JPS62259606A - Method for controlling sectional profile of sheet in cold rolling of thin sheet - Google Patents

Abstract

PURPOSE:To obtain a sectional profile which is nearly rectangular by changing the overlap quantity of the tapered parts of work rolls onto the ends of a sheet so as to meet the region where the sheet thickness distribution can be changed by the sheet thickness, thereby controlling the sectional profile of the sheet. CONSTITUTION:The work rolls of a rolling mill have the straight tapered parts at one end of the body length. Such work rolls are disposed point symmetrically above and below and are shifted in opposite directions. The sectional profile of the sheet is controlled in this case by changing the overlap quantity of the tapered parts on the ends of the sheet so as to meet the region where the sheet thickness distribution can be varied by the sheet thickness for each of rolling passes or stands. More specifically, the shift quantity of the work rolls is in creased in the front stage where the sheet thickness is large, i.e., the overlap quantity of the tapered parts on the sheet ends is increased and the overlap quantity is successively decreased in the rear stage in the case of rolling with the multi-stands rolling mill or rolling of several passes with single stand. The sectional profile of the sheet is thereby effectively controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for controlling the cross-sectional profile of a sheet in cold rolling of a thin sheet.

[Conventional technology]

Shape control for thin plate rolling is a method of controlling the elastic shape of the roll as '+t]l,
■Work roll penda method, ■Middle roll shift.

■The work roll bender method is a method in which a hydraulic cylinder is installed in the work roll bearing part to apply bending moment to the work roll.■The intermediate roll shift method is a method in which the intermediate roll of a six-high mill is shifted in the axial direction. This is a method of controlling the deformation of song 9.

In addition, we believe that one of the causes of shape defects is that the material structure is different in the four parts of the plate (crystal grains become coarser). There are ways to prevent the temperature from dropping.

[Problem to be solved by the invention]

Conventional techniques (1) and (2) are methods for controlling the bending deformation of the roll, and it is impossible to cause steep deformation. For this reason, the shape of a relatively wide part of the plate edge is controlled, and local edge drops at the plate edge cannot be effectively dealt with. However, the elastic flatness of the roll has not been resolved and sufficient effects have not yet been obtained.

It is an object of the present invention to provide a method for controlling the cross-sectional profile of a plate that can solve the above-mentioned problems.

[Means to resolve the problem]

In a rolling mill in which work rolls having a linear tapered part at one end of the body are arranged symmetrically in the upper and lower points and shifted in the opposite direction, the amount of overlap of the tapered part to the plate end is determined for each rolling pass or stand. , the plate thickness distribution is changed according to the plate thickness, and the plate cross-sectional profile is controlled by changing it in accordance with the area.

[For production]

The inventor conducted experiments and found that the area from the plate edge where the distribution of the plate cross-sectional profile can be changed is influenced by the plate thickness based on the characteristics of plastic deformation during plate rolling. An example of this situation is shown in FIG. In other words, the head of the hatching in the figure becomes wider as the plate thickness increases, indicating that the thickness distribution can change to a point closer to the center of the plate width, and conversely, if the plate thickness is thinner, the head of the hatching will become wider at a portion closer to the center of the plate width. Indicates that it cannot be changed.

Also, if you change the thickness distribution in areas relatively close to the center of the plate when the plate thickness is thick, the plate thickness will become thinner in the fifth rolling, so at least the thickness distribution in the area near the temporary center will change. Indicates that it remains unchanged.

Using this characteristic, when rolling several passes in a multi-stand rolling mill or in one stand, the shift of the work roll is greatly reduced in the front stage where the plate is thick, that is, the overlap of the tapered part towards the edge of the plate is greatly reduced. In the latter stage, the plate cross-sectional profile can be effectively controlled by reducing this overlap f by the 111th order.

Further, the optimum values of the roll shift amount and taper angle can be estimated as follows.

For example, when rolling a steel plate with a thickness of 1ru and a width of 300 Jll at a rolling reduction of 401, the inclination angle of the taper is 0.0.
016.0.005.0.01 by changing the shift amount for each roll to adjust the weight V= on the steel plate at the tapered part from 0 to ('1Qf
FIG. 2 shows how the value Se-, which makes the edge-up constant λ, changes when l is changed. As you can see, shift i
As it becomes thicker and the weight of the tapered part increases,
Edge drop tends to become smaller and edge up increases. However, the way the edge drop changes, the way the edge up changes, and the taper angle differ.
A weight amount such that both 8e+ and Se- are 0 exists only at a special taper angle. In the example shown in the figure, when the taper angle is 0.0n16 and 0.01, edge-up, edge-drop, or both will exist no matter how you change the taper weight, but if the taper angle is 0.
In the case of 005, S when taper weight is prohibited 301!7j
[Example] It has been shown that suitable control is possible with both e+ and 8 e- being 0.
Product thickness Q, l'i IJ with stand tandem rolling mill
The case of rolling to J will be explained.

Figure 3 shows the rune condition of the taper part in the valley stand. In Fig. 1, the plate thickness is temporarily pressed on the outlet side of each stand, and the plate thickness distribution corresponding to this plate thickness can be changed by 1.5 times the upper limit of the 17 DLI area (indicated by the broken line). It has been shifted.

A case where all stand flat rolls are used as a comparative example, and ■3rd. Rolling was carried out with a shift of 4 (ljl) on the fourth stand.

Fig. 4 shows a real side view of the distribution of the plate thickness in the plate width direction at the exit side of the fifth stand.

For those using all-stand flat rolls, the third
．． When rolling with a large shift in the 4th stand,
Although the thickness of the plate is thicker at the edge of the plate, the area is iG from the edge of the plate to the area 201, and no twisting effect is obtained closer to the center of the plate.

On the other hand, if control is performed using the characteristics of side deformation as in the present invention, the effect can be obtained even in the range of 40 to 50 mm from the plate, and a more rectangular meat surface profile can be obtained.

〔Effect of the invention〕

Used for simple force dot line roll crown gold shift roll,
A nearly rectangular plate cross-sectional profile can be obtained by simply setting the amount of i of the tapered portion according to the plate thickness in accordance with the predetermined deformation characteristics.

By obtaining a cross-sectional profile that is close to a rectangle, it is possible to reduce the weight of the product, for example in the case of a product that guarantees a minimum thickness, and it is also possible to reduce the amount of cutting at the end of the plate, which improves the yield of the product. Dogs can contribute a lot.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram showing an example of the possible range of plate thickness distribution based on the 71i deformation characteristics, and Fig. 2 is an explanatory diagram showing the relationship between the taper size, the overlap amount of the taper part, and edge up and edge drop. , FIG. 3 is an explanatory diagram showing the overlapping state of the tapered portions in each stand in one embodiment of the present invention, and FIG. 4 is an explanatory diagram showing the plate thickness distribution of the product according to the present invention together with a comparative example. Applicant's agent Patent attorney Takehiko Suzue Figure 2

Claims (1)

[Claims] In a rolling mill in which work rolls having a linear tapered part at one end of the body length are arranged symmetrically up and down and shifted in the opposite direction, the amount of overlap of the tapered part with the plate end is determined for each rolling pass or stand. A method for controlling a plate cross-sectional profile in cold rolling of a thin plate, characterized in that the plate cross-sectional profile is controlled by changing the plate thickness distribution in accordance with a changeable area according to the plate thickness.