Large thin-walled titanium alloy ring piece ring rolling stage instability suppression parameter linkage control method

Abstract

The application discloses a parameter linkage control method for ring rolling of large thin-wall titanium alloy ring pieces in stages, and belongs to the technical field of ring piece rolling. The ring rolling process is divided into a hole expanding initial stage, a hole expanding stable stage and a finish rolling control stage, and a linkage control system in stages is established, which comprises ring speed-up, main roller speed, roller holding pressure, roller lifting parameters and laser measurement feedback. The ring machine control system automatically calls corresponding parameter combinations according to the current rolling stage and size feedback, realizes stable biting in the hole expanding initial stage, considers both efficiency and stability in the hole expanding middle stage, and suppresses size fluctuation and roundness error in the finish rolling stage. The application overcomes the problems of dispersed parameter setting and insufficient consideration of stage difference in the prior art, significantly reduces the shaking, deflection, local instability and finish rolling size fluctuation in the ring rolling process of large thin-wall titanium alloy ring pieces, and improves the stability of the ring rolling process and the product consistency.

Description

Technical Field

[0001] This invention belongs to the field of ring rolling technology, specifically relating to an automatic parameter linkage control method for suppressing instability during the ring rolling process of large thin-walled titanium alloy rings. Background Technology

[0002] During the ring rolling process of large thin-walled titanium alloy rings, problems such as vibration, swaying, local instability, final rolling dimensional fluctuations, increased roundness error, and increased risk of local cracking occur due to the large outer diameter, relatively thin wall thickness, large heat capacity, and significant differences in rolling stages.

[0003] For large, thin-walled titanium alloy rings, the ring rolling process is not a single, stable condition, but rather includes multiple rolling stages such as the initial expansion stage, the expansion stabilization stage, and the final rolling control stage. At different stages, the stress state, support requirements, dimensional response speed, and instability sensitivity between the ring and the main roll, clamping roll, and mandrel are all different. If the main roll speed, clamping roll pressure, roll lifting control parameters, or ring speed increase are set separately using preset parameters or empirical rules, without establishing a linkage control relationship around different rolling stages, or without enabling the equipment control system to automatically switch based on the rolling stage and dimensional feedback, problems such as unstable biting and vibration can easily occur in the initial expansion stage, mismatch between the expansion rhythm and support state in the middle stage, and premature or delayed roll lifting, dimensional fluctuations, and amplified roundness deviations can occur in the final rolling stage.

[0004] The core problem this invention aims to solve is not how to set a single parameter value, but rather how to establish a set of parameter linkage control methods for different rolling stages, focusing on the instability risk during the ring rolling process of large thin-walled titanium alloy rings, thereby forming a staged parameter linkage control method suitable for large thin-walled titanium alloy rings.

[0005] In the current technology for controlling the ring rolling of large thin-walled ring parts, the following methods are typically used: ① The main roller speed, roller clamping pressure, heat shrinkage amount, roller lifting position and cycle speed are set separately in advance, but most parameters are set separately and independently, or although they are executed by the equipment, they lack a phased automatic linkage relationship established around the goals of suppressing vibration, sway, size fluctuation and roundness error; ② A fixed speed or simple segmented speed control is used throughout the ring rolling process, but the support requirements and instability sensitivity of the ring at different rolling stages are not included in the system control; ③ Dimensions are monitored by laser measurement, but usually only laser is used as a measurement method, without further coordination with roller lifting control parameters, speed increase switching and fan direction control; ④ For the control parameters of roll lifting, final rolling allowance and speed reduction in the final rolling stage, existing technologies still mostly rely on operational experience or on-site control based on dimensional feedback, lacking clear, stable and reproducible staged control logic.

[0006] Existing technologies are more prone to the following problems during the ring rolling process of large thin-walled titanium alloy rings: ① The stability requirements of large thin-walled ring parts are different in the initial, middle and final rolling stages of hole expansion. If a single speed strategy or simple experience-based speed adjustment is always used, it is difficult to simultaneously ensure bite stability, hole expansion efficiency and final rolling dimensional control accuracy. ② If the main roller speed, clamping roller pressure and ring speed are set independently, when one parameter changes, other support parameters are not adjusted synchronously, which can easily cause uneven local force on the ring, leading to shaking, swaying or instantaneous instability. ③ If the roll lifting control parameters in the final rolling stage are unreasonable, such as lifting the roll too early, it will weaken the stability constraint on the ring and amplify the roundness deviation; if the roll lifting is too late, it may lead to insufficient space for final rolling dimension correction or increased dimension fluctuation. ④ Although laser measurement can provide dimensional feedback, if the direction of the laser cooling fan is not properly controlled, an additional cooling effect may be formed near the measurement area, which will increase the local temperature drop and thus affect the stability of dimensional response and final rolling control.

[0007] Therefore, the fundamental deficiency of existing technologies is not just that "the parameters are not set well enough", but that there is a lack of a staged parameter linkage control method that focuses on the changes in the rolling stage and takes the suppression of jitter, sway, dimensional fluctuation and roundness error as control objectives. Summary of the Invention

[0008] To overcome the above shortcomings, this invention incorporates heat shrinkage, main roll speed, roll clamping pressure, roll lifting parameters, phased growth rate, and laser measurement coordination into a unified control framework. This allows each parameter to change in stages around the targets of vibration, sway, dimensional fluctuation, and roundness error suppression, thereby overcoming the problems of dispersed parameter settings, insufficient consideration of stage differences, and unstable final rolling control in the prior art.

[0009] The technical solution of the present invention is as follows: A parameter-linked control method for suppressing staged instability during the rolling of large thin-walled titanium alloy rings includes the following steps: (1) The ring rolling process of large thin-walled titanium alloy rings is divided into the initial stage of hole expansion, the stable stage of hole expansion, and the final rolling control stage according to the instability sensitivity and dimensional response characteristics. (2) Establish a linkage parameter system that includes the ring speed increase, main roll speed, roll clamping pressure, roll lifting parameters and size detection feedback; (3) The rolling mill control system automatically calls up the parameter combination corresponding to the current rolling stage and the real-time dimensional detection results to execute the following linkage control: (3-1) In the initial stage of hole expansion, a low ring speed is adopted and controlled in coordination with the main roll speed and the clamping roll pressure to achieve stable bite; (3-2) During the stabilization period of hole expansion, increase the ring speed, and maintain the main roller speed and clamping roller pressure to match the support capacity of the hole expansion state, so as to avoid local instability caused by simply increasing the speed; (3-3) During the final rolling control period, the speed of the fall ring is increased, and the lifting control parameters are controlled in combination with the size detection feedback to reduce the size fluctuation and roundness error in the final rolling stage; (3-4) When vibration, sway or abnormal dimensional response is detected, the control system performs combined correction of the cycle speed, clamping pressure, main roll speed and lifting control parameters according to the preset linkage sequence to suppress support imbalance and final rolling fluctuation.

[0010] Control steps: Step R1: Before ring rolling, pre-adjust the equipment and tooling to bring the main roll, core roll, cone roll and related tooling into a stable rolling state.

[0011] Step R2: In the initial stage of hole expansion, the ring mill control system calls the initial hole expansion parameter combination to enter the rolling process with a lower ring speed and corresponding main roll speed and clamping roll pressure, so that the ring can be stably bitten in, reducing the risk of initial vibration and instability.

[0012] Step R3: When the ring machine control system recognizes that the ring has entered the expansion and stabilization period, it automatically switches to the expansion and stabilization period parameter combination to increase the ring speed and keep the main roller speed and clamping roller pressure within a range that matches the current expansion state, so as to balance expansion efficiency and stability and avoid insufficient support or instantaneous instability caused by excessive speed increase.

[0013] Step R4: When the size detection feedback indicates that the ring is close to the final size, the ring mill control system automatically enters the final rolling control period, reduces the ring speed, and switches the roll lifting control parameters according to the size detection results to reduce size fluctuations and roundness errors in the final rolling stage.

[0014] Step R5: When tremors, swaying, local instability or abnormal dimensional response occur during the ring rolling process, the ring mill control system prioritizes the combined adjustment of the ring speed increase, roll clamping pressure, main roll speed and roll lifting control parameters according to the preset linkage rules, rather than making large corrections to a single parameter, so as to avoid amplifying new support imbalances, dimensional fluctuations or instability factors.

[0015] Applicable implementation scenarios: This method is applicable to the ring rolling process of large thin-walled titanium alloy rings, and can also be used for parameter extrapolation based on scaled-down part processes or existing large thin-walled part processes. For larger workpieces, the absolute values ​​of the parameters can be adjusted equivalently according to equipment capacity and target specifications, but the phased linkage logic of the initial hole expansion stage—the hole expansion stabilization stage—the final rolling control stage remains unchanged.

[0016] Key control points: ①The core of this invention is not a certain absolute parameter value itself, but the interconnected changes in different parameters around the instability risk at different rolling stages of large thin-walled ring parts; ② In the initial stage of hole enlargement, priority should be given to ensuring stable bite and sufficient support, and the pursuit of hole enlargement speed should be avoided. ③ The stabilization period of hole enlargement should be balanced between efficiency improvement and stability maintenance; ④ In the final rolling stage, dimensional stability should be controlled by adjusting the speed reduction, laser feedback, and roll lifting parameters. ⑤ When a shaking or instability trend occurs, the linkage parameter should be adjusted first, rather than a single point parameter adjustment, so as to avoid further amplification of new support imbalance or size fluctuation.

[0017] Preferably, in the above-mentioned linkage parameter system, the heat shrinkage amount is set to 1.0% to 1.2%.

[0018] Preferably, in the above linkage parameter system, the main roller speed is set to 600-800 mm / s.

[0019] Preferably, in the above linkage parameter system, the clamping roller pressure is set to 60% to 80% of the maximum pressure.

[0020] Preferably, in the above-mentioned linkage parameter system, the control parameter for lifting the roll at the distance from the final rolling is set to 120–180 mm.

[0021] Preferably, the above-mentioned growth rate is switched in stages as follows: 1.5 to 2.5 mm / s in the initial stage of hole expansion, 3.0 to 3.5 mm / s in the stable stage of hole expansion, 4.0 to 5.0 mm / s in the stage of maximum growth rate, and then drops back to 1.5 to 2.5 mm / s in the stage of final rolling size control.

[0022] Preferably, a standard ring is used for pressure calibration before the above-mentioned ring rolling, and the main roll, core roll, cone roll and tooling are preheated.

[0023] Preferably, the outer diameter of the above-mentioned large thin-walled titanium alloy ring is not less than 3000 mm, and the ratio of wall thickness to height is not greater than 1:10.

[0024] Preferably, the aforementioned phased automatic parameter switching is automatically executed by the ring mill control system based on dimensional detection feedback and preset phase status, wherein the dimensional detection feedback includes laser ranging feedback, online dimensional detection feedback, or equivalent detection feedback.

[0025] The beneficial effects of this invention are: 1. Phased ring speed control, coordinated with main roll speed, roll clamping pressure and roll lifting parameters, to match the stability requirements and parameter changes at different rolling stages; The stress state and stability requirements of thin-walled titanium alloy rings differ in the initial, middle, and final rolling stages of hole expansion. In the initial stage of hole expansion, the ring has not yet established a stable rolling state. If the ring speed is too high, it is prone to vibration and instability due to unstable bite, insufficient support, or local stress fluctuations. In the middle stage of hole expansion, it is required to improve hole expansion efficiency while maintaining stability. In the final rolling stage, more attention is paid to dimensional convergence and roundness control.

[0026] This invention achieves phased switching of the cycle speed increase and coordinates it with the main roll speed and clamping roll pressure control. Its mechanism is as follows: On the one hand, using a lower ring speed increase in the early stage of hole expansion helps the ring gradually enter a stable rolling state under the drive of the main roll and the support of the clamping roll, reducing bite fluctuations; On the other hand, gradually increasing the ring speed after the hole expansion is stable can improve efficiency on a stable basis, while reducing the speed in the final rolling stage is beneficial to suppress dimensional overshoot, final rolling fluctuation and roundness error amplification. Therefore, this method is not a simple speed adjustment, but rather a phased linkage between speed parameters and support parameters to address the risk of instability.

[0027] 2. The roller lifting parameters are linked with laser measurement to convert the dimensional monitoring results into stable rolling control actions.

[0028] Large, thin-walled rings in the final rolling stage are extremely sensitive to the roll lifting control parameters. If the rolls are lifted too early, the support constraint weakens, and the ring is more prone to amplifying roundness errors; if the rolls are lifted too late, there is insufficient adjustment space in the final rolling, and the dimensional response is prone to lag.

[0029] This invention combines laser measurement results with roller lifting parameters, and its mechanism is as follows: On the one hand, laser measurement provides real-time dimensional feedback for the final rolling stage, so that the switching of roll lifting control parameters no longer depends entirely on manual experience judgment, but can be automatically executed by the control system based on dimensional detection feedback; On the other hand, limiting the roll lifting control parameters to a certain range from the final rolling size can gradually release the final rolling size adjustment space while maintaining necessary support stability, thereby reducing size fluctuations and roundness errors in the final rolling stage. Therefore, the linkage between the roll lifting parameters and laser feedback essentially transforms the dimensional monitoring results into stable rolling control actions, rather than simply relying on back-end detection and correction.

[0030] 3. Laser measurement is used in conjunction with fan direction control to improve the effectiveness of dimensional feedback and avoid localized additional cooling in the measurement area; Laser measurement is used for dimensional control, but if the laser cooling fan blows directly onto the billet, additional cooling may occur near the measurement area, leading to a faster local temperature drop, which in turn affects the dimensional change pattern and the stability of the final rolling control in that area.

[0031] This invention requires that the direction of the cooling airflow in the detection system avoids the measurement area on the surface of the billet. The mechanism is as follows: On the one hand, it avoids the measurement system causing additional cooling interference to the surface of the measured ring; On the other hand, it enables the dimensional feedback obtained by laser measurement to better reflect the true change trend of the ring under normal hot conditions, thereby improving the accuracy of parameter adjustment in the final rolling stage; Therefore, this invention does not use laser measurement in isolation, but rather integrates the laser system, cooling fan direction, and final rolling control actions to serve stable rolling.

[0032] The technical effects of this invention can be further verified through the following comparative method: using a fixed speed or empirical parameter adjustment method as the control group, and the phased parameter linkage control method of this invention as the experimental group, the frequency of jitter or sway during ring rolling, the final rolling roundness error, the final rolling dimensional fluctuation range, and the number of abnormal shutdowns are compared and recorded. If the experimental group performs better in the above indicators, it can further prove the effectiveness of the phased parameter linkage control of this invention in suppressing jitter, sway, dimensional fluctuation, and roundness error in the ring rolling of large thin-walled titanium alloy rings, and in establishing the phased parameter linkage rules.

[0033] The above technical effects can be verified through the following indicators: ① The amplitude change of vibration or sway during ring rolling; ② Roundness error and dimensional fluctuation during the final rolling stage; ③ The convergence of dimensions before and after lifting the roller; ④ Stable rolling performance in the initial, middle and final rolling stages of hole expansion; ⑤ Frequency of instability compared to traditional single speed or empirical parameter tuning methods. Attached Figure Description

[0034] Figure 1 This is a photograph of the actual shape of a large thin-walled titanium alloy ring after ring rolling in Example 1. Detailed Implementation

[0035] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0036] Example 1: Description of parameters and control level of a large-scale thin-walled titanium alloy ring rolling mill A large, thin-walled titanium alloy ring was selected as the implementation object, weighing 4300-4500 kg. The cold-state dimensions before ring rolling were an outer diameter of 2450-2490 mm, a wall thickness of 120-130 mm, and a height of 1180-1200 mm, with a height-to-thickness ratio close to 10:1. Hot rolling was performed using a ring rolling mill, which can roll rings with an outer diameter of up to 10 mm. The cold-state dimensions after ring rolling were required to be an outer diameter of 3400-3410 mm, a wall thickness of 75-80 mm, and a height of 1180-1190 mm.

[0037] Parameter settings: Heat shrinkage: 1.0%~1.2%; Main roller speed: 600~800 mm / s; Roller clamping pressure: 60%~80% (maximum pressure); Distance to final roll lifting parameters: 120~180 mm; Phased shift in growth rate: Initial stage of hole enlargement: 1.5–2.5 mm / s; Hole stabilization period: 3.0~3.5 mm / s; Maximum ring speed increase phase: 4.0–5.0 mm / s; Final rolling dimensional control stage: reduce to 1.5–2.5 mm / s; Laser measurement data is used as the basis for size control, and the direction of the laser cooling fan is controlled so that it does not blow towards the blank.

[0038] Before ring rolling, the main roll, core roll, tapered roll, and related tooling are pre-adjusted and preheated, and a standard ring is used for pressure calibration. Based on existing implementation records of this type of large thin-walled titanium alloy ring, the heat shrinkage is set within the range of 1.0% to 1.2%, the main roll speed is set within the range of 600 to 800 mm / s, the clamping pressure is set within the range of 60% to 80%, the distance from the final rolling lifting control parameter is set within the range of 120 to 180 mm, and the ring speed increase is within the corresponding optimal range in the initial stage of hole expansion, the stable stage of hole expansion, the maximum hole expansion stage, and the final rolling control stage.

[0039] During ring rolling, the ring mill control system first calls upon the initial parameter combination for the expansion stage, using a lower ring speed increase in conjunction with the corresponding main roll speed and clamping roll pressure to ensure stable ring engagement. As the expansion process progresses, the control system automatically switches to the parameter combination for the stable expansion stage based on the current rolling phase, balancing expansion efficiency and support stability. When dimensional detection feedback indicates that the ring is approaching its final size, the control system automatically enters the final rolling control phase, reducing the ring speed increase and switching the roll lifting control parameters to minimize dimensional fluctuations and roundness errors in the final rolling stage.

[0040] During the rolling process, the detection system continuously provides dimensional feedback, and the laser cooling fan is directed away from the billet surface to reduce localized additional cooling in the measurement area. If the system detects jitter, sway, or abnormal dimensional response, it automatically adjusts the cycle speed, main roll speed, roll clamping pressure, and roll lifting control parameters according to preset linkage rules.

[0041] After adopting the above method, the ring achieved stable engagement in the initial stage of hole expansion, and no obvious swaying or local instability occurred during the ring rolling process. The final ring shape is as follows. Figure 1 As shown, the overall shape of the ring is stable, with no obvious bulging, flared mouth, or local out-of-roundness. There is no visible difference in the dimensions of the upper and lower end faces and the waist. After final rolling and complete cooling, the inner diameter, outer diameter, wall thickness, and corresponding height of eight evenly distributed positions on the upper and lower end faces of the ring were measured. The eight evenly distributed positions on the upper and lower end faces correspond to each other. The test results are shown in Table 1. The process requirements are met and the ellipticity does not exceed 10 mm. This indicates that the staged automatic parameter linkage control method described in this invention can meet the process requirements of establishing staged parameter linkage rules for the ring rolling of large thin-walled titanium alloy rings with the control objectives of suppressing jitter, sway, dimensional fluctuation, and roundness error.

[0042] In the above embodiments, the specific parameters can be adjusted within the preferred range according to different workpiece specifications, but the automatic linkage control logic of the initial hole expansion stage, the hole expansion stabilization stage, and the final rolling control stage remains unchanged.

[0043] Table 1. Cold-state dimensions of a large thin-walled titanium alloy ring after ring rolling

[0044] ①This invention does not merely provide empirical values ​​for several main roll speeds, clamping roll pressures, or ring speeds, but rather establishes a linkage relationship between these parameters around the instability risks at different rolling stages of large thin-walled rings, and the ring mill control system automatically switches parameters according to the stage status; ②This invention does not adopt a uniform speed strategy throughout the entire ring rolling process, but divides the rolling process into the initial stage of hole expansion, the stable stage of hole expansion, and the final rolling control stage, and configures corresponding parameter combinations for each stage; ③ This invention does not only use laser measurement as a detection method, but incorporates laser measurement, roll lifting parameters and fan direction control into the same final rolling stability control logic; ④ The ingenuity of this invention lies in: organizing the originally scattered, isolated, and experience-dependent ring rolling parameter settings into a set of automatic parameter linkage control methods for ring rolling of large thin-walled titanium alloy ring parts, with the control objectives of suppressing jitter, sway, dimensional fluctuation and roundness error, and establishing phased parameter linkage rules.

[0045] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for staged instability suppression parameter linkage control of large thin-walled titanium alloy ring rolling, characterized in that, Includes the following steps: (1) The ring rolling process of large thin-walled titanium alloy rings is divided into the initial stage of hole expansion, the stable stage of hole expansion, and the final rolling control stage according to the instability sensitivity and dimensional response characteristics. (2) Establish a linkage parameter system that includes the ring speed increase, main roll speed, roll clamping pressure, roll lifting parameters and size detection feedback; (3) The rolling mill control system automatically calls up the parameter combination corresponding to the current rolling stage and the real-time dimensional detection results to execute the following linkage control: (3-1) In the initial stage of hole expansion, a low ring speed is adopted and controlled in coordination with the main roll speed and the clamping roll pressure to achieve stable bite; (3-2) During the stabilization period of hole expansion, increase the ring speed, and maintain the main roller speed and clamping roller pressure to match the support capacity of the hole expansion state, so as to avoid local instability caused by simply increasing the speed; (3-3) During the final rolling control period, the speed of the fall ring is increased, and the lifting control parameters are controlled in combination with the size detection feedback to reduce the size fluctuation and roundness error in the final rolling stage; (3-4) When vibration, sway or abnormal dimensional response is detected, the control system performs combined correction of the cycle speed, clamping pressure, main roll speed and lifting control parameters according to the preset linkage sequence to suppress support imbalance and final rolling fluctuation.

2. The method for staged instability suppression parameter linkage control of large thin-walled titanium alloy ring rolling as described in claim 1, characterized in that, In the aforementioned linkage parameter system, the heat shrinkage amount is set to 1.0% to 1.2%.

3. The parameter linkage control method for staged instability suppression in the rolling of large thin-walled titanium alloy rings according to claim 1, characterized in that, In the linkage parameter system, the main roller speed is set to 600-800 mm / s.

4. The method for staged instability suppression parameter linkage control of large thin-walled titanium alloy ring rolling as described in claim 1, characterized in that, In the aforementioned linkage parameter system, the clamping roller pressure is set to 60% to 80% of the maximum pressure.

5. The parameter linkage control method for suppressing staged instability during ring rolling of large thin-walled titanium alloy rings according to claim 1, characterized in that, In the linkage parameter system, the control parameter for lifting the roll at the distance from the final rolling mill is set to 120–180 mm.

6. The method for staged instability suppression parameter linkage control of large thin-walled titanium alloy ring rolling as described in claim 1, characterized in that, The rate of increase is switched in stages as follows: 1.5-2.5 mm / s in the initial stage of hole expansion, 3.0-3.5 mm / s in the stable stage of hole expansion, 4.0-5.0 mm / s in the stage of maximum rate of increase, and then drops back to 1.5-2.5 mm / s in the stage of final rolling size control.

7. The method for staged instability suppression parameter linkage control of large thin-walled titanium alloy ring rolling as described in claim 1, characterized in that, Before ring rolling, pressure calibration is performed using a standard ring, and the main roll, core roll, cone roll, and tooling are preheated.

8. The method for staged instability suppression parameter linkage control of large thin-walled titanium alloy ring rolling as described in claim 1, characterized in that, The outer diameter of the large thin-walled titanium alloy ring is not less than 3000 mm, and the ratio of wall thickness to height is not greater than 1:

10.

9. The method for staged instability suppression parameter linkage control of large thin-walled titanium alloy ring rolling as described in claim 1, characterized in that, The phased automatic parameter switching is automatically executed by the ring mill control system based on the size detection feedback and the preset stage status. The size detection feedback includes laser ranging feedback, online size detection feedback, or equivalent detection feedback.

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