JPH0353041B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a rough rolling process such as thick plate rolling or hot strip rolling, or an edger rolling method in blooming rolling or the like.

[Conventional technology]

For example, in the rough rolling in the hot strip rolling described above, the rolled material is rolled to a thickness that can be rolled in the subsequent continuous finishing mill, and width adjustment rolling is performed to obtain a predetermined product width. In this width adjustment rolling, that is, edger rolling, when performing width adjustment rolling using a vertical scale breaker (VSB) or a pair of cylindrical hard rolls as edgers,
When a rolling force is applied to a rolled material, one side of the rolled material that is in contact with the hard roll often lifts up, making it impossible to achieve sufficient width reduction, resulting in a decrease in width dimensional accuracy. Steps are formed on the side end faces of the rolled material, resulting in a decrease in perpendicularity, which in turn leads to a decrease in yield.
In particular, when the above-mentioned one-sided lifting phenomenon of the rolled material occurs, the lifting direction appears alternately on the working side and the driving side in each width reduction pass, which increases the width dimension of the rolled material. This promotes a decrease in accuracy and deterioration of the shape of the side end surface. These phenomena also appear in the thick plate rolling process or edger rolling in the blooming process.

For this reason, various edger rolling methods have been proposed in the past. For example, a typical edger rolling method uses a tapered roll whose diameter expands upward as a hard roll, or
There is a method in which hard cylindrical rolls are arranged to be inclined in the width direction (Japanese Unexamined Patent Publication No. 116259/1982) to generate a pressing force against the rolled material during rolling to prevent backling or lifting.

Furthermore, a method has been proposed in which a presser roll is attached to press the center portion of the rolled material.

Furthermore, it has been proposed to use a caliber roll as a hard roll (Tokuko Showa).
55-7322).

[Problem that the invention seeks to solve]

In the method explained in the conventional technology, lifting of the rolled material cannot be completely prevented,
Another problem is that the perpendicularity of the side end surfaces of the rolled material decreases due to the taper of the hard roll or the inclination in the width direction of the hard roll.

In addition, in the method (2), although it can be assumed that the effect of preventing buckling and lifting is achieved, the rolling equipment becomes complicated and maintenance is difficult, and if the rolled material is warped, the rolled material must be replaced. This has the problem of not only colliding with the push rolls and causing damage to the equipment, but also interfering with smooth operations.

Furthermore, the method originally aimed at reducing the rolled material by a large width to reduce the occurrence of biting defects and slipping, and when the thickness of the material becomes thinner than the caliber dimension, the lifting phenomenon occurs. The problem is that it cannot be prevented.

In this way, it must be said that the various conventional edger rolling methods are extremely insufficient in solving the buckling and lifting phenomena, and in particular, there is no specific way to solve the lifting phenomenon on one side. The current situation is that no solution can be found.

[Knowledge of the invention]

Therefore, the inventors of the present invention conducted various analyzes on the lifting phenomenon on one side of the rolled material during edger rolling, and conducted repeated experiments using a plastic model from an experimental rolling mill. As a result of various analyses, the phenomenon of lifting up on one side of the rolled material was found to be: (1) non-uniformity of the shape at the side edge of the rolled material (2) horizontal direction of the rolled material due to the inclination in the width direction of the roller table that conveys the rolled material Inclination (3) It was found that the inclination of Etzier's hard roll was the main cause.

Among the above factors, factors (2) and (3) can be solved by improving the rolling equipment to eliminate the lifting phenomenon on one side of the rolled material. Due to the shape of the material,
During rolling, it is necessary to fully understand the behavior of the rolled material depending on the shape of the side edges.

In other words, as shown in Figure 1, (a) the rectangularity of the cross-sectional shape of the rolled material (slab) is deformed, and (b) the pulges formed during thickness adjustment rolling (horizontal pass) are unbalanced. (c) Rolled material corners may be symmetrically deformed (rolled). When these types of rolled material are edge rolled, one side of the rolled material may rise due to the behavior described below. becomes. To explain the case of reducing the width of a plate material with the typical cross-sectional shape shown in Fig. 1a, first, a moment _M1 is generated due to the reaction force caused by the cross-sectional shape (see the black arrow), and the A side lifts up. Trying to grow. However, when there is friction on the end face, the B side rises up.

That is, the flow of the material in the plate thickness direction due to plastic deformation due to rolling is large in the upward direction in the A section and downward in the B section, and small in the downward direction of the A section and the upward direction in the B section. Therefore, the reaction force due to the frictional force from the hard roll against the flow of material (see the white arrow) is downward in part A, and downward in part B.
part acts upwards, resulting in a moment _M2 . This moment M ₂ is the above moment M ₁
If it is larger, side B will rise up.
In other words, one side of the rolled material will rise. It should be noted that the behavior shown in FIGS. 1b and 1c is similar, although there are differences in degree.

[Means for solving problems]

The present invention has been made based on the above-mentioned knowledge, and is characterized in that in edger rolling of a plate material in which a rolled material is rolled to a required width by a width reduction stand having a pair of hard rolls, the width is adjusted by the hard rolls. The method consists in that the material to be rolled is processed in advance so that the width of both lower side edges thereof is smaller than the width of the upper side edges, and then the material is rolled.

[Effect]

That is, the present invention is based on the above-mentioned material flow phenomenon in edger rolling, and pre-processes the width of the cross-sectional shape of the rolled material before rolling so as to actively give a difference in the amount of material flow on both the upper and lower sides of the rolled material. The basic idea is to prevent one side of the rolled material from lifting up by providing a restraining force that presses the rolled material against the conveying roller table.

〔Example〕

A more detailed explanation will be given below with reference to the drawings.

The cause of the lifting phenomenon on one side of the rolled material is greatly influenced by the material flow, and the restraining force generated as a reaction to the material flow is used as a restraining force against the lifting of the rolled material. From this point of view, the shape of the side edges of the rolled material is changed as shown in FIG. 2, an example of which is shown in FIG. 2, to actively cause a change in material flow between the upper and lower sides of the rolled material. That is, as shown in Fig. 2a, corner portions are removed _c1 from both side edges of the lower side of the rolled material s with dimensions of thickness h and width W;
Or, as shown in b, a step c ₂ with thickness h and width w
Alternatively, as shown in c, a tapered surface c ₃ with an appropriate width W and an angle θ is formed, and a chamfer part c is formed on both lower side edges of the predetermined pressure material s. However, in any case, the upper width dimension WT and lower width dimension WB of the rolled material are WT>
Before the rolled material is subjected to width adjustment rolling with hard rolls so as to satisfy the WB relationship, the cross-sectional shape of the rolled material s is preformed. Various dimensions can be considered to perform chamfer processing on this rolled material s. For example, in the case of gas cutting, press forming, cutting, or rolling, the optimum size can be selected from the manufacturing cost and equipment cost conditions. You just have to choose the method.

Now, to show an example of the case where chamfer processing is performed by rolling, Fig. 3a shows a case where the chamfer processing is performed using an edger rolling mill formed with a caliber, and a pair of hard rolls 1 on the left and right are formed. A caliber 2 is formed, the upper side of which is a side wall 3 in a horizontal plane parallel to the pass line that restrains the upper surface of the rolled material s, and the lower side thereof is an inclined side wall that forms a chamfer part c with respect to the rolled material s. 4, the chamfer part is formed by rolling down the rolled material s from both sides with this hard roll 1, and the chamfer part is formed between a pair of upper and lower rolling rolls in the one shown in Fig. 3b. In the case of performing the forming process of c, the chamfer part c of the rolled material s is formed between a pair of rolls, a smooth cylindrical upper roll 5 and a stepped roll 7 having sloped surfaces 7 on both sides. It is something.

When the rolled material s, which has been formed with the chamfer part c in advance in this manner, is subjected to width adjustment rolling with a pair of left and right hard rolls 10, as shown in FIG. 4, the upper and lower corners of the rolled material s , the material flow state changes, and the formation of the dog bone at the top becomes larger than the dog bone at the bottom, and at this stage, the load applied from the hard roll 10 to the rolled material s as a reaction to the material flow.
Since the relationship between f ₁ and f ₂ is smaller when the chamfer part c is provided, the resulting restraining force acts on the rolled material s, and acts as a force that presses the rolled material s against the conveying roller table. This means that lifting of the rolled material s can be suppressed and prevented. hard roll 10
When the width adjustment rolling is followed by the thickness adjustment rolling using horizontal rolls, a double bulge is formed at the side edge of the resulting rolled material s' as shown in Fig. 5, but the width adjustment at the previous stage Since there is a difference in the amount of dog horn formed during rolling, the upper part of this bulge also protrudes outward to a large extent.
As a result, the side edges of the rolled material s are uneven, and even when the rolled material s' is further subjected to the width adjustment rolling shown in FIG. 6, the material flow of the rolled material is The same movement as shown in FIG. 4 occurs, and this can prevent the rolled material s' from floating up. The same thing will be repeated in the following edger rolling. However, in order to more reliably prevent the rolled material from lifting up, prior to the width adjustment rolling by the hard rolls at each stage, the chamfer portions are actively pressed against the lower side edges of the rolled material as shown in Fig. 3. By performing the molding process using the means illustrated in FIG. 4, the width can be stably adjusted under pressure.

〔Effect of the invention〕

As is clear from the above explanation, according to the edger rolling method according to the present invention, the rolled material to be width-adjusted rolled by hard rolls is subjected to chamfer processing on both lower side edges in advance. Since the phenomenon of lifting of the rolled material does not occur, it is possible to perform sufficient width adjustment reduction, improve the width accuracy, and minimize the cut off portion of the edge after rolling. Its effects, such as improving manufacturing yield, are of great value in terms of industrial contribution.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view showing the cross-sectional shape of the rolled material;
FIG. 2 is a sectional view showing the cross-sectional shape of the rolled material applied to the present invention, FIG. 3 is an explanatory view showing an example of forming processing,
4 to 6 are schematic explanatory diagrams showing the deformation process of a rolled material in edger rolling according to the present invention. 1, 10...hard roll, 2...caliber, 4...
... Sloped side wall, s... Rolled material, c... Chamfer portion.

Claims (1)

[Scope of Claims] 1. In an edger rolling method for plate materials in which a rolled material is rolled to a required width by a width reduction stand having a pair of hard rolls, the rolled material to be width-adjusted by the hard rolls is preliminarily coated with the following: 1. A method for edger rolling a plate material, which comprises processing the widths of both side edges to be smaller than the upper side edges, and then rolling.