JPH0115323B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for rolling T-shaped steel, and an object of the present invention is to provide a method by which a T-shaped steel of any size can be rolled with high precision using a triaxial rolling mill.

The hole method is generally known as a rolling method for T-section steel, but in this type of rolling method, the hole shape is determined by the size of the T-section steel to be rolled. Mold (roll)
As a result, it is necessary to rearrange the rolls every time the size is changed, and the time required for this roll rearranging work is a major factor that impedes the productivity of shaped steel. Further, when rolling a T-shaped steel using this rolling method, there is a problem unique to T-shaped steel in that it is difficult to increase the height of the stem portion because no horizontal reduction is applied.

The present invention was devised in view of the shortcomings of the conventional method, and in particular, in the stages after the intermediate rolling after rough forming, rolling is performed using a triaxial rolling mill with multiple stands, and each of these rolling steps is performed by an upper roll. By controlling the shaft angle, it is possible to accurately roll a T-shaped steel of any side, thickness, and stem size using a common rolling roll. That is, the present invention has a flat horizontal lower roll and two upper rolls having convex roll surfaces whose roll axes are inclined with respect to the horizontal and whose top sides are tapered on both sides on the same vertical plane. Using a triaxial rolling mill equipped with a 3-axis rolling mill, a roughly formed material to be rolled having a stem part at the upper center of the flat part is rolled, and a horizontal lower roll hits the lower surface of the flat of the material to be rolled.
The top of the convex roll surface of each upper roll hits each corner of the stem part and flat part of the material to be rolled, and the tapered surfaces on both sides of the top contact each stem part side surface and flat part bordering on the stem top part. The upper roll is rolled on two or more rolling stands including a finishing rolling mill, and during the rolling, the axis angle from the horizontal of the upper roll in the 3-axis rolling mill is set to be smaller as the rolling mill is downstream of the rolling mill. , and its basic feature is that rolling is carried out with the above-mentioned axial angle of the upper roll of the finishing triaxial rolling mill set in the range of 15 to 25 degrees.

The present invention will be explained below with reference to the drawings.

Figure 1 shows a three-axis (three-roll) rolling mill and the rolling situation of T-beams by it. 1 is a flat horizontal lower roll, 2a and 2b are a pair of left and right upper rolls, and these rolls are are arranged on the same vertical plane. Each upper roll has a convex roll surface, and both sides of the top 20 of the roll surface are configured with tapered surfaces 21 and 22, and the roll axes of these upper rolls are inclined with respect to the horizontal. It is arranged as follows.

Further, 3 is a material to be rolled, and the material to be rolled 3 has a stem portion 30 at the upper center of a flat portion 31 .

According to the above triaxial rolling mill, the lower horizontal roll 1 hits the lower surface of the flat portion 31 of the material to be rolled 3, and the top portion 20 of the convex roll surface of each upper roll 2a, 2b touches the stem portion of the material to be rolled 3. The material to be rolled 3 is rolled in such a way that the tapered surfaces 21 and 22 on both sides of the top are in contact with the side surfaces of each stem part bordering on the top of the stem part and the top surface of the flat part. be exposed.

The present invention performs a series of rolling mainly using this 3-axis rolling mill at the stage after the intermediate rolling after rough shaping, including a 3-axis finishing mill and 3-axis intermediate rolling mill with one or more stands. Rolling is performed by a rolling mill.

In the present invention, in such rolling, the axial angle θ of the upper roll 2 from the horizontal is set smaller as the rolling mill is downstream (downstream side), and the axial angle θ of the upper roll of the finishing triaxial mill is set to be smaller. Rolling is performed with θ set in the range of 15 to 25°. As shown in FIG. 1, according to a three-axis rolling mill, a material to be rolled 3 having a stem portion 30 in the center and flat on both sides is rolled in a direction perpendicular to a flat portion 31 by upper rolls 2a and 2b. It is possible to perform rolling while applying a horizontal reduction to the stem portion 30. The height and thickness of the stem can be adjusted by rolling down the upper rolls 2a and 2b in the horizontal direction. The larger the
It has the property of being easy to release. That is, the upper rolls 2a and 2b are used to grow the stem portion by inserting meat into the stem portion from both sides, and the larger the axis angle θ, the greater the degree of growth. In addition, in the rolling of T-shaped steel, as shown in Figure 2,
During rolling, the stem portion 30 is displaced in the width direction (l ₁ <
l ₂ ) However, there is a problem in that the material to be rolled is not sufficiently centered, but in rolling using a triaxial rolling mill, the larger the axis angle θ, the greater the effect of centering the material to be rolled. That is, due to the action of both upper rolls 2a and 2b, forces F ₁ and F ₂ act on the rolled material 3 from both sides in the stem direction, but F ₁ =μ・P ₁ ≒μ・ρ・l ₁ F ₂ = μ・P ₂ = μ・ρ・l ₂ μ: Friction coefficient P ₁ , P ₂ : Pressure force on flat part ρ: Force that acts per unit area of flat part, and at this time, the axial angle of upper roll 2 The larger θ
The values of F ₁ and F ₂ are increased, and therefore the centering performance is improved, thereby ensuring the dimensional accuracy of the flange dimensions (length of the left and right sides).

On the other hand, in terms of the stem shape and centering of the rolled material as described above, in terms of rolling scratches and roll friction, the larger the axis angle θ, the larger the roll circumferential speed difference. The degree of occurrence and roll friction increase.

Therefore, in the present invention, the above-mentioned axis angle θ is set large in the initial stand during rolling by a 3-axis rolling mill in the stages after intermediate rolling, thereby ensuring the stem height and flange dimensional accuracy due to material centering. In the later stand, the shaft angle θ is set small to prevent rolling defects, and the first aspect of the present invention is to regulate the shaft angle θ depending on the rolling stage. It is a characteristic of In the present invention, a finishing 3-axis rolling mill and a
This is carried out using a triaxial rolling mill for intermediate rolling of a stand or more, and in rolling by these plurality of triaxial mills, the axis angle θ of the upper roll 2 is set to be smaller toward the downstream side of the rolling.

In the present invention, the stem thickness can be arbitrarily adjusted because rolling is performed using a 3-axis rolling mill in the finish rolling stage, but in this case, the stem height is The accuracy of the dimensions must be maintained constant. The inventors of the present invention have studied this point and found that if rolling is carried out in a finishing mill with the axis angle θ of the upper roll 2 set in the range of 15 to 25 degrees, the stem height will increase regardless of the amount of reduction. It has been found that the increase can be kept approximately constant to a level that poses no practical problems. Therefore, in the present invention, rolling is performed within such a range of axis angles θ, and this is the second feature of the present invention. FIG. 3 shows the relationship between the amount of reduction and the amount of increase in stem height at each axis angle θ. According to this, when θ is about 20°, the amount of increase in stem height Δh is almost constant regardless of the magnitude of the reduction amount, and when θ becomes larger than that, the amount of increase in stem height increases as the amount of reduction increases. becomes θ again
When it becomes smaller than 20°, it tends to decrease as the rolling reduction increases. Here, if the amount of reduction is less than -0.2, there is almost no stem reduction, and the amount of reduction is
Since 0.6 is almost the material bite limit, and the stem height tolerance according to the JIS standard is ±1.5 mm, the reduction amount: -0.2 to 0.6 must be within the above dimensional tolerance. Looking at the range, θ is 15
In the range of ~25°, even if the rolling reduction is 0.6, which is the maximum in practice, the increase in stem height is within ±1.5 mm. Therefore, if rolling is performed within the above range of θ, the stem height will increase. It can be seen that the increase can be kept approximately constant within a range that poses no practical problem.

In the present invention, as described above, by performing intermediate rolling and finish rolling while regulating the axis angle θ of the upper roll of a triaxial rolling machine, T-beams with arbitrary side lengths, thicknesses, and stem dimensions can be manufactured with high precision. It is possible to perform rolling while reducing the occurrence of rolling defects.

As described above, the present invention has the excellent effect of being able to roll a T-shaped steel to any desired side length, thickness, and stem height with high precision while suppressing the occurrence of rolling defects.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a triaxial rolling mill and the rolling state thereof. FIG. 2 is an explanatory diagram showing the centering effect of rolled material in a triaxial rolling mill.
FIG. 3 shows the relationship between the amount of reduction at each axis angle of the upper roll of the triaxial rolling mill and the amount of increase in stem height. In the figure, 1 is the lower horizontal roll, 2a and 2b are the upper rolls, 3 is the rolled material, 20 is the top, 21, 22
30 represents a tapered portion, 30 represents a stem portion, 31 represents a flat portion, and θ represents an axial angle.

Claims (1)

[Claims] 1 A flat horizontal lower roll and two upper rolls each having a convex roll surface with a roll axis inclined with respect to the horizontal and tapered surfaces on both sides of the top on the same vertical plane 3 Using an axial rolling mill,
A roughly formed material to be rolled having a stem part at the center of the upper part of the flat part is placed so that the horizontal lower roll hits the lower surface of the flat of the material to be rolled, and the top of the convex roll surface of each upper roll touches the stem part of the material to be rolled. Two or more rolling stands, including a finishing mill, are placed in contact with each corner of the flat part, and the tapered surfaces on both sides of the top part are in contact with the side surfaces of each stem part bordering on the top part of the stem part, and the top surface of the flat part. During the rolling, the axial angle of the upper roll of the 3-axis rolling mill from the horizontal is set smaller as it is in the downstream rolling mill, and the axial angle of the upper roll of the finishing 3-axial mill is set to 15~
A method for rolling T-beam steel using a triaxial rolling mill, characterized in that the rolling angle is set within a 25° range.