Production method for improving the stability of high-speed bar modular finishing mill

Abstract

The present invention relates to a production method for improving the stability of a modular finishing mill for high-speed bars, and belongs to the technical field of high-speed bar production in the steel and metallurgical industry. By matching the first finishing mill group with the second finishing mill group, the high-speed bars are rolled with a small reduction by the first two stands of the second finishing mill group, thereby reducing the frequent impact on the roller rings and bearings of the modular rolling mill due to low-temperature and large reduction rolling when the tension is unstable. By rolling with a large reduction by the last two stands of the second finishing mill group, the grain refinement of the threaded steel products is achieved. By using the small aspect ratio of the elliptical hole type after the second finishing mill group, the instability caused by the frequent steel biting and speed drop of the modular rolling mill is reduced, thereby improving the stability and hourly output of the unit. The finishing mill group adopts low-temperature rolling, and improves the mechanical properties of the finished product through fine grain strengthening and phase transformation strengthening. The tension adjustment is achieved by adjusting the speed between the finishing mill groups and between the stands of the finishing mill group, thereby improving the dimensional accuracy of the head and tail of the rolled piece and improving the smoothness of the final product.

Description

Technical Field

[0001] The invention belongs to the technical field of high-speed bar production in the iron and steel metallurgical industry, and relates to a production method for improving the stability of a high-speed bar modular finishing mill. Background Art

[0002] As one of the important products of the steel industry, rebar bars are widely used in construction, bridges, railways and other industries. In recent years, the output has continued to increase, reaching 27.49 million tons in 2021.

[0003] To increase rebar production and maintain stability, steel mills have adopted high-speed steel loading devices in recent years. By increasing rolling and loading speeds, they reduce the high accident rate caused by slitting and rolling, thereby increasing hourly output and improving economic benefits. High-speed steel loading devices primarily include: pinch rolls, switch, multi-length flying shear, dual-channel tail brake, and dual-channel rotating hub 16.

[0004] However, with the continuous promotion and application of low-temperature rolling technology, hot machine rolling technology, controlled rolling and controlled cooling technology in the production of high-speed rebar bars, the instability of modular finishing mills in the current high-speed bar production methods has become more and more serious, especially when rolling specifications of 18mm and above, frequent roller explosions and oil film bearing damage have occurred, resulting in low rolling line efficiency and inability to achieve low-temperature rolling. Summary of the Invention

[0005] In light of this, the present invention aims to provide a production method for improving the stability of a high-speed modular finishing mill for bar production. This production line and method offer low design and construction costs, ease of industrialization, and high stability, high hourly production line output, and high efficiency, resulting in significant economic benefits.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A production method for improving the stability of a high-speed bar modular finishing mill, the production method specifically comprising the following steps:

[0008] S1 continuous casting billet heating;

[0009] S2 roughing mill rolling: the billet heated in S1 is rolled in the roughing mill using horizontal and vertical alternating rolling or flat roll rolling;

[0010] S3 intermediate rolling mill group rolling: the rolled piece obtained in S2 is rolled in the intermediate rolling mill group;

[0011] S4 pre-finishing mill rolling: the rolled piece obtained in S3 is rolled in the pre-finishing mill;

[0012] S5 controlled cooling and finishing rolling: the rolled piece obtained in S4 is cooled before finishing rolling and then finished rolling;

[0013] S6 controlled cooling and finishing rolling two groups: the rolled piece obtained in S5 is subjected to cooling before finishing rolling two groups and finishing rolling two groups;

[0014] S7 controlled cooling after rolling and high-speed steel feeding;

[0015] S8 cooling bed, fixed-length flying shear, cold shearing and fixed-length cutting, bundle collection.

[0016] Optionally, a heating furnace or an electromagnetic induction furnace is used in S1 to heat the continuous casting billet.

[0017] Optionally, the cross-section of the continuous casting billet in S1 is 150 mm × 150 mm to 180 mm × 180 mm or a rectangular billet of equal area; the billet temperature after heating is 950° C. to 1230° C.

[0018] Optionally, in S2, the square billet is rolled by the roughing mill for 6 passes, and the rectangular billet is rolled by the roughing mill for 5 or 7 passes.

[0019] Optionally, in step S2, hole-type rolling is adopted, and the rough rolling mill is a box-type-box-elliptical-round hole-type system. During the rolling process, the deformation compression ratio of each pass is controlled to be 1.25~1.48, the deformation temperature is 880℃~1150℃, and the running speed of the rolled piece during the rolling process of the rough rolling mill is 0.075m / s~3.00m / s.

[0020] Optionally, in step S3, 4 to 8 passes of medium rolling are performed by the rolling mill group, the hole type system during rolling is an elliptical-circular hole type system, the deformation compression ratio of each pass is controlled to be 1.20 to 1.45, the deformation temperature is 850℃ to 1100℃, and the rolling speed is 0.5m / s to 8.00m / s.

[0021] Optionally, in step S4, the hole type system during rolling is an elliptical-circular hole type system, the deformation compression ratio of each pass is controlled to be 1.20-1.40, the deformation temperature is 850°C-1050°C, and the rolling speed is 2.0m / s-20.00m / s.

[0022] Optionally, in step S5, a group of pre-cooling is performed in a water tank, and after recovery, a group of 2 to 4 horizontal and vertical top-cross cantilever finishing rolling is performed. The finishing rolling mill adopts low-temperature and large-reduction rolling. The hole type system during rolling is an elliptical-circular hole type system. During the rolling process, the deformation compression ratio of each pass is controlled to be 1.20 to 1.35, the deformation temperature is 800℃ to 950℃, and the rolling speed of the rolled piece is 5.0m / s to 20.00m / s.

[0023] Optionally, in step S6, controlled cooling is performed through a water tank, and a recovery section is set after controlled cooling to control the temperature entering each rolling mill and the core surface temperature difference. After the recovery, the rolled piece is subjected to two groups of 1-to-1 or 1-to-2 transmission form, 4 stands, 45° top-cross cantilever heavy-load finishing rolling. The first two stands of the two finishing groups adopt low-temperature small reduction rolling, and the last two stands adopt low-temperature rolling. The hole type system during rolling is an elliptical-circular hole type system. During the rolling process, the deformation compression ratio of each of the first two passes is controlled to be 1.10-1.20, and the deformation compression ratio of each of the last two passes is controlled to be 1.12-1.28. The deformation temperature is 730℃-980℃, and the rolled piece running speed is 6.0m / s-50.00m / s.

[0024] Optionally, in step S7, the rolled piece after the second group of finishing rolling in step (6) is water-cooled and recovered after water cooling in a water tank after the second group of finishing rolling. The water tank is arranged in multiple sections and the recovery after water cooling is taken into consideration. During cooling, the surface temperature is not lower than the martensite start transformation temperature to obtain an ideal uniform microstructure and better product mechanical properties. After the rolled piece is cooled, it is transported through a dual-channel high-speed steel-loading device; the temperature of the cooling bed on the rolled piece is 600℃~950℃ to control the final microstructure and surface red rust problem of the rolled piece; the running speed of the rolled piece of the high-speed steel-loading device is 6.0m / s~60m / s; in step S8, the temperature of the cooling bed below the rolled piece is 300℃~600℃.

[0025] Optionally, the number of the second finishing rolling stands is 4 stands. When rolling all specifications, the number of the second finishing rolling stands is 4.

[0026] Optionally, the average compression ratio of the first two passes of the second finishing rolling group is less than 1.2.

[0027] Optionally, the average compression ratio of the last two passes of the second finishing rolling group is not less than 1.2.

[0028] Optionally, the aspect ratio of the two groups of elliptical pass profiles in the finishing rolling process is greater than 1.6 and less than 2.

[0029] Optionally, one set of finishing rolling mill stands is a horizontal vertical top-cross cantilever mill or a 45° top-cross cantilever mill, with two stands.

[0030] Optionally, the diameter of the roller ring of a finishing cantilever rolling mill is greater than 270 mm.

[0031] Optionally, the second finishing rolling group adopts a 1-to-1 or 1-to-2 transmission form, a 4-stand 45° top-cross cantilever heavy-load finishing mill.

[0032] Optionally, the second finishing rolling group adopts a 1-to-1 or 1-to-2 transmission mode. The diameter of the roller of the 4-stand 45° top-cross cantilever heavy-duty finishing mill is greater than 220mm and less than 270mm.

[0033] Optionally, water tanks and recovery sections are provided before and after the first finishing rolling group and after the second finishing rolling group;

[0034] Optionally, the diameter specification of the rebar produced by the production line and production method is 6mm-25mm.

[0035] The beneficial effects of the present invention are:

[0036] 1) Improve the instability of modular rolling mills caused by frequent steel biting and speed drop, improve the stability of the unit and hourly output, the production line is stable, the yield rate is high, and the failure rate is low.

[0037] 2) Temperature-controlled water tanks are installed before and after the first finishing rolling mill and after the second finishing rolling mill to control the rolling temperature of the finishing mill. The finishing mill adopts low-temperature rolling, which improves the mechanical properties of the finished product through fine grain strengthening and phase transformation strengthening, and reduces the alloy cost through controlled rolling and controlled cooling.

[0038] 4) The 1-to-1 or 1-to-2 modular finishing mill is used for rolling, which ensures stable tension between mills, reduces dimensional fluctuations, and increases the yield rate.

[0039] 5) Tension adjustment is achieved through speed adjustment between finishing mill groups and between the stands of the finishing mill group, which can improve the dimensional accuracy of the head and tail of the rolled piece and improve the smoothness of the final product;

[0040] 6) It can achieve high-precision negative deviation rolling and improve metal yield;

[0041] 7) It can produce threaded steel bars with specifications ranging from Φ6mm to 25mm, with a wide range of product specifications.

[0042] The present invention achieves low-pressure rolling of high-speed bars by the first two stands of the second finishing rolling group through matching between the first finishing rolling group and the second finishing rolling group, reduces the frequent impact on the roller rings and bearings of the modular rolling mill due to low-temperature high-pressure rolling when the tension between the first finishing rolling group and the second finishing rolling group is unstable, realizes grain refinement of threaded steel products by the high-pressure rolling of the two stands after the second finishing rolling group, reduces impact speed drop by the small aspect ratio of the elliptical hole after the second finishing rolling group, reduces the instability caused by frequent steel biting speed drop of the modular rolling mill, and improves the stability and hourly output of the unit; by arranging temperature-controlled water tanks before and after the first finishing rolling group and after the second finishing rolling group, the rolling temperature of the finishing rolling unit is controlled, the finishing rolling unit adopts low-temperature rolling, improves the mechanical properties of the finished product by fine grain strengthening and phase transformation strengthening, and reduces the alloy cost by controlled rolling and controlled cooling; by speed adjustment between the finishing rolling units and between the stands of the finishing rolling units, tension adjustment is achieved, the dimensional accuracy of the head and tail of the rolled piece is improved, and the smoothness of the final product is improved.

[0043] Other advantages, objects, and features of the present invention will be described in part in the following description and, in part, will be apparent to those skilled in the art upon examination of the following description or may be learned from practice of the present invention. The objects and other advantages of the present invention may be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below with reference to the accompanying drawings, in which:

[0045] Figure 1 This is a schematic diagram of the layout of a single high-speed bar production line and production method of the present invention;

[0046] Figure 2 This is a schematic diagram of the layout of the dual high-speed bar production line and production method of the present invention;

[0047] Figure 3 This is a schematic diagram of a 1-on-2 and 1-on-1 modular finishing mill unit according to the present invention; wherein:

[0048] Figure 3 (1) is a schematic diagram of a 1-to-2 modular finishing mill unit;

[0049] Figure 3 (2) is a schematic diagram of a 1-to-1 modular finishing mill;

[0050] Figure 4 This is the second pass structure diagram of the finishing rolling of the present invention; wherein:

[0051] Figure 4 (1) is the elliptical hole structure diagram;

[0052] Figure 4 (2) is a diagram of a circular hole structure.

[0053] Figure numerals: 1—heating furnace 1; 2—roughing mill group; 3—flying shear after roughing; 4—intermediate rolling mill group; 5—flying shear before pre-finishing; 6—pre-finishing mill group (pre-finishing slitting mill group); 7—front water tank of finishing mill group 1; 8—flying shear before finishing mill group 1; 9—finishing mill group 1; 10—front water tank of finishing mill group 2; 11—flying shear before finishing mill group 2; 12—double-module finishing mill group 2 (finishing mill group 2); 13—rear water tank of finishing mill group 2; 14—pinch roll and high-speed flying shear; 15—high-speed steel feeding device; 16—hub 16; 17—cooling bed. DETAILED DESCRIPTION

[0054] The following describes the embodiments of the present invention by means of specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present invention, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0055] Among them, the accompanying drawings are only for illustrative purposes and represent only schematic diagrams rather than actual pictures, and should not be understood as limiting the present invention. In order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, enlarged or reduced, and do not represent the dimensions of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions may be omitted in the accompanying drawings.

[0056] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "front", "back", etc. indicating directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operate in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0057] See also Figures 1 to 4 ,in, Figure 4 The meanings of the symbols in (1) are as follows: R-ellipse radius; H-hole height; h-hole half height; A-hole width; e-roll gap; Figure 4 The meanings of the symbols in (2) are as follows: R-circle radius; H-hole height; h-hole half height; A-hole width; s-roll gap; α-expansion angle. Figure 1 and Figure 2 Two different types of production lines are provided, the main difference between them is Figure 2 The rolled pieces are diverted by the pre-finishing rolling and slitting unit 6, and a two-way finishing rolling unit 9 and a double-module finishing rolling unit 2 12 are provided.

[0058] Example 1 (Single high-speed bar - rolling specification Φ12mm)

[0059] Reference Figure 1 、 Figure 3 、 Figure 4As shown in Table 1, according to the present invention, the production process sequence includes: heating by a heating furnace 1 or electromagnetic induction heating, rolling by a roughing mill 2, trimming of the steel heads and tails by a flying shear 3 after roughing, rolling by an intermediate rolling mill 4, trimming of the steel heads and tails by a flying shear after intermediate rolling, rolling by a pre-finishing mill 6, water cooling before finishing the first group, trimming of the steel heads and tails before finishing the first group, rolling by a finishing group, water cooling after finishing the first group, trimming of the steel heads and tails before finishing the second group, rolling by a finishing group, water cooling after finishing the second group, pinching and shearing by a pinch roller and a high-speed flying shear 14, braking by a high-speed brake on the steel clamp, loading of the steel by a rotating hub 16, cooling by a double-length cooling bed 17, collection, bundling, alignment, and weighing. The process is specifically as follows:

[0060] (1) Heating: The continuous casting slab is heated in a heating furnace 1 or an electromagnetic induction furnace. The cross-section of the continuous casting slab is 165 mm × 165 mm × 12000 mm and the weight of the casting is 2516 kg. After heating, the casting temperature is 1050°C ± 30°C.

[0061] (2) Rolling by roughing mill 2: After descaling by high-pressure water, the billet heated in step (1) is subjected to 6 passes of roughing mill 2 pass rolling by alternating horizontal and vertical rolling. The pass system is a box-box-elliptical-circular pass system. During rolling, each stand is provided with a guide before and after. During the rolling process, the average compression ratio of the roughing mill is controlled to be 1.331, the total elongation is 5.558, the cross-sectional diameter after 6 passes of rolling is 80 mm, the deformation temperature is 900°C to 1000°C, the bite speed of the 1H stand during the roughing mill 2 is 0.171 m / s, and the exit speed of the 6V stand after 6 passes of rolling is 0.953 m / s;

[0062] (3) Rolling by the intermediate rolling mill group 4: The rolled piece after being rolled by the roughing mill group 2 in step (2) is subjected to head and tail trimming by the flying shear 3 after roughing and then rolled by the intermediate rolling mill group 4 for 6 passes. The hole system during rolling is an elliptical-circular hole system. Guides are provided before and after each rolling mill. During the rolling process, the average compression ratio of the intermediate rolling mill group 4 is controlled to be 1.282, the total elongation is 4.432, the cross-sectional diameter after 6 rolling passes is 38 mm, the deformation temperature is 900°C to 1000°C, the bite speed of the rolled piece of the 7H stand during the rolling process of the intermediate rolling mill group 4 is 0.953 m / s, and the exit speed of the 12V stand after 6 rolling passes is 4.220 m / s;

[0063] (4) Pre-finishing mill group 6 rolling: After the rolled piece in step (3) is rolled by the intermediate rolling mill group 4, it is subjected to controlled cooling and then cut off the head and tail by the pre-finishing flying shear 5 before pre-finishing rolling, and then rolled by the pre-finishing mill group 6 for two passes. The hole system during rolling is an elliptical-circular hole system. Each rolling mill is provided with a guide before and after. During the rolling process, the average compression ratio of the pre-finishing mill group 6 is controlled to be 1.310, the total elongation is 1.717, the cross-sectional diameter after two rolling passes is 29 mm, and the deformation temperature is 880°C to 1050°C. During the rolling process of the pre-finishing mill group 6, the 13H stand rolled piece bite speed is 4.220 m / s, and the 16V stand outlet speed after two rolling passes is 7.250 m / s.

[0064] (5) Controlled cooling and finishing rolling: The rolled piece rolled by the pre-finishing mill group 6 in step (4) is cooled by the water tank 7 before finishing rolling. After recovery, it is rolled by a flat top cross cantilever mill or a 45° top cross cantilever mill for two passes. The roller ring diameter of the finishing cantilever mill group is greater than 270 mm. The finishing mill group adopts low temperature and large reduction rolling. The hole system during rolling is an elliptical-circular hole system. Guides are provided before and after each rolling mill. A front flywheel is provided before the finishing rolling group 9. Shear 8 shears the head and tail, and a looper is set in front of the unit to control the tension between the finishing rolling unit 9 and the pre-finishing rolling unit 6 to achieve tension-free rolling. During the rolling process, the average compression ratio of the finishing rolling unit 9 is controlled to be 1.261, the total elongation is 1.590, the cross-sectional diameter after two rolling passes is 23.0mm, the deformation temperature is 830℃~930℃, and the bite speed of the 17# stand during the finishing rolling unit 2 is 7.25m / s. After two rolling passes, the exit speed of the 18# stand is 11.53m / s.

[0065] (6) Controlled cooling and finishing rolling of the second group: The rolled piece in step (5) is controlled and cooled by the water tank 10 before the finishing rolling group. After the controlled cooling, a recovery section is set to control the temperature entering each rolling mill and the temperature difference between the core and the surface. After the recovery, the rolled piece is subjected to 1-to-1 or 1-to-2 transmission mode, 4-stand 45° top-cross cantilever heavy-load finishing rolling of the second group. The roller diameter of the 45° top-cross cantilever heavy-load rolling mill is greater than 220mm and less than 270mm. The first two stands of the finishing rolling group adopt low-temperature small reduction rolling, and the average compression ratio of each pass is less than 1.2. The last two stands adopt low-temperature large reduction rolling, and the average compression ratio of each pass is less than 1.2. is not less than 1.2, the pass system during rolling is an elliptical-circular pass system, and each rolling mill is equipped with guides before and after. A flying shear 11 is set in front of the finishing rolling unit 2 in front of the double-module finishing rolling unit 12 to shear the head and tail. During the rolling process, the average compression ratio of the finishing rolling unit 2 is controlled to be 1.191, the total elongation is 2.095, the cross-sectional diameter after 4 rolling passes is 23mm, the deformation temperature is 750℃~900℃, and the biting speed of the rolled piece of the 19# stand during the finishing rolling unit 2 is 11.53m / s, and the exit speed of the 22# stand after 4 rolling passes is 23.2m / s;

[0066] (7) Controlled cooling after rolling and high-speed steeling: The rolled piece after the second group of finishing rolling in step (6) is water-cooled and recovered after water cooling in the water tank 13 after the second group of finishing rolling. The water tank is arranged in multiple sections and the recovery after water cooling is taken into consideration. During cooling, the surface temperature is not lower than the martensite transformation temperature to obtain an ideal uniform microstructure and better product mechanical properties. After the rolled piece is cooled, it is transported through a dual-channel high-speed steeling device. The temperature of the cooling bed on the rolled piece is 650℃~920℃ to control the final microstructure and surface red rust problem of the rolled piece; the running speed of the rolled piece of the high-speed steeling device 15 is 23.2m / s, and the high-speed flying shear speed of the high-speed steeling device 15 is not less than 24m / s;

[0067] (8) Cooling on cooling bed: The rolled pieces conveyed on high speed in step (7) are cooled on cooling bed 17. The temperature of the rolled pieces on cooling bed 17 is 350℃~600℃. After being conveyed by roller, they are cold sheared to length, sawed, sorted, counted, bundled and collected.

[0068] Example 2 (Single high-speed bar - rolling specification Φ16mm)

[0069] Reference Figure 1 、 Figure 3 、 Figure 4 As shown in Table 1, according to the present invention, the production process sequence includes: heating by a heating furnace 1 or electromagnetic induction heating, rolling by a roughing mill 2, trimming of the steel heads and tails by a flying shear 3 after roughing, rolling by an intermediate rolling mill 4, trimming of the steel heads and tails by a flying shear after intermediate rolling, rolling by a pre-finishing mill 6, water cooling before finishing the first group, trimming of the steel heads and tails before finishing the first group, rolling by a finishing group, water cooling after finishing the first group, trimming of the steel heads and tails before finishing the second group, rolling by a finishing group, water cooling after finishing the second group, pinching and shearing by a pinch roller and a high-speed flying shear 14, braking by a high-speed brake on the steel clamp, loading of the steel by a rotating hub 16, cooling by a double-length cooling bed 17, collection, bundling, alignment, and weighing. The process is specifically as follows:

[0070] (1) Heating: The continuous casting slab is heated in a heating furnace 1 or an electromagnetic induction furnace. The cross-section of the continuous casting slab is 165 mm × 165 mm × 12000 mm and the weight of the casting is 2516 kg. After heating, the casting temperature is 1050°C ± 30°C.

[0071] (2) Rolling by roughing mill 2: After descaling by high-pressure water, the billet heated in step (1) is subjected to 6 passes of roughing mill 2 pass rolling by alternating horizontal and vertical rolling. The pass system is a box-box-elliptical-circular pass system. During rolling, each stand is provided with a guide before and after. During the rolling process, the average compression ratio of the roughing mill is controlled to be 1.331, the total elongation is 5.558, the cross-sectional diameter after 6 passes of rolling is 80 mm, the deformation temperature is 900°C to 1000°C, the bite speed of the 1H stand during the roughing mill 2 is 0.187 m / s, and the exit speed of the 6V stand after 6 passes of rolling is 1.04 m / s;

[0072] (3) Rolling by the intermediate rolling mill group 4: The rolled piece after being rolled by the roughing mill group 2 in step (2) is subjected to the head and tail trimming by the flying shear 3 after roughing and then rolled by the intermediate rolling mill group 4 for 6 passes. The hole system during rolling is an elliptical-circular hole system. Guides are provided before and after each rolling mill. During the rolling process, the average compression ratio of the intermediate rolling mill group 4 is controlled to be 1.282, the total elongation is 4.432, the cross-sectional diameter after 6 rolling passes is 38 mm, the deformation temperature is 900°C to 1000°C, the bite speed of the rolled piece of the 7H stand during the rolling process of the intermediate rolling mill group 4 is 1.04 m / s, and the exit speed of the 12V stand after 6 rolling passes is 4.61 m / s;

[0073] (4) Pre-finishing mill group 6 rolling: After the rolled piece in step (3) is rolled by the intermediate rolling mill group 4, it is subjected to controlled cooling and then cut off the head and tail by the pre-finishing flying shear 5 before pre-finishing rolling, and then rolled by the pre-finishing mill group 6 for 4 passes. The hole system during rolling is an elliptical-circular hole system. Each rolling mill is provided with a guide before and after. During the rolling process, the average compression ratio of the pre-finishing mill group 6 is controlled to be 1.314, the total elongation is 2.983, the cross-sectional diameter after 4 rolling passes is 22 mm, the deformation temperature is 880°C to 1050°C, the 13H stand rolled piece bite speed during the pre-finishing mill group 6 is 4.61 m / s, and the 16V stand outlet speed after 4 rolling passes is 13.74 m / s;

[0074] (5) Controlled cooling and finishing rolling of group 9: The rolled piece rolled by the pre-finishing mill group 6 in step (4) is cooled by the water tank 7 before finishing rolling of group 1, and after recovery, it is rolled by a flat top cross cantilever mill or a 45° top cross cantilever mill for 2 passes. The roller ring diameter of the finishing cantilever mill group is greater than 270mm. The finishing mill group adopts low temperature and large reduction rolling. The hole system during rolling is an elliptical-circular hole system. Guides are provided before and after each rolling mill. A front flywheel is provided before the finishing rolling group 9. Shear 8 shears the head and tail, and a looper is set in front of the unit to control the tension between the finishing rolling unit 9 and the pre-finishing rolling unit 6 to achieve tension-free rolling. During the rolling process, the average compression ratio of the finishing rolling unit 9 is controlled to be 1.250, the total elongation is 1.563, the cross-sectional diameter after two rolling passes is 17.6mm, the deformation temperature is 830℃~930℃, and the bite speed of the 17# stand during the finishing rolling unit 2 is 13.74m / s. After two rolling passes, the exit speed of the 18# stand is 21.48m / s.

[0075] (6) Controlled cooling and finishing rolling of the second group: The rolled piece in step (5) is controlled and cooled by the water tank 10 before the finishing rolling group. After the controlled cooling, a recovery section is set to control the temperature entering each rolling mill and the temperature difference between the core and the surface. After the recovery, the rolled piece is subjected to 1-to-1 or 1-to-2 transmission mode, 4-stand 45° top-cross cantilever heavy-load finishing rolling of the second group. The roller diameter of the 45° top-cross cantilever heavy-load rolling mill is greater than 220mm and less than 270mm. The first two stands of the finishing rolling group adopt low-temperature small reduction rolling, and the average compression ratio of each pass is less than 1.2. The last two stands adopt low-temperature large reduction rolling, and the average compression ratio of each pass is less than 1.2. is not less than 1.2, the pass system during rolling is an elliptical-circular pass system, and each rolling mill is equipped with guides in front and behind. A flying shear 11 is set in front of the finishing rolling unit 2 in the double-module finishing rolling unit 12 to shear the head and tail. During the rolling process, the average compression ratio of the finishing rolling unit 2 is controlled to be 1.203, the total elongation is 2.095, the cross-sectional diameter after 4 rolling passes is 17.6mm, the deformation temperature is 750℃~900℃, and the biting speed of the 19# stand during the finishing rolling unit 2 is 13.74m / s, and the exit speed of the 22# stand after 4 rolling passes is 45m / s;

[0076] (7) Controlled cooling after rolling and high-speed steel feeding: The rolled piece after the second group of finishing rolling in step (6) is water-cooled and recovered after water cooling in the water tank 13 after the second group of finishing rolling. The water tank is arranged in multiple sections and the recovery after water cooling is taken into consideration. During cooling, the surface temperature is not lower than the martensite transformation temperature to obtain an ideal uniform microstructure and better product mechanical properties. After the rolled piece is cooled, it is transported through a dual-channel high-speed steel feeding device 15. The temperature of the cooling bed on the rolled piece is 650℃~920℃ to control the final microstructure and surface red rust problem of the rolled piece; the running speed of the rolled piece in the high-speed steel feeding device 15 is 45m / s, and the high-speed flying shear speed of the high-speed steel feeding device 15 is not less than 46m / s;

[0077] (8) Cooling on cooling bed: The rolled pieces conveyed on high speed in step (7) are cooled on cooling bed 17. The temperature of the rolled pieces on cooling bed 17 is 350℃~600℃. After being conveyed by roller, they are cold sheared to length, sawed, sorted, counted, bundled and collected.

[0078] Example 3 (Dual High-Speed ​​Bars—Rolling Specification Φ12mm)

[0079] Reference Figure 2 、 Figure 3 、 Figure 4 As shown in Table 2, according to the present invention, the production process sequence includes: heating by a heating furnace 1 or electromagnetic induction heating, rolling by a roughing mill 2, trimming of heads and tails by a flying shear 3 after roughing, rolling by an intermediate rolling mill 4, trimming of heads and tails by a flying shear after intermediate rolling, slitting and rolling by a pre-finishing mill 6, double-pass water cooling before finishing one group, double-pass trimming of heads and tails before finishing one group, double-pass rolling of a finishing group, double-pass water cooling after finishing one group, double-pass trimming of heads and tails by a flying shear before finishing two groups, double-pass rolling of finishing two groups, double-pass water cooling after finishing two groups, pinching and shearing by a pinching roller and a high-speed flying shear 14, braking by a high-speed steel clamping brake, steel loading by a rotating hub 16, cooling by a double-length cooling bed 17, collection, bundling, alignment, and weighing. The process is specifically as follows:

[0080] (1) Heating: The continuous casting slab is heated in a heating furnace 1 or an electromagnetic induction furnace. The cross-section of the continuous casting slab is 170 mm × 170 mm × 12000 mm and the weight of the casting is 2670 kg. The temperature of the casting slab after heating is 1050°C ± 30°C.

[0081] (2) Rolling by roughing mill 2: After descaling by high-pressure water, the billet heated in step (1) is subjected to 6 passes of roughing mill 2 pass rolling by alternating horizontal and vertical rolling. The pass system is a box-box-elliptical-circular pass system. During rolling, each stand is provided with a guide before and after. During the rolling process, the average compression ratio of the roughing mill is controlled to be 1.317, the total elongation is 5.226, the cross-sectional diameter after 6 passes of rolling is 85 mm, the deformation temperature is 900°C to 1000°C, the bite speed of the 1H stand during the roughing mill 2 is 0.352 m / s, and the exit speed of the 6V stand after 6 passes of rolling is 1.841 m / s;

[0082] (3) Rolling by the intermediate rolling mill group 4: The rolled piece after being rolled by the roughing rolling mill group 2 in step (2) is subjected to the head and tail trimming by the flying shear 3 after roughing and then rolled by the intermediate rolling mill group 4 for 6 passes. The hole system during rolling is an elliptical-circular hole system. Guides are provided before and after each rolling mill. During the rolling process, the average compression ratio of the intermediate rolling mill group 4 is controlled to be 1.286, the total elongation is 4.516, the cross-sectional diameter after 6 rolling passes is 40 mm, the deformation temperature is 900°C to 1000°C, the bite speed of the rolled piece of the 7H stand during the rolling process of the intermediate rolling mill group 4 is 1.841 m / s, and the exit speed of the 12V stand after 6 rolling passes is 8.320 m / s;

[0083] (4) Pre-finishing mill group 6 rolling: the rolled piece after being rolled by the intermediate rolling mill group 4 in step (3) is subjected to controlled cooling and then to head and tail trimming by the pre-finishing flying shear 5, and then to four passes of pre-finishing mill group 6 two-cut rolling. The hole system during rolling is a flat box-vertical box-pre-cutting-cutting hole system. Each rolling mill is provided with a guide before and after. During the rolling process, the average compression ratio of the pre-finishing mill group 6 is controlled to be 1.134, the total elongation is 1.653, the cross-sectional diameter after four passes of rolling is 22 mm, the deformation temperature is 930°C to 1050°C, the 13H stand rolled piece bite speed during the pre-finishing mill group 6 is 8.320 m / s, and the 16H stand outlet speed after four passes of rolling is 13.74 m / s;

[0084] (5) Controlled cooling and finishing rolling of a group 9: The two-way rolled pieces cut and rolled by the pre-finishing rolling mill group 6 in step (4) are respectively cooled by the front water tank 7 of the two-way finishing rolling group, and after recovery, they are finished by a flat top-cross cantilever rolling mill or a 45° top-cross cantilever rolling mill for 2 passes. The diameter of the roller ring of the finishing rolling group cantilever rolling mill is greater than 270mm. The finishing rolling mill group adopts low-temperature and large-reduction rolling. The hole system during rolling is an elliptical-circular hole system. Guide guards are provided before and after each rolling mill. A finishing rolling is set before the finishing rolling group 9. A group of front flying shears 8 shear the head and tail, and a looper is set in front of the unit to control the tension between the finishing rolling unit 9 and the pre-finishing rolling unit 6 to achieve tension-free rolling. During the rolling process, the average compression ratio of the finishing rolling unit 9 is controlled to be 1.250, the total elongation is 1.563, the cross-sectional diameter after two rolling passes is 17.6mm, and the deformation temperature is 830℃~930℃. During the finishing rolling unit 2 rolling process, the 17# stand has a rolling piece bite speed of 13.74m / s, and the 18# stand has an exit speed of 21.48m / s after two rolling passes.

[0085] (6) Controlled cooling and finishing rolling: The two-way rolled pieces of step (5) are respectively cooled by the front water tank 10 of the finishing rolling group 2. After controlled cooling, a recovery section is set to control the temperature entering each rolling mill and the temperature difference between the core and the surface. After recovery, the rolled pieces are subjected to 1-to-1 or 1-to-2 transmission mode, 4-stand 45° top-cross cantilever heavy-load finishing rolling in the second group. The roller diameter of the 45° top-cross cantilever heavy-load rolling mill is greater than 220mm and less than 270mm. The first two stands of the finishing rolling group 2 adopt low-temperature small reduction rolling, and the average compression ratio of each pass is less than 1.2. The last two stands adopt low-temperature large reduction rolling, and the average compression ratio of each pass is less than 1.2. The reduction ratio is not less than 1.2. The pass system during rolling is an elliptical-circular pass system. Guides are provided before and after each rolling mill. A flying shear 11 is provided in front of the finishing mill 2 in the double-module finishing mill 2 to shear the head and tail. During the rolling process, the average reduction ratio of the finishing mill 2 is controlled to be 1.203, the total elongation is 2.095, the cross-sectional diameter after 4 rolling passes is 17.6mm, the deformation temperature is 750℃~900℃, the bite speed of the rolled piece of the 19# stand during the finishing mill 2 is 13.74m / s, and the exit speed of the 22# stand after 4 rolling passes is 45m / s.

[0086] (7) Controlled cooling after rolling and high-speed steel feeding: The two-pass rolled pieces after the two groups of finishing rolling in step (6) are respectively subjected to water cooling after rolling and recovery after water cooling. The water tank is arranged in multiple intervals, and the recovery after water cooling is taken into consideration. During cooling, the surface temperature is not lower than the martensite start transformation temperature to obtain an ideal uniform microstructure and better product mechanical properties. After cooling, each pass of rolled pieces is transported through a dual-channel high-speed steel feeding device 15. The temperature of the cooling bed on the rolled pieces is 650℃~920℃ to control the final microstructure and surface red rust problem of the rolled pieces; the running speed of the rolled pieces of the high-speed steel feeding device 15 is 45m / s, and the high-speed flying shear speed of the high-speed steel feeding device 15 is not less than 46m / s;

[0087] (8) Cooling on cooling bed: The rolled pieces conveyed on high speed in step (7) are cooled on cooling bed 17. The temperature of the rolled pieces on cooling bed 17 is 350℃~600℃. After being conveyed by roller, they are cold sheared to length, sawed, sorted, counted, bundled and collected.

[0088] Example 4 (Single high-speed bar - rolling specification Φ16mm)

[0089] Reference Figure 2 、 Figure 3 、 Figure 4As shown in Table 2, according to the present invention, the production process sequence includes: heating by a heating furnace 1 or electromagnetic induction heating, rolling by a roughing mill 2, trimming of heads and tails by a flying shear 3 after roughing, rolling by an intermediate rolling mill 4, trimming of heads and tails by a flying shear after intermediate rolling, slitting and rolling by a pre-finishing mill 6, double-pass water cooling before finishing one group, double-pass trimming of heads and tails before finishing one group, double-pass rolling of a finishing group, double-pass water cooling after finishing one group, double-pass trimming of heads and tails by a flying shear before finishing two groups, double-pass rolling of finishing two groups, double-pass water cooling after finishing two groups, pinching and shearing by a pinching roller and a high-speed flying shear 14, braking by a high-speed steel clamping brake, steel loading by a rotating hub 16, cooling by a double-length cooling bed 17, collection, bundling, alignment, and weighing. The process is specifically as follows:

[0090] (1) Heating: The continuous casting slab is heated in a heating furnace 1 or an electromagnetic induction furnace. The cross-section of the continuous casting slab is 170 mm × 170 mm × 12000 mm and the weight of the casting is 2670 kg. The temperature of the casting slab after heating is 1050°C ± 30°C.

[0091] (2) Rolling by roughing mill 2: After descaling by high-pressure water, the billet heated in step (1) is subjected to 6 passes of roughing mill 2 pass rolling by alternating horizontal and vertical rolling. The pass system is a box-box-elliptical-circular pass system. During rolling, each stand is provided with a guide before and after. During the rolling process, the average compression ratio of the roughing mill is controlled to be 1.317, the total elongation is 5.226, the cross-sectional diameter after 6 passes of rolling is 85 mm, the deformation temperature is 900°C to 1000°C, the bite speed of the 1H stand during the roughing mill 2 is 0.323 m / s, and the exit speed of the 6V stand after 6 passes of rolling is 1.688 m / s;

[0092] (3) Rolling by the intermediate rolling mill group 4: The rolled piece after being rolled by the roughing rolling mill group 2 in step (2) is subjected to the head and tail trimming by the flying shear 3 after roughing and then rolled by the intermediate rolling mill group 4 for 4 passes. The hole system during rolling is an elliptical-circular hole system. Guides are provided before and after each rolling mill. During the rolling process, the average compression ratio of the intermediate rolling mill group 4 is controlled to be 1.266, the total elongation is 2.572, the cross-sectional diameter after 4 rolling passes is 53 mm, the deformation temperature is 900°C to 1000°C, the bite speed of the rolled piece of the 7H stand during the rolling process of the intermediate rolling mill group 4 is 1.688 m / s, and the exit speed of the 12V stand after 6 rolling passes is 4.341 m / s;

[0093] (4) Pre-finishing mill group 6 rolling: the rolled piece after being rolled by the intermediate rolling mill group 4 in step (3) is subjected to controlled cooling and then cut by the flying shear 5 before pre-finishing rolling, and then subjected to four passes of two-splitting rolling by the pre-finishing mill group 6. The hole system during rolling is a flat box-vertical box-pre-splitting-splitting hole system. Each rolling mill is provided with a guide before and after. During the rolling process, the average compression ratio of the pre-finishing mill group 6 is controlled to be 1.137, the total elongation is 1.670, the cross-sectional diameter after four passes of rolling is 29 mm, the deformation temperature is 930°C to 1050°C, the bite speed of the rolled piece of the 13H stand during the rolling of the pre-finishing mill group 6 is 4.341 m / s, and the exit speed of the 16H stand after four passes of rolling is 7,250 m / s;

[0094] (5) Controlled cooling and finishing rolling of a group 9: The two-way rolled pieces cut and rolled by the pre-finishing rolling mill group 6 in step (4) are respectively cooled by the front water tank 7 of the two-way finishing rolling group, and after recovery, they are finished by a flat top-cross cantilever rolling mill or a 45° top-cross cantilever rolling mill for 2 passes. The diameter of the roller ring of the finishing rolling group cantilever rolling mill is greater than 270mm. The finishing rolling mill group adopts low-temperature and large-reduction rolling. The hole system during rolling is an elliptical-circular hole system. Guide guards are provided before and after each rolling mill. A finishing rolling is set before the finishing rolling group 9. A front flying shear 8 shears the head and tail, and a looper is set in front of the unit to control the tension between the finishing mill group 9 and the pre-finishing mill group 6 to achieve tension-free rolling. During the rolling process, the average compression ratio of the finishing mill group 9 is controlled to be 1.261, the total elongation is 1.590, the cross-sectional diameter after two rolling passes is 17.6mm, and the deformation temperature is 830℃~930℃. During the finishing rolling group 2 rolling process, the 17# stand has a rolling piece bite speed of 7.250m / s, and the 18# stand has an exit speed of 11.53m / s after two rolling passes.

[0095] (6) Controlled cooling and finishing rolling: The two-way rolled pieces of step (5) are respectively cooled by the front water tank 10 of the finishing rolling group 2. After controlled cooling, a recovery section is set to control the temperature entering each rolling mill and the temperature difference between the core and the surface. After recovery, the rolled pieces are subjected to 1-to-1 or 1-to-2 transmission mode, 4-stand 45° top-cross cantilever heavy-load finishing rolling in the second group. The roller diameter of the 45° top-cross cantilever heavy-load rolling mill is greater than 220mm and less than 270mm. The first two stands of the finishing rolling group 2 adopt low-temperature small reduction rolling, and the average compression ratio of each pass is less than 1.2. The last two stands adopt low-temperature large reduction rolling, and the average compression ratio of each pass is less than 1.2. The reduction ratio is not less than 1.2. The pass system during rolling is an elliptical-circular pass system. Guides are provided before and after each rolling mill. A flying shear 11 is provided in front of the finishing mill 2 in the double-module finishing mill 2 to shear the head and tail. During the rolling process, the average reduction ratio of the finishing mill 2 is controlled to be 1.191, the total elongation is 2.013, the cross-sectional diameter after 4 rolling passes is 23mm, the deformation temperature is 750℃~900℃, the bite speed of the rolled piece of the 19# stand during the finishing mill 2 is 11.53m / s, and the exit speed of the 22# stand after 4 rolling passes is 23.2m / s.

[0096] (7) Controlled cooling after rolling and high-speed steel feeding: The two-pass rolled pieces after the two groups of finishing rolling in step (6) are respectively subjected to water cooling after rolling and recovery after water cooling. The water tank is arranged in multiple intervals, and the recovery after water cooling is taken into consideration. During cooling, the surface temperature is not lower than the martensite start transformation temperature to obtain an ideal uniform microstructure and better product mechanical properties. After cooling, each pass of rolled pieces is transported through a dual-channel high-speed steel feeding device 15. The temperature of the cooling bed on the rolled pieces is 650℃~920℃ to control the final microstructure and surface red rust problem of the rolled pieces; the running speed of the rolled pieces of the high-speed steel feeding device 15 is 23.2m / s, and the high-speed flying shear speed of the high-speed steel feeding device 15 is not less than 24m / s;

[0097] (8) Cooling on cooling bed: The rolled pieces conveyed on high speed in step (7) are cooled on cooling bed 17. The temperature of the rolled pieces on cooling bed 17 is 350℃~600℃. After being conveyed by roller, they are cold sheared to length, sawed, sorted, counted, bundled and collected.

[0098] Table 1 Typical specification single high-speed bar reduction distribution table

[0099]

[0100] Table 2 Typical specification double high-speed bar pass reduction distribution table

[0101]

[0102]

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions, which should all be included in the scope of the claims of the present invention.

Claims

1. A production method for improving the stability of a high-speed bar modular finishing mill, characterized in that: The production method specifically comprises the following steps: S1 continuous casting billet heating; S2 roughing mill rolling: the billet heated in S1 is rolled in the roughing mill using horizontal and vertical alternating rolling or flat roll rolling; S3 intermediate rolling mill group rolling: the rolled piece obtained in S2 is rolled in the intermediate rolling mill group; S4 pre-finishing mill rolling: The rolled piece obtained in S3 is rolled in the pre-finishing mill. The pass system during rolling is an elliptical-circular pass system. During the rolling process, the compression ratio of each pass is controlled to be 1.20-1.40, the deformation temperature is 850℃-1050℃, and the rolling speed is 2.0m / s-20.00m / s. S5 controls cooling and finishing rolling: the rolled piece obtained in S4 is cooled before finishing rolling and then rolled, and then cooled before finishing rolling by a water tank. After recovery, a horizontal vertical top cross cantilever finishing rolling is performed for 2 to 4 passes. The finishing mill adopts low-temperature and high-reduction rolling. The pass system during rolling is an elliptical-circular pass system. During the rolling process, the deformation compression ratio of each pass is controlled to be 1.20 to 1.35, the deformation temperature is 800°C to 950°C, and the running speed of the rolled piece is 5.0m / s to 20.00m / s. S6 controlled cooling and finishing rolling two groups: the rolled piece obtained in S5 is subjected to pre-finishing rolling two groups cooling and finishing rolling two groups, and controlled cooling is carried out through a water tank. After controlled cooling, a recovery section is set to control the temperature entering each rolling mill and the core surface temperature difference. After recovery, the rolled piece is subjected to 1-to-1 or 1-to-2 transmission form 4-stand 45° top-cross cantilever heavy-load finishing rolling two groups. The first two stands of the finishing rolling two groups adopt low-temperature small reduction rolling, and the last two stands adopt low-temperature rolling. The pass system during rolling is an elliptical-circular pass system. During the rolling process, the deformation compression ratio of each of the first two passes is controlled to be 1.10-1.20, and the deformation compression ratio of each of the last two passes is controlled to be 1.12-1.

28. The deformation temperature is 730℃-980℃, and the rolling piece running speed is 6.0m / s-50.00m / s. S7 controlled cooling and high-speed steel feeding after rolling. The rolled pieces after S6 finishing rolling group 2 are water-cooled and recovered after water cooling in the water tank after finishing rolling group 2. The water tank adopts a multi-stage interval arrangement and takes into account the recovery after water cooling. During cooling, the surface temperature is not lower than the martensite start transformation temperature to obtain an ideal uniform microstructure and better product mechanical properties. After cooling, the rolled pieces are transported through a dual-channel high-speed steel feeding device; the temperature of the rolled pieces on the cooling bed is 600℃~950℃ to control the final microstructure and surface red rust problem of the rolled pieces; the running speed of the high-speed steel feeding device is 6.0m / s~60m / s; S8 cooling bed, fixed-length flying shear, cold shearing to fixed length, bundling and collection; the temperature of the cooling bed under the rolled piece is 300℃~600℃.

2. The production method for improving the stability of a high-speed bar modular finishing mill according to claim 1, characterized in that: In S1, a heating furnace or an electromagnetic induction furnace is used to heat the continuous casting billet.

3. The production method for improving the stability of a high-speed bar modular finishing mill according to claim 1, characterized in that: The cross section of the continuous casting billet in S1 is 150mm×150mm~180mm×180mm or a rectangular billet of equal area; the billet temperature after heating is 950℃~1230℃.

4. The production method for improving the stability of a high-speed bar modular finishing mill according to claim 1, characterized in that: In S2, the square billet is rolled by the roughing mill for 6 passes, and the rectangular billet is rolled by the roughing mill for 5 or 7 passes.

5. The production method for improving the stability of a high-speed bar modular finishing mill according to claim 1, characterized in that: In step S2, pass rolling is adopted, and the roughing mill is a box-type-box-elliptical-round pass system. During the rolling process, the deformation compression ratio of each pass is controlled to be 1.25-1.48, the deformation temperature is 880°C-1150°C, and the running speed of the rolled piece during the rolling process of the roughing mill is 0.075m / s-3.00m / s.

6. The production method for improving the stability of a high-speed bar modular finishing mill according to claim 1, characterized in that: In step S3, 4 to 8 passes of rolling are performed by the intermediate rolling mill group. The hole system during rolling is an elliptical-circular hole system. During the rolling process, the deformation compression ratio of each pass is controlled to be 1.20 to 1.45, the deformation temperature is 850°C to 1100°C, and the rolling speed is 0.5m / s to 8.00m / s.

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