JPH0460722B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to an edger rolling method for rolling a rolled material from the width direction in a thick plate rolling process, a rough rolling process of hot strip rolling, a blooming process, etc. It is.

(Prior art) For example, in the rough rolling step of hot strip rolling, after rolling the rolled material to a thickness that can be rolled in a subsequent continuous finishing mill, width adjustment rolling is performed to obtain a predetermined product width. It will be done. In this width adjustment rolling, that is, edger rolling, when width adjustment rolling is performed using a vertical scale breaker (VSB) or a pair of cylindrical vertical rolls as an edger, when a rolling force is applied to the rolled material, One side of the rolled material that is in contact with the vertical rolls often lifts up. As a result, it is not possible to perform sufficient width reduction, resulting in a decrease in width dimension accuracy.Furthermore, due to lifting, a step is formed on the side end surface of the rolled material, resulting in a decrease in perpendicularity, which in turn leads to a decrease in yield. will be invited. In particular, if this one-sided lifting phenomenon occurs in the medium reduction pass, and the lifting direction is different for each pass and appears alternately on the working side and the driving side, the width dimension accuracy of the rolled material will further decrease and the side end shape will deteriorate. This will encourage These phenomena also appear in the thick plate rolling process or edger rolling in the blooming process.

Furthermore, even if the above-mentioned one-sided lifting does not occur during this edger rolling, if the width reduction amount, which is the rolling amount in the width direction, is too large, the rolled material S conveyed on the table roller 2 as shown in FIG. The width reduction force F is applied by the pair of vertical rolls 1, causing an upward curve deformation as shown by S', and in extreme cases, a buckling phenomenon occurs, so the width reduction amount is limited. For example, when hot rolling is performed using a continuously cast slab, the amount of width reduction during rough rolling is at most
The width reduction was limited to about 50 to 60 mm, and it was desired to increase the width reduction in order to improve the operating rate of continuous casting equipment.

For this reason, various edger rolling methods have been proposed. As a first method, a tapered roll whose diameter expands upward is used as a vertical roll, or a cylindrical vertical roll is arranged to be inclined in the width direction (Japanese Patent Application Laid-open No. 116259/1983), and the rolling Some methods generate a pressing force against the material to prevent buckling or one side lifting. In addition, as a second method, there is a method in which a pressure roll is attached to press the center part of the rolled material. Furthermore, as a third method, rolling using caliber rolls as vertical rolls has been proposed (Japanese Patent Publication No. 7322/1983).

(Problems to be Solved by the Invention) However, in the first method, it is not possible to completely prevent one side from rising;
The taper of the vertical roll or the inclination in the width direction of the vertical roll reduces the perpendicularity of the side end surfaces of the rolled material. Further, in the second method, although the effects of preventing buckling and lifting of one side can be presumed, the rolling equipment becomes complicated and maintenance becomes difficult. If the rolled material warps upward, the rolled material will collide with the presser rolls, which will not only cause damage to the equipment but also impede smooth operation. Furthermore, the third method is originally aimed at significantly reducing the rolled material to reduce the occurrence of biting defects and slipping, and when the thickness of the sheet becomes thinner than the caliber dimension, it prevents the phenomenon of one side lifting. It has drawbacks that cannot be prevented.

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

The present invention has been made in view of such problems, and an object of the present invention is to provide an edger rolling method that can suppress the buckling phenomenon and the one-sided lifting phenomenon and can achieve a large reduction.

Therefore, the present inventors conducted various analyzes of the one-sided lifting phenomenon and buckling phenomenon of the rolled material during edger rolling, and conducted repeated experiments using a plasticine model using an experimental rolling mill. the result,
The phenomenon of one-sided lifting of the rolled material during edge rolling is caused by: (1) Non-uniformity in the shape of the side edges of the rolled material (2) Horizontal inclination of the rolled material due to the inclination in the width direction of the table roller that conveys the rolled material (3) It was found that the main cause was the inclination of the vertical rolls of the Ezzier rolling mill.

Among the above factors, factors (2) and (3) can be eliminated by improving the rolling equipment to eliminate the phenomenon of lifting of one side of the rolled material caused by these factors. However, regarding (1), which is caused by the shape of the rolled material, it is necessary to fully understand the behavior of the rolled material caused by the shape of the side edges during rolling.

As shown in Figures 6 to 8, the shapes of the side edges are (a) a rolled material (slab) whose rectangularity is deformed in cross-section (Figure 6), and (b) thickness-adjusted rolling. (c) Pulges formed in the horizontal pass are unbalanced (Fig. 7), or (c) the corners of the rolled material are symmetrically deformed (rolled) (Fig. 8). be. When a rolled material having such a side edge shape is edge rolled, material flow occurs due to plastic deformation of the rolled material due to width reduction. The thickness direction component of the material flow amount is greater in the portion A in the figure, which protrudes more outward, than in the portion B, regardless of the shape of the side edge of any rolled material. The reaction force of the material flow from the vertical rolls to the rolled material is A
As a result, the reaction of the material flow to parts A and B acts as a couple that rotates the rolled material, resulting in rotation of the rolled material in the direction of the arrow in the figure,
In other words, one side of the rolled material will be lifted up.

On the other hand, the buckling phenomenon occurs when a large width reduction is performed.
As a result of the rolled material being curved upward in the width direction,
It has become clear that this will occur.

(Means for Solving the Problems) In order to solve the above problems, the present invention is based on the above findings, and provides an edger rolling method in which a rolled material is rolled to a required width using a width reduction stand having a pair of vertical rolls. The rolled material is processed in advance by an upstream edger rolling mill with vertical rolls inclined in the width direction of the rolled material so that the width of the lower side edges is smaller than the upper side edges. , rolling.

(Function) That is, the present invention is based on the material flow phenomenon in the edger rolling, and pre-processes the rolled material before width adjustment rolling to actively differentiate the material flow rate on the upper and lower surfaces of the rolled material. The basic idea is to form the cross-sectional shape of the rolled material in such a way as to give the rolling material a restraining force that presses the rolled material against the conveying roller table, thereby preventing one side of the rolled material from lifting up.

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

The cause of one-sided lifting of a rolled material is largely influenced by material flow, and this material flow depends on the shape of the side edge of the rolled material. The present invention utilizes the restraining force generated as a reaction to the material flow as a restraining force against lifting of the rolled material on one side.

On the other hand, the mechanism that can prevent the buckling phenomenon is as follows. In other words, when rolling a rolled material in which the width of the lower side edges is smaller than the upper side edge, the rolling force distribution on the side end faces is larger on the upper side and smaller on the lower side, so the rolled material is lowered in the width direction. A force acts that causes it to curve downward in a convex manner. Since the rolled material curved in a downwardly convex manner is restrained from its curved deformation by the table, it does not buckle and can be rolled down in width.

From this point of view, the shape of the side edge of the rolled material is changed as shown in FIGS. 9 to 11, an example of which is shown in FIGS. That is, as shown in FIG. 9, the lower side edges of the rolled material S have dimensions of thickness h and width w, and the corner portion _C1 is removed, or as shown in FIG. , to form a stepped portion _C2 with a width w, or as shown in FIG. 11, with an appropriate width w,
Also, a tapered surface _C3 having an angle θ is formed. In other words, the chamfer parts C are formed on both edges of the lower side of the rolled material S, and in any case, the upper width dimension W _T and the lower dimension W _B of the rolled material are such that W _T > W _B
The rolled material is subjected to forming processing prior to width adjustment rolling using vertical rolls so that the following relationship is achieved. Various methods can be considered for the chamfer processing of this rolled material S, such as gas cutting, pressing, forming, cutting, or rolling, but considering conditions such as manufacturing cost and equipment cost, Just choose the most suitable method.

(Example) Next, an example of the present invention will be described in which the chamfer processing shown in FIG. 11 is performed by edger rolling.

As shown in FIG. 1, the axes of the pair of left and right vertical rolls 3 of the upstream edger rolling mill are tilted at appropriate angles so that they are wide at the top and narrow at the bottom in the width direction. Then, chimfer processing is performed by performing edger rolling in this state. In this case, since the rolling is performed on the upstream side, the thickness of the rolled material S is thick, and there is no fear of one side lifting up. If it floats up, use a caliber roll or a roll with a spit on the top.

When the rolled material S, which has been formed with the chamfer portion C in advance in this manner, is subjected to width adjustment rolling with a pair of left and right vertical rolls 1, as shown in FIG. 3, the rolled material S
At the upper and lower corners of the rolled material S, the flow state of the material changes, and the formation of a dog bone in the upper part becomes larger than that in the lower part, and at this stage, the rolled material S
Load as a reaction to material flow f ₁
Regarding the relationship between f ₂ and f ₂ , since the load on the side where the chamfer portion C is provided is smaller, the difference acts on the rolled material S as a deterrent force. As a result of this restraining force acting as a force that presses the rolled material S against the conveyance roller table, lifting of one side of the rolled material S is suppressed.

On the other hand, when the rolled material S is width-reduced, the tip portion is rolled down toward the upper side, so that it curves convexly downward in the width direction of the rolled material S. The curved rolled material S is supported by the table roller 2, and the progress of the curve deformation is suppressed by the reaction force of the table roller 2. According to this method, it is possible to avoid a phenomenon in which the rolled material S curves convexly downward in the width direction and develops into buckling during width reduction (FIG. 2).

When width adjusting rolling is performed by the vertical rolls 1 and then thickness adjusting rolling is performed by the horizontal rolls, a double bulge is formed at the side edge of the rolled material S' after rolling, as shown in FIG. However, since there is a difference in the amount of dog bones formed during the width adjustment reduction in the previous stage, the upper bulge also protrudes outward to a large extent. When this rolled material S' is further subjected to width adjustment rolling as shown in Fig. 5, the material flow of the rolled material changes as shown in Fig. 3, and as a result, one side of the rolled material S' is raised. and buckling is prevented. The same thing will be repeated in the following edger rolling.

However, in order to more reliably prevent one-sided lifting and buckling of the rolled material S and perform stable width adjustment rolling, the lower side edges of the rolled material S must be It is preferable that the edges be actively chamfered by the means illustrated in FIG.

Next, an example of a mechanism for making the inclination of the axes of the pair of left and right vertical rolls 3 of the upstream edger rolling machine variable in the width direction will be described. In FIG. 1, a pair of left and right vertical rolls 3 for carrying a rolled material S on a table roller 2 are rotatably supported by a pair of upper and lower jocks 4. As shown in FIG. The vertical roll 3 is moved forward and backward in the axial direction by a worm 7 and a worm wheel 8. It is inclined in the width direction of the rolled material S. Therefore, by moving each rolling screw 6 back and forth appropriately using the worm 7 and worm wheel 8 to tilt the pair of vertical rolls 3 in a V-shape when viewed from the traveling direction of the rolled material S, edger rolling is performed. Chamfer processing is performed on the side edges of the rolled material S.

(Effects of the Invention) As is clear from the above explanation, according to the edger rolling method according to the present invention, the phenomenon of one side of the rolled material lifting up and the buckling phenomenon are suppressed, so that width adjustment reduction can be performed sufficiently. This has the effect of improving the width accuracy, minimizing the amount of cut off of the edges after rolling, and improving the yield of the product.

[Brief explanation of the drawing]

FIG. 1 is a front view showing the processing state of the side end surface of a rolled material by the method according to the present invention, and FIGS.
The figure is a front view showing the rolled state according to the method according to the present invention, FIGS. 6 to 8 are cross-sectional views showing the cross-sectional shape of the rolled material before rolling, and FIGS. 9 to 11 are FIG. 12 is a cross-sectional view showing the cross-sectional shape of the rolled material used in this method, and a front view showing the state of rolling by the conventional method. 1... Vertical roll, 2... Table roller, S...
...Rolled material, 3... Upstream vertical roll.

Claims (1)

[Claims] 1 In the Edger rolling method in which a rolled material is rolled to a required width using a width reduction stand having a pair of vertical rolls, the rolled material is rolled in advance by an upstream Edger rolling mill with vertical rolls inclined in the width direction of the rolled material. An edger rolling method characterized in that the width of the lower side edges of the material is smaller than that of the upper side edge, and then the material is rolled.