JPS6174702A - Manufacture of h-beam - Google Patents

Abstract

PURPOSE:To prevent the generation of a deviation between the centers of flange width and web thickness, in break down rolling, by forming a recessing part of longitudinal direction at the center of the flange outer-surface of a rough H-shaped billet before rolling the billet by an universal mill equipped with specific vertical rolls, in manufacturing a H-beam by rolling. CONSTITUTION:In case of rolling a rough H-shaped billet rolled by a break down mill; a recessing part 12 is formed at the central part of the outer face of a flange part 11 along the longitudinal direction, in rolling the rough H- shaped billet 10. For a vertical roll 16 at the 1st pass of said universal mill used for rolling the billet 10; a projecting part 17 is previously formed at the outer periphery of the central part in the longitudinal direction of roll 16, and taper parts 18 increasing gradually in diameter toward both sides of the roll 16 are formed at the same time. By rolling said billet 10 by using these vertical rolls 16; an H-beam, having a flange part 11 and a web part 15 whose centers of width and thickness are aligned with each other, is stably manufactured.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for manufacturing H-section steel, and more particularly to a method for manufacturing H-section steel using a universal mill.

Conventional technology In general, H-shaped steel sections with flanges and ridges are rolled by a universal mill with a pair of left and right vertical rolls and a pair of upper and lower horizontal rolls arranged in the same vertical plane. There is. Universal mills have various advantages such as easy manufacture of parallel and wide flanges, good shape and dimensional accuracy, uniform roll wear, and easy O-ru turning. A problem with rolling is that it is extremely difficult to roll the web so that the center position in the width direction of the flange coincides with the center position of the web thickness.

The problem to be solved by the invention is that, as shown in a schematic cross-sectional view in FIG. If the center of is shifted vertically from the center of the gap between the horizontal rolls 30,
The force between the surface of the flange part 10 and the roll is strong, whereas the strength at the base of the wear part 2 relative to the flange part 1 is weak, so when the wear part 2 is bitten, the wear part 2 receives a shearing force. As a result, the flange width center A-A and the wear thickness center B-B are shifted by ΔL as shown in FIG. 9. There is.

The above-mentioned deviation in the vertical direction during rolling is particularly likely to occur in the first pass of rolling a rough shaped steel piece rolled by a breakdown mill with a rough universal mill, and the deviation affects the entire rolling process as shown in Fig. 9. This results in an H-section steel with the cross-sectional shape shown in .

In other words, in the conventionally commonly used method, the Rn bus of a breakdown mill has a
-11! Since the rough shaped steel slab 5 is rolled with the open hole die 4 on the Fi plane, the shape of the rough shaped steel billet 5 is as shown in the eleventh factor, due to the inclined surface of the hole die 4, the part corresponding to the outer surface of the flange. The center part of 6 has a somewhat protruding shape.

On the other hand, the side surface 8 of the horizontal roll 7 in the rough universal mill is set at a certain angle of inclination with respect to the vertical plane, as shown in FIG. 12, in consideration of the material biting property and roll modification. Accordingly, in order to make the outer peripheral surface parallel to the side surface 8 of the horizontal roll 7, the vertical roll 9 is formed to have a large diameter at the center of the roll body length, as shown in FIG. Therefore, when the rough-shaped steel piece 5 is bitten by the rough universal mill, the protrusion 10 of the vertical roll 9 is bitten by the protrusion at the center of the outer surface of the flange, so that the rough-shaped steel piece 5 can be guided extremely accurately. If this is not done, the position where the flange portion 1 is bitten into the vertical roll 9 will tend to shift in the width direction of the flange portion 1, and therefore the center B- of the web thickness as described above will tend to shift.
8 and the center A-A of the flange width. This deviation in the first pass can be corrected to some extent by shaping the tip of the flange 1 with the edger roll 11 as shown in FIG. 13, but as shown in FIG. In order to ensure that only the tip of the 7 langes contacts the roll 11 during rolling down and the web portion 2 is not rolled down by the roll 11, the center B-8 of the thickness of the wear portion 2 is
Half of the difference between the thickness of the wear portion 2 and the gap between the wear portion of the roll 11 remains offset from the center A-A of the flange width. In addition, since the center 12 of the V-shaped recess formed on the outer surface of the flange portion 1 according to the shape of the vertical roll 9 of the universal mill remains shifted from the center A-A of the flange width, the rough shaped steel piece 5 is When the flange portion 1 is inserted into the universal mill, the recess becomes a guide groove and the flange portion 1 is again shifted in the width direction.

In order to solve these inconveniences, a technology has already been proposed in which the rolled material is guided by a guiding @ position and its control device, but when such a device is used, the equipment is expensive and the equipment is too expensive. Problems such as difficulty in maintenance arise.

This invention was made in view of the above circumstances, and it is possible to manufacture an H-section steel without misalignment between the center of the flange width and the center of the wear thickness when the H-section steel is rolled by a universal mill. The object of the present invention is to provide a rolling method.

Means for Solving the Problems In order to achieve the above object, the present invention forms a recess along the longitudinal direction in the center of the outer surface of the flange of an H-shaped rough-shaped steel billet during breakdown rolling, and In a universal mill following the mill, the rough-shaped steel billet is rolled using a vertical roll having a protrusion on the outer periphery of the center part of the roll body length and tapered surfaces with gradually larger diameters on both ends of the body. That is.

In other words, in the method of the present invention, when the shape of the rolled material is not yet determined, that is, during breakdown rolling, in addition to rolling into an H-shaped rough shape, a recessed portion to serve as a guide groove is formed in the center of the outer surface of the flange. , the concave portion is extremely unlikely to shift with respect to the center of the flange width, and in a universal mill that follows the breakdown mill, the rolled material is rolled into vertical rolls by the axial component force on the tapered surface formed at each end of the body. The vertical roll is guided by the center in the axial direction, and then the protrusion and recess of the vertical roll engage.
There is no misalignment of the biting position in the first pass of the rough universal mill, which greatly affects the product shape.

Embodiment To explain the method of the present invention step by step, first, when rolling an H-shaped rough shaped steel piece 10 with a breakdown mill, the flange portion 11 is rolled as shown in the cross section in FIG.
A recess 12 is formed along the longitudinal direction at the center of the outer surface. As a method for this purpose, for example, as shown in FIG. 2, the center of the outer surface of the flange portion 11 is rolled by rolling in the height direction of the wear portion 15 using a box hole mold 14 having a bulging portion 13 formed at the bottom of the hole. A method can be adopted in which the recess 12 is formed in the center of the outer surface of the 7-run 9 part 11 by making a recess in the part and performing the final groove rolling of the fast breakdown rolling. Another method, as shown in FIG. 3, is to use the depression on the outer surface of the flange, which is caused by the flange portion 11 falling outward during wear width expansion rolling during breakdown rolling, as the recess 12. can be adopted. In any of these methods, since the recess 12 is formed at the same time as the breakdown rolling of the rough shaped steel piece, the recess 88 is formed with only a slight deviation from the center of the outer surface of the flange portion 11.
12 can be formed.

The above rough shaped steel billet 10 is then rolled by a rough universal mill. The vertical roll 16 of the first pass in the rough universal mill has the shape shown in FIG. That is, it has a shape in which a protrusion 17 is formed on the outer periphery of the central part of the roll body length, and a tapered surface 18 whose diameter gradually becomes larger is formed on both eyes, that is, at each end of the protrusion 17. Here, the protrusion angle of the protrusion 17 (tilt angle with respect to the axial direction)
To explain θ, apex angle α, and l11B (refer to Fig. 5, respectively), if only one rough universal mill is installed, the protrusion angle θ of the protruding portion 17 is the angle of the vertical roll of the conventional rough universal mill. (for example, 5 degrees), and its 11ilB is set to be equal to the 7 rank width of R holly finish rolling. On the other hand, when there are two or more rough universal mills, the protrusion angle θ of the protrusion 17 is made larger than the angle in a normal rough universal mill, and the width B is narrower, so that the protrusion 1
It is preferable to increase the effect of guiding the flange portion 11 by the protrusion 17 in the second and subsequent buses by reducing the apex angle α of 7.

When the rough shaped steel piece 10 obtained by the breakdown mill is rolled by the rough universal mill including the vertical rolls 16, in the first pass, the center part of the outer surface of the flange part 11 is rolled by the protruding part 17 (in contact with First, both ends of the outer surface of the 7-run 9 part 11 come into contact with the tapered surface 18 of the vertical roll 16 as shown in FIG. It acts on the shaped steel piece 10. Therefore, for example, if the rough shaped steel piece 10 is bitten upward in FIG.
Since the rolling blade at the upper end of the flange part 11 becomes larger,
When the steel strip 10 is pushed down and, conversely, shifted downward and bites into the rough-shaped steel piece 10, the rolling blade at the lower end of the flange becomes larger, and the flange 11 is pushed up, and as a result, the flange The center portion of the portion 11 in the width direction and the center portion of the vertical roll 16 in the axial direction automatically match. In this way, the rough shaped steel piece 10 is gripped while its position in the vertical direction is adjusted, and then the protrusion 17 of the vertical roll 16 bites into the outer surface of the 7-run 9 section 11. In that case, as described above, the center part of the flange width of the rough shaped steel slab 10 is the vertical roll 1.
6, the recess 12 on the outer surface of the flange portion 11 is
By engaging the protruding portion 17, it is formed accurately and clearly at the center of the outer surface of the flange portion. Since the concave portion 12 thus formed acts as a guide groove in each subsequent pass, the rough shaped steel slab 10 is rolled without any deviation in the width direction of the 7 ranks, and is finally bound to the center of the flange width and the wear thickness. It is possible to create an H-beam whose center is precisely aligned.

In addition, if the width B of the protruding part 17 in the first pass of the vertical roll of the rough universal mill is made narrower than the flange width, and the protruding angle θ is made large, 7 runs 9
There is one bulge on the outer surface of the portion 11 as shown in the seventh factor.
However, one of these bulges is rolled and corrected with a rough universal mill or an intermediate universal mill, and does not pose a problem.

Effects of the Invention As is clear from the above explanation, according to the method of the present invention, the vertical position of the rough shaped steel billet is automatically adjusted in the first bus of the rough universal mill, and Then, since the protruding part provided on the outer periphery of the center part of the roll length of the vertical roll bites into the outer surface of the 7 flange, the concave part that acts as a guide groove in the 1st downward pass is aligned with the center part of the flange width. Therefore, in the method of the present invention, the rolled material does not shift in the flange width direction during rolling, so that a regular shape in which the center of the 7-run width and the center of the web thickness coincide with each other. H of
Shaped steel can be obtained.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing the cross-sectional shape of a rough-shaped copper piece obtained by breakdown rolling in the method of this invention, and Fig. 2 shows an example of a method for forming recesses in a rough-shaped steel piece during breakdown rolling. Fig. 3 is a schematic wt drawing showing another example of forming recesses in a rough shaped steel billet during breakdown rolling, Fig. 4 shows the shape of the first bath roll of a rough universal mill. A schematic diagram, Figure 5 shows the dimensions of each part of the vertical roll.
An explanatory diagram for displaying the angle, Figure 6 is a schematic diagram showing the contact part between the vertical roll and the rough shaped steel piece, and Figure 7 is an example of the shape of the flange part after the first bath in the rough universal mill. Fig. 8 is a schematic diagram to explain the occurrence of misalignment of the wear part with respect to the 7-run part during the rolling process, and Fig. 9 is a cross-sectional view of an H-section steel in which the center of the flange width and the center of the web edge are misaligned. Cross-sectional view, No. 10 is a schematic diagram showing the state of breakdown rolling in the conventional method, FIG. 11 is a cross-sectional view of a rough shaped steel slab obtained by breakdown rolling in the conventional method, No. 1
FIG. 2 is a schematic diagram for explaining the rolling state of the first bus of rough universal rolling in the conventional method, and FIG. 13 is a schematic diagram showing the rolling state with edger rolls adjacent to the rough universal mill. 10...Rough shaped steel piece, 11...Flange part, 12
... recessed portion, 15... web portion, 16... vertical roll, 17... protrusion, 18... tapered surface.

Claims (1)

[Claims] After rolling an H-shaped rough-shaped steel slab by a breakdown mill, the rough-shaped steel slab is rolled by a rolling mill group including a universal mill to produce an H-shaped steel. In addition to forming a recess along the longitudinal direction at the center of the outer surface of the flange, in the universal mill following the breakdown mill, a protrusion is provided at the outer periphery of the center of the roll body length, and a tapered surface with a gradually larger diameter on both body end sides. A method for manufacturing H-beam steel, comprising rolling the rough shaped steel piece using vertical rolls provided with.