JPH0150481B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method of rolling a rough-shaped steel piece such as an H-section steel or an I-section steel.

(Prior art) As shown in Fig. 1, in a bus line consisting of a heating furnace HF, a breakdown mill BD, a universal roughing mill UR, an edger mill E, and a universal finishing mill UF, flat slabs are used as raw materials without using beam bangs. Direct (in 1 heat) H
Shaped steel is manufactured, but in such a case, a flat slab is rolled down from the width direction in a BD mill, the ends are bulged, and rolled into a rough shaped steel piece.

In general, in order to turn a flat slab into a rough-shaped steel slab without causing collapse, as shown in Figure 2, a large number of box hole shapes K-i (i = 1 ~ n-1), the width of the flat slab 1 is reduced and the end portions are bulged, and finally a rough shaped steel piece 2 is obtained by the hole K-n.

However, in the case of this method, large-sized H-beams require a large number of box holes, as shown in Figure 3, and are usually stored within the roll body length of one BD mill. The problem arises that it cannot be done.

Furthermore, different from this, as shown in FIG.
Then, the split groove 4 is enlarged to a predetermined depth using a split hole mold K-2 having a split protrusion 5 to obtain a wedge-shaped slot 6, and then the next box hole mold K-2 is used.
-3, there is a method of expanding the split groove 6 to obtain the flange width.

This method has a greater effect of widening the width of the end than the method shown in FIG. 2, and can reduce the number of box holes for etching. However, this method also works for large size H of H700 x 300 or more.
As for shaped steel, as shown in Figure 5, the required hole shape cannot be accommodated within the length of the BD roll body (for example, within 3 m).

Therefore, for large sizes, it is difficult to roll a CC slab in one heat, so the CC slab is shaped into a rough-shaped steel slab at a blooming factory, then reheated at a large factory and then rolled into an H-beam. Currently, a two-heat method is used.

(Objective of the Invention) This invention was proposed in view of the above circumstances, and its purpose is to accommodate the grooves necessary for large-size rolling in the normal roll body length, and to provide flat slabs even for large-size rolling. It is an object of the present invention to provide a method for rolling a rough shaped steel billet that can be rolled in one heat using the method.

(Structure of the Invention) The method for rolling a rough-shaped steel slab according to the present invention is such that in rough rolling of H-beam steel using a slab, first a crack is made on the short side of the slab using a dedicated split hole die, and then The collar part between multiple box hole molds with flat bottoms and different hole bottom widths used for pushing out the split is used as the split protrusion, and the depth of the split given to the short side of the slab is defined as the collar part. The split protrusions are used to gradually increase the depth, and then the box hole type is used to expand the split part to form a flange-equivalent part of the H-shaped steel, and the split hole type and box hole type are overlapped to create a large size. It is also possible to roll rough-shaped steel slabs.

(Example) The present invention will be described below based on an illustrative example. As shown in FIG. 6, the rolls of the BD mill include split-hole type K-, which has a split protrusion 10 with a V-shaped cross section, box-hole type K-, and K-, in which the hole width increases in order. , the final hole type K-V is formed, and furthermore, the roll collar part between the box hole types K- and K- is formed with a split protrusion 11 having a V-shaped cross section.
As a result, the split hole type K- is formed overlapping the box hole types K- and K-. Note that the cutting protrusions 10 and 11 have the same tip angle,
The cutting protrusion 11 has a longer protrusion length.

In such a configuration, the flat slab 1 is first heated to a predetermined temperature, and a wedge-shaped groove 12 is formed in the center of the short side of the slab using the hole K-1. At this time, it is necessary to restrain the end portion of the slab by the hole-shaped side wall 13 so that the split groove 12 is accurately placed in the center of the short side of the slab.

Next, the groove 12 is expanded to a predetermined depth using the hole K- to obtain a wedge-shaped groove 14. At this time, since the cutting protrusion 11 guides the material, there is no need to worry about the material falling over, and there is no need to restrain the ends of the slab.

Subsequently, the end portion of the material is expanded by the hole mold K- to the width of the hole, and further expanded by the hole K- until the dividing groove 14 becomes completely flat.

This example is for H900×300, and the fifth
While the conventional example shown in the figure requires four independent split-hole dies and box-hole dies, the present invention allows rough rolling of similar large-sized rough-shaped steel slabs using essentially three pore dies. Can be done. In other words, it is possible to reduce the roll body length to within 3 m, which was previously impossible to accommodate, and it is now possible to perform one-heat rolling using CC slabs even for large sizes. Furthermore, according to such a method, rough rolling of all sizes of H-section steel up to H1000×450 is possible.

If there is no restriction on the length of the roll body, it is also possible to obtain a rough shaped steel piece with a large flange width by increasing the number of split hole types and box hole types, as shown in FIG.

(Effects of the Invention) As described above, according to the present invention, the number of required grooves can be reduced, the grooves necessary for large-size rolling can be accommodated in the normal roll body length, and even large-size rolling can be done flatly. One-heat rolling can be performed using a slab, and the blooming process can be omitted, resulting in a significant reduction in manufacturing costs.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram showing a production line for H-beam steel;
2 and 3 are front views showing a conventional roll hole arrangement, FIGS. 4 and 5 are front views showing another conventional roll hole arrangement, and FIGS. 6 and 7 are front views showing a conventional roll hole arrangement. FIG. 2 is a front view showing a roll hole arrangement according to the present invention. 1... Flat slab, 2... Rough shaped steel piece, 3, 5...
... Split protrusion, 4, 6... Split groove, 10, 11...
... Split protrusion, 12, 14... Split groove, 13...
Hole-shaped side wall.

Claims (1)

[Claims] 1 In the rough rolling of H-beam steel using a slab, a crack is first made on the short side of the slab using a dedicated split hole die, and then the hole has a flat bottom and has a different hole bottom width used to expand the split. The collar portion between the plurality of box hole molds is used as a cracking protrusion, and the depth of the crack provided on the short side of the slab is sequentially deepened by the splitting protrusion of the collar portion, and then the box hole mold is 1. A method for rolling a rough shaped steel billet, the method comprising: expanding a split portion to form a portion corresponding to a flange of an H-shaped steel.