JPH0115322B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for finish rolling angle iron. The groove method is generally known as a method for rolling angle iron, but in this type of rolling method, the hole shape is determined by the size of the angle iron to be rolled, so the hole shape ( rolling roll)
In addition, it is necessary to change the rolls every time the size is changed, and the time required for this roll change operation is a major cause of hindering the productivity of shaped steel. For these reasons, the present inventors have been considering so-called size-free rolling, which allows the common use of rolling rolls for several sizes of angle irons. The purpose of the present invention is to provide a rolling method that can finish rolled materials with high precision. In the size-free rolling method, when rolling angle steel of arbitrary side length and thickness while sharing a rolling roll, it is thought that rolling will be mainly performed using a biaxial rolling mill or a triaxial rolling mill with an open hole type. However, in rolling with such a rolling mill, unlike conventional closed-hole rolling, the toe part of the rolled material is not shaped, and therefore it is necessary to use the vertical rolls of a universal rolling mill in the intermediate rolling stage. It is thought that it will be necessary to mold the tip of the foot. In order to appropriately and easily form the toe in this universal rolling mill, it is necessary to form the rolled material in a flat state as shown in Figure 1. During the rolling stage, 3 consists of a lower roll and a pair of inclined upper rolls.
It is formed into a predetermined angle using an axial rolling mill. However, in finish rolling from such a flat type, if the rolled material is particularly thick (for example, product dimensions of 20 mm or more), there may be problems such as defects such as scratches and sink marks, and ridge bite depending on the material. found. The present invention aims to solve such problems, and its basic feature is that a rolled material that has been rolled in a flat type during initial shaping and intermediate rolling is rolled from a flat state to a 20
After preliminary bending at an angle of ~30°, a horizontal lower roll having a chevron-shaped roll surface with a top angle of approximately right angle and tapered surfaces on both sides of the top, and a horizontal lower roll having a chevron-shaped roll surface configured with a tapered surface on both sides of the top, and a roll facing toward the top of the angle iron to be rolled. A three-axis rolling mill equipped with two upper rolls on the same vertical plane, each having a roll face with a face angle of 15 to 30° due to its small diameter structure, and the roll axes of which are inclined with respect to the horizontal. Accordingly, finish rolling is performed such that the roll surface of the horizontal lower roll contacts the inner surface of both flanges of the angle iron, and the roll surface of each upper roll contacts the outer surface of each flange of the angle iron. The present invention will be explained below based on the drawings. Figures 2a and b show an example of an intermediate rolling stage in size-free rolling, and the rolled material S is in the second stage.
As shown in Figure a, it is rolled into a flat type by a triaxial rolling mill (a biaxial rolling mill with an open hole type may also be used) consisting of a lower roll 6 and a pair of upper rolls 7, 7, and as shown in Figure 2b. As shown, the toe portion is formed by vertical rolls 10, 10 of a universal rolling mill having upper and lower rolls 8, 9 and vertical rolls 10, 10. In the present invention, in finishing rolling the rolled material S thus rolled into a flat type, first,
As shown in FIG. 3, preliminary bending is performed prior to finish rolling. When a thick rolled material is finish-rolled all at once from a flat shape (intermediate rolling) to an angle iron shape, each part of the cross-section of the rolled material may not be uniformly bitten in the early stages of being bitten into the finishing 3-axis rolling mill. As a result, vibration and a reduction in the centering effect of the material occur, and furthermore, "sink marks" occur on the outer surface of the flange. For this reason, in the present invention, preliminary bending is performed at an angle in the range of 20 to 30 degrees with respect to the product angle of 45 degrees.
This avoids the above-mentioned problems during finish rolling. In Figure 3, an open-hole type P is shown between the upper and lower rolls 1 and 2.
The preliminary bending is performed using a biaxial rolling mill having a 2-axis rolling mill, and rolling is performed with θ ₁ in the range of 20 to 30°. Here, when θ ₁ <20°, the preliminary bending effect is not sufficient, and therefore, the biting property to the finishing roll is poor, and sink marks occur on the outer surface of the flange. Also θ＞
If the angle is 30°, scratches will occur on the outer surface of the flange during preliminary bending, which is not preferable. Table 1 is AB300
The influence of θ ₁ mentioned above was investigated regarding the preliminary bending of angle iron of size ×300 × 45, and the following rolling mill was used for preliminary bending and finish rolling. ●Two-axis rolling mill for preliminary bending Upper roll diameter...1000mm Lower roll diameter...960mm ●Triaxial rolling mill for finishing rolling Upper roll diameter...480mm Lower roll diameter...1080mm

[Table] After such preliminary bending, the rolled material S is rolled by a three-axis roll mill equipped with a pair of left and right upper rolls 3, 3 and a horizontal lower roll 4, as shown in FIG. The horizontal rolls 4 of this triaxial rolling mill have mountain-shaped roll surfaces whose top angles are approximately right angles and which have tapered surfaces 41 on both sides of the top 40, and each upper roll 3 is used for rolling. By making the diameter of the angle iron narrower toward the top, it has a roll surface with a face angle (angle of inclination of the roll surface to the roll axis) of 15 to 30 degrees, and the roll axis is inclined with respect to the horizontal. It is located. And these horizontal lower rolls 4
and a pair of upper rolls 3 are placed on the same vertical plane,
Finish rolling of the rolled material S is performed such that the tapered surface 41 of the lower horizontal roll 4 contacts the inner surfaces of both flanges of the angle iron, and the roll surface of the upper roll 3 contacts the outer surface of each flange of the angle iron. . Here, the reason why rolling is performed using the upper roll having a truncated conical roll surface with a predetermined face angle as described above is as follows. That is, as shown in FIG. 5a, when an upper roll without a face angle, that is, a cylindrical upper roll 3', is used, the difference in circumferential speed in the axial direction of the lower roll 4' directly affects rolling. The elongation of the peaks of the rolled material is greater than that of the sides, resulting in bending (lifting) on the entry side as shown in the figure, causing the peaks to protrude. In addition, 5 is an entry side presser roll. Figure 5b shows the circumferential speed of the upper and lower rolls, where ν _T is the circumferential speed of the upper roll, ν _B is the circumferential speed of the lower roll, and the circumferential speed ν _B of the lower roll directly affects rolling. I understand that. On the other hand, in the present invention, which uses the upper roll 3 having a truncated conical roll surface as shown in FIG. Since they cancel each other out, rolling can be performed without causing the above-mentioned bending of the rolled material and the resulting ridge part bite. The reason for specifying the face angle θ ₂ in the range of 15 to 30° is that when θ ₂ <15°, the effect of preventing the peak from being squeezed out by adding a face angle is insufficient, and when θ ₂ >
This is because if the angle is 30°, the difference in circumferential speed of the upper roll itself becomes too large, causing scratches on the outer surface of the flange, which is not preferable. The angle iron is symmetrically rolled as shown in Fig. 4, and the face angle of the upper roll 3 is 15~15.
Since it is set in the range of 30 degrees, the axis angle θ ₃ of the upper roll 3 from the horizontal naturally takes a value in the range of 30 to 15 degrees. Table 2 shows the effect of the face angle θ ₂ on finish rolling of AB300×300×30 size angle steel, and the following finishing triaxial rolling mill was used. Upper roll diameter 480~640mm Lower roll diameter 1080mm

[Table] As described above, according to the present invention, a thick material that has been rolled into a flat type can be finished and rolled into a predetermined shape with high precision and without causing defects in biting, sink marks on the outer surface of the flange, rolling defects, etc. This can be said to be a useful finishing rolling method in free-size rolling of thick materials, which is based on flat-type rolling.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the cross-sectional shape of a flat type rolled material. Figures 2a and 2b are explanatory diagrams showing rolling conditions at the intermediate rolling stage in size-free rolling, of which a shows rolling by a triaxial rolling mill, and b shows toe forming rolling by a universal rolling mill. There is. FIG. 3 is an explanatory diagram showing a preliminary bending situation according to the present invention. FIG. 4 is an explanatory diagram showing the finish rolling situation according to the present invention. Figures 5a and 5b show a case where a cylindrical roll is used as the upper roll of a finishing rolling machine, where a is an explanatory diagram showing the rolling situation and b is an explanatory diagram showing the circumferential speed of the upper and lower rolls. In Fig. 6, a and b show the case where a truncated conical roll is used as the upper roll of the finishing rolling machine, a is an explanatory diagram showing the rolling situation, and b is an explanatory diagram showing the circumferential speed of the upper and lower rolls. . In the figure, 1 is the upper roll, 2 is the lower roll, 3
is a truncated conical upper roll, 4 is a horizontal lower roll, 40
is the top, 41 is the tapered surface, S is the rolled material, θ ₁ is the preliminary bending angle of the rolled material, and θ ₂ is the face angle of the upper roll.

Claims (1)

[Claims] 1 Rolled material rolled in a flat type during initial shaping and intermediate rolling is rolled from a flat state to 20
After preliminary bending at an angle of ~30°, a horizontal lower roll having a chevron-shaped roll surface with a top angle of approximately right angle and tapered surfaces on both sides of the top, and a horizontal lower roll having a chevron-shaped roll surface configured with a tapered surface on both sides of the top, and a roll facing toward the top of the angle iron to be rolled. A 3-axis rolling mill that has a roll surface with a view angle of 15 to 30 degrees due to its small diameter structure, and is equipped with two upper rolls whose roll axes are inclined with respect to the horizontal on the same vertical plane. An angle iron characterized in that finish rolling is carried out in such a manner that the roll surface of the horizontal lower roll hits the inner surface of both flanges of the angle iron, and the roll surface of each upper roll hits the outer surface of each flange of the angle iron. Finish rolling method.