CN111389929B

CN111389929B - Method for improving stability of plate type control system of rolling mill

Info

Publication number: CN111389929B
Application number: CN202010195809.XA
Authority: CN
Inventors: 黄崇辉; 王立国; 郑明哲; 李明远; 张文强; 郎文勇
Original assignee: Nanjing Iron and Steel Co Ltd
Current assignee: Nanjing Iron and Steel Co Ltd
Priority date: 2020-03-19
Filing date: 2020-03-19
Publication date: 2021-11-19
Anticipated expiration: 2040-03-19
Also published as: CN111389929A

Abstract

The invention discloses a method for improving the stability of a plate type control system of a rolling mill, which is characterized in that a roll bending system is optimized, and the method comprises the following steps: optimizing the position of a bending roller pipeline and optimizing the position of a pressure acquisition point of a bending roller control system. The bending roll hose designed by the invention replaces the existing bending roll hard pipe, is simple and easy to realize, and has strong replaceability and obvious damping effect. After optimization, the impact vibration borne by the working roll bending control system is obviously reduced. The invention optimizes the position of the pressure acquisition point of the bending roll, can reduce pressure loss, has stable pressure acquisition point and accurate pressure acquisition and improves the pressure control precision of the plate type control system.

Description

Method for improving stability of plate type control system of rolling mill

Technical Field

The invention belongs to the technical field of steel, and particularly relates to a rolling mill plate type control system.

Background

The thick plate rolling of a wide and thick plate factory is characterized by various dimensions and specifications and often needs widening rolling in the rolling process. The working rolls are under the comprehensive influence of thermal expansion and friction with rolled pieces, and are continuously abraded, so that the roll shapes are changed all the time. The bending roll is an important means for controlling the shape of the plate, and the working roll bending roll can control the shape of a roll gap, so that the influence of rolling force on the shape of the plate is eliminated, the shape of the steel plate is improved, and the flatness of the steel plate is improved. Because the rolling mill impacts and vibrates in the rolling process of steel biting and rolling, the reverse impact force borne by a bending roll system is extremely large, and the bending roll servo valve fault and the bending roll pipeline fault of the rolling mill are easily caused. The rolled plate profile camber rises to 0.08% due to roll bending system instability. The mechanical fault of the rolling mill area caused by the bending roll system is stopped for 35 percent to about 500 minutes, and the leakage of the hydraulic oil is caused, which accounts for about 42 percent of the annual oil consumption to about 80 barrels. The existing bending rolls are all connected by hard pipes, and a sensor of a bending roll system is arranged at the tail end of the bending roll, so that the force detection of the bending roll is inaccurate indirectly.

Disclosure of Invention

In order to solve the stability problem of a bending control system of a rolling mill in a wide and thick plate factory, the invention provides a method for improving the stability of a plate type control system of the rolling mill, which is used for reducing the faults of the bending system and is also suitable for improving the stability of a hydraulic system under high pressure and high vibration impact.

The invention adopts the following specific technical scheme:

a method for improving the stability of a plate type control system of a rolling mill is characterized in that a roll bending system is optimized, and comprises the following steps:

redesigning a bending roller pipeline, and arranging pipes: mainly focuses on two aspects of the bending roll connecting flange and the bending roll hard pipe

1. By comparing a plurality of method flange welding core cracking objects, the fact that stress concentration is easily caused at the step processing position of an original flange welding core is found, cracks are easily generated at the step processing position under frequent impact vibration, therefore, the welding core step is processed into a reinforced welding core joint with 45-degree oblique angle transition, the stress concentration coefficient is reduced, in addition, 12.9-grade M16-50 full-tooth screw rods of the method flange connected with a bending roller block are replaced by 10.9-grade M16-55 non-full-tooth screw rods, and 8.8-grade M16 spring gaskets are added at the bottoms of bolts for shock-proof treatment.

2. The high-pressure resistant rubber hose with the reinforced square flange welding core and the improved square flange and the high-pressure resistant rubber hose with 45-degree and 90-degree transition bends are designed according to the connection form of the bent roller hard pipe.

3. Through the bending roll trouble of comparing the historical statistics, with the outer bending roll pipeline on the rolling mill export operation side, export operation side in the no pole chamber bending roll pipeline down, the outer bending roll pipeline under the rolling mill entry operation side, go up the many position hard tubes of no pole chamber bending roll pipeline four places trouble, use the rubber hose of design to replace to regularly carry out the whole change for 1 year.

4. Through on-site investigation and analysis, because of on-site bending roller hard tube pipeline is whole pipeline, nearly 10 meters are long, and the transition is curved more than 8, and the flange transition face is narrow and small space, and fault handling is very difficult, also carries out the stringing again with the bending roller hard tube that has the pole chamber on the entry operation side to add the rubber hose that has strenghthened type huff flange from the main design.

Secondly, optimizing the position of a pressure acquisition point of the roller bending control system:

through analyzing the real object and the actual measurement data of the pressure taking point, the pressure taking point of the originally designed bending roller pipeline is downward and has a distance of more than 1 meter from a user point, the actual measurement of pressure loss during pressure acquisition is about 0.2bar, the control force fluctuation of a pressure control system is easily caused, and the oil liquid of the lower pressure taking point is difficult to circulate, so that the pressure taking point is easily blocked due to impurity aggregation; the optimized pressure taking point of the bending roll pipeline is 5 centimeters away from the user point, the on-way pressure loss of hydraulic oil is reduced, the pressure taking point is arranged towards the centers of the left side and the right side of the pipeline, the optimized pressure taking point of the bending roll pipeline cannot be blocked, pressure collection is accurate, and the error is about 0.05%.

The bending roll hose designed by the invention replaces the existing bending roll hard pipe, is simple and easy to realize, and has strong replaceability and obvious damping effect. After optimization, the impact vibration borne by the working roll bending control system is obviously reduced, the bending roll pipeline faults and the clamping rate of the bending roll servo valve are basically O%, and the service life of the servo valve is prolonged from 3 months to more than 12 months. Meanwhile, the invention optimizes the position of the pressure acquisition point of the bending roll, can reduce pressure loss, has stable pressure acquisition point and accurate pressure acquisition, improves the pressure control precision of the plate type control system, and has an error of about 0.05 percent. After the technical scheme is implemented, the camber of the rolling mill is estimated to be reduced from 0.1% to 0.05%, the occurrence rate of wide and thin buckling is reduced by 1.01%, the rolling waste rate is reduced by 0.06%, the annual oil consumption in the area of the rolling mill is reduced by 40%, and the economic benefit is obvious.

Drawings

FIG. 1 is a schematic structural view of a reinforced half flange welding core;

FIG. 2 is a schematic view of a square flange configuration with transition chutes;

FIG. 3 is a rubber hose with a reinforced half flange;

FIG. 4 is a 45-degree curved rubber hose with a reinforced half flange welding core;

FIG. 5 is a 90-degree rubber hose with a reinforced half flange welding core;

FIG. 6 is a schematic view of a pressure point;

FIG. 7 is a schematic view of the original roll pipe layout;

FIG. 8 is a schematic view of the piping of the bending roll being re-piped.

Detailed Description

The technical solution of the present invention is further described in detail below.

A method for improving the stability of a rolling mill plate type control system optimizes the rolling mill plate type control system, and comprises the following steps:

1. through analyzing the weak points which may cause impact and vibration in a roller bending control system, an original standard SAE B40-6 Haff flange welding core is changed into a reinforced flange welding core with an inclined plane having chamfer transition, so that the local stress concentration caused by turning is relieved, meanwhile, the local annular thickness is enhanced, and the stress concentration coefficient is reduced. A square flange matched with the square flange is synchronously designed, a 3mm transition chute shown in figure 2 is turned at the joint, the original standard square flange is replaced, the stress concentration generated in the manufacturing process of the half flange is reduced, and the cracking of the bending roll flange is avoided.

2. The service grade of the bolt is reduced, the length of the bolt is prolonged, and a spring gasket is added. The original M16 x 50 full-pressure 12.9 grade jin Yi high-strength screw is replaced by a M16 x 55 non-full-tooth 10.9 grade jin Yi high-strength screw, and meanwhile, a 8.8 grade high-strength spring gasket is added at the bottom of a square flange bolt connected with a bending roller block, so that the strength of the bolt is ensured, the toughness of the bolt is improved, the stress concentration of the head of the bolt is reduced, the fatigue fracture of the bolt caused by vibration impact is reduced, and the pressing force of the square flange is ineffective.

3. And manufacturing a rubber hose similar to a hard pipe connected with the roller cylinder and a high-pressure resistant rubber hose bent at 45 degrees and 90 degrees as shown in figures 3, 4 and 5. A Hebei Hehengyu standard rubber hose (4S/38) with the length of 1.1m and the model number of 4SP40-SFS-24-24-FK-1100 is used, the end joint of a square flange of an original hose is cut off, two ends of the original hose are both polished to be chamfer angles of 8mm, a designed reinforced flange welding core is used for butt joint, argon arc welding is used for backing 3mm, a CHS102(2.5mm) welding rod is used for reinforcing, and the rubber hose which is 1.1m long and is provided with a 45-degree or 90-degree elbow and a reinforced flange welding core is manufactured.

4. The method has the advantages that the hard pipe (such as the bending roll hard pipe with a rod cavity in the operation side of the inlet of a 5M rolling mill) with a part of narrow parts and difficult to remove a flange is subjected to pipe rearrangement, oil way bend is reduced, a 1.1M hose underneath type stiffening pipe connecting body (shown in figure 8) is added, the number of optimized transition hard pipe transition bends is reduced from 4 (shown in figure 7) to 1, and the hydraulic impact and vibration of the bending roll pipeline with high pressure and large flow and multiple bend lines are effectively relieved.

5. And optimizing pressure taking points of the roller bending sensors on the inlet transmission side and the outlet operation side. As shown in fig. 6, the bending roll pressure taking position designed by the original simmak belongs to a down-set type, and is more than 1m away from a user point, so that the bending roll sensor is easily blocked, pressure loss occurs, the pressure taking error is about 0.2bar, and the bending roll force is greatly influenced. The optimized pressure taking point of the bending roll is in a left-right center type (the center of the left side surface and the right side surface of the pipeline is taken), the distance from the user point is about 5 centimeters, the on-way pressure loss is less, the oil liquid in the position has good fluidity, and bubbles and impurities are not easy to gather on the side surface, so that the blockage phenomenon cannot occur, the reconstructed pressure sensor has accurate acquisition value, and the error is about 0.05%.

Claims

1. A method for improving the stability of a plate type control system of a rolling mill is characterized in that a roll bending system is optimized, and comprises the following steps:

optimizing a roller bending pipeline:

(1) changing a square flange welding core into a reinforced half flange welding core with chamfer transition on the inclined surface, reducing the bolt grade of the square flange connected with the bending roll block, and adding a spring gasket at the bottom of the bolt for shockproof treatment;

(2) designing a high-pressure-resistant rubber hose with a reinforced square flange welding core and an improved square flange and a high-pressure-resistant rubber hose with 45-degree and 90-degree transition bends according to the connection form of the bent roller hard pipe;

(3) replacing hard pipes at four fault multi-occurrence positions of an upper outer bending roller pipeline at the outlet operation side of the rolling mill, a lower inner rodless cavity bending roller pipeline at the outlet operation side of the rolling mill, a lower outer bending roller pipeline at the inlet operation side of the rolling mill and an upper inner rodless cavity bending roller pipeline with rubber hoses;

(4) adding a bending roll hose to the bending roll hard pipe which is difficult to remove the original half flange for re-pipe distribution, and reducing the transitional bending number of the bending roll hard pipe;

(II) optimizing the position of a pressure acquisition point of the roll bending control system:

the pressure taking points of the roll bending sensors on the inlet transmission side and the outlet operation side of the rolling mill are arranged in the right centers of the left side surface and the right side surface of the pipeline, and the distance from the pressure taking points to a user point is 5 centimeters.

2. The method of claim 1, wherein the enhanced huff flange weld core bevel transition angle is 45 degrees.

3. The method for improving the stability of the plate type control system of the rolling mill as claimed in claim 1, wherein a square flange matched with a welding core of the reinforced huff flange is synchronously designed, and a 45-degree transition chute is turned at the joint of the square flange and the reinforced huff flange.

4. The method for improving the stability of a plate shape control system of a rolling mill as claimed in claim 1, wherein the original 12.9-grade full-tooth screw is replaced by a 10.9-grade non-full-tooth screw.

5. The method of improving the stability of a mill plate profile control system of claim 1 wherein said spring shim is an 8.8 grade M16 spring shim.

6. The method for improving the stability of the plate shape control system of the rolling mill as claimed in claim 1, wherein the side length of the chamfer is 0.5-3 mm.

7. The method of improving the stability of a mill plate profile control system of claim 6, wherein said chamfer has a side length of 3 mm.