CN110788142A

CN110788142A - Method for improving rolled plate shape of twenty-roller mill

Info

Publication number: CN110788142A
Application number: CN201910949821.2A
Authority: CN
Inventors: 贾增本; 苏皓璐; 岳军; 赵健; 王祥辉; 吴振宇; 林勇
Original assignee: Angang Steel Co Ltd
Current assignee: Angang Steel Co Ltd
Priority date: 2019-10-08
Filing date: 2019-10-08
Publication date: 2020-02-14

Abstract

The invention relates to a method for improving the rolled plate shape of a twenty-roller mill, which comprises the following steps: 1) the length of a middle roller cone is 280-300 mm, and the cone angle is 2.4-2.8 per mill; 2) and two intermediate roll crown: the convexity of the middle upper driven roll and the convexity of the middle lower driven roll are 300-400 mm; 3) target curve for plate shape: the convexity is 0.002-0.004 mm; 4) roll shifting set value in the middle before starting: the upper and lower shifting rollers are 40-60 mm; 5) and setting seven sections of racks of the bending roller from the operation side to the transmission side: 20. 30, 40, 50, 40, 30, 20. The advantages are that: the taper and the taper length of a middle part are adjusted, so that the axial stroke (overlapping amount) of an intermediate roller during rolling is increased, the effective plane amount is increased, and the plate edge control capability is enhanced.

Description

Method for improving rolled plate shape of twenty-roller mill

Technical Field

The invention relates to the field of rolling of cold-rolled strips, in particular to a method for improving the rolled strip shape of a twenty-roller rolling mill.

Background

The twenty-high roll mill is an important process for producing the oriented silicon steel, the rolled plate shape quality is one of important indexes of products, and the qualified rolled plate shape quality is a prerequisite condition for ensuring the qualified quality of a final finished product. However, since the twenty-high roll mill is put into production, the rolled plate shape is always poor, and the rolled plate shape of the mill is about 15I, which is far lower than that of other steel mills in the same industry. The influence on production caused by poor plate shape mainly has two aspects: on the one hand, the product quality is affected. The shape of the rolled plate is too poor to be eliminated at the outlet of a continuous annealing line, so that the finished roll has a wave shape. On the other hand, the rolling efficiency is influenced, and the production cost is increased.

The twenty-high rolling mill plate shape influencing factors include roll shape: the roll shape of the twenty-high roll mill roll system is different from that of the roll system of Bao steel, Wu steel, first steel and the like in the same industry, and the diameter, the material and the like of the roll are different, so that the reference cannot be drawn. Therefore, it is necessary to optimize the characteristics of the twenty-high rolling mill itself.

The twenty-high rolling mill consists of 8 supporting rolls, 6 second intermediate rolls, 4 first intermediate rolls and 2 working rolls. 4 middle rollers are respectively processed into a taper at one end, the taper is arranged in pairs up and down and in the opposite direction, and the shape of a roll gap is changed through the axial movement of one middle roller in the rolling process to control the plate shape. The fact that the middle roller is adjusted is that the position of a conical shoulder at the joint of a cylinder and a cone changes, the plate edge corresponding to the cone part is subjected to rolling pressure which is gradually reduced from the conical shoulder to the outside, so that the deflection of a working roller at the edge of strip steel is reduced, therefore, in order to eliminate strip steel edge waves caused by the pressure, an upper middle roller and a lower middle roller can move in the same direction, in the opposite direction or in a single-action mode, the axial movement of one middle roller not only has great effect on the extension deformation of the edge part of the strip steel, but also has certain influence on the extension of the middle part of the strip steel, see figure: (x) ef (L/2-T + x) ═ L-2T +2x, where: l is the first intermediate roll body length; t is the first intermediate roll taper length; a is the first intermediate roll cone angle; EF is the effective contact length of the first intermediate roll with the work roll; o is the weight of the strip steel and the cone part; x is the first intermediate roll traverse amount.

Because the end part of one middle roller has a cone angle and the two middle driven rollers have convexity, in order to reduce the deflection deformation of the working roller during rolling, the extension deformation of the edge part of the strip steel is effectively controlled, the length of a cantilever of a non-contact section of one middle roller and the two middle rollers is increased, the deflection of the cantilever part of the two middle rollers is increased, the pressure peak value of the cone shoulder position of one middle roller is increased, the cone shoulder position is rapidly worn in the rolling and axial moving processes, the contour of the working roller seam at the corresponding position is suddenly changed, the contact pressure of the cone part of one middle roller corresponding to the edge part of the plate and the two middle rollers is increased, and the edge part of the plate needs to be controlled by continuously increasing the overlapping amount. Because the overlapping amount is continuously increased, under the condition of the same pass pressure, the plane contact length between one intermediate roller and two intermediate rollers is reduced, the plane contact pressure between the rollers is increased, the elastic flattening is increased, and the rolled plate shape is influenced.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide a method for improving the rolled plate shape of a twenty-rolling mill, change the cone shape of a roller, change an operation method and achieve the aim of improving the plate shape.

In order to achieve the purpose, the invention is realized by the following technical scheme:

a method of improving a rolled sheet shape of a twenty-roll mill, comprising:

1) the length of a middle roller cone is 280-300 mm, and the cone angle is 2.4-2.8 per mill;

2) and two intermediate roll crown: the convexity of the middle upper driven roll and the convexity of the middle lower driven roll are 300-400 mm;

3) target curve for plate shape: the convexity is 0.002-0.004 mm;

4) roll shifting set value in the middle before starting: the upper and lower shifting rollers are 40-60 mm;

5) and setting seven sections of racks of the bending roller from the operation side to the transmission side: 20. 30, 40, 50, 40, 30, 20.

Compared with the prior art, the invention has the beneficial effects that:

the taper and the taper length of a middle part are adjusted, so that the axial stroke (overlapping amount) of an intermediate roller during rolling is increased, the effective plane amount is increased, and the plate edge control capability is enhanced.

Optimizing the target curve of the plate shape, matching the comprehensive roll shape of the roll system and rolling to obtain an ideal plate shape.

The rolling parameters applicable to the invention are as follows:

diameter of the working roll: 60-75 mm.

An intermediate roll diameter: 90-105 mm.

Diameter of the intermediate roll: 170-175 mm.

The invention improves the shape of the rolled plate and improves the yield. The plate shape is reduced from the average I value of 14.8I to 7.8I, and the 8I yield is improved by 81 percent from 31 percent.

Meanwhile, the accident of strip breakage is reduced, the yield is improved from 95.62% to 96.26%, and the yield of the rolling mill is improved by 0.64%.

Drawings

FIG. 1 is a schematic view of the operation of an existing intermediate roll.

Fig. 2 is a schematic view of the structure of an intermediate roll.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings, but it should be noted that the present invention is not limited to the following embodiments.

Referring to fig. 2, a method for improving a rolled sheet shape of a twenty-rolling mill includes:

1) the length of a middle roller cone is 280-300 mm, preferably 298mm, 300mm, 292mm and 288mm, and the cone angle is 2.4-2.8 per mill, preferably 2.6 per mill, 2.8 per mill and 2.7 per mill;

2) and two intermediate roll crown: the convexity of the middle upper driven roll and the convexity of the middle lower driven roll are 300-400 mm; preferably, the convexity of the two middle upper rolls is 300mm, and the convexity of the lower driven roll is 400 mm.

3) Optimizing a plate-shaped target curve: the convexity is 0.002-0.004 mm;

5) roll bending seven-segment rack setting (from operating side to drive side): 20. 30, 40, 50, 40, 30, 20.

In addition, the target curve of the shape is adjusted slightly, the convexity of the convexity curve is increased, and the bending of two sides is reduced. In the aspect of operation methods, the first-time vehicle lifting is used for manually adjusting the press-down roller bending device, raising the speed and manually adjusting a middle shifting roller. And the second-pass start-up manually adjusts the press-down roller bending device, and automatically puts a middle shifting roller into the press-down roller bending device. And the plate shape is automatically closed-loop controlled in the third to fifth passes.

Claims

1. A method for improving a rolled sheet shape of a twenty-high rolling mill, comprising:

3) target curve for plate shape: the convexity is 0.002-0.004 mm;