass systems struggle to ensure uniform deformation of the titanium alloy during rolling, leading to poor product dimensional accuracy, such as common issues like excessive ellipticity. Furthermore, due to poor matching between the pass design and the properties of the titanium alloy material, defects such as tassels and folds are easily generated during rolling, severely impacting product quality and yield. In addition, an unreasonable pass design can also lead to coarse grains, affecting product performance.

[0003] Therefore, existing technologies still need improvement. Summary of the Invention

[0004] The main objective of this invention is to provide a method for continuous rolling of titanium alloy discs to solve the technical problems of low dimensional accuracy, high defect rate, and coarse grains in titanium disc rolling.

[0005] According to one aspect of the present invention, a continuous rolling method for titanium alloy wire rod is proposed. The continuous rolling method is carried out using a continuous rolling mill, which includes a roughing mill, an intermediate mill, a finishing mill, a reduction and sizing mill, and a high-speed wire rod mill arranged sequentially along the continuous rolling direction. The continuous rolling method includes: for the roughing mill, setting multiple roughing mill pass types sequentially along the continuous rolling direction as box-shaped passes, symmetrical hexagonal passes, and elliptical passes; for the intermediate mill, setting multiple intermediate mill pass types sequentially along the continuous rolling direction as composite passes including elliptical and circular passes, and asymmetrical hexagonal passes; for the finishing mill, setting multiple finishing mill pass types sequentially along the continuous rolling direction as elliptical passes and circular passes; for the reduction and sizing mill, dynamically compensating the pass opening degree based on the workpiece temperature and rolling speed; and for the high-speed wire rod mill, dynamically generating suitable pass parameters based on the workpiece temperature, rolling speed, and workpiece diameter using a pass parameter generation model.

[0006] According to one embodiment of the present invention, the multiple roughing mills of a roughing mill unit are divided into multiple roughing mill units, wherein each roughing mill unit includes one or more roughing mills; for the first roughing mill unit: a box-type bore is used and the width spread coefficient is controlled at 1.05-1.08; for the second roughing mill unit: a symmetrical hexagonal bore is used and the strain rate is controlled at 5-8s. -1 Within the specified range; for the third roughing mill unit: elliptical holes with a major axis to minor axis ratio of 2.2-2.5 are adopted.

[0007] According to one embodiment of the present invention, the intermediate rolling mills of the intermediate rolling mill group are divided into multiple intermediate rolling mill units, wherein each intermediate rolling mill unit includes one or more intermediate rolling mills; for the first intermediate rolling mill unit: a composite hole including an elliptical hole and a circular hole is adopted, wherein the ellipticity is set to 1.08-1.12, the convexity of the circular hole is 0.03-0.05mm, and the elongation coefficient per pass is controlled to be 1.25-1.3, and the cumulative strain is 1.8-2.2; for the second intermediate rolling mill unit: an asymmetric hexagonal hole is adopted, wherein the angle difference between the two opposite hypotenuses of the asymmetric hexagonal hole on both sides of the vertical center line and the vertical center line is 2-3°.

[0008] According to one embodiment of the present invention, the rolling temperatures of a plurality of intermediate rolling mills are set to 920-980°C, 860-900°C, and 800-840°C respectively along the continuous rolling direction, and the pass expansion angles of the plurality of intermediate rolling mills are set to 22-27 degrees, 16-20 degrees, and 10-14 degrees respectively along the continuous rolling direction.

[0009] According to one embodiment of the present invention, the multiple finishing mills of the finishing mill unit are divided into multiple finishing mill units, wherein each finishing mill unit includes one or more finishing mills; for the first finishing mill unit: an elliptical hole with an exponentially decreasing radius of curvature along the rolling direction is adopted; for the second finishing mill unit: a circular hole is adopted, the deviation between the rolled diameter and the target diameter is controlled within a predetermined deviation threshold, the surface roughness of the rolled workpiece is within a predetermined roughness threshold, and an anti-folding guide device is provided.

[0010] According to one embodiment of the present invention, when the rolling speed is greater than a predetermined speed threshold, a cooling mist of 0.2-0.5 MPa is applied to the workpiece between the outlet of the finishing mill and the inlet of the reducing mill.

[0011] According to one embodiment of the present invention, the deformation amounts applied by the roughing mill, intermediate mill and finishing mill are controlled to be 38%-42%, 28%-32% and 18%-22%, respectively.

[0012] According to one embodiment of the present invention, for a reducing sizing mill, the opening compensation amount is calculated based on the workpiece temperature and rolling speed according to the following formula:

[0013] in, △S This is the amount of compensation for the opening degree; T For the temperature of the rolled piece, v This refers to the rolling speed.

[0014] According to one embodiment of the present invention, for a reducing sizing mill, a composite bore pattern including an asymmetric elliptical bore and a circular bore is adopted, wherein the ratio of the major axis to the minor axis of the asymmetric elliptical bore is 1.15-1.25, and the inclination angles of the upper roll sidewall and the lower roll sidewall constituting the asymmetric elliptical bore differ by 2-3°.

[0015] According to one embodiment of the present invention, the aperture parameter generation model is obtained by using a BP neural network and through training.

[0016] In the technical solution of this invention, the roughing mill adopts a progressive pass pattern combination of "box-shaped pass → symmetrical hexagonal pass → elliptical pass," achieving grain refinement through the deformation characteristics of different pass patterns; the intermediate mill adopts a pass pattern combination of "composite pass of elliptical and round passes → asymmetrical hexagonal pass," improving microstructure uniformity and eliminating residual stress; the finishing mill adopts a pass pattern combination of "elliptical pass → round pass," achieving precise dimensional control; the sizing mill dynamically compensates for the pass opening based on workpiece temperature and rolling speed, improving dimensional accuracy; the wire rod mill dynamically adapts pass pattern parameters based on workpiece temperature, rolling speed, and workpiece diameter through a pass pattern parameter generation model, ensuring the dimensional accuracy of the final product. Therefore, the technical solution of this invention can improve dimensional accuracy, reduce defects, refine grains, and enhance the overall performance of titanium alloy wire rods. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the 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.

[0018] Figure 1 A schematic diagram of the pass profile of a roughing-intermediate-finishing mill according to an embodiment of the present invention is shown; Figure 2 This diagram illustrates the gradient deformation control of a roughing-intermediate-finishing mill according to an embodiment of the present invention. Figure 3 The metallographic structure of the titanium alloy disk obtained in Example 1 of the present invention is shown. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be further described in detail below with reference to specific examples and the accompanying drawings.

[0020] It should be noted that all uses of "first" and "second" in the embodiments of the present invention are for the purpose of distinguishing two entities or parameters with the same name but different names. It is clear that "first" and "second" are only for the convenience of expression and should not be construed as limiting the embodiments of the present invention. Subsequent embodiments will not explain this in detail.

[0021] The inventors of this application recognize that current continuous rolling technology for titanium discs has at least three limitations. First, existing roll pass systems largely follow carbon steel design theory, failing to adapt to the sharp drop in high-temperature rheological stress in titanium alloys (rheological stress at 1000℃ is 2-3 times higher than that of carbon steel) and their nonlinear deformation characteristics. This leads to unstable metal flow during rolling, with edge cracking and folding defects generally exceeding 6%. Second, the lack of multi-unit coordinated control results in an imbalance in deformation distribution from roughing to finishing (elongation coefficient fluctuations reaching 40%), causing severe oscillations in rolling force (amplitude > 25%), limiting rolling speed increases (typically < 10 m / s). Third, titanium alloys… β Grain boundaries are temperature-sensitive, and conventional processes require a temperature control accuracy of ±30℃, leading to insufficient dynamic recrystallization and a finished product grain size deviation of >50%, with dimensional tolerances only maintained at ±0.15mm. Furthermore, existing technologies lack active control over thermo-coupling effects, failing to suppress the propagation of microcracks and the accumulation of residual stress on the surface of the rolled piece, severely restricting the demand for high-precision titanium discs (tolerance ≤ ±0.08mm) in aerospace and other fields. Inappropriate roll pass design can also lead to uneven roll wear, increasing equipment maintenance costs and reducing production efficiency. Based on the above understanding, this application provides a continuous rolling method for titanium alloy discs in one or more of the following embodiments to address the aforementioned problems in the prior art.

[0022] refer to Figure 1 This invention proposes a continuous rolling method for titanium alloy wire rods. The continuous rolling method employs a continuous rolling mill, which includes a roughing mill, an intermediate mill, a finishing mill, a sizing mill, and a wire rod mill arranged sequentially along the rolling direction. The continuous rolling method includes: for the roughing mill, setting multiple roughing mill pass types sequentially along the rolling direction as box-shaped passes, symmetrical hexagonal passes, and elliptical passes; for the intermediate mill, setting multiple intermediate mill pass types sequentially along the rolling direction as composite passes including elliptical and circular passes, and asymmetrical hexagonal passes; for the finishing mill, setting multiple finishing mill pass types sequentially along the rolling direction as elliptical passes and circular passes; for the sizing mill, dynamically compensating for the pass opening based on workpiece temperature and rolling speed; and for the wire rod mill, dynamically generating suitable pass parameters based on workpiece temperature, rolling speed, and workpiece diameter using a pass parameter generation model.

[0023] In the technical solution of this invention, the roughing mill adopts a progressive pass pattern combination of "box-shaped pass → symmetrical hexagonal pass → elliptical pass," achieving grain refinement through the deformation characteristics of different pass patterns; the intermediate mill adopts a pass pattern combination of "composite pass of elliptical and round passes → asymmetrical hexagonal pass," improving microstructure uniformity and eliminating residual stress; the finishing mill adopts a pass pattern combination of "elliptical pass → round pass," achieving precise dimensional control; the sizing mill dynamically compensates for the pass opening based on workpiece temperature and rolling speed, improving dimensional accuracy; the wire rod mill dynamically adapts pass pattern parameters based on workpiece temperature, rolling speed, and workpiece diameter through a pass pattern parameter generation model, ensuring the dimensional accuracy of the final product. Therefore, the technical solution of this invention can improve dimensional accuracy, reduce defects, refine grains, and enhance the overall performance of titanium alloy wire rods.

[0024] In some embodiments, the multiple roughing mills of a roughing mill unit are divided into multiple roughing mill units, wherein each roughing mill unit includes one or more roughing mills. For example, a roughing mill unit may include six roughing mills and be divided into three roughing mill units, each of which includes two roughing mills. For the first roughing mill unit: a box-shaped bore is used and the width spread factor is controlled between 1.05 and 1.08; for the second roughing mill unit: a symmetrical hexagonal bore is used and the strain rate is controlled between 5 and 8 s. -1 Within the specified range; for the third roughing mill unit: elliptical holes with a major axis to minor axis ratio of 2.2-2.5 are adopted.

[0025] The roughing mill employs a three-stage deformation optimization design: a progressive hole holder combination of "box-shaped hole → hexagonal hole → elliptical hole" is used to control the gradient of the high-temperature characteristics of titanium discs. The first roughing mill unit (e.g., stands 1-2) uses a box-shaped hole, applying a large deformation of 38-42% in the initial pass. The strong constraint of the box-shaped hole breaks up the coarse-grained structure of the cast state, with the width spread coefficient strictly controlled between 1.05 and 1.08 to avoid edge tearing caused by free width spread. The second roughing mill unit (e.g., stands 3-4) uses a hexagonal hole, stabilizing the strain rate at 5-8 s through a symmetrical bite design of the hexagonal hole. -1 The range is expanded to eliminate the V-shaped strain concentration zone generated during the box-type pass stage. The third roughing mill unit (e.g., the 5th-6th stand) adopts an elliptical pass, introducing an elliptical pass with a major axis / minor axis ratio of 2.2-2.5, superimposed with 30%-40% shear strain components, triggering the twinning deformation mechanism of titanium alloys. The roughing mill adopts a three-stage progressive pass design, breaking through the traditional carbon steel pass design framework. By controlling the gradient deformation amount (e.g., 42%→38%→36%) to match the dynamic recrystallization window of titanium alloys, the grain size can be refined from the initial 500μm to below 150μm.

[0026] In some embodiments, the multiple intermediate mills of an intermediate mill group are divided into multiple intermediate mill units, wherein each intermediate mill unit includes one or more intermediate mills. For example, an intermediate mill group may include 6 intermediate mills and be divided into two intermediate mill units, each of which includes 3 intermediate mills. For the first intermediate mill unit: a composite hole including elliptical and circular holes is used, wherein the ellipticity is set to 1.08-1.12, the circular hole convexity is set to 0.03-0.05mm, and the elongation coefficient per pass is controlled to be 1.25-1.3, and the cumulative strain is 1.8-2.2; for the second intermediate mill unit: an asymmetric hexagonal hole is used, wherein the angle difference between the two opposite hypotenuses of the asymmetric hexagonal hole located on both sides of the vertical centerline and the vertical centerline is 2-3° (i.e., there is a difference in the inclination of the two opposite hypotenuses). In some embodiments, the rolling temperatures of the multiple intermediate rolling mills are set to 920-980℃, 860-900℃, and 800-840℃ respectively along the continuous rolling direction, and the pass expansion angles of the multiple intermediate rolling mills are set to 22-27 degrees, 16-20 degrees, and 10-14 degrees respectively along the continuous rolling direction.

[0027] The intermediate rolling mill is used to homogenize the microstructure: it adopts a "elliptical-round hole → asymmetric hexagonal hole" stand combination. β The phase content is reduced from 85% to 65%. The first intermediate mill unit (e.g., stands 7-9) uses elliptical-circular holes. The second intermediate mill unit (e.g., stands 10-12) uses improved asymmetric hexagonal holes with an angle difference of 2-3°, actively inducing lateral metal flow and eliminating residual stress. A stepped temperature control zone (e.g., 950℃→880℃→820℃) is set in the intermediate rolling stage, matching the hole expansion angle (e.g., 25°→18°→12°). Through the coordinated regulation of temperature and hole parameters, the β phase content is precisely controlled and residual stress is eliminated. A phase transformation-strain coupling design is adopted for the intermediate rolling mill. The introduction of asymmetric hexagonal holes (angle difference of 2-3°) and temperature steps (950℃→820℃) in the intermediate rolling stage can achieve the following: β The phase content was precisely controlled from 85% to 65%.

[0028] In some embodiments, the multiple finishing mills of a finishing mill unit are divided into multiple finishing mill units, wherein each finishing mill unit includes one or more finishing mills. For example, a finishing mill unit may include six finishing mills and be divided into two finishing mill units, each of which includes three finishing mills. For the first finishing mill unit: an elliptical hole with a radius of curvature that decreases exponentially along the rolling direction is used; for the second finishing mill unit: a circular hole is used, the deviation between the rolled diameter and the target diameter is controlled within a predetermined deviation threshold (e.g., 0.05 mm), the surface roughness of the rolled workpiece is controlled within a predetermined roughness threshold (e.g., 1.6 μm), and an anti-folding guide device is provided.

[0029] The finishing mill prioritizes precise dimensional control to suppress work hardening. It employs an "elliptical hole → round hole" stand combination. The first finishing mill unit (e.g., stands 13-15) uses pre-finished elliptical holes with a curvature radius designed to decrease exponentially along the rolling direction. This exponentially decreasing curvature design, combined with a hydraulic servo system, reduces rolling force fluctuations and prevents surface micro-cracks caused by work hardening. The second finishing mill unit (e.g., stands 16-18) uses high-precision round holes, maintaining diameter tolerances within 0.05 mm and surface roughness within 1.6 μm. Anti-folding guide devices can also be installed on stands 16-18, allowing for adjustable guide roller inclination angles within the 5-8° range. By configuring adjustable guide rollers in the finishing mill and optimizing guide distances through fluid dynamics simulation, V-shaped folding defects can be eliminated, reducing the folding rate from 4.5% to 0.3%.

[0030] In some embodiments, a surface microcrack repair process is developed in which, when the rolling speed is greater than a predetermined speed threshold, a dynamic mist of 0.2-0.5 MPa is applied to the workpiece for cooling between the outlet of the finishing mill and the inlet of the reducing and sizing mill. This allows the Leidenfrost effect to be used to heal surface microcracks in situ, thereby significantly reducing the crack density.

[0031] refer to Figure 2 In some embodiments, the deformation applied by the roughing mill, intermediate mill, and finishing mill is controlled to be 38%-42%, 28%-32%, and 18%-22%, respectively. Gradient deformation is controlled for roughing, intermediate milling, and finishing to achieve progressive control of the microstructure and dimensional accuracy of titanium discs.

[0032] In some embodiments, for a reduction sizing mill, a composite pass profile including an asymmetric elliptical pass and a circular pass is adopted, wherein the ratio of the major axis to the minor axis of the asymmetric elliptical pass is 1.15-1.25, and the inclination angles of the upper and lower roll sidewalls constituting the asymmetric elliptical pass differ by 2-3° (wherein the inclination angle of the sidewall can be the angle between the tangent at the midpoint of the sidewall and the vertical direction). In some embodiments, for a reduction sizing mill, the opening compensation amount is calculated based on the workpiece temperature and rolling speed according to the following formula:

[0033] in, △S This is the amount of compensation for the opening degree; T For the temperature of the rolled piece, v This refers to the rolling speed.

[0034] Dynamic compensation optimization of the sizing mill: A thermo-mechanical coupling compensation is achieved through dynamic adjustment of geometric parameters using an asymmetric elliptical-circular die system. The asymmetric elliptical design primarily involves pre-setting the major axis length to 1.15-1.25 times the minor axis length to compensate for the anisotropic cooling shrinkage of titanium alloys (axial shrinkage rate 0.12% / ℃, radial shrinkage rate 0.15% / ℃). In the elliptical die design for rolling titanium alloys, the sidewall inclinations of the upper and lower rolls are intentionally designed to be asymmetric, differing by 2 to 3 degrees. This slight geometric difference allows for proactive control of the filling sequence and path of the metal in the width direction. Metal from the lower roll (with a larger inclination angle) preferentially flows to both sides, while metal from the upper roll (with a smaller inclination angle) extends more longitudinally. This avoids defects such as "ears" or "folds" caused by metal simultaneously and disorderly flowing to both sides; it also compensates for the effects of uneven temperature or fluctuations in incoming material dimensions, resulting in a more regular shape, smaller dimensional tolerances, and improved dimensional accuracy of the final rolled piece. With the addition of an intelligent compensation algorithm as shown in the formula above, the opening degree automatically increases by 1.2 mm for every 10℃ increase in workpiece temperature (reference temperature 850℃); and the opening degree is compensated by 0.08 mm for every 1m / s increase in rolling speed (reference speed 12m / s), effectively offsetting the dimensional drift caused by thermal expansion and strain rate effects. A linear motor with 0.01mm resolution can be used for drive, achieving a 50ms-level dynamic response and ensuring real-time roll gap adjustment. By establishing a temperature-speed dual-variable compensation model in the sizing mill, the effects of thermal expansion and strain rate on the workpiece can be offset in real time, reducing dimensional fluctuations from ±0.15mm to ±0.05mm.

[0035] In some embodiments, the pore size parameter generation model employs a backpropagation (BP) neural network and is obtained through training. The formula for the pore size parameter generation model is:

[0036] in, f(T,v,D) This refers to the output quantity, i.e., the optimal aperture parameters; T , v , D The input variables are the workpiece temperature, rolling speed, and workpiece diameter, respectively. x k For the k-th node of the input layer (corresponding to) T , v , D (e.g., normalized values) ω jk These are the connection weights from the input layer to the hidden layer; b j is the bias term (threshold) of the j-th node in the hidden layer; tanh is the activation function that maps the input to the interval [-1,1], introducing non-linearity; ω ij∑ represents the connection weights from the hidden layer to the output layer; ∑ represents the weighted sum of the outputs of all hidden layer nodes to obtain the final output.

[0037] The high-speed wire rod mill employs adaptive system optimization, achieving dynamic die matching based on a digital twin-based closed-loop control system. It utilizes an adaptive dynamic circular die, integrating an online laser diameter gauge (accuracy ±0.005mm), an infrared thermal imager (temperature resolution 0.5℃), and surface defect detection data to construct a full-dimensional state matrix for the rolled piece. A database containing thousands of historical process cases is established, and a nonlinear mapping relationship between input parameters (temperature T, speed v, diameter D) and the optimal die curve is established using a BP neural network, as shown in the equation above. Based on online detection data, the die parameters can be updated every 0.5 seconds, achieving a response speed 5 times faster than traditional PID control, and dynamically adjusting the range to cover ±15% of the nominal value. When a new alloy grade or abnormal operating condition is detected, an incremental training mode can be automatically initiated, generating an adaptive die solution within 10 minutes using a reinforcement learning algorithm, shortening the development cycle by 90%.

[0038] The following description is based on specific embodiments and comparative examples.

[0039] Example 1 1. Three-stage deformation optimization design of the roughing mill: A progressive hole holder combination of "box-shaped hole → hexagonal hole → elliptical hole" is adopted to control the gradient at high temperatures for titanium discs. Box-shaped holes are used in stands 1-2 of the roughing mill, with a large deformation of 40% applied in the initial pass. The strong constraint of the box-shaped hole breaks up the coarse-grained structure in the cast state, and the width spread coefficient is strictly controlled at 1.06 to avoid edge tearing caused by free width spread. Hexagonal holes are used in stands 3-4. Through the symmetrical bite design of the hexagonal holes, the strain rate is stabilized at 5s. - ¹ Scope, eliminating the V-shaped strain concentration zone generated during the box-type hole stage. Frames 5-6 employ elliptical holes, introducing an elliptical hole type with a major axis / minor axis ratio of 2.5, superimposed with a 35% shear strain component, triggering the titanium alloy twinning deformation mechanism, refining the grain size from the initial 500μm to below 150μm.

[0040] 2. Homogenization of Microstructure in the Intermediate Rolling Mill: A "elliptical-round hole → asymmetric hexagonal hole" stand combination was adopted to reduce the β-phase content from 85% to 65%. The 7-9 stands of the intermediate rolling mill use an elliptical-round hole configuration with an ellipticity of 1.10, a round hole crown of 0.04 mm, an elongation coefficient of 1.28 per pass, and a cumulative strain of 2.0. The 10-12 stands of the intermediate rolling mill employ an improved asymmetric hexagonal hole configuration with an angle difference of 2-3°, actively inducing lateral metal flow and eliminating residual stress. A stepped temperature control zone (950℃→880℃→820℃) is set in the intermediate rolling stage, matching the hole expansion angle θ to 25°→18°→12°.

[0041] 3. The finishing mill stands prioritize dimensional precision control to suppress work hardening: A "elliptical hole → round hole" stand combination is employed. Finishing mill stands 13-15 utilize pre-finished elliptical holes with a curvature radius designed to decrease exponentially along the rolling direction. Finishing mill stands 16-18 employ high-precision round holes, maintaining diameter tolerances within 0.05 mm and surface roughness within 1.6 μm. Anti-folding guide devices are installed in stands 16-18, allowing for a 6° adjustable guide roller inclination angle. A surface micro-crack repair process has also been developed; when the rolling speed exceeds 15 m / s, 0.5 MPa air mist cooling is added at the inlet of the reducing and sizing mill after passing through the finishing mill.

[0042] 4. Dynamic Compensation Optimization of the Sizing and Reducing Mill: A thermo-mechanical coupling compensation is achieved through dynamic adjustment of geometric parameters using an asymmetric elliptical-circular orifice system. The asymmetric elliptical design primarily involves presetting the major axis to 1.20 times the minor axis length to compensate for the anisotropic cooling shrinkage of titanium alloys (axial shrinkage rate 0.12% / ℃, radial shrinkage rate 0.15% / ℃). Furthermore, the inclination angles of the upper and lower roll sidewalls forming the asymmetric elliptical orifice differ by 2-3°. As mentioned earlier, an intelligent compensation algorithm is incorporated: for every 10℃ increase in workpiece temperature (reference temperature 850℃), the opening automatically increases by 1.2mm; for every 1m / s increase in rolling speed (reference speed 12m / s), the opening is compensated by 0.08mm, effectively offsetting dimensional drift caused by thermal expansion and strain rate effects. A 0.01mm resolution linear motor drive is used to achieve a 50ms-level dynamic response, ensuring real-time roll gap adjustment.

[0043] 5. Optimization of the high-speed wire rod mill's adaptive system, achieving dynamic die matching based on a digital twin-based closed-loop control system: An adaptive dynamic circular die is employed, integrating an online laser diameter gauge (accuracy ±0.005mm), an infrared thermal imager (temperature resolution 0.5℃), and surface defect detection data to construct a full-dimensional state matrix for the rolled piece. A database containing thousands of historical process cases is established, and a nonlinear mapping relationship between input parameters (temperature T, speed v, diameter D) and the optimal die curve is established through a BP neural network, as described above. Die parameters are updated every 0.5 seconds, with a dynamic adjustment range covering ±15% of the nominal value. When a new alloy grade or abnormal operating condition is detected, an incremental training mode is automatically initiated, generating an adaptive die scheme within 10 minutes through a reinforcement learning algorithm.

[0044] The metallographic structure of the titanium alloy disk obtained using Example 1 is as follows: Figure 3 As shown in Table 1, the specific performance indicators are as follows.

[0045] Comparative Example 1 1. The roughing mill adopts a combination of "box-type hole → elliptical hole" pass holders. Stands 1-2 of the roughing mill use box-type holes, applying a large deformation of 40% in the initial pass. The strong constraint of the box-type hole breaks up the coarse-grained structure in the cast state, with the width spread strictly controlled at 1.06 to avoid edge tearing caused by free width spread. Stands 3-6 use elliptical holes, with a reduction of 35%.

[0046] 2. The 7th to 12th stands of the intermediate rolling mill all use symmetrical circular holes, the single-pass reduction is uniformly 25%, and the temperature is controlled at 900℃. Gradient temperature control is not used.

[0047] 3. The finishing mill stands 13-18 all use fixed curvature circular holes with a curvature radius of 75mm. There is no dynamic curvature adjustment, the fixed guide wheel angle is 0°, the rolling speed is constant at 12m / s, and no air mist cooling process is used.

[0048] 4. The die shape of the reducing and sizing-high-speed wire rod mill is adjusted manually based on experience. The die shape is manually adjusted according to visual inspection of surface quality and caliper sampling dimensions (at 30-minute intervals). The rollers are fine-tuned using a mechanical handle, with a minimum adjustment of 0.1 mm. The specific performance indicators of the titanium alloy wire rod obtained using Comparative Example 1 are shown in Table 1.

[0049] Table 1 Performance indicators of Example 1 and Comparative Example 1

[0050] As shown in Table 1, the titanium alloy discs obtained in Example 1 show significantly improved performance compared to Comparative Example 1.

[0051] In summary, this invention proposes a roll pass system and multi-stage collaborative process method for a high-speed continuous rolling production line dedicated to titanium discs. This method can reduce the rolling steel accumulation rate by 3-5%, improve the ellipticity by 0.10 mm, achieve dimensional accuracy of ±0.05 mm, and increase material utilization by 5-8%, significantly improving production efficiency and product competitiveness, and has great application prospects.

[0052] This invention, through four innovative dimensions—multi-level bore structure design, thermo-mechanical coupling dynamic compensation, cross-scale defect suppression, and data-driven optimization—has for the first time constructed a full-process collaborative control system for high-speed continuous rolling of titanium alloys. It solves long-standing technical bottlenecks such as coarse grains, high defect rate, and low dimensional accuracy in titanium disc rolling, providing core technical support for the large-scale production of high-end titanium materials for aerospace.

[0053] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention (including the claims) is limited to these examples. Within the framework of the invention, technical features of the above embodiments or different embodiments can be combined, and many other variations of the different aspects of the invention as described above exist, which are not provided in the details for the sake of brevity. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

Claims

1. A method for continuous rolling of titanium alloy discs, characterized in that, The continuous rolling method employs a continuous rolling mill unit, which includes a roughing mill unit, an intermediate mill unit, a finishing mill unit, a sizing mill unit, and a high-speed wire rod mill unit arranged sequentially along the continuous rolling direction. The continuous rolling method includes: For the roughing mill unit, the pass types of multiple roughing mills are set as follows along the continuous rolling direction: box-shaped pass, symmetrical hexagonal pass, and elliptical pass; For the aforementioned intermediate rolling mill, the pass types of multiple intermediate rolling mills are arranged sequentially along the continuous rolling direction as a composite pass including elliptical passes and circular passes, and an asymmetrical hexagonal pass; For the aforementioned finishing mill unit, the pass types of multiple finishing mills are set as elliptical passes and circular passes in sequence along the continuous rolling direction; For the aforementioned sizing mill, the opening degree of the roll pass is dynamically compensated based on the workpiece temperature and rolling speed. For the high-speed wire rod mill, the appropriate pass parameters are dynamically generated based on the workpiece temperature, rolling speed, and workpiece diameter using a pass parameter generation model.

2. The continuous rolling method according to claim 1, characterized in that, The roughing mill unit is divided into multiple roughing mill units, each of which includes one or more roughing mills. For the first roughing mill unit: a box-type bore is used, and the width spread coefficient is controlled between 1.05 and 1.

08. For the second roughing mill unit: a symmetrical hexagonal bore is used, and the strain rate is controlled between 5 and 8 s. -1 Within the specified range; for the third roughing mill unit: elliptical holes with a major axis to minor axis ratio of 2.2-2.5 are adopted.

3. The continuous rolling method according to claim 1, characterized in that, The intermediate rolling mill group is divided into multiple intermediate rolling mill units, each of which includes one or more intermediate rolling mills. For the first intermediate rolling mill unit: a composite hole including elliptical and circular holes is adopted, wherein the ellipticity is set to 1.08-1.12, the convexity of the circular hole is 0.03-0.05mm, and the elongation coefficient per pass is controlled to be 1.25-1.3, and the cumulative strain is 1.8-2.

2. For the second intermediate rolling mill unit: an asymmetric hexagonal hole is adopted, wherein the angle difference between the two opposite hypotenuses of the asymmetric hexagonal hole on both sides of the vertical center line and the vertical center line is 2-3°.

4. The continuous rolling method according to claim 1, characterized in that, The rolling temperatures of the plurality of intermediate rolling mills are set to 920-980℃, 860-900℃, and 800-840℃ respectively along the continuous rolling direction, and the pass expansion angles of the plurality of intermediate rolling mills are set to 22-27 degrees, 16-20 degrees, and 10-14 degrees respectively along the continuous rolling direction.

5. The continuous rolling method according to claim 1, characterized in that, The multiple finishing mills of the finishing mill unit are divided into multiple finishing mill units, wherein each finishing mill unit includes one or more finishing mills; for the first finishing mill unit: an elliptical hole with an exponentially decreasing radius of curvature along the rolling direction is adopted; for the second finishing mill unit: a circular hole is adopted, the deviation between the rolled diameter and the target diameter is controlled within a predetermined deviation threshold, the surface roughness of the rolled workpiece is within a predetermined roughness threshold, and an anti-folding guide device is provided.

6. The continuous rolling method according to claim 1, characterized in that, When the rolling speed is greater than the predetermined speed threshold, a cooling mist of 0.2-0.5 MPa is applied to the workpiece between the outlet of the finishing mill and the inlet of the reducing mill.

7. The continuous rolling method according to claim 1, characterized in that, The deformation amounts applied by the roughing mill, the intermediate mill, and the finishing mill are controlled to be 38%-42%, 28%-32%, and 18%-22%, respectively.

8. The continuous rolling method according to claim 1, characterized in that, For the aforementioned reducing and sizing mill, the opening compensation amount is calculated based on the workpiece temperature and rolling speed using the following formula: in, △S This is the amount of compensation for the opening degree; T For the temperature of the rolled piece, v This refers to the rolling speed.

9. The continuous rolling method according to claim 1, characterized in that, For the aforementioned sizing mill, a composite bore pattern including asymmetric elliptical bores and circular bores is adopted, wherein the ratio of the major axis to the minor axis of the asymmetric elliptical bore is 1.15-1.25, and the inclination angles of the upper and lower roll sidewalls constituting the asymmetric elliptical bore differ by 2-3°.

10. The continuous rolling method according to claim 1, characterized in that, The aperture parameter generation model is obtained by using a BP neural network and through training.

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