JPH0150482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for rolling a section steel having holes in its web, and more particularly to a warm and hot rolling method for such a section steel.

Conventionally, steel sections with holes in their webs have been manufactured from simple channel steel sections that are formed by bending plates by cold forming. This steel section is made by cold channel forming using a two-high rolling mill system, followed by slits and widening rolling.Due to cold rolling, the deformation resistance of the material is extremely high, making it difficult to form large cross-sections. Moreover, the strain caused by bending concentrates in the corners and causes work hardening, so the load characteristics as a section steel are poor and it is easy to break, so there are limits to its use as a section steel for large structures. Ta.

The present invention was made in view of the above circumstances, and its gist is to continuously roll a steel billet material through rough rolling, intermediate finishing rolling consisting of a two-high rolling mill system and a universal rolling mill system, and finishing rolling. When shaping steel sections in warm or hot conditions,
A slit rolling process is inserted as a pre-process of finish rolling to provide the web part of the shaped material with slits that penetrate linearly in the thickness direction of the web at appropriate intervals and patterns. This is a method of rolling steel sections with holes in the web, which is characterized by widening.

Next, the method of the present invention will be explained in detail with reference to the drawings.

Figure 1 shows the steps of the present invention method of rolling an H-section steel with holes in the web portion in a warm or hot manner using a two-high rolling mill system and a universal rolling mill system following rough rolling. be. Heated billet material 1
is shaped into a predetermined shape by rough rolling mill groups A and B, then shaped into an intermediate finished H-beam shape by universal intermediate finishing mill C, and then shaped into a predetermined shape by two-high rolling mill D. controlled. By passing through these rolling mills C and D several times, the flange and web are shaped into a predetermined shape.
After being finished to more accurate dimensions by a universal intermediate finishing mill E, slits are given to the web at appropriate intervals and patterns in a slitting mill F, and finally the web is widened by a finishing universal mill G. By enlarging the slits to form holes, a predetermined perforated web section is formed.

FIG. 2 is a schematic diagram illustrating the process of FIG. 1 in more detail. FIGS. 2A and 2B show an example of the groove shapes 9 and 10 formed by the upper and lower rolls 8a and 8b used in the rough rolling mill groups A and B. The steel billet material 1 passes through the grooves 9 and 10 several times, and is further shaped into the shape of the groove 13 by a universal intermediate finishing mill C comprising vertical rolls 11a and 11b and horizontal rolls 12a and 12b. Next, 2 with a hole 15 formed by the upper and lower rolls 14a and 14b.
The height of the flange is controlled by the plate rolling mill D at the same time as the thinning and widening of the web, and furthermore, the universal rolling mill E having vertical rolls 17a, 17b and horizontal rolls 16a, 16b is used to roll the web as shown in the groove 18. The thickness is further reduced and the finished size is approximately the same. Next, as shown in the hole pattern 20, the upper and lower rolls 19
Slit rolling machine F with projections 21 on a and 19b
Then, slit marks are made at appropriate intervals and in a pattern to obtain a slit pattern as shown in FIG. 3b, which will be described later. The roll protrusions 21 of the slitting mill are attached to both the upper and lower rolls, and as the rolls rotate, the opposing protrusions are pressed against both surfaces of the web to form slits. The spacing and pattern of the slits can be freely changed by appropriately selecting the shapes and positions of the protrusions on the upper and lower rolls 19a, 19b of the slit rolling mill F. The slitted section steel is finally passed through vertical rolls 22a, 22b and horizontal rolls 23a, 23.
The flange portion 25 is widened and rolled while applying a tensile force to the flange portion 25 by the vertical rolls 22a and 22b of the finishing universal rolling mill G having the finishing universal rolling mill G. As a result of this, the slits are enlarged to form holes 26, and a section steel having holes in the web can be obtained.

In this case, in the present invention, warm means from 200℃ to
700°C and hot generally refer to the temperature range from 700°C to 1250°C, respectively, and the reason for adopting these warm and hot processes is that warm rolling improves dimensional accuracy and toughness, while hot rolling This is because rolling aims to create a large cross-section by reducing deformation resistance.

Furthermore, the relationship β=1.03α is satisfied between the web widths of universal rolling mills E and G in Figure 2, and in the forming process G, the web is rolled down and the thinning rate is 3%.
If the thickness is above, the thickness will be uniform, which is desirable, but if a uniform thickness is not required for the performance of the product, it is not necessary to press down the web. Furthermore, the forming process shown in FIG. 2 can be easily applied to forming channels, sheet piles, and I-beams.

Note that FIG. 3 shows an example of the shape of the H-section steel processed in the steps shown in FIGS. 1 and 2 at an intermediate stage of forming, and FIG. An example of the shape of the shaped material 2 that has passed through the groove of the universal intermediate finishing mill in FIG. 2, and FIG. Example of shape of 3, Fig. 3c
is the finishing universal rolling mill G in Figures 1 and 2.
This is an example of an H-section steel 5 having a hole 26 in the web portion that has passed through the hole shape. Note that 25 is a flange portion.

As explained in detail above, by hot-working or warm-working a section steel with holes in the web using a process that combines a universal rolling mill system, a two-high rolling mill system, and a slit rolling mill, it is possible to accurately form corners. In addition, it is possible to easily and economically manufacture large cross-sectional steel sections with holes and web widths of up to 1000 mm, which could not be manufactured conventionally.

The effects of the present invention will be illustrated in more detail by way of examples below.

Using the present invention, a section steel was manufactured using the rolling mill system shown in FIG. 1 having the groove type shown in FIG. A billet of 250 mm x 250 mm and SM50 steel was used as the material, and after 11 passes, the web width was 286 mm, the flange width was 121 mm, the web thickness was 4.4 mm, and the hole in the web part was 30 mm x 9 mm high. An H-section steel as shown was manufactured. That is, in Figure 2
Billet 1 of 250 mm x 250 mm square is heated to 1200°C and then passed through the grooves of two-high rolling mills A and B twice.
It is roughly formed into an H-beam by the universal rolling mill D, the width and flange height are controlled by the two-high rolling mill D, and it is shaped twice by the universal rolling mill E. After that, the web width is 238 mm. ,
Finished as a rough H-beam with a flange width of 120.8mm and a web thickness of 4.8mm. After that, a slit with a width of 30 mm was formed on the center line of the web and on a line half the height of the web using a two-high rolling mill F for slit forming, and finishing was performed using a finishing universal rolling mill G. . At this time, the width is increased by α=238mm.
β = 286 mm was selected, and the rolling reduction ratio of the web was 8%. The finishing temperature at the web portion was 600°C.

The H-shaped steel obtained by this method has significantly less cracking in the web holes than the lightweight section steel with the same section modulus obtained by cold rolling, so it has extremely high resistance to fracture, and the flange The results of repeated bending tests with the same strain value of 0.05% generated at the tip showed that the manufacturing method of the present invention broke while the lightweight section steel produced by the conventional method broke after 10,000 cycles. The shaped steel obtained by this method did not break even after 50,000 cycles.

As is clear from the above examples, the present invention makes it possible to accurately maintain the shape of a section steel with arbitrary holes in the web while rolling it into a thin wall, and the industrial effect is extremely significant. There is.

[Brief explanation of drawings]

Figures 1 and 2 are schematic diagrams showing the process of manufacturing an H-section steel with holes in the web by the method of the present invention, and Figure 3 is a schematic diagram showing the process of manufacturing an H-section steel with holes in the web by the method of the present invention.
FIG. 2 is a perspective view showing an example of the shape of a shaped steel in the middle of forming. A, B... Rough rolling mill; C, E... Universal intermediate finishing rolling mill; D... Two-high rolling mill; F... Slit rolling mill; G... Finishing universal rolling mill; 1
... Steel billet material; 2, 3 ... Shaping material; 4 ... Slit; 5 ... H-beam steel with holes; 8a, 8b ... Upper and lower rolls of rough rolling mill; 9, 10 ... Rough rolling mill hole Type;
11a, 11b, 17a, 17b, 22a, 22
b... Vertical roll of universal rolling mill; 12a,
12b, 16a, 16b, 23a, 23b...Horizontal rolls of the universal rolling mill; 13, 18...
Hole type of universal rolling mill; 14a, 14b...
Upper and lower rolls of the two-high rolling mill; 15... Hole shape of the two-high rolling mill; 19a, 19b... Upper and lower rolls of the slit rolling mill; 20... Hole shape of the slit rolling mill; 21...
... Roll protrusion of slit rolling mill; 25 ... Flange portion; 26 ... Hole.

Claims (1)

[Claims] 1 Rough rolling of steel billet material, intermediate finishing rolling consisting of a two-high rolling mill system and a universal rolling mill system,
When forming a section steel in warm or hot conditions through continuous finishing rolling, a slit rolling process is inserted as a pre-process to finishing rolling to form web plates at appropriate intervals and patterns in the web part of the forming material. A method of rolling a section steel having holes in a web, characterized in that a slit that penetrates linearly in the thickness direction is provided in advance, and the width of the web portion is widened in the next step of finish rolling.