JPS6213203A - Roll for rolling - Google Patents

Abstract

PURPOSE:To decrease the incidence of a length defect and to improve yield by providing a specific initial crown of a projecting shape to a roll so that a plate crown is formed with good accuracy in the same manner as with a roll having a roll bender function without providing said function to the roll. CONSTITUTION:The initial crown of the projecting shape expressed by the equation is provided to the roll in the stage of controlling the plate crown of the steel plate by the initial crown of the projecting shape provided to the roll. In the equation, C1' is the corrected initial crown, C1 is the initial crown, Cp is the actual plate crown, wi is the roll and rolling splitting width.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a roll for rolling steel plates.

<Conventional technology> The conventional technology is replaced by the following two.

C6 For example, published by Maruzen■ Steel Handbook I [1-(1) P-
411, a sine without an inflection point (Sin
) A roll with an initial crown created by a curve.

b0 A roll provided with an initial crown having two inflection points in the roll width direction as proposed by the present applicant in Japanese Patent Application No. 109860/1986.

<Problem to be solved by the invention> As is generally well known, a roll without an inflection point a, for example, a sine curve or a quadratic curve, has a small differential coefficient in the center of the roll, which makes it difficult to correspond. The differential coefficient is large at the end of the roll, and if the material to be rolled is a narrow material, it will have a convex plate crown, or if it is a wide material, it will have a concave plate crown, and in the former case, the product will have too much excess wall thickness, which will significantly reduce the yield. □Down. The latter causes problems with shape and size, such as insufficient thickness of the product.

The roll with an initial crown with two inflection points in the width direction of the roll shown in b has an initial crown determined experimentally or empirically. It is extremely difficult to keep Great Crown close to 0 at all times due to the influence of changes in .

As a method to prevent or reduce this, use of a roll bender as shown in Maruzen ■ Steel Handbook 1 [1 (2) P. 253 to P. 255 or Japanese Patent Application Laid-Open No. 48-65153
As proposed in the publication, the combined use of roll shifting was proposed, but the equipment costs would increase accordingly.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the present invention provides a rolling roll for controlling the crown of a steel plate by adding a convex initial crown to the roll. The method uses a roll for rolling steel plates, which is characterized by being provided with a convex initial crown that satisfies the following.

Ct'(Wl) = 0x(Wl) Op("1)
However, CX': Corrected initial crown CX: Initial crown CP: Actual plate crown Wi: Roll and rolling division width effect> The effect of all the above means will be explained below based on the results of experiments and studies by the present inventors.

Generally, rolling widthwise great crown CP by hot rolling
(wi) is roll width direction initial crown CI (town)
, rolling width direction thermal crown CT (wl), roll wear Cm (town), roll deflection δ (town), and other factors are said to be formed by a complex interaction.

However, according to the results of experiments conducted by the inventors of the present invention, which have analyzed a large number of results, it has been found that, as a first approximation, the plate crown can be achieved by a simple superposition of the above-mentioned factors. According to this knowledge, the plate crown Cp(Wl) is expressed by the following formula (1).

Cp(wl) = Cs(wl) + CT(wl)
+Cg(vrl)+δ(W,) (1) Here, if the initial crown t-Cr'(wl) is such that the plate crown is 0, then equation (1) becomes equation (2) below.

0- CI'(w4) + CT(wl) + Cg
′(w,) 10δ'(Wt) −・・・−・(2
) Also, as a result of analyzing a large number of actual data, Ct (Wl): CT' (Town) - Cm (Town) YuC
z' (it 1) *δ(wi)Σδ'(Wl)
There is a problem with the relationship, as well as thermal crown, roll wear,
Roll swivel is initial crown C! It was also found that there is almost no effect on changing '(vl), and the value is practically negligible. From this, Great Crown't
Corrected initial crown amount C to be −0! It has become clear that '(wl) can be obtained from equations (1)-(2) and equation (3).

C0'(vl) -Cx(wl) -Cp(vl)
-・""13) Below, the roll curve (2) obtained by the present invention is shown in FIG. The corrected initial roll crown of the present invention is calculated over the entire width of the roll using the formula (3) above based on the conventional initial roll crown, sine curve (2), and the actual great crown on that curve.

The initial crown of the roll according to the present invention is a steeper curve in the narrow portion (≦3800 square meters) and a rough curve in the wider portion than a sine curve without an inflection point. , In addition, compared to the initial crown ■ which has two inflection points, it is 1 width 2
Below 200" it becomes very steep, and above that it becomes very sloping. The results of using the roll initial crown according to the present invention are shown in Figures 2 and 3. Figure 2 shows the curve at the inflection point. Figure 3 shows a comparison of the rolling results with a curved roll with two black inflection points.

As is clear from each figure, it has been found that regardless of the plate thickness, a reduction in great crown of 25 μm or more can be achieved in the former case and 10 μm or more in the latter case.

<Example> Corrected initial crown calculated using equation (3) from the relationship between past great crown and initial crown. Roll according to the present invention applied to a roll with a body length of 15,500 and the amount of great crown in this rolling. are shown in Table 1 along with comparative examples.

As is clear from Table 1, when comparing product widths, the present invention reduces the great crown by 22 to 38 μm for sine curve rolls that do not have a roll bender function, and by 14 to 19 μm for two-inflection point curve rolls. did.

<Effects of the Invention> As described above, the present invention imparts the entire initial curve to the roll based on equation (3), so it can produce a great crown like a roll with a roll bender function without providing a roll bender function. Since it is formed with high precision, the incidence of length defects can be significantly reduced, and yields can be significantly improved.

[Brief explanation of the drawing]

Fig. 1 is a graph showing a comparison example of the roll curve calculated from equation (3) and a conventional curve; Fig. 2 is a graph comparing the great crown reduction effect of the present invention with a sine curve without an inflection point; FIG. 3 is a graph comparing the plate crown reduction effect according to the present invention with a roll curve having two inflection points. Figure 1

Claims (1)

[Scope of Claims] A rolling roll for controlling the plate crown of a steel plate by a convex initial crown provided on the roll, characterized in that the roll is provided with a convex initial crown that satisfies the following formula: Roll for rolling. C_I′(w_i)=C_I(w_i)−C_P(w_
i) However, C_I': Corrected initial crown C_I: Initial crown C_P: Actual plate crown w_i: Roll and rolling division width