JPS63119902A - Molding and rolling method for rough h-shaped billet - Google Patents

Abstract

PURPOSE:To efficiently roll a rough H-shaped billet having a desired flange thickness by subjecting a dogbone-shaped material to cross rolling down of flanges with intermediate caliber rolls for molding having two stages of tapered surfaces then rolling said material with the ensuing caliber rolls. CONSTITUTION:The dogbone-shaped material is first subjected to the cross rolling down of the flanges by the intermediate caliber rolls for molding having two stages of the tapered surfaces A, B having different taper angles on the flange surfaces of the calibers while the thickness at the front end of the flanges is controlled at the time of rolling the dogbone-shaped material with an open caliber roll. The bulging near the front ends of the flanges is thereby prevented and the overall flange thickness tF2 is increased. The material is successively subjected to the cross rolling reduction by the caliber rolls of which the caliber flange surfaces are straight taper surfaces. The thickness near the front ends of the flanges is thereby increased and the rough H-shaped billet having the flanges of the desired thickness is obtd.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention involves forming a slab-like steel piece into a dogbone-like material by edging rolling, etc., rolling this into an H-shaped rough-shaped steel piece using a hole-opening roll, and then rolling this into an H-shaped rough-shaped steel piece. The present invention relates to a method for shape-rolling a dogbone-like material into an H-shaped rough-shaped steel piece in the process of rolling a dogbone-like material into an H-shaped steel piece using a universal mill.

[Conventional technology and its problems]

In order to obtain H-shaped steel from a slab-shaped steel slab, the slab-shaped steel slab is edge-rolled in the width direction to form a dogbone-shaped material as shown in Fig. 3, and this is turned into an H-shaped rough-shaped steel slab using a hole-opening roll. Shaped and rolled.

Furthermore, a method is adopted in which this is rolled into H-beam steel using a universal mill.

The above-mentioned H-shaped rough section steel slab requires a predetermined flange thickness depending on the flange thickness of the H-section steel to be manufactured, but when the above-mentioned etching rolling is performed with flat rolls, as shown in Fig. 3, Although the flange width of the dogbone material becomes larger, it is not possible to increase the flange thickness tF.

There is a problem that it is not possible to secure the necessary flange thickness for the H-shaped rough section steel piece. Therefore, in order to ensure the flange thickness, the fourth
Edging rolling is performed with the flange width constrained in a box hole type as shown in the figure, but when the flange width is constrained in this way, there is a problem that the inner surface of the flange becomes overhanging. And, once an overhang condition occurs like this, it cannot be removed by subsequent groove rolling, and in order to remove it by subsequent universal rolling, the flange reduction must be increased, and in the end, The flange ends up being thin.

To solve this problem, as shown in Figures 5 (b) to (cl), firstly, edge rolling is performed using a box hole die without excessively restricting the flange width (Figure 5 (a)), and then this is A method is adopted in which the flange width is reduced by rolling with grooved rolls (FIGS. 5(b) and 5(c)). However, even with this method, there is a problem in that an overhang shape is generated in which the vicinity of the flange foot swells due to hole-concealed rolling.

In view of these conventional problems, the present invention provides a method that can roll an H-shaped rough shaped steel piece with a desired flange thickness from a dog bone material without causing an overhang on the inner surface of the flange. That is.

[Means to solve the problem]

For this reason, the present invention first rolls a dogbone-shaped material using an intermediate forming groove roll with a grooved flange surface having a two-step tapered surface to reduce the flange width while regulating the thickness of the flange tip. Its basic feature is that it is then rolled into a predetermined shape by a subsequent slotted roll.

The present invention will be specifically explained below.

FIG. 1 shows the rolling process of the present invention.

This is an example of a process in which a dogbone-shaped material is obtained by edge rolling.

A slab-shaped steel piece is first edge-rolled through a box hole, as shown in FIG. 1(a).

This edging rolling is carried out so that the flange width of the dog bone is restricted once, but excessive restriction of the flange width should be avoided in order to avoid causing overhangs as shown in Figure 4. be. By performing edge rolling using a box-hole type in this way, the flange thickness tF
1 large dogbone-like material can be obtained.

In the present invention, when rolling such a dogbone-like material with a hole opening roll, first, the thickness of the flange tip is regulated and the flange width is reduced using an intermediate forming hole roll as shown in FIG. 1(b). This intermediate forming groove roll, which performs rolling, has two tapered surfaces A and B with different taper angles on the groove flange surface.By rolling with such a groove roll, overlapping is achieved. The average flange thickness tF is increased by reducing the flange width while preventing the occurrence of bulges in the vicinity of the flange tips that cause hanging.

After such rolling, as shown in Fig. 1(c), the thickness near the tip of the flange is increased by reducing the width of the flange using a groove roll whose grooved flange surface is a straight tapered surface. , obtain a predetermined thick-walled flange H-shaped rough shaped steel piece.

In the intermediate forming hole type roll shown in ) in Fig. 1, the tapered surface A
The taper angle θ1 of the tapered surface B and the taper angle θ of the tapered surface B are configured to be θ1 and θ2 with respect to the horizontal direction. As the hole dimensions that allow the flange width to be appropriately reduced without causing overhang, the difference Δθ between the above O1 and θ depth is 6 to 12, and the height b of the tapered surface A is the inside of the hole flange. For the law, b=0.4h! It is preferable to set it as 0.5 h.

In addition to those obtained by edge rolling, for example, as shown in Fig. 2, dogbone-shaped materials can be obtained by rolling a slab-shaped steel piece (1) from left, right, top and bottom into molds (2b) (3a).
) (3b) may be obtained by pressing.

〔Example〕

Thick-walled H-section steel of H400XB400 was manufactured by a rolling process using the method of the present invention and a rolling process using a conventional method. Table 1 shows the dimensions and presence or absence of overhang at each rolling stage.

Note that each dimension in the table is based on FIG. 1 (method of the present invention) and FIG. 5 (conventional method).

Table 1 (Dimensional units other than angles are 0.5 mm) As described above, according to the method of the present invention, thick-walled flange H-shaped rough-shaped steel pieces, and even H-shaped steel pieces made of this material, can be produced without overhanging the inner surface of the flange. Shaped steel can be obtained.

〔Effect of the invention〕

According to the present invention described above, it is possible to obtain a thick-walled flange H-shaped rough-shaped steel piece from a dogbone-like material without creating an overhang on the inner surface of the flange, and thereby a thick-walled flange can be obtained even from a relatively thin slab. H-shaped products can be rolled efficiently. Further, according to the present invention,
Continuously cast slabs can be applied to the production of large quantities of thick-walled H-section steel, and this type of H-section steel can be manufactured efficiently at low cost.

1A to 1C are explanatory diagrams showing step by step the rolling process according to the method of the present invention. Figures 2 (G) and (0) show other manufacturing examples of dogbone-shaped materials that are rolled materials according to the present invention. Figure 2 (A) is a front view, and Figure 2 (middle) is a
FIG. FIG. 3 is an explanatory diagram showing the state of edge rolling using flat rolls. FIG. 4 is an explanatory diagram showing the box-hole type etching rolling and the resulting overhang formation. Fifth
Figures (a) to (c) are explanatory diagrams showing step-by-step rolling conditions according to the conventional method.

Patent applicant: Nippon Kokan Co., Ltd. Seven inventors: Takeshi Hirasawa, Shido, Kiyoshi Morioka, Takado
Yoshiyuki Takao Patent Attorney Sho Yoshihara Sando Masato Tomabechi Lawyer Hiroko Yoshihara Figure 1 Figure 2 (A) Figure 143? j144 figure

Claims (1)

[Claims] In a forming rolling method for an H-shaped rough-shaped steel billet in which a dog-bone-like material is rolled into an H-shaped rough-shaped steel billet using a hole-opening roll, the hole-shaped flange surface of the dog-bone-like material is An H shape characterized by performing rolling to reduce the flange width while regulating the thickness of the flange tip using an intermediate forming groove roll having a tapered surface, and then rolling into a predetermined shape using a subsequent groove roll. Shape rolling method for rough shaped steel billet.