Steel wire rod round steel size precision control method
By optimizing the die-cutting system and guide clamping force, combined with looper buffer control, the problems of dimensional fluctuation and non-roundness of finished wire rod round bars were solved, achieving high-precision dimensional control and stable production.
Patent Information
- Application Number
- CN202511230644.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-30
- Publication Date
- 2025-11-18
AI Technical Summary
In the existing technology, Φ9mm to Φ13mm wire rod round steel has problems such as large fluctuations in finished product size, alternating ears or incomplete filling on both sides, and out-of-roundness exceeding the critical limit, making it difficult to meet the higher C-level precision requirements.
By optimizing the roll pass system in the pre-finishing and finishing stages, alternating elliptical and circular roll passes are adopted, large guides are configured to enhance the clamping force, and the rolling speed and clamping force are controlled during the rolling process. Combined with looper buffer control, the guide opening degree is monitored and adjusted in real time, and the roll gap value and elongation coefficient are optimized to achieve stable clamping and rounding of the rolled workpiece.
It significantly reduces finished product dimensional deviation, improves dimensional control accuracy, ensures that finished products meet the C-level accuracy standard, reduces dimensional fluctuations and shape abnormalities, and improves production stability and finished product qualification rate.
Smart Images
Figure CN120961623A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to the technical field of metal rolling processing, in particular to a wire rod round steel size precision control method. BACKGROUND
[0002] Wire rod round steel is an important steel product, and its size precision is a key indicator for measuring product quality, directly affecting subsequent deep processing technology and the performance of the final product.
[0003] In current high-speed wire rod production, especially for Φ9mm to Φ13mm bright round wire rod, there are generally problems such as large size fluctuation of finished products, ears or underfilling alternately appearing on both sides, and critical out-of-roundness exceeding the standard, etc. For example, the size of 12 specification XGL finished product fluctuates between 11.80-12.20, and the staff at the finishing post has difficulty in balancing the alternately appearing edge and out-of-roundness, especially the size precision of large specification products can only reach B level, which has a gap with the higher C level precision requirement. The size of wire rod and the allowable deviation are shown in the following table. Figure 1 SUMMARY
[0004] In order to overcome the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a wire rod round steel size precision control method.
[0005] The technical scheme adopted by the present application to solve its technical problems is: a wire rod round steel size precision control method applied to a continuous rolling production line including a rough rolling mill group, a medium rolling mill group, a pre-finishing rolling mill group and a finishing rolling mill group, comprising the following steps:
[0006] Pass type and material type optimization: based on the target finished product specification, the pass type system of the pre-finishing and finishing stages is designed for matching, an elliptical pass type and a circular pass type are alternately arranged in the pass type system, the cross-sectional shape of the pre-finishing outlet rolled piece is a regular circle, and the finishing mill group is allocated with a decreasing cross-sectional area for each pass;
[0007] Guide system improvement: identify the rack in the finishing mill group that causes the rolling piece to swing due to insufficient guide clamping force, and configure the inlet rolling guide of the rack with no less than eight-inch large guide to enhance the radial clamping force of the rolling piece and reduce the swing of the rolling piece in the mill group;
[0008] Rolling process control: in the rolling process, the rolling speed of each rack of the finishing mill group is controlled to be in an increasing configuration, and the rolling piece is completed in a micro-tension state.
[0009] As a further improvement of the present application, it further comprises:
[0010] Pressure sensors and displacement sensors are installed at the inlet and outlet of the guide, to monitor the clamping force data changes in real time;
[0011] The guide opening degree is dynamically adjusted by hydraulic or electric actuator, and the guide opening degree is dynamically adjusted according to sensor feedback, so that the clamping force is maintained stable in the interval suitable for rolling working condition.
[0012] The actuator communicates with the rolling mill control system to realize automatic compensation and alarm function of the clamping force, and when the clamping force deviates from the set threshold, the parameter adjustment or sound and light alarm is automatically triggered.
[0013] As a further improvement of the application: when the total number of stands of the finishing rolling mill group is N, the inlet rolling guide of the N-4th stand to the last stand is configured with a guide not less than 8 inches.
[0014] As a further improvement of the application: it also includes:
[0015] Loop buffer control: a loop controller is arranged between the pre-finishing rolling mill group and the finishing rolling mill group, the loop height is monitored and adjusted in real time, and the size difference of the rolling piece and the flow fluctuation generated by the closed rolling mill and single / double line alternating rolling of the intermediate rolling mill group are absorbed and buffered.
[0016] As a further improvement of the application: the pass type and material type optimization steps specifically include:
[0017] Based on the target finished product diameter D, a group of decreasing roll gap values are set for the passes from the last stand of the pre-finishing rolling mill to the last stand of the finishing rolling mill;
[0018] According to the set roll gap value and pass system, the rolling piece height and width of each pass are calculated and determined, so that the pre-finishing rolling mill outlet rolling piece cross section shape is regular circular, and the elliptical pass fullness degree = cross-sectional area / (pass height x pass width x 0.866) is controlled in 86%-92%; the circular pass fullness degree = cross-sectional area / (π x (pass nominal diameter / 2)) is controlled in 92%-98%; and the finished product pass fullness degree is controlled in 97.8%-99.9%. 2
[0019] As a further improvement of the application: it also includes setting the roll gap of each stand based on the rolling program table, and the rolling program table is established by the following model:
[0020] According to the blank size and target finished product specification, the total elongation coefficient is determined, and the total elongation coefficient is distributed to each pass according to the pass system of the alternating arrangement of elliptical pass and circular pass, wherein the elongation coefficient of each pass is controlled between 1.10 and 1.42;
[0021] According to the distributed pass elongation coefficient and blank cross-sectional area, the target cross-sectional area, rolling piece height and rolling piece width of each pass are reversely calculated;
[0022] According to the calculated rolling piece width, height and pass drawing parameters, the roll gap set value of each stand is determined.
[0023] As a further improvement of the present application: the elongation coefficient of each pass is specifically distributed in the range of:
[0024] The elongation coefficient of the rough rolling mill pass is 1.25-1.42, the elongation coefficient of the intermediate rolling mill pass is 1.20-1.40, the elongation coefficient of the pre-finishing rolling mill pass is 1.15-1.35, and the elongation coefficient of the finishing rolling mill pass is 1.05-1.25.
[0025] The difference between the elongation coefficients of adjacent passes is ≤0.15.
[0026] The elongation coefficient of the oval pass is ≤1.35, and the elongation coefficient of the round pass is ≤1.25.
[0027] As a further improvement of the present application: in the pass system in which the oval pass and the round pass are arranged alternately, the width-to-height ratio of the rolled piece is greater than 1.1 in the oval pass, and the width-to-height ratio of the rolled piece is between 0.9 and 1.1 in the round pass.
[0028] As a further improvement of the present application: the target finished product diameter D is Ф8mm-Ф13mm, the roll gap value of the finishing rolling mill is 0.07D-0.09D, and the roll gap value of the finishing rolling mill is set to be not greater than 2.0mm.
[0029] As a further improvement of the present application: the finishing rolling speed is inversely proportional to the target finished product diameter D.
[0030] Compared with the prior art, the present application has the beneficial effects that:
[0031] The present application optimizes the pass and material parameters in the pre-finishing and finishing stages, accurately processes the intermediate or pre-finishing outlet semi-finished product, suppresses the abnormal loop fluctuation of the rolled piece due to rotation in the continuous rolling process from the source, and simultaneously uses a large guide and guard structure to strengthen the stable clamping of the rolled piece, thereby significantly reducing the finished product size deviation and improving the size control precision. BRIEF DESCRIPTION OF DRAWINGS
[0032] Figure 1 It is a schematic diagram of the existing steel product technical conditions QP001-2024.
[0033] Figure 2 It is a schematic diagram of the 9-specification rolling program table.
[0034] Figure 3 It is a schematic diagram of the 11-specification rolling program table.
[0035] Figure 4 It is a schematic diagram of the 12-specification size comparison before and after the guide and guard clamping are improved.
[0036] Figure 5 It is a schematic diagram of the 9-specification round size condition record after improvement.
[0037] Figure 6 Schematic diagram for improving the record of the size of the finished 11 gauge round bar. DETAILED DESCRIPTION
[0038] In order to make the objects, technical solutions and advantages of the present application clearer, the technical solutions of the present application will be described below in connection with the specific embodiments of the present application and corresponding drawings. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative work fall within the scope of protection of the present application.
[0039] In order to solve the technical problems in the prior art, the present application will be further described in connection with the drawings and embodiments:
[0040] As shown in Figures 2 to 6 The present application discloses a round steel size precision control method, which is applied to a continuous rolling production line including a rough rolling mill group, a medium rolling mill group, a pre-precision rolling mill group and a precision rolling mill group, and includes the following steps:
[0041] Pass and material type optimization: based on the target finished product specification, the pass system of the pre-precision rolling and the precision rolling stage is designed for matching, an elliptical pass and a circular pass are alternately arranged in the pass system, the cross-sectional shape of the rolled piece at the pre-precision rolling outlet is regular circular, and the precision rolling mill group is allocated with a decreasing cross-sectional area for each pass;
[0042] Guide system improvement: the guide system is improved by identifying the machine frame in the precision rolling mill group that causes the rolling piece to swing due to insufficient guide clamping force, configuring the inlet rolling guide of the machine frame with a guide not less than eight inches, and increasing the radial clamping force of the rolling piece to reduce the swing of the rolling piece in the mill group;
[0043] Rolling process control: during the rolling process, the rolling speed of each machine frame of the precision rolling mill group is controlled to be increasing, and the rolling piece is rolled in a micro-tension state.
[0044] In view of the loop abnormality and size fluctuation problem caused by the rotation of the rolling piece in the continuous rolling production, the present application solves the problem by double technical means: on the one hand, the pass and material type design of the pre-precision rolling and the precision rolling is optimized, the semi-finished product at the outlet of the medium rolling or the pre-precision rolling is efficiently rounded, and the attitude deviation of the rolling piece is avoided; on the other hand, the large guide is configured to enhance the clamping stability of the rolling piece, and the double cooperation effectively reduces the size fluctuation of the finished product, and ensures that the size precision meets the standard.
[0045] By optimizing the pass system and material shape parameters of pre-finishing and finishing, the precise roundness of the semi-finished product at the outlet of the intermediate rolling or pre-finishing is realized, and the abnormal loop caused by the rotation of the rolled piece is fundamentally avoided; the reliable clamping of the rolled piece by the large guide is further weakened, which provides key technical support for the improvement of the size precision of the finished product.
[0046] In some embodiments, when the total number of machine stands of the finishing rolling unit is N, the inlet rolling guide of the N-4th stand to the last stand is configured with a guide not less than 8 inches.
[0047] The N-4th stand to the last stand of the finishing rolling unit is the key pass for sizing the finished product size, and is uniformly configured with a guide not less than 8 inches to ensure that the clamping force of the rolled piece in this interval meets the high-precision shape control requirements, avoids local size deviation caused by insufficient guide specifications of some key stands, realizes the size uniformity in the full length range of the finished product, and reduces the cutting amount of the head, tail and other easy-to-exceed parts.
[0048] Some embodiments further comprise:
[0049] Pressure sensors and displacement sensors are installed at the inlet and outlet of the guide to monitor the change of clamping force data in real time; the opening degree of the guide is dynamically adjusted by a hydraulic or electric actuator, the opening degree of the guide is dynamically adjusted according to the sensor feedback, and the clamping force is maintained stable in the interval suitable for rolling conditions; the actuator communicates with the rolling mill control system to realize the automatic compensation and alarm function of the clamping force, and when the clamping force deviates from the set threshold, the parameter adjustment or sound and light alarm is automatically triggered.
[0050] The pressure sensors and displacement sensors at the inlet and outlet of the guide can capture the change of clamping force in real time, break the hysteresis of traditional manual experience judgment, timely find the clamping force abnormality (such as looseness, tightness), provide accurate data support for subsequent adjustment, and avoid batch size deviation caused by failure to timely detect the clamping force problem. The hydraulic or electric actuator dynamically adjusts the opening degree of the guide according to the sensor feedback, so that the clamping force is stable in the adaptive interval, avoids the clamping force fluctuation caused by the slight change of the rolled piece size or the wear of the guide, further reduces the rolling piece swing, ensures the posture stability of the rolled piece in the finishing rolling stage, and improves the reliability of the size precision control.
[0051] Some embodiments further comprise: loop buffer control: a loop controller is arranged between the pre-finishing rolling unit and the finishing rolling unit, and the loop height is adjusted in real time to absorb and buffer the rolled piece size difference and flow fluctuation caused by the closed rolling of the intermediate rolling unit and the single and double line alternating rolling.
[0052] The intermediate rolling closed mill is insufficient in rigidity, has large springback, and single and double line rolling is prone to produce size difference of rolling piece. The loop controller absorbs the difference by adjusting the loop height, avoids size fluctuation from being transmitted to the finishing rolling mill set, prevents the problems of local partial flattening and out-of-roundness of finished products caused by uneven size of incoming materials in the finishing rolling stage, and improves the size consistency of finished products.
[0053] The loop can buffer the rolling piece flow difference between the intermediate rolling and the pre-finishing rolling and the finishing rolling, avoid the problems of steel stacking or steel drawing caused by flow mismatch, ensure the coordination of rolling rhythm between each mill set, reduce the size deviation caused by process interruption (such as the abnormal size of the head when restarting rolling), and improve the production stability and the finished product qualification rate.
[0054] In some embodiments, the pass and material type optimization step specifically includes:
[0055] Based on the target finished product diameter D, a set of decreasing roll gap values are set for the passes from the last stand of the pre-finishing rolling to the last stand of the finishing rolling;
[0056] According to the set roll gap values and the pass system, the rolling piece height and width of each pass are calculated and determined, so that the cross-sectional shape of the pre-finishing rolling outlet rolling piece is a regular circle, and the oval pass fullness = cross-sectional area / (pass height x pass width x 0.866) is controlled within 86%-92%; the circular pass fullness = cross-sectional area / (π x (pass nominal diameter / 2)) is controlled within 92%-98%; and the finished product pass fullness is controlled within 97.8%-99.9%. 2
[0057] Based on the target finished product diameter D, the decreasing roll gap values are set, so that the cross-sectional shrinkage law of the rolling piece of each pass is controllable, the problems of too large or too small rolling piece size caused by arbitrary roll gap setting are avoided, the rolling piece height and width are calculated in combination with the pass system, and the regular circle of the pre-finishing rolling outlet rolling piece is further ensured, laying a foundation for accurate rolling of finished products in the finishing rolling.
[0058] The fullness control of the oval pass 86%-92%, the circular pass 92%-98%, and the finished product pass 97.8%-99.9% can avoid over-fullness (ear production) or under-fullness (insufficient size) of the pass, ensure perfect fitting of the rolling piece and the pass, improve the cross-sectional shape precision of the rolling piece, reduce the size out-of-tolerance caused by abnormal fullness, and help the finished product to reach the C-level precision standard.
[0059] In some embodiments, the method further includes setting the roll gap of each mill stand based on a rolling program table, and the rolling program table is established by the following model:
[0060] The total elongation coefficient is determined according to the blank size and the target finished product specification, and is distributed to each pass according to the pass system in which the oval pass and the circular pass are alternately arranged, and the elongation coefficient of each pass is controlled within 1.10 to 1.42;
[0061] According to the assigned pass elongation coefficient and the blank cross-sectional area, the target cross-sectional area, the rolled piece height and the rolled piece width of each pass are reversely calculated;
[0062] According to the calculated rolled piece width, height and pass drawing parameters, the roll gap setting value of each stand is determined.
[0063] The total elongation coefficient is determined by the blank size and the finished product specification, and is distributed to each pass in combination with the pass system, and the elongation coefficient is controlled in a reasonable range of 1.10-1.42, avoiding the quality defects (such as cracks) of the rolled piece caused by too large single-pass elongation coefficient or the waste of rolling passes caused by too small single-pass elongation coefficient, and ensuring uniform deformation of the rolled piece and stable performance.
[0064] In some embodiments, the elongation coefficient of each pass is specifically distributed in the range of:
[0065] The elongation coefficient of the rough rolling mill group pass is 1.25-1.42, the elongation coefficient of the intermediate rolling mill group pass is 1.20-1.40, the elongation coefficient of the pre-finishing rolling mill group pass is 1.15-1.35, and the elongation coefficient of the finishing rolling mill group pass is 1.05-1.25; the difference value of the elongation coefficient of adjacent passes is ≤0.15; the elongation coefficient of the elliptical pass is ≤1.35, and the elongation coefficient of the circular pass is ≤1.25.
[0066] The elongation coefficient gradient distribution of rough rolling (1.25-1.42), intermediate rolling (1.20-1.40), pre-finishing rolling (1.15-1.35), and finishing rolling (1.05-1.25) adapts to the equipment capacity of each mill group (such as the need for rapid reduction of cross-section in rough rolling and precise shape control in finishing rolling), avoids equipment overload or size deviation caused by mismatch between elongation coefficient and mill group performance, and at the same time ensures smooth transition of cross-section shrinkage of the rolled piece from the blank to the finished product, improving deformation uniformity.
[0067] The difference value of the elongation coefficient of adjacent passes is ≤0.15, avoiding stress concentration in the rolled piece caused by sudden change in deformation, reducing the risk of cracks and other quality defects; the limitation of the elongation coefficient of the elliptical pass ≤1.35 and the circular pass ≤1.25 ensures the adaptation of the deformation amount and pass structure of different pass types, avoids pass overload or abnormal shape of the rolled piece, and further guarantees size accuracy and rolled piece quality.
[0068] In some embodiments, in the pass system in which the elliptical pass and the circular pass are alternately arranged, the width-to-height ratio of the rolled piece is greater than 1.1 in the elliptical pass, and the width-to-height ratio of the rolled piece is between 0.9 and 1.1 in the circular pass.
[0069] In some embodiments, the target finished product diameter D is Ф8mm-Ф13mm, the roll gap value of the finishing mill final stand is 0.07D-0.09D, and the roll gap value of the finishing mill stand is set to be not greater than 2.0mm. The final rolling speed is inversely proportional to the target finished product diameter D.
[0070] The setting of the roll gap value of the last stand of the finish rolling is 0.07D-0.09D, which ensures that the roll gap is accurately matched with the finished product diameter, and avoids the size out-of-tolerance of the finished product caused by the imbalance between the roll gap and the diameter. The roll gap value of the finish rolling stand is not greater than 2.0 mm, which ensures that the cross-section shrinkage of the rolled piece in the finish rolling stage is in a high-precision control range, and avoids the expansion of the size fluctuation range of the rolled piece caused by the excessively large roll gap (such as the finished product diameter exceeding the deviation of ±0.20 mm), especially for the small and medium-sized finished products of Ф8 mm-Ф13 mm, the size deviation can be further limited to ensure that the finished product reaches the C-level precision standard.
[0071] Case 1:
[0072] The embodiment of the application discloses a wire rod round steel size precision control method, aiming at the problem of large size fluctuation of round steel, the roll gap of part of the size of the pass design is small, the key pass is the non-circular material type design, and the size control is difficult. The pre-finish rolling and finish rolling pass and material type are re-calculated and optimized, and on this basis, the 9, 11 and 13 size material type control is re-designed according to the existing pass system Figure 2 The 9 size rolling program table is Figure 3 The 11 size rolling program table, and the R value in the table means the extension coefficient. The newly designed material type further rounds the intermediate product at the exit of the intermediate rolling or the pre-finish rolling, avoids the abnormal change of the loop caused by the rotation of the rolled piece in the continuous rolling, and affects the precision of the finished product.
[0073] The "small" guide and guard clamping force of the finish rolling 6-inch roller ring stand is weak, and there is a problem that the "ears" alternately appear on both sides of the finished product. Analyzing the original finish rolling guide and guard configuration, the 19#, 21# imported rolling guide and guard are used for large guide and guard, and the 23#, 25# and 27# imported six-inch small guide and guard are used, and when Ф9 mm, Ф10 mm and Ф11 mm are produced, the 18# and 19# are empty, the deformation of the finish rolling is small, the six-inch small guide and guard used by the 23# imported guide and guard has the problem of insufficient clamping force, which causes the rolled piece to swing too large in the rolling mill, and causes large fluctuation of the size of the finished product. To this end, the 23# imported guide and guard is improved to use 8-inch large guide and guard, which ensures the clamping effect of the guide and guard on the rolled piece, and effectively reduces the size fluctuation.
[0074] The implementation situation after improving the guide and guard is shown in the table Figure 4 As shown in the table, on August 19, 12 size XGL was produced, and the small and large guide and guard were used on the AB line for comparison and analysis. The clamping capacity of the large guide and guard is more stable, and the size of the finished product is more stable. Compared with the original scheme of using six-inch small guide and guard, the finished product alternately changes seriously on both sides, is easy to alternately produce hair ears, and is difficult to control the ear amplitude by trying to control the oval, and the guide and guard needs to be frequently replaced; and after the 8-inch large guide and guard is used in the embodiment, the finished product alternately changes slightly on both sides, and it is easier to adjust to reach the C-level precision, and the service life of the guide and guard is normal.
[0075] By optimizing the hole type and the material type and improving the guide and clamp, the stability of the round size is greatly improved, the average cutting amount of Ф9mm, Ф11mm head and tail size is reduced by about 15 turns. After the optimization and improvement, the Ф9mm, Ф11mm finished product size record is shown as Figure 5 、 Figure 6 indicated.
[0076] In this embodiment, by optimizing the hole type and the material type and improving the guide and clamp, the size precision of 11, 12 and 13 large specifications reaches C-level precision as a whole, the finished product guide and clamp stability ensures the stability of the finished product size on both sides, and no alternating change occurs, so that the "6-inch to 8-inch" of the roller box can be continuously promoted.
[0077] In summary, after reading the present application file, according to the technical solution and technical concept of the present application, other various corresponding transformation schemes can be made without creative mental labor, which all belong to the scope protected by the present application.
Claims
1. A method for controlling the dimensional accuracy of wire rod round steel, characterized in that, Applied to a continuous rolling production line including a roughing mill, intermediate mill, pre-finishing mill, and finishing mill, characterized by comprising the following steps: Pass and material shape optimization: Based on the target finished product specifications, the pass system of the pre-finishing and finishing stages is designed to match. An alternating elliptical and circular pass system is adopted to make the cross-sectional shape of the pre-finishing exit piece a regular circle, and the cross-sectional area of each pass of the finishing mill is allocated to each pass in a progressively decreasing manner. Improved guide system: Identify stands in the finishing mill where the workpiece swings due to insufficient guide clamping force, and configure the inlet rolling guides of such stands to be no less than eight inches in size; Rolling process control: During the rolling process, the rolling speed of each stand of the finishing mill is controlled to be incrementally configured, and the workpiece is rolled under micro-tension.
2. The method for controlling the dimensional accuracy of wire rod round steel according to claim 1, characterized in that, Also includes: Pressure and displacement sensors are installed at the guide entrance and exit to monitor changes in clamping force data in real time. The guide opening is dynamically adjusted by hydraulic or electric actuators, and the guide opening is dynamically adjusted based on sensor feedback to maintain the clamping force stable within the range suitable for rolling conditions. The actuator communicates with the rolling mill control system to achieve automatic compensation and alarm functions for clamping force. When the clamping force deviates from the set threshold, it automatically triggers parameter adjustment or audible and visual alarms.
3. The method for controlling the dimensional accuracy of wire rod round steel according to claim 1, characterized in that, When the total number of stands in the finishing mill is N, from the N-4th stand to the last stand, the inlet rolling guides are all configured with guides of not less than 8 inches.
4. The method for controlling the dimensional accuracy of wire rod round steel according to claim 1, characterized in that, Also includes: Loop buffer control: A loop controller is installed between the pre-finishing mill and the finishing mill. By monitoring and adjusting the loop height in real time, the loop controller absorbs and buffers the difference in the size of the rolled bar and the fluctuation in the flow rate caused by the use of closed-type rolling mills and alternating single and double-line rolling in the intermediate rolling mill.
5. The method for controlling the dimensional accuracy of wire rod round steel according to claim 1, characterized in that, The specific steps for optimizing the orifice shape and material shape include: Based on the target finished product diameter D, a set of decreasing roll gap values are set for the number of passes from the pre-finishing last stand to the finishing last stand; Based on the set roll gap value and pass system, calculate and determine the height and width of the rolled piece for each pass, so that the cross-sectional shape of the pre-finishing exit rolled piece is a regular circle, and the filling degree of the elliptical pass in the finishing stage is controlled between 86% and 92% (cross-sectional area / (pass height × pass width × 0.866)). The filling degree of the circular pass is calculated as (cross-sectional area / (π × (nominal diameter of pass / 2))). 2 The fill rate should be controlled between 92% and 98%; the finished hole filling rate should be controlled between 97.8% and 99.9%.
6. The method for controlling the dimensional accuracy of wire rod round steel according to claim 5, characterized in that, It also includes setting the roll gap for each stand based on a rolling program table, which is established using the following model: The total elongation coefficient is determined based on the billet size and the target finished product specifications, and the total elongation coefficient is allocated to each pass according to the alternating arrangement of elliptical and round hole types. The elongation coefficient of each pass is controlled between 1.10 and 1.
42. The target cross-sectional area, roll height, and roll width for each pass are calculated in reverse based on the allocated pass elongation coefficient and billet cross-sectional area. Based on the calculated workpiece width, height, and roll pass parameters, determine the roll gap settings for each stand.
7. The method for controlling the dimensional accuracy of wire rod round steel according to claim 6, characterized in that, The specific allocation range of the extension coefficient for each pass is as follows: The elongation coefficient of the roughing mill passes is 1.25 to 1.42, the elongation coefficient of the intermediate mill passes is 1.20 to 1.40, the elongation coefficient of the pre-finishing mill passes is 1.15 to 1.35, and the elongation coefficient of the finishing mill passes is 1.05 to 1.
25. The difference in extension coefficient between adjacent passes is ≤0.15; The elongation coefficient for elliptical holes is ≤1.35, and the elongation coefficient for circular holes is ≤1.
25.
8. The method for controlling the dimensional accuracy of wire rod round steel according to claim 1, characterized in that, In the alternating elliptical and circular pass system, the aspect ratio of the rolled piece is greater than 1.1 in the elliptical pass and between 0.9 and 1.1 in the circular pass.
9. The method for controlling the dimensional accuracy of wire rod round steel according to claim 5, characterized in that, The target finished product diameter D is Ф8mm~Ф13mm, the roll gap value of the last stand of the finishing mill is 0.07D~0.09D, and the roll gap value of the finishing mill stand is set to be no more than 2.0mm.
10. The method for controlling the dimensional accuracy of wire rod round steel according to claim 9, characterized in that, The final rolling speed is inversely proportional to the target finished product diameter D.