JPH02147111A - Edger mill between stands and method for rolling - Google Patents

Abstract

PURPOSE:To improve the edging efficiency and sheet width accuracy by bringing shape rolls composing an edger mill to be formed into a grooved roll and forming a slant flange part regulated by specific conditions between upper and lower bodies of the rolls. CONSTITUTION:A 4-high horizontal rolling mill is used as finish rolling mills F1, F2. A strip 53 rolled by the horizontal mill F1 is edged by edger rolls 52 of an edger mill 50 in the downstream. After forming a prescribed dog bone at a sheet end, the strip 53 is horizontally rolled by a succeeding horizontal rolling mill. An edger 50 between stands uses grooved rolls as edger rolls 52 and a flange part 54 edging sides of the strip 53 is formed. A slant flange part meeting requirements by formulas I and II is formed between upper and lower bodies of the rolls 52. A shape of dog bone by edging at sheet ends is improved and sheet width accuracy and edge drops are also improved by forming a groove having a prescribed shape on the rolls 52.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an inter-stand edger mill that performs width reduction rolling of a strip between strip mill stands, and a rolling method using the same.

(Prior Art) Conventionally, width reduction of a rolled plate such as a hot strip is generally performed by a width rolling mill provided near a rough rolling mill on the upstream side of a rolling line. However, when width reduction is performed on the upstream side of the rolling line, edge drops occur at the edges of the material due to thickness reduction performed on the downstream side of the rolling line, deteriorating the cross-sectional shape of the plate.
Further, there was a problem that the error between the target plate width of the product after rolling and the obtained plate width became large, resulting in a decrease in the plate width accuracy.

Therefore, in recent years, consideration has been given to performing width reduction rolling between finishing stands on the downstream side of the rolling line to improve the cross-sectional shape and width accuracy of the strip.

In FIG. 1, horizontal finishing rolls 11p+=h are arranged in the strip running direction indicated by arrows, and a jagger roll 14 is provided between them. Etsiya at this time
The roll 14 is a vertical cylindrical roll, that is, a flat roll.

Furthermore, as a related method, in order to perform width reduction rolling of a thin strip without causing buckling, the upper surface of the strip near the roll gap of the edger roll is held down by an upper presser roll, and the upstream side of the strip is A method has also been proposed in which the width of the strip is reduced while the winding angle of the strip with respect to the upper presser roll is maintained constant by raising the strip with a looper roll.

FIG. 2 is an explanatory diagram schematically showing this, and in the figure,
When the strip 22 leaving the upstream roll 20 and heading toward the downstream roll 21 is lifted by the looper roll 24 and sent to the edger roll 28 equipped with the upper presser roll 26, the winding angle with respect to the upper presser roll 26 is adjusted. is adjusted to a constant value (JP-A-63-10006).

Furthermore, in order to enhance the edging effect on thin plate strips, a series of horizontal finishing stands F are installed as shown in Figure 3.
1, Edger mill 14 consecutively between F2, F3, and F4
．． A method of installing 14 has also been proposed.

(Unexamined Japanese Patent Publication No. 61-279302) (Problem to be solved by the invention) However, hot or cold finishing star.

When width reduction rolling is performed on the strip between the throats, since the strip thickness is smaller than the width of the strip, the metal flow when width reduction is applied by engraving is concentrated at the edge of the plate, forming tongue bones. However, the deformation generally does not extend to the center of the board width. FIG. 4 shows a tongue bone 42 formed at the edge of the strip 22 during width reduction rolling.
It is a partial sectional view showing the shape of. The shape of the edge of the strip 22 after etching is as shown by the dashed-dotted line, but when it undergoes etching, it takes on a raised portion 40 with a cross-sectional shape shown by diagonal lines due to the metal flow shown by the arrow in the figure. .

Therefore, in the horizontal rolling performed after etching, the raised part 40 of the tongue bone 42 is rolled down, and at that time, most of the raised part 40 flows outward in the sheet width (to the left in the drawing), resulting in a large width. In addition to the curling, edge drops occur at the ends, deteriorating the cross-sectional shape of the plate.

Therefore, due to the large width return during horizontal rolling after such etching, that is, the etching efficiency (-∆reduction/∆ga, ∆We: width adjustment amount after horizontal rolling, ∆-: engraving amount) is low. In order to improve plate width accuracy, it is necessary to increase the amount of edging required.However, if this is done, buckling in the width direction will easily occur due to the thinner plate thickness, and in the end, the amount of edging will increase. This created a paradoxical phenomenon in which it was impossible to obtain a large size, which was a major obstacle in practical use.

On the other hand, as exemplified as a conventional technique, a presser roll or the like is used to prevent buckling when the width of the strip is reduced.
There have been attempts to increase the amount of width reduction as much as possible and proposals to increase the amount of width adjustment by performing multi-stage engineing, but for the former, it is possible to prevent buckling and increase the amount of width reduction slightly Even if this is attempted, there is no change in the low etching efficiency as described above, so there is a limit to the actual amount of width adjustment, and there is also a drawback that it cannot be applied when there is no looper. Furthermore, regarding the latter, if the plate thickness is thin, it is necessary to install a large number of edger mills between stands in order to ensure the amount of width adjustment, which is wasteful in terms of equipment cost.

Therefore, in view of the above-mentioned problems of the conventional edger mill between finishing stands, an object of the present invention is to improve the cutting efficiency and precision of the strip width when reducing the width of a strip with a small thickness relative to the strip width. An object of the present invention is to provide an inter-stand edger mill and a rolling method using the stand-to-stand edger mill, which can improve the cross-sectional shape of a plate material with less edge drop.

(Means for Solving the Problems) Thus, the inventor of the present invention investigated whether or not it is possible to achieve the purpose by controlling the shape of tongue bones if the generation of tongue bones is unavoidable. The present invention was completed based on the knowledge that by doing so, the metal flow during subsequent horizontal rolling can be well controlled, shape defects can be prevented, and the required amount of etching can be ensured.

Here, the present invention provides an edger mill installed between strip mill stands to perform width reduction rolling of strip, wherein the vertical rolls constituting the edger mill are grooved rolls, and the body of the vertical roll is This is an inter-stand edger mill characterized in that it is provided with inclined flange portions above and below that satisfy the following relationship.

1.0≦B8. ≦1.3 ... (1) and 2° ≦ θ ≦ 20" ・ ・ ・ ・ (2) Here, B is the length of the body part of the vertical roll, to is the strip thickness θ is the inclined flange part of the vertical roll It is the angle that the side makes with respect to the horizontal line.

Another aspect of the present invention is a rolling method using an interstand edger mill in which an edger mill having the above-mentioned configuration is installed between hot or cold horizontal rolling mills to reduce the width of a strip. be.

According to the present invention, Bc. Since the length of the body of the vertical roll must be changed according to the thickness of the strip, in other words, the roll must be changed, the length of the body of the vertical roll must be changed according to the strip thickness. In the case of a vertical roll of 21-, 21m-≧t.

For strips with a thickness in the range ≧16.1 ms, width reduction can be carried out by the same vertical roll.

The rolling method according to the present invention is particularly effective when applied to hot rolling.

(Operation) Next, the present invention will be described in more detail with reference to the accompanying drawings.

As shown in a side view in FIG. 5, the inter-stand edger 50 according to the present invention uses a slotted roll as the edger roll 52, and is provided with a flange portion 54 for reducing the width of the end of the strip 53. As shown in a partially enlarged view in the same figure, when the inclination angle θ of the flange portion and the length B of the vertical roll body are assumed, these relationships are as shown in the above-mentioned equations (1) and (2). Note that D″ is the length of the inclined flange portion 54.

Conventionally, in the middle of the edge between stands, the vertical roll 52
It is unnecessary to use a grooved roll (in most cases, a flat roll was used. Even if it is a grooved roll,
An inclination with the conditions as in the present application was not specified in the flange portion.

Moreover, according to the present invention, the body length (B) and strip thickness (t, ) of the vertical roll, as well as the angle (θ) formed with the horizontal line of the side surface of the vertical roll flange, must satisfy the following relationship. .

1.0≦e/lo≦1.3 and 2°≦θ≦20″ Here, if B8 above exceeds 1.3, it will not be possible to achieve the same level of etching efficiency as can be achieved with flat rolls,
On the other hand, if the angle θ of the flange part is less than 1.0, the improvement in etching efficiency will be saturated even if it is made smaller than this, and if the flange angle θ is less than 2°, the etching efficiency will be saturated; If it is exceeded, no contribution can be made to improving the shape of the tongue bone that is inevitably formed.

FIG. 6 shows changes in the thickness of the edge portion according to the present invention.
This is an explanatory diagram schematically showing a comparison with the case of a conventional edge roll.As shown in the figure, compared to the conventional flat roll engine, the raised part of the board thickness is formed more inside the board width. This is to suppress metal flow toward the outside of the sheet width when the raised portion is flattened during subsequent horizontal rolling.

When width rolling of a strip is performed using the inter-stand edger of the present invention, as shown by the broken line in FIG.
(shown by the solid line), the bulge in the board thickness extends further into the board width, and the amount of edging near the board edges is suppressed to the same level as the board thickness.

After that, the raised part is flattened by horizontal rolling, but most of the raised parts formed by conventional edger rolls are deformed as metal flows outward in the width direction of the sheet, reducing the etching efficiency and causing the sheet edge to become flat. In contrast, the above-mentioned bulge formed by the edger roll of the present invention flows evenly in the outer and inner directions of the sheet width, and is caused by the width return after horizontal rolling. At the same time, a decrease in etching efficiency is suppressed, and at the same time, an appropriate metal flow in the outer direction of the plate width is ensured. The situation at this time is the 7th
As shown schematically in the figure, the raised portion 62 of the tongue bone 60 formed at the plate end of the strip 53 is formed slightly inside the plate width end. When horizontal rolling is performed, metal flow occurs in the direction of the arrow in the figure.
- The plate end shape is as shown by the dotted chain line, which helps in forming a flat part at the plate end and improves edge drop.

In addition, among the Esoger roll shapes of the present invention shown in FIG.
As for the dimensions of B, to, and θ, the shape of the tongue bone differs depending on the value of the engine angle ΔW, so it cannot be strictly specified, but it is smaller than the distance from the peak of the raised part 62 of the tongue bone to the edge of the plate. It is better to design it larger.

Next, the effects of the vertical roll shape in the edge between stands of the present invention will be described with reference to examples.

Example 1 In this example, the results of a series of hot rolling experiments conducted by the present inventor are firstly B8. (B is the length of the body of the vertical roll, to is the strip thickness; see Figure 5) and the relationship between the etching efficiency is summarized in a graph in Figure 8, and the roll arrangement in this case is shown in Figure 10. As shown in Fig. 5, the shape of the Esoger roll in this case is B = 21 mm, θ
−6°, D = 100 mm, and the roll body has a diameter of 2
0 (1 mm). The thickness between Fl and Fl of the strip was 20 m5.

In addition, finishing rolling mills P,, F! Generally, a four-layer horizontal rolling mill is used.

In this example, the strip 53 rolled by the horizontal rolling aF+ shown in FIG.
After width reduction rolling is performed with the edger roll 52 of 0 to form a predetermined dog bone at the edge of the plate, subsequent horizontal rolling 11aF is performed.
It was horizontally rolled at t.

As you can see from the graph in Figure 8, it is B8. When the ratio exceeds 1.3, the etching efficiency becomes lower than that of a conventional flat roll, and the object of the present invention cannot be achieved. On the other hand, if 8/10 is less than 1.0, the etching efficiency will be saturated and no improvement can be expected, but the edge of the plate will start to bite from the roll hole pattern, causing scratches. In addition, the load that acts on the roll during engine (
The roll separation force) suddenly increased, forcing us to take measures to make the edger mill more rigid than necessary.
On the contrary, there were many disadvantages.

Example 2 In this example, the results of a series of hot rolling experiments conducted by the present inventor will be summarized based on the angle θ゛~(5th The relationship between (see figure) and etching efficiency is summarized in a graph, as shown in FIG. 9. The roll arrangement, shape, etc. were the same as in Example 1.

As can be seen from Fig. 9, as θ is increased (as
The raised part of the edge of the board formed by etching moves toward the outside of the board width, taking a shape similar to the tongue bone created by conventional edger rolls, so the etching efficiency gradually decreases. The etching efficiency has become lower than that of conventional furantrol. On the other hand, in the range of 2° below θ, the restriction of the strip end by the hole pattern becomes large, and the load acting on the roll during engineing increases rapidly, and the frequency of occurrence of folding defects at the strip end due to edging increases. On the other hand, no particular improvement in etching efficiency could be expected.

Example 3 In this example, as shown in FIG.
The relationship between etching efficiency and etching amount was evaluated.

The shape of the edger roll in this case is B in Figure 5.
−21 ms, θ=6°, D=100 s+m, and the roll body had a diameter of 200 mm. Also, the strip F1~
The thickness between F2 was 201III11.

Note that a four-layer horizontal rolling mill is generally used as the finishing rolling mills F1 and F2.

In this example, the strip 53 rolled by the horizontal rolling mill F in FIG.
0 edger roll 52 to form a predetermined tongue bone at the edge of the plate, followed by a horizontal rolling machine F! horizontally rolled.

It is shown by taking M(Δ-). For comparison, similar relationships when using a conventional edger mill with flat rolls are also shown. As is clear from the results shown in this figure, when the Esoger Mill of the present invention is used,
It can be seen that the etching efficiency (Δ direction/Δ distance) is improved.

FIG. 12 shows the horizontal rolling t! in this example. The results of measuring the shape of the edge of the plate after rolling with Pt are shown, and it can be seen that when the edger of the present invention is used, the cross section of the edge of the plate becomes more rectangular than when the conventional edger is used. It can be seen that the edge drop has been improved.

Note that the present invention is not limited to the above-mentioned embodiments, and may also be applied to cases where presser rolls of various shapes are installed in or near the edger mill in order to prevent buckling of the strip other than the edge rolls. Needless to say, various modifications can be made without departing from the gist of the present invention.

(Effects of the Invention) As described above, according to the inter-stand edger of the present invention, by providing the edger roll with a hole having a predetermined shape, it is possible to improve the tongue bone shape of the edge of the plate due to etching. In addition to increasing the edging efficiency and improving the sheet width accuracy, it also has the excellent effect of improving edge drop.

[Brief explanation of the drawing]

1 to 3 are layout diagrams of a conventional edger mill between stands. FIG. 4 is a schematic explanatory diagram of a dogbone shape formed by the conventional technique. FIG. 5 is an example of an edger roll shape of the present invention. Figure 6 is an explanatory diagram of the difference in dog bone shape between the conventional edger and the edger of the present invention; Figure 7 is a schematic side view showing the edge of the plate by horizontal rolling after engraving according to the present invention; Explanatory diagram of the metal flow in the section; Figure 8 is Bc. Graph showing the relationship between θ and etching efficiency; FIG. 9 is a graph showing the relationship between θ and etching efficiency; FIG. 10 is a layout diagram of an etching mill showing an embodiment of the present invention; FIG. FIG. 12 is a graph showing an example of the improvement effect of edge drop according to the present invention. No. 1, 21211: #, 3 concave

Claims (2)

[Claims] (1) An edger mill that is installed between strip mill stands and performs width reduction rolling of the strip, in which the vertical rolls constituting the edger mill are grooved rolls, and the following relationship is satisfied between the top and bottom of the body of the vertical rolls: An inter-stand edger mill characterized by having an inclined flange portion. 1.0≦B/t_0≦1.3 and 2°≦θ≦20° Here, B is the body length of the vertical roll, t_0 is the strip thickness θ is relative to the horizontal line of the side surface of the inclined flange part of the vertical roll. It's an angle. (2) A rolling method using an interstand edger mill, in which the edger mill according to claim 1 is installed between horizontal rolling mills to perform width reduction rolling of the strip.