KR20070112879A - A continuous casting and rolling method for medium plate - Google Patents

Abstract

A continuous casting and rolling method for medium hot strip is comprised of following steps: continuous casting, during molten steel passing through crystallizers, to form casting blanks having a section thickness of 100-170mm and a width of 900-2000mm by hydraulic oscillating, continuously bending and continuously straightening ; direct rolling, hot feeding and hot charging casting blanks by a two machine with four streams and four streams merging one technique, achieving rapid hot feeding and hot charging or direct rolling for continuous casting blanks ; roughing by a rougher with front and back vertical rolls ; finishing using raising speed rolling by a finishing mill each stand of which are provided with a device for axial shifting and bending rolls, wherein the maxium speed is 22.8m/s and the speed of rollers table is up to 5.89m/s; stream cooling using a three stages stream cooling control technique; coiling with a full-hydraulic coiler controlled by a stepping control technique. The invention provided improvements on layout, apparatus, production process etc., improving production capacity, development for kinds of product, product quality and organization of production.

Description

A continuous casting and rolling method for medium plate

TECHNICAL FIELD This application relates to the field of metallurgical metalworking, and more particularly to a continuous casting and rolling process for medium thickness plates.

At present, the production technology of continuous hot rolled sheet is roughly divided into the traditional process and the CSP process. Traditional processes include continuous casting of thick billets, flame cutting, heating by walking-beam furnaces, descaling, rough rolling and shearing (200 mm to 250 mm thick). shearing, descaling, rolling by finishing rolling train, stream cooling and coiling. This process has the advantages of being available in all categories, high output, flexibility of production organization, high rolling rate, but heavy casting equipment, long rolling lines, high workshops, and large space. There are disadvantages such as required, large investment of equipment, large billet storage space, and large energy consumption. The CSP process consists of continuous thin billet casting, flame cutting, tunnel furnace heating, descaling, finishing rolling, laminar flow cooling, and winding, 50 mm to 70 mm thick. This process has the advantages of low investment and production costs, elimination of rough rolling, reinforcement of finishing rolling, and reinforcement of rolling capacity, but high casting speed, high breakout ratio, and production. There are many shortcomings, such as excessive restrictions on types, difficulty in developing new grades, high investment in tunnels, complex equipment, difficulties in operation and maintenance, low flexibility in production organization, high cost of handling incidents and low yield. Applicant's Chinese Patent No. 02132970.2 discloses a continuous casting and rolling process (ASP process) for medium / thin thickness plates. The ASP process consists of converter steelmaking, continuous casting of thick billets 100 mm to 150 mm thick, flame cutting, heating by working beam heating furnace, descaling, rough rolling by 3 + 1 rolling train, hot coil box, It consists of shearing, descaling, finishing rolling, laminar flow cooling, and winding. The ASP process has the advantages of low cost, low investment, flexibility of production organization, simplicity of maintenance and low accident rate. However, the use of too many older devices, the low motor power of the finishing rolling train, the low speed of the roller table, the insufficient water supply capacity, the insufficient strength of the rolling mill conveying system, the power It also has drawbacks such as the aging of the supply system. Therefore, advances in technology are somewhat limited, yields are less than demand, production advances are limited, and width accuracy, surface quality and shape control are limited.

The present invention aims to eliminate the drawbacks of the plate production process described above. It is an object of the present invention to improve several important techniques for energy saving, to improve the heating quality of the billet as well as to improve the uniformity of the plate thickness and the quality of the plate shape. The present invention has the advantage of high width accuracy, improves the work rate and output of the mill, and allows the continuous casting and rolling process for medium thickness plates to meet modern manufacturing needs.

The production process of the present invention employs a large part of Chinese Patent No. 01132970.2, and based on the process, it improves several points based on the process, improving the production capacity, and widening the production category range, while controlling the form, width accuracy control, surface quality Achieve new innovations in the field of control. The present invention can also implement direct rolling of certain steel grades.

In order to achieve the above object, the present invention provides a continuous casting and rolling process for an intermediate thickness plate comprising the following steps.

Continuous casting: forming a continuous casting billet having a cross section thickness of 100 mm-170 mm and a width of 900 mm-2000 mm by hydraulic vibration, continuous bending and straightening while molten steel passes through the mold;

Direct rolling, hot feeding and hot charging: two continuous casting machines with four streams and four streams combined to make one continuous Each of the knockout roller tables of the casting machine is connected with the entering roller table and exiting roller table of the furnace, respectively, to achieve rapid hot feeding and hot charging or direct rolling for the continuous casting billet; The continuous casting billet is fed to the entry roller table of the furnace via the conveying roller table and then to the working beam furnace by the long-course steel loader of the working beam furnace for heating. ; The exit roller table of the continuous casting machine is connected with the entrance roller table of the furnace to allow the continuous casting billet to be fed directly into the furnace by the roller table for hot charging, the hot charging temperature being above 700 ° C. on average; And one exit roller table of the continuous casting machine is connected to the exit roller table of the furnace;

Rough rolling: employs a rough rolling machine with front and rear vertical rollers, where the maximum single-pass side-pressing amount of the vertical roller is 50 mm, the maximum rolling pressure is 3800 kN, and the rolling speed Is 0 to 5.89 m / s; In rolling, in each pass, the operation of the front vertical rollers and the opening of the rear vertical rollers are done automatically by the computer, and automatic control of the width is realized by hydraulic automatic width control (AWC). ;

Finishing rolling: speed-up rolling with a finishing rolling train of F1 to F7 at a maximum speed of 22.8 m / s, provided with a vertical roller before F1; When the thickness of the intermediate stage billet is 50 mm, the maximum rolling amount is 10 mm and the maximum rolling pressure is 1000 kN; Both F1-F7 finishing rolling trains are provided with axial shifting and bending work rollers with a maximum axial shifting course of ± 200 mm and a maximum bending force of 1500 kN to improve plate thickness difference and plate shape control. To realize free rolling; The maximum speed of the roller table before the finishing rolling train is 5.89 m / s; Edge heaters are provided before the finishing rolling train;

Laminar flow cooling: adopts three-stage laminar cooling technology, which is provided with a coarse valve set, a precisely regulated valve set and an online high-level water tank to stabilize the water flow and water pressure in each cooling stage; Side water-jet pressure is 1 Mpa-1.2 Mpa to ensure temperature uniformity across the plate length; And,

Winding: employs a stepping controlled full hydraulic coiler, where automatic step control is a collapsible reel of hydraulically controlled side guides, pinch rollers, wrapper rollers, and high Performed by a reactive wrapper roller, it precisely centers the plate to wind the micro-tension to reduce the shape of the tower, prevent the head of the plate from colliding with the wrapper roller and Eliminates the effects of head and wrapper rollers.

In the continuous casting, direct rolling, hot feeding and hot charging, and rough rolling, the temperature drop of the casting billet and the temperature difference between the head and tail of the intermediate step billet are reduced so that the billet temperature when entering the finishing mill is 30 ° C to 50 The exit roller table is covered with a thermal insulation cover so that the temperature is increased by ° C and the temperature difference between the head and tail of the billet is reduced by 30 ° C to 50 ° C.

In the rough rolling, the vertical rollers of the front and rear vertical rollers of the rough rolling mill are of the top-attaching driven type, the size of the roller is Φ 1200 mm / Φ1100 mm x 430 mm, and the power of the main motor is AC1200kW × 2 × 200/400 r / min

In the finishing rolling, the vertical roller of the vertical roller provided before F1 is of the upper attachment driving type, the size of the roller is Φ 750 mm / Φ600 mm × 350 mm, and the main drive motor is 2-AC370 kW × 550 r / min.

In the finishing rolling, hydraulic low-inertia kinks are provided between the finishing rolling stands to control the tension between the finishing rolling trains and to improve the quality of the plate.

In the laminar flow cooling, the cooling device is provided with twelve sets of on-line high-level water tanks having a quantity of 1700 m ³ / h and a water pressure of 0.05 Mpa to 0.08 Mpa.

The mold is a mold for continuous billet casting, with four corners having a cavity in the form of a right or round angle or a straight bevel angle, wherein the right mold has two wide sidewalls and two A traditional billet mold consisting of narrow sidewalls with each wide sidewall and narrow sidewalls forming a right angle; Round or straight inclination molds for continuous casting of billets consist of two wide sidewalls and two narrow sidewalls, each having a row of flanges in the form of right triangles on either side of each narrow sidewall, i. The hypotenuse surface of the flange faces inward, one orthogonal surface is engaged with the inner surface of the narrow sidewall, and the other orthogonal surface is in the same plane as the side of the narrow sidewall, ie on the extension of the side of the narrow sidewall.

By performing three types of visual control: billet merging timing control, billet passing through logistics bottleneck timing control, and billet exiting timing control. By comparing cushioning ability, heating ability, and rolling ability, the four-streams-merging-one technique is a medium thickness in a single roller table of two casting machines with four flows. Optimizing the logistics in three working beam furnaces with cushioning zones to which the plates are directly supplied, the production capacity of the casting machine, the furnace, and the rolling line is exhibited, which is half of the rolling line, the furnace, and the casting machine. Make sure to implement a half-rigid connection.

The three kinds of timing control are:

Billet Joining Visual Control: Which will pass first if the two flows from casting machine A join; What will pass first if the two streams from casting machine B join; What will pass first if the flow from casting machine A and casting machine B joins; Decide according to the principle that "when a bilet joins, the flow that arrives first at the confluence passes first; if both flows arrive at the same time, the straight flow passes first";

Billet Pass Logistic Bottleneck Visual Control: Confirmation of the time when Billet flow # 1 enters # 1 larry; Confirmation of the time when Billet flows into # 3 Larry; Confirmation of the time at which Billet 1 and 2 Billet Joining Flow enters # 2 Larry; The billet charged in the furnace confirmed # 1 of time leaving the _first roller table A; To confirm the time when Billet enters the furnace; Confirmed by the principle that "when a bilet joins, the flow that arrives first at the confluence passes first;

Billet Exit Time Control: Checking the buffer capacity and heating capacity of the furnace and rolling capacity of the rolling line, and by tandem superimpose-calculating the values of the billet at each critical timing, Discover the billet values at the critical time and implement semi-rigid connections of the casting, furnace and rolling lines, but "When the billets join, the first flow at the confluence first passes and if both flows simultaneously When it arrives, a straight stream passes first. "

Compared with the prior art, the present invention has the following advantages.

1. In the present invention, a new mold is used, wherein the edge cooling is adjusted from two-dimensional cooling to almost one-dimensional cooling while molten steel solidifies and becomes a billet shell in the mold, and as a result, the billet shell solidification is relatively uniform and nonuniform. Surface defects caused by billet edge cooling solidification or cracks caused by too low edge temperatures during direct rolling are prevented.

2. The long-course steel loader used in the present invention not only allows the furnace to heat the billet but also has the cushioning ability to fit the continuous casting and rolling face. If the mill temporarily stops for a while, up to nine buffer billets can be stored, so that casting production is not affected.

3. The device for axial movement and bending work rollers provided on all finishing rolling trains is able to control plate thickness differences (crowns and wedges) and plate flatness, as well as free rolling to increase rolling yield. Hydraulic low inertia kinks used in production lines to achieve rolling can help to control tension and improve plate quality between finishing rolling trains. The speed-up rolling technique used in the finishing rolling train reduces the feed time of the roller table, reduces the temperature drop, improves the thickness uniformity and form quality and improves the mill output.

4. Edge heaters help to improve the uniformity of billet temperature, reduce edge cracks, improve edge microstructure, and stabilize the operation of finishing mills.

5. By adopting three-stage laminar flow cooling technology, by providing a coarse and precisely regulated valve set, it stabilizes the quantity and water pressure in each cooling stage and ensures the temperature uniformity over the plate length. This ensures uniformity of the microstructure of the plate and overcomes production defects caused by water supply inefficiency in the prior art.

The invention applies to a continuous casting and rolling process for 2150 medium thick plates.

Molten steel passes through three 250t top-bottom blowing converters, two molten iron desulfurization and slag skimming stations, two LF ladle furnaces and one RH-TB vacuum treatment unit, prior to casting, Molten steel can be refined with an LF ladle or by an RH-TB vacuum treatment apparatus.

Continuous casting: The hydraulic cast, continuously bend and continuously straighten the molten steel through the mold to form a continuous cast billet with a cross section thickness of 100 mm-170 mm, width 900 mm-2000 mm, length 11 m to 18 m Then, flame cut the billet. The billet has a maximum single weight of 38 tons, the average number of continuous casting furnaces is 30, and the average casting time is 37.3 minutes per furnace. Employing mold hydraulic vibration technology can improve the quality of cast billets and eliminate billet surface defects.

Direct rolling, hot feeding and hot charging: two casting machines with four flows and four flows combine to form a four-streams-merging-one technique. Wherein each of the knockout roller tables of the two continuous casting machines are respectively connected with the entry roller table and exiting roller table of the furnace, so that the rapid hot feeding and hot charging for the continuous casting billet or Achieve direct rolling; The continuous casting billet is fed to the entry roller table of the furnace via the conveying roller table and then to the working beam furnace by the long-course steel loader of the working beam furnace to be heated. . The exit roller table of the continuous casting machine is connected with the entrance roller table of the furnace so that the continuous casting billet is fed directly into the furnace by the roller table for hot charging. The hot charging temperature is at least 700 ° C on average. One exit roller table of the continuous casting machine is connected to the exit roller table of the furnace. When the billet is on the connecting roller table, its length is automatically measured and its temperature is also measured by a pyrometer so that the billet can be centered according to the layout and then heated. A computer is used to optimize the heating control based on the temperature of the billet entering the furnace. The billet is heated in the furnace to 1150 ° C. to 1250 ° C., carried out of the furnace by an extractor of the furnace and placed on the exit roller table. This not only saves energy, but also shortens the heating time and improves the heating quality of the billet. Some types of carbon steel and some types of low alloy steels, such as silicon steels, for example, can be applied to "lower temperature exiting" rolling techniques to achieve different steel grades.

The long-course steel loader used in the present invention not only allows the furnace to heat the billet but also has the cushioning ability to fit the continuous casting and rolling face. If the mill temporarily stops for a while, up to nine buffer billets can be stored, so that casting production is not affected.

By performing three types of visual control: billet merging timing control, billet passing through logistics bottleneck timing control, and billet exiting timing control. By comparing cushioning ability, heating ability, and rolling ability, the four-streams-merging-one technique is a medium thickness in a single roller table of two casting machines with four flows. Optimizing the logistics in three working beam furnaces with cushioning zones to which the plates are directly supplied, the production capacity of the casting, heating and rolling lines is achieved. Make sure to implement a half-rigid connection.

The three kinds of timing control are:

Billet Joining Visual Control: Which will pass first if the two flows from casting machine A join; What will pass first if the two streams from casting machine B join; What will pass first if the flow from casting machine A and casting machine B joins; Decide according to the principle that "when a bilet joins, the flow that arrives first at the confluence passes first; if both flows arrive at the same time, the straight flow passes first";

Billet Pass Logistic Bottleneck Visual Control: Confirmation of the time when Billet flow # 1 enters # 1 larry; Confirmation of the time when Billet flows into # 3 Larry; Confirmation of the time at which Billet 1 and 2 Billet Joining Flow enters # 2 Larry; The billet charged in the furnace confirmed # 1 of time leaving the _first roller table A; To confirm the time when Billet enters the furnace; Confirms by the principle that "when a bilet joins, the flow that first arrives at the confluence passes first; if both flows arrive simultaneously, the straight flow passes first";

Billet Exit Time Control: Checking the buffer capacity and heating capacity of the furnace and rolling capacity of the rolling line, and by tandem superimpose-calculating the values of the billet at each critical timing, Discover the billet values at the critical time and implement semi-rigid connections of the casting, furnace and rolling lines, but "When the billets join, the first flow at the confluence first passes and if both flows simultaneously When it arrives, the straight stream passes first. "

Rough rolling: The heated or directly rolled billet is transported by roller tables and then descaled through a high pressure water descaling box after the furnace, and then a four-roller reversible for rolling. rough rolling mill). Four-roller heated roughing mills are fitted with top-attaching driven type front and rear vertical rollers. The roller size is Φ 1200 mm / Φ1100 mm × 430 mm, the maximum single-pass side-pressing amount of the vertical roller is 50 mm, the maximum rolling pressure is 3800 kN, and the rolling speed is 0 ~ 5.89 m / s and main motor power is AC1200kW × 2 × 200/400 r / min. In rolling, in each pass, the operation of the front vertical rollers and the opening of the rear vertical rollers are done automatically by the computer, and the automatic control of the width is realized by hydraulic automatic width control (AWC). The front vertical rollers perform odd pass rolling and the rear vertical rollers perform even pass rolling. The maximum side-pressing amount of each pass is 50 mm. After three to five passes rolling in a four-roller reversible roughing mill, the billets are intermediate stage billets 30 to 60 mm thick. While rolling in a four roller reversible roughing mill, high pressure water is used before and after the four roller reversible roughing mill to remove the regenerated scale of the billet. The front and rear vertical rollers of the four-roller reversible roughing mills are provided with an automatic width control (AWC) system, the main purpose of which is to correct the error of the billet width caused by the change of rolling pressure and the width difference between the billet head and tail Is in correcting. A four-roller reversible roughing mill is provided with a width gage and pyrometer to monitor the width and temperature of the billet to provide correction data for setting up the finishing mill. Four-roller reversible roughing mills are also provided with a dust removal device.

In order to reduce the temperature drop of the intermediate stage billet and the temperature difference between the head and tail, the exit roller table is provided with an insulating cover. The intermediate stage billet is conveyed to a truncate scissor via an insulating cover so that its head and tail are cut. A detector is provided in front of the cutting scissors to detect the shape of the billet head, reducing the temperature drop of the intermediate billet and the temperature difference between the billet's head and tail, and also the billet as it enters the finishing mill. The temperature may be increased by 30 ° C.-50 ° C. and the temperature difference between the head and tail of the billet may be reduced by 30 ° C.-50 ° C. Thus, optimized cutting of the cutting shears can be realized to reduce the cutting loss and increase the yield.

Prior to the cutting shears an edge heater is provided. The parameters of the heater are as follows: the power of the main motor is 2 × 3000 kW, the heating depth is from 40 mm to 60 mm, the heating width is from 100 mm to 150 mm and the temperature rise is from 60 ° C to 100 ° C. This improves the temperature uniformity of the billet, reduces edge cracking, and improves edge microstructure. It also helps to stabilize the operations of the finishing mill, and at the same time, it can meet the requirements of the development of dual phase steel.

After the head and tail are cut off, the billet enters the high-pressure water descaling box before the four-roller for descaling.

Finish rolling: The billet passes through the small vertical roller device F1E before the finishing mill F1. When the thickness of the intermediate stage billet is 50 mm, the maximum rolling amount is 10 mm, the maximum rolling pressure is 1000 kN, and the main drive motor is 2-AC370 kW x 550 r / min. Billet then enters the finishing rolling train. Passing the F1 to F7 four roller finishing rolling train, the billet is rolled into a 1.8 mm to 25.4 mm final plate.

The F1 to F7 finishing rolling trains all adopt an axial moving and bending work roller unit with a maximum axial moving course of ± 200 mm and a maximum bending force of 1500 kN (ASP only uses F3 to F6 for axial moving and bending work rollers. Device for bending, the bending force has no negative value and only positive value). This can not only control the thickness difference (crown and wedge) of the plate cross section and the plate flatness, but also realize the free rolling to increase the yield.

The production line employs hydraulic low-inertia kinks to control the tension between the finishing rolling trains and to improve plate quality.

Laminar Flow Cooling: Employs three-stage laminar flow cooling technology, which is provided with a coarse valve set, a precisely regulated valve set, and 12 sets of online high-level water tanks to Stabilize. It has a yield of 1700 m ³ / h and a water pressure of 0.05 Mpa to 0.08 Mpa, and a side water-jet pressure of 1 Mpa to 1.2 Mpa, which ensures temperature uniformity over the plate length.

Winding: employs a stepping controlled full hydraulic coiler, where automatic step control is a collapsible reel of hydraulically controlled side guides, pinch rollers, wrapper rollers, and high Performed by a reactive wrapper roller, it precisely centers the plate to wind the micro-tension to reduce the towered-shape, prevent the head of the plate from colliding with the wrapper roller and Eliminate the influence of the plate head and wrapper rollers.

The automatic system of the production line is three grade computer control system, the first grade is the basic automation system, the second grade is the process control computer system, and the third grade is the production control computer system.

The present invention improves the continuous casting and rolling process for medium / thin thickness plates in terms of layout, apparatus, and production process to improve production capacity, development of new grades, and production quality. According to the present invention, the production capacity reaches 5,000,000 tons per year, the width accuracy within 0-10 mm reaches 98.5%, and the ability to adjust the form control and crown control to the advanced world standard. The ability to control the surface quality completely meets the quality standard requirements of high-grade panels of automobiles, and the ratio of thin plates reaches the leading world standard.

Claims (9)

Continuous casting: forming a continuous casting billet having a cross section thickness of 100 mm-170 mm and a width of 900 mm-2000 mm by hydraulic vibration, continuous bending and straightening while molten steel passes through the mold; Direct rolling, hot feeding and hot charging: two continuous casting machines with four streams and four streams combined to make one continuous Each of the knockout roller tables of the casting machine is connected with the entering roller table and exiting roller table of the furnace, respectively, to achieve rapid hot feeding and hot charging or direct rolling for the continuous casting billet; The continuous casting billet is fed to the entry roller table of the furnace via the conveying roller table and then to the working beam furnace by the long-course steel loader of the working beam furnace for heating. ; The exit roller table of the continuous casting machine is connected with the entrance roller table of the furnace to allow the continuous casting billet to be fed directly into the furnace by the roller table for hot charging, the hot charging temperature being above 700 ° C. on average; And one exit roller table of the continuous casting machine is connected to the exit roller table of the furnace; Rough rolling: employs a rough rolling machine with front and rear vertical rollers, where the maximum single-pass side-pressing amount of the vertical roller is 50 mm, the maximum rolling pressure is 3800 kN, and the rolling speed Is 0 to 5.89 m / s; In rolling, in each pass, the operation of the front vertical rollers and the opening of the rear vertical rollers are done automatically by the computer, and automatic control of the width is realized by hydraulic automatic width control (AWC). ; Finishing rolling: speed-up rolling with a finishing rolling train of F1 to F7 at a maximum speed of 22.8 m / s, provided with a vertical roller before F1; When the thickness of the intermediate stage billet is 50 mm, the maximum rolling amount is 10 mm and the maximum rolling pressure is 1000 kN; Both F1-F7 finishing rolling trains are provided with axial shifting and bending work rollers with a maximum axial shifting course of ± 200 mm and a maximum bending force of 1500 kN to improve plate thickness difference and plate shape control. To realize free rolling; The maximum speed of the roller table before the finishing rolling train is 5.89 m / s; Edge heaters are provided before the finishing rolling train; Laminar flow cooling: adopts three-stage laminar cooling technology, which is provided with a coarse valve set, a precisely regulated valve set and an online high-level water tank to stabilize the water flow and water pressure in each cooling stage; Side water-jet pressure is 1 Mpa-1.2 Mpa to ensure temperature uniformity across the plate length; And, Winding: employs a stepping controlled full hydraulic coiler, where automatic step control is a collapsible reel of hydraulically controlled side guides, pinch rollers, wrapper rollers, and high Performed by a reactive wrapper roller, it precisely centers the plate to wind the micro-tension to reduce the shape of the tower, prevent the head of the plate from colliding with the wrapper roller and Eliminates the influence of the head and wrapper rollers, Continuous casting and rolling process for a medium thickness plate, characterized in that it comprises a step of. 2. The billet as set forth in claim 1, wherein in the continuous casting, direct rolling, hot feeding and hot charging, and rough rolling, the temperature drop of the casting billet and the temperature difference between the head and tail of the intermediate step billet are reduced to enter the finishing mill. The exit roller table covered with a thermal insulation cover so that the temperature is increased by 30 ° C. to 50 ° C. and the temperature difference between the head and tail of the billet is reduced by 30 ° C. to 50 ° C., Continuous casting and rolling process for medium thickness plate, characterized in that. 2. The roller of claim 1, wherein in the rough rolling, the vertical rollers of the front and rear vertical rollers of the rough rolling mill are of a top-attaching driven type, and the size of the rollers is Φ 1200 mm / Φ 1100 mm x 430 mm. , The power of the main motor is AC1200kW × 2 × 200/400 r / min, Continuous casting and rolling process for medium thickness plate, characterized in that. 2. The vertical roller of the vertical roller provided before F1 in the finishing rolling is of the upper attachment driving type, the size of the roller is Φ 750 mm / Φ 600 mm × 350 mm, and the main drive motor is 2-AC370 kW × Being 550 r / min, Continuous casting and rolling process for medium thickness plate, characterized in that. The hydraulic low-inertia kinks of claim 1, wherein in the finishing rolling, hydraulic low-inertia kinks are provided between the finishing rolling stands to control the tension between the finishing rolling trains and improve the quality of the plate. , Continuous casting and rolling process for medium thickness plate, characterized in that. 2. The laminar flow cooling system according to claim 1, wherein in the laminar flow cooling, the cooling device is provided with 12 sets of online high-level water tanks having a quantity of 1700 m ³ / h and a hydraulic pressure of 0.05 Mpa to 0.08 Mpa, Continuous casting and rolling process for medium thickness plate, characterized in that. 2. The mold of claim 1 wherein the mold is a mold for continuous billet casting and has four cavities in the form of right angles or round angles or straight bevel angles, wherein the right angle molds are two A traditional billet mold consisting of two wide sidewalls and two narrow sidewalls, wherein each wide sidewall and narrow sidewall form a right angle; Round or straight inclination molds for continuous casting of billets consist of two wide sidewalls and two narrow sidewalls, each having a row of flanges in the form of right triangles on either side of each narrow sidewall, i. The hypotenuse surface of the flange is inward, one orthogonal surface is joined with the inner surface of the narrow sidewall, and the other orthogonal surface is in the same plane as the side of the narrow sidewall, ie on the extension of the side of the narrow sidewall, Continuous casting and rolling process for medium thickness plate, characterized in that. 2. The three types of visual control of claim 1: billet merging timing control, billet passing through logistics bottleneck timing control, and billet exiting timing control. By conducting and comparing the cushioning ability, heating ability, and rolling capability, the four-streams-merging-one technique is a method of two casting machines with four flows. Optimized logistics in three working beam furnaces with cushioning zones to which medium-thick plates in a single roller table are directly fed, to achieve the production capacity of casting machines, furnaces, and rolling lines, resulting in rolling lines, heating Furnace, and to realize a half-rigid connection of the casting machine, Continuous casting and rolling process for medium thickness plate, characterized in that. 9. The method of claim 8, wherein the three kinds of timing control are: Billet Joining Visual Control: Which will pass first if the two flows from casting machine A join; What will pass first if the two streams from casting machine B join; What will pass first if the flow from casting machine A and casting machine B joins; Decide according to the principle that "when a bilet joins, the flow that arrives first at the confluence passes first; if both flows arrive at the same time, the straight flow passes first"; Billet Pass Logistic Bottleneck Visual Control: Confirmation of the time when Billet flow # 1 enters # 1 larry; Confirmation of the time when Billet flows into # 3 Larry; Confirmation of the time at which Billet 1 and 2 Billet Joining Flow enters # 2 Larry; The billet charged in the furnace confirmed # 1 of time leaving the _first roller table A; To confirm the time when Billet enters the furnace; Confirmed by the principle that "when a bilet joins, the flow that arrives first at the confluence passes first; if both flows arrive at the same time, the straight flow passes first"; Billet Exit Time Control: Checking the buffer capacity and heating capacity of the furnace and rolling capacity of the rolling line, and by tandem superimpose-calculating the values of the billet at each critical timing, Discover the billet values at the critical time and implement semi-rigid connections of the casting, furnace and rolling lines, but "When the billets join, the first flow at the confluence first passes and if both flows simultaneously According to the principle that when it arrives, the straight stream passes first. " Continuous casting and rolling process for medium thickness plate, characterized in that.