Hot Strip Roughing Double Stand Rolling Process

Abstract

The present invention provides a hot-rolled steel strip rough rolling double-stand rolling process, which is carried out according to the following procedures: the first procedure: the original steel strip billet is transported to the rough rolling vertical roller mill one via an entrance roller table, and the rough rolling vertical roller mill one performs width hot rolling on the original steel strip billet to obtain the steel strip billet one; the second procedure: the rough rolling flat roller mill one performs thickness hot rolling on the steel strip billet one to obtain the steel strip billet two; the third procedure: the rough rolling flat roller mill two performs thickness hot rolling on the steel strip billet two to obtain the steel strip billet three; the fourth procedure: the steel strip billet three enters the rough rolling vertical roller mill two from the entrance of the rough rolling vertical roller mill two and is output via the outlet of the rough rolling vertical roller mill two, but the rough rolling vertical roller mill two does not roll the steel strip billet three, and then transports it to the exit roller table. The hot-rolled steel strip rough rolling double-stand rolling process of the present invention can improve the output of steel strips, the precision of steel strips and the yield rate.

Description

Technical Field

[0001] The invention relates to the technical field of rough rolling zone rolled steel strip, in particular to a double-stand rough rolling process for hot rolled steel strip. Background Art

[0002] With the development of my country's economy in recent years, the hot-rolled strip production line has also made rapid progress. With the continuous improvement of people's consumption level and the vigorous development of civil construction, automobile and other industries, new requirements have been put forward for the output and product precision of hot-rolled strip. In response to market demand, enterprises actively seek product transformation and equipment upgrades, especially the production process urgently needs to be improved and optimized. The existing hot-rolled strip production line adopts a reversible single-frame unit consisting of a roughing vertical roll mill and a roughing flat roll mill in the roughing rolling area to reciprocate and reversibly roll the strip steel billet. This rolling method inevitably includes the process that the strip steel billet enters the roughing vertical roll mill after being rolled by the roughing flat roll mill. However, due to the influence of the rolling environment of the roughing flat roll mill, the head of the strip steel billet after being rolled by the roughing flat roll mill will be warped or buckled. During the rolling process of the roughing vertical roll mill, the strip steel billet is squeezed through two opposite vertical roll holes to roll the width. Due to the groove structure of the vertical roll hole, the strip steel billet with warped or buckled head will appear when entering the vertical roll hole, resulting in poor steel product quality and low yield. And the reversible single-stand unit performs five reciprocating rolling processes, in which the rough rolling vertical roll mill rolls the hot-rolled steel billet three times in width, and the rough rolling flat roll mill rolls the hot-rolled steel billet five times in thickness. The five reciprocating rolling processes have many rolling times, low rolling capacity and slow rolling speed. Summary of the invention

[0003] In view of this, the present invention aims to propose a hot-rolled steel strip rough rolling double-stand rolling process, which can improve the output, quality and yield rate of the hot-rolled steel strip.

[0004] In order to solve the above technical problems, the technical solution adopted by the present invention is: providing a hot-rolled steel strip rough rolling double-stand rolling process, and the hot-rolled steel strip rough rolling double-stand rolling process is carried out according to the following steps:

[0005] First process: the original steel strip is transported to the first roughing vertical rolling mill via the inlet roller table, and the first roughing vertical rolling mill performs width hot rolling on the original steel strip to obtain the first steel strip;

[0006] The second step: a roughing flat roll mill performs thickness hot rolling on the strip steel billet 1 to obtain the strip steel billet 2;

[0007] The third step: the rough rolling flat roll mill 2 performs thickness hot rolling on the strip steel billet 2 to obtain the strip steel billet 3;

[0008] The fourth process: the strip steel billet 3 enters from the inlet of the roughing vertical rolling mill 2 and is output from the outlet of the roughing vertical rolling mill 2, but the roughing vertical rolling mill 2 does not roll the strip steel billet 3, and then transports it to the outlet roller table;

[0009] The fifth step: the tail of the strip steel billet 3 is used as the front end and transported in reverse to the roughing vertical roller mill 2 via the exit roller table. The roughing vertical roller mill 2 performs width hot rolling on the strip steel billet 3 to obtain the strip steel billet 4;

[0010] The sixth step: the rough rolling flat roll mill 2 performs thickness hot rolling on the strip steel billet 4 to obtain the strip steel billet 5;

[0011] The seventh step: a roughing flat roll mill performs thickness hot rolling on the strip steel billet 5 to obtain a strip steel billet 6;

[0012] The eighth step: the strip steel billet 6 enters from the inlet of the roughing vertical roller mill and is output from the outlet of the roughing vertical roller mill, but the roughing vertical roller mill does not roll the strip steel billet 6, and then transports it to the inlet roller table.

[0013] Ninth step: using the tail of the strip steel billet 6 as the front end, the strip steel billet is transported in reverse to the roughing vertical roller mill 1 through the entrance roller table, and the roughing vertical roller mill 1 performs width hot rolling on the strip steel billet 6 to obtain the strip steel billet 7;

[0014] The tenth step: a pair of roughing flat roll mills perform thickness hot rolling on the strip steel billet seven to obtain a strip steel billet eight;

[0015] The eleventh step: the rough rolling flat roll mill 2 performs thickness hot rolling on the strip steel billet 8 to obtain the strip steel billet 9;

[0016] The twelfth process: the strip steel billet 9 enters from the entrance of the rough rolling vertical roller mill 2 and is output from the exit of the rough rolling vertical roller mill 2, but the rough rolling vertical roller mill 2 does not roll the strip steel billet 6, and then transports it to the exit roller table.

[0017] Further, a centering operation is performed by a centering device after the second process and before the third process, a centering operation is performed by a centering device after the sixth process and before the seventh process, and a centering operation is performed by a centering device after the tenth process and before the eleventh process.

[0018] Furthermore, in the first process, the width of the steel strip blank one is reduced by 15-35mm compared with the width of the original steel strip blank; in the second process, the thickness of the steel strip blank two is reduced by 15-35% compared with the thickness of the steel strip blank one; in the third process, the thickness of the steel strip blank three is reduced by 15-35% compared with the thickness of the steel strip blank two; in the fifth process, the width of the steel strip blank four is reduced by 25-45mm compared with the width of the steel strip blank three; in the sixth process, the thickness of the steel strip blank five is reduced by 25-45% compared with the thickness of the steel strip blank four; in the seventh process, the thickness of the steel strip blank six is ​​reduced by 25-45% compared with the thickness of the steel strip blank five; in the ninth process, the width of the steel strip blank seven is reduced by 15-35mm compared with the width of the steel strip blank six; in the tenth process, the thickness of the steel strip blank eight is reduced by 15-35% compared with the thickness of the steel strip blank seven; in the eleventh process, the thickness of the steel strip blank nine is reduced by 15-35% compared with the thickness of the steel strip blank eight.

[0019] Furthermore, the rolling time of the first process is 3-5 seconds, the rolling time of the second process is 2-3 seconds, and the rolling time of the third process is 2-3 seconds; the operation time of the fourth process is 12-20 seconds; the rolling time of the fifth process is 3-5 seconds, the rolling time of the sixth process is 2-3 seconds, the rolling time of the seventh process is 2-3 seconds, and the operation time of the eighth process is 12-20 seconds; the rolling time of the ninth process is 3-5 seconds, the rolling time of the tenth process is 2-3 seconds, and the rolling time of the eleventh process is 2-3 seconds; the operation time of the twelfth process is 6-10 seconds.

[0020] Furthermore, the temperature of the original steel strip in the first process is 1100-1150°C, and the temperature of the steel strip in the twelfth process is 750-900°C.

[0021] Furthermore, the centering device includes a hydraulic cylinder, an upper push rod, a transmission mechanism and a lower pull rod, the hydraulic cylinder is connected to the upper push rod, the lower pull rod is located obliquely below the upper push rod, and the upper push rod and the lower pull rod can be synchronously and symmetrically moved together and apart through the transmission mechanism.

[0022] Furthermore, it also includes a pressure roller, an idler roller and a guide roller, the pressure roller is arranged at the upper part of the upper push rod, the idler roller is arranged at the lower part of the lower pull rod, and the guide roller includes an upper guide roller and a lower guide roller, the upper guide roller is arranged at the lower part of the upper push rod, and the lower guide roller is arranged at the lower part of the lower pull rod.

[0023] The advantages and positive effects of the present invention are:

[0024] (1) The original process of reversible single-stand reciprocating reversible rolling of two rolling mills consisting of one roughing vertical roll mill and one roughing flat roll mill is changed to reversible double-stand reciprocating reversible rolling of four rolling mills consisting of two roughing vertical roll mills and two roughing flat roll mills. The number of rolling mills is increased, which in turn improves the rolling efficiency and increases the steel output.

[0025] (2) The process layout comprises a roughing vertical roll mill 1, a roughing flat roll mill 1, a roughing flat roll mill 2 and a roughing vertical roll mill 2 arranged in sequence. During the process production process, the steel strip billet after being rolled by the roughing flat roll mill is prevented from entering the roughing vertical roll mill for rolling, which effectively avoids the occurrence of steel piling accidents caused by the warped steel strip billet after being rolled by the roughing flat roll mill entering the hole groove of the vertical roll of the roughing vertical roll mill, thereby improving the quality and precision of steel and increasing the yield rate by 10%-20%.

[0026] (3) The number of reciprocating rolling passes in the present invention is reduced, and the number of horizontal rolling passes is increased. For the hot-rolled steel billet thickness and width dimensions rolled into the 35mm thick strip steel billet required by the subsequent finishing mill, the reversible single-frame unit in the original process produces 5 processes in a reciprocating manner, wherein the rough rolling vertical roll mill rolls the hot-rolled steel billet width 3 times, and the rough rolling flat roll mill rolls the hot-rolled steel billet thickness 5 times, while the reversible double-frame unit of the present invention produces 3 processes in a reciprocating manner, wherein the rough rolling vertical roll mill rolls the hot-rolled steel billet width 3 times, and the rough rolling flat roll mill rolls the hot-rolled steel billet thickness 6 times. That is, the process production process is adjusted from the original reversible single-frame unit reciprocating rolling 5 times to the reversible double-frame unit reciprocating rolling 3 times. The corresponding rough rolling flat roll mill rolling times (horizontal rolling passes) are adjusted from rolling 5 times to rolling 6 times.

[0027] (4) Reducing the number of rolling reciprocating times can improve the rolling capacity and rolling speed of the rough rolling unit, so that the output of the rough rolling unit matches that of the finishing rolling unit. In addition, reducing the number of rolling reciprocating times can reduce the temperature drop of rough rolling, thereby reducing the furnace discharge temperature and reducing gas consumption. At the same time, the reduction of the furnace discharge temperature can prevent the quality of the steel billet from being degraded or burned due to intergranular precipitation caused by excessive heating temperature. If the temperature-controlled rolling process of the rolled piece is considered, the furnace discharge temperature can be further reduced. Temperature-controlled rolling can make the steel strip microstructure strength about 10% higher than that of conventional steel strip.

[0028] (5) Increasing the number of horizontal rolling passes of rough rolling flat rolls can reduce the amount of reduction in each rolling pass, which is conducive to better controlling the width of the strip and better improving the large head and large tail shape of the rolled piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0030] Figure 1 It is a schematic diagram of a hot-rolled steel strip rough rolling double-stand rolling process of the present invention;

[0031] Figure 2 It is a structural schematic diagram of the centering device of the present invention.

[0032] Description of reference numerals:

[0033] 1-entry roller; 2-roughing vertical roller mill one; 3-roughing flat roller mill one; 4-roughing flat roller mill two; 5-roughing vertical roller mill two; 6-exit roller; 7-centering device; 71-hydraulic cylinder; 72-upper push rod; 721-transmission side guide plate; 73-transmission device; 731-upper rack; 732-gear shaft; 733-lower rack; 74-lower pull rod; 741-operation side guide plate; 75-pressure roller; 76-supporting roller; 77-guide roller; 771-upper guide roller; 772-lower guide roller. DETAILED DESCRIPTION

[0034] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0035] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred to or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0036] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0037] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0038] In the original strip production process, the heated hot-rolled steel strip is transported to the roughing vertical roller mill via the entrance roller table. The roughing vertical roller mill rolls the edge of the hot-rolled steel strip to adjust the width of the hot-rolled steel strip. After being rolled by the roughing vertical roller mill, the steel strip arrives at the roughing flat roller mill. The roughing flat roller mill rolls the hot-rolled steel strip in the thickness direction to adjust the thickness of the hot-rolled steel strip. The rolled steel strip is transported to the exit roller table. After that, the exit roller table rotates in the opposite direction to send the steel strip to the roughing flat roller mill again. The roughing flat roller mill rolls the hot-rolled steel strip in the thickness direction. The entrance of the roughing vertical roller mill in front of the roughing flat roller mill is opened, and the roughing vertical roller mill does not roll the steel strip in the width direction after being rolled by the roughing flat roller mill. At this time, the steel strip is directly transported to the entrance roller table, and a reversible rolling process of the roughing mill group is completed. The thickness and width of the hot-rolled steel strip billet are rolled into the 35mm thick steel strip billet required by the subsequent finishing mill, which needs to be produced in a round trip process as described above. The rough rolling vertical roll mill rolls the hot-rolled steel strip billet in width. The rough rolling flat roll mill rolls the hot-rolled steel strip billet in thickness. Since the hot-rolled billet is rolled back and forth on the single-stand rough rolling mill, the rolling time in the rough rolling area is long, the production rhythm is slow, the production capacity of the rough rolling area on the rolling line is less than the production capacity of the finishing area, and the entire rolling line cannot be matched. For tropical steel billets, the temperature loss is large during the rolling process, especially the temperature drop at the head and tail of the steel strip is large. Therefore, the production cannot guarantee the stability of strip production, and the dimensional accuracy of the head and tail cannot be guaranteed. This link directly affects the extreme and quality of the product, so the production process needs to be solved urgently.

[0039] like Figure 1-2 As shown, the hot-rolled steel strip rough rolling double-stand rolling process of the present invention. This process is mainly based on the original production process, and a rough rolling flat roll mill 2 4 and a rough rolling vertical roll mill 2 5 are added after the rough rolling flat roll mill 1 3. The heated original steel strip billet is transported to the rough rolling vertical roll mill 1 2 via the entrance roller table 1. The rough rolling vertical roll mill 1 2 rolls the edge of the original steel strip billet to adjust the width size of the steel strip billet to obtain the steel strip billet 1. After being rolled by the rough rolling vertical roll mill 1 2, the steel strip billet 1 arrives at the rough rolling flat roll mill 1 3. The rough rolling flat roll mill 1 3 rolls the steel strip billet 1 in the thickness direction to adjust the thickness size of the steel strip billet to obtain the steel strip billet 2. After being rolled by the roughing flat roll mill 1 3 , the obtained strip steel billet 2 reaches the roughing flat roll mill 2 4 . The roughing flat roll mill 2 4 rolls the strip steel billet 1 in the thickness direction to adjust the thickness of the hot-rolled steel billet to obtain the strip steel billet 3 .

[0040] However, the head of the steel strip will bend after being rolled by the rough rolling flat roll mill. This is mainly due to the following reasons: (1) Since the upper and lower surfaces of the hot rolled steel strip have different contact environments, the upper surface is naturally cooled by air, while the lower surface is in contact with the roller for conduction heat dissipation. The natural heat dissipation rate is lower than the conduction heat dissipation rate. Therefore, after being rolled by the rough rolling flat roll mill, the steel strip has a high elongation rate on the upper surface with a high temperature and a low heat dissipation rate, while the steel strip has a low elongation rate on the lower surface with a low temperature and a high heat dissipation rate. Therefore, the head of the steel strip will bend downward. (2) During the rolling process of the rough rolling flat roll mill in the hot rolled steel strip production line, the roll surface will be worn. The wear of the roll will cause the roll diameter to change, and the linear speed of the contact position between the roll surface and the steel strip will change during the rolling process. Due to the uncertainty of the wear of the roll surface, the grinding degree of the upper and lower rolls is different, which makes the linear speed uncertain during the rolling process of the upper and lower rolls, which will cause the steel strip to bend. The steel strip with a small diameter on the upper roll will bend upward, and the steel strip with a small diameter on the lower roll will bend downward, resulting in the bending of the head of the steel strip. (3) The rolling mills on the hot-rolled steel strip production line are all equipped with roller cooling water to prevent equipment damage. After the steel strip passes through the rough rolling flat roll mill, the surface of the hot-rolled steel billet may also be affected by the cooling water of the rough rolling flat roll mill, causing the head of the steel billet to bend up and down. The head of the steel strip may warp or buckle, and the groove structure of the vertical roll hole groove in the rough rolling vertical roll mill prevents the head of the steel strip from smoothly entering the vertical roll hole groove, which is prone to steel accumulation accidents and reduces the yield and quality of the material. However, the tail of the steel strip does not warp or buckle. Therefore, the present invention opens the entrance of the rough rolling vertical roll mill 2 5 after the rough rolling flat roll mill 2 4, and the steel strip 3 enters from the entrance of the rough rolling vertical roll mill 2 5 and is output through the outlet of the rough rolling vertical roll mill 2 5, but the rough rolling vertical roll mill 2 5 does not roll the steel strip 3, and then transports it to the exit roller table 6. After that, the exit roller table 6 rotates in the reverse direction to transport the strip in the reverse direction, that is, the tail end of the strip enters the vertical roller hole groove in the rough rolling vertical roller mill 2 5 with the tail end as the front end for width rolling, avoiding the steel piling accident caused by the head of the strip entering the rough rolling vertical roller mill 2 5.

[0041] After being rolled by the roughing vertical roll mill 25, the strip steel billet 4 is obtained, and the strip steel billet 4 reaches the roughing flat roll mill 24. The roughing flat roll mill 24 rolls the strip steel billet 4 in the thickness direction to adjust the thickness of the hot-rolled steel billet, and obtains the strip steel billet 5. After being rolled by the roughing flat roll mill 24, the strip steel billet 5 reaches the roughing flat roll mill 13. The roughing flat roll mill 13 rolls the strip steel billet 5 in the thickness direction to adjust the thickness of the hot-rolled steel billet, and obtains the strip steel billet 6. The entrance of the roughing vertical roll mill 12 after the roughing flat roll mill 13 is opened, and the strip steel billet 6 enters the roughing vertical roll mill 12 from the entrance of the roughing vertical roll mill 12 and is output through the outlet of the roughing vertical roll mill 12, but the roughing vertical roll mill 12 does not roll the strip steel billet 6, and then transports it to the entrance roller table 1. The strip steel billet is directly transported to the entrance roller table 1, at which time a back-and-forth rolling process of a rough rolling double-stand unit is completed. The thickness and width of the hot rolled steel billet are rolled into the 35mm thick steel billet required by the subsequent finishing rolling unit. After a back and forth rolling process, it is necessary to roll the strip steel billet six with the tail as the front end, that is, the strip steel billet six is ​​transported back to the rough rolling vertical roller mill 1 through the entrance roller table 1, and the rough rolling vertical roller mill 1 performs width hot rolling on the strip steel billet six to obtain the strip steel billet seven; the rough rolling flat roller mill 1 performs thickness hot rolling on the strip steel billet seven to obtain the strip steel billet eight; the rough rolling flat roller mill 24 performs thickness hot rolling on the strip steel billet eight to obtain the strip steel billet nine; the strip steel billet nine enters from the entrance of the rough rolling vertical roller mill 25 and is output from the outlet of the rough rolling vertical roller mill 25, but the rough rolling vertical roller mill 25 does not roll the strip steel billet six, and then transports it to the exit roller table 6, and the whole rolling process is completed through the above process. It can be seen from the above steps that the reversible double-frame unit of the present invention performs three reciprocating production processes, wherein the rough rolling vertical roll mill rolls the hot-rolled steel billet three times in width, and the rough rolling flat roll mill rolls the hot-rolled steel billet six times in thickness. Compared with the reversible single-frame unit in the original process, which performs five reciprocating production processes, wherein the rough rolling vertical roll mill rolls the hot-rolled steel billet three times in width, and the rough rolling flat roll mill rolls the hot-rolled steel billet five times in thickness, the number of reciprocating rolling passes in the present invention is reduced, the number of horizontal rolling passes is increased, the rolling capacity of the rough rolling unit and the rough rolling speed are improved, the output of the rough rolling unit is increased, and the width of the strip billet is better controlled.

[0042] In addition, in the first process, the width of the strip steel blank 1 is reduced by 15-35mm compared with the original strip steel blank width; in the second process, the thickness of the strip steel blank 2 is reduced by 15-35% compared with the thickness of the strip steel blank 1; in the third process, the thickness of the strip steel blank 3 is reduced by 15-35% compared with the thickness of the strip steel blank 2; in the fifth process, the width of the strip steel blank 4 is reduced by 25-45mm compared with the width of the strip steel blank 3; in the sixth process, the thickness of the strip steel blank 5 is reduced by 25-45% compared with the thickness of the strip steel blank 4; in the seventh process, the thickness of the strip steel blank 6 is reduced by 25-45% compared with the thickness of the strip steel blank 5. For a round trip process, the width reduction value in the present invention increases from 15-35mm to 25-45mm with the process sequence, and the width reduction increases. Similarly, the thickness reduction value increases from 15-35% to 25-45% with the process sequence, and the thickness reduction increases. The width reduction and thickness reduction gradually increase with the progress of the rolling process, which effectively ensures the accuracy of the width and thickness. In the ninth process, the width of the strip steel blank seven is reduced by 15-35mm compared with the width of the strip steel blank six; in the tenth process, the thickness of the strip steel blank eight is reduced by 15-35% compared with the thickness of the strip steel blank seven; in the eleventh process, the thickness of the strip steel blank nine is reduced by 15-35% compared with the thickness of the strip steel blank eight.

[0043] The rolling time of the first process is 3-5 seconds, the rolling time of the second process is 2-3 seconds, and the rolling time of the third process is 2-3 seconds; the operation time of the fourth process is 12-20 seconds; the rolling time of the fifth process is 3-5 seconds, the rolling time of the sixth process is 2-3 seconds, the rolling time of the seventh process is 2-3 seconds, and the operation time of the eighth process is 12-20 seconds; the rolling time of the ninth process is 3-5 seconds, the rolling time of the tenth process is 2-3 seconds, and the rolling time of the eleventh process is 2-3 seconds; the operation time of the twelfth process is 6-10 seconds. The temperature of the original strip steel billet in the first process is 1100-1150℃, and the temperature of the strip steel billet in the twelfth process is 750-900℃. For the rough rolling process of hot-rolled strip, the rolling time of the vertical roll mill and the flat roll mill is relatively short, but the turning time at the exit roller table and the entrance roller table is relatively time-consuming. Therefore, four rolling mills are set up for hot rolling, and the number of back and forth rolling times is reduced, which effectively reduces the time spent on turning at the exit roller table and the entrance roller table, shortens the entire rolling process, and improves rolling efficiency.

[0044] In addition, the present invention provides a centering device used in the hot strip roughing double-stand rolling process, that is, the centering operation is performed by the centering device 7 after the second process and before the third process, the centering operation is performed by the centering device 7 after the sixth process and before the seventh process, and the centering operation is performed by the centering device 7 after the tenth process and before the eleventh process. The centering device centers the strip steel blank output from the roughing flat roll mill 1 to prevent it from running off so that it can smoothly enter the roughing flat roll mill 2.

[0045] Specifically, the centering device 7 includes a hydraulic cylinder 71, an upper push rod 72, a transmission mechanism 73 and a lower pull rod 74. The hydraulic cylinder 71 is connected to the upper push rod 72. The lower pull rod 74 is located obliquely below the upper push rod 72. The upper push rod 72 and the lower pull rod 74 can be synchronously symmetrically brought together and separated through the transmission mechanism 73. It also includes a pressure roller 75, a support roller 76 and a guide roller 77. The pressure roller 75 is arranged on the upper part of the upper push rod 72, the support roller 76 is arranged on the lower part of the lower pull rod 74, and the guide roller 77 includes an upper guide roller 771 and a lower guide roller 772. The upper guide roller 771 is arranged on the lower part of the upper push rod 72, and the lower guide roller 772 is arranged on the lower part of the lower pull rod 74.

[0046] The transmission device 73 includes an upper rack 731, a gear shaft 732, and a lower rack 733. The upper rack 731 is fixed to the lower part of the upper push rod 72, and the lower rack 733 is fixed to the upper part of the lower pull rod 74. The upper rack 731 and the lower rack 733 are meshed through the gear shaft 732, which can ensure the synchronous movement of the two rods. A transmission side guide plate 721 is provided at the end of the upper push rod 72, and an operating side guide plate 741 is provided at the end of the lower pull rod 74. The transmission side guide plate 721 and the operating side guide plate 741 are arranged opposite to each other, forming a strip steel blank placement area therebetween. The transmission side guide plate 721 and the operating side guide plate 741 maintain relative horizontal movement under the push of the upper push rod 72 and the lower pull rod 74. Wear-resistant plates are provided on the contact surfaces of the transmission side guide plate 721 and the operating side guide plate 741 with the strip steel blank, which can extend the service life of the equipment. When the output shaft of the hydraulic cylinder 71 extends, the upper push rod 72 is pushed forward, and the gear shaft 732 drives the lower pull rod 74 to pull backward, so that the transmission side guide plate 721 and the operating side guide plate 741 are synchronously and symmetrically moved toward the rolling center line, squeezing the strip steel billet until it is on the symmetrical rolling center line. Conversely, when the output shaft of the hydraulic cylinder 71 is retracted, the transmission side guide plate 721 and the operating side guide plate 741 are synchronously opened away from the rolling center line. The pressure roller 75 prevents the upper push rod 72 from falling out, and the upper guide roller 771 is arranged at the lower part to guide the movement of the upper push rod 72. The lower part of the lower pull rod 74 is provided with a lower guide roller 772 and a support roller 76. The lower guide roller 772 guides the lower pull rod 74, and the support roller 76 keeps the stable movement of the lower pull rod 74.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A hot strip rough rolling double-stand rolling process, characterized in that: The hot strip rough rolling double-stand rolling process is carried out according to the following steps: The first step: the original steel strip is transported to the rough rolling vertical roller mill (2) via the entrance roller table (1), and the rough rolling vertical roller mill (2) performs width hot rolling on the original steel strip to obtain the steel strip; The second step: the rough rolling flat roll mill 1 (3) performs thickness hot rolling on the strip steel billet 1 to obtain the strip steel billet 2; The third step: the rough rolling flat roll mill 2 (4) performs thickness hot rolling on the strip steel billet 2 to obtain the strip steel billet 3; The fourth step: the steel strip 3 enters the rough rolling vertical rolling mill 2 (5) from the entrance of the rough rolling vertical rolling mill 2 (5) and is output from the rough rolling vertical rolling mill 2 (5) through the exit of the rough rolling vertical rolling mill 2 (5), but the rough rolling vertical rolling mill 2 (5) does not roll the steel strip 3, and then transports it to the exit roller table (6); The fifth step: the tail of the strip steel billet 3 is used as the front end and is transported in reverse to the rough rolling vertical roller mill 2 (5) via the exit roller table (6). The rough rolling vertical roller mill 2 (5) performs width hot rolling on the strip steel billet 3 to obtain the strip steel billet 4; The sixth step: the rough rolling flat roll mill 2 (4) performs thickness hot rolling on the strip steel billet 4 to obtain the strip steel billet 5; Step 7: The rough rolling flat roll mill 1 (3) performs hot rolling on the strip steel billet 5 to obtain the strip steel billet 6; Step 8: The steel strip 6 enters the roughing vertical rolling mill 1 (2) from the entrance of the roughing vertical rolling mill 1 (2) and is output from the roughing vertical rolling mill 1 (2) through the exit of the roughing vertical rolling mill 1 (2), but the roughing vertical rolling mill 1 (2) does not roll the steel strip 6, and then transports it to the entrance roller table (1); Ninth step: using the tail of the strip steel billet 6 as the front end and transporting it in reverse direction through the inlet roller table (1) to the rough rolling vertical roller mill 1 (2), and the rough rolling vertical roller mill 1 (2) performs width hot rolling on the strip steel billet 6 to obtain the strip steel billet 7; The tenth step: the rough rolling flat roll mill 1 (3) performs thickness hot rolling on the strip steel billet 7 to obtain the strip steel billet 8; The eleventh step: the rough rolling flat roll mill 2 (4) performs thickness hot rolling on the strip steel billet 8 to obtain the strip steel billet 9; Step 12: The steel strip 9 enters the rough rolling vertical rolling mill 2 (5) from the entrance of the rough rolling vertical rolling mill 2 (5) and is output from the rough rolling vertical rolling mill 2 (5) outlet. However, the rough rolling vertical rolling mill 2 (5) does not roll the steel strip 6, and then transports it to the outlet roller table (6).

2. The hot strip rough rolling double-stand rolling process according to claim 1, characterized in that: The centering operation is performed by the centering device 7 after the second process and before the third process, the centering operation is performed by the centering device 7 after the sixth process and before the seventh process, and the centering operation is performed by the centering device 7 after the tenth process and before the eleventh process.

3. The hot strip rough rolling double-stand rolling process according to claim 2, characterized in that: In the first process, the width of the strip steel blank one is reduced by 15-35mm compared with the width of the original strip steel blank; in the second process, the thickness of the strip steel blank two is reduced by 15-35% compared with the thickness of the strip steel blank one; in the third process, the thickness of the strip steel blank three is reduced by 15-35% compared with the thickness of the strip steel blank two; in the fifth process, the width of the strip steel blank four is reduced by 25-45mm compared with the width of the strip steel blank three; in the sixth process, the thickness of the strip steel blank five is reduced by 25-45% compared with the thickness of the strip steel blank four; in the seventh process, the thickness of the strip steel blank six is ​​reduced by 25-45% compared with the thickness of the strip steel blank five; in the ninth process, the width of the strip steel blank seven is reduced by 15-35mm compared with the width of the strip steel blank six; in the tenth process, the thickness of the strip steel blank eight is reduced by 15-35% compared with the thickness of the strip steel blank seven; in the eleventh process, the thickness of the strip steel blank nine is reduced by 15-35% compared with the thickness of the strip steel blank eight.

4. The hot strip rough rolling double-stand rolling process according to claim 3, characterized in that: The rolling time of the first process is 3-5 seconds, the rolling time of the second process is 2-3 seconds, and the rolling time of the third process is 2-3 seconds; the operation time of the fourth process is 12-20 seconds; the rolling time of the fifth process is 3-5 seconds, the rolling time of the sixth process is 2-3 seconds, the rolling time of the seventh process is 2-3 seconds, and the operation time of the eighth process is 12-20 seconds; the rolling time of the ninth process is 3-5 seconds, the rolling time of the tenth process is 2-3 seconds, and the rolling time of the eleventh process is 2-3 seconds; the operation time of the twelfth process is 6-10 seconds.

5. The hot strip rough rolling double-stand rolling process according to claim 4, characterized in that: In the first process, the temperature of the original steel strip is 1100-1150°C, and in the twelfth process, the temperature of the steel strip is 750-900°C.

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