JPS6188901A - Manufacture of h-beam - Google Patents

Abstract

PURPOSE:To manufacture efficiently rough formed billets used respectively for plural kins of H-beams, by forming a continuously cast slab of the same dimensions into a rough formed stock of specific dimensions and correcting its cross-sectional dimensions and shape by using the same forming rolls. CONSTITUTION:A continuously cast slab (a) having comparatively small thick ness and small width is edged by a 2-Hi break down mill BD, to form a dog- bone-shaped rough formed stock (d) having a web inside-dimension smaller than the minimum dimension of an aimed product dimension. The thickness of web is subjected to rolling reduction to enlarge its inside dimension and the shapes of flange parts are corrected by a 2-Hi forming mill R1 provided with plural caliber rolls for enlarging the web inside-dimension, and the inside dimension of web is enlarged in sequence as shown by (f), (g), (h) to obtain an aimed rough formed steel for an H-beam. Thereafter, the aimed H-beams (f'), (g'), (h') are obtained by the rolling of a series of universal mills U1, E1. UF.

Description

Detailed Description of the Invention "Object of the Invention" The present invention relates to a method for manufacturing H-section steel, in which a continuous cast slab is rolled (edged) in the width direction, and then the web thickness is reduced by a shaping roll. When producing products using a universal mill, it prevents slab buckling during etching, and also prevents cross-cutting at the leading and trailing ends of the material during shaping.
The purpose of this invention is to provide a method that can reduce knot losses and moreover enable efficient rolling by sharing a shaping roll for several sizes of H-beam steel.

Industrial applications I] Form rule 1 manufacturing technology.

Conventional technology: Etching the slab and then rolling it through a colander 5-
Various methods for manufacturing ζFI type tIA have been proposed in the past, and dozens of methods are known in public announcements or publications.

especially! 14 Kaisho 5? In Japanese Patent No. 146405, it is described that the height of the web is increased by repeatedly subjecting the web to partial reduction during molding using a force of 11 bars.

Problems to be Solved by the Invention However, in the conventional method as described above, there is a problem in that the material collapses and buckles during etching, and this causes the problem that a comparatively thin and wide slab is used to reduce the web reduction. In particular, the occurrence of buckling is a fatal drawback that makes it impossible to perform the edging for the purpose of forming a so-called dogbone shape. In addition, when a thick slab is used, the number of web rolling passes during caliber shaping increases, resulting in deterioration of rolling efficiency and a decrease in rolling temperature. Of course, when this thick slab is used, the amount of web reduction in caliber modeling increases, so the so-called tongue increases, and the black/nobles increase.

Furthermore, since a shaping caliber roll is not required for each size (series) of H-section steel, the number of rolls to be stored increases, and there is no choice but to waste a lot of time for changing rolls.

The method disclosed in Japanese Unexamined Patent Publication No. 57-146405 described above has disadvantages in that the rolling operation is complicated and the material lacks stability.

``Structure of the Invention'' Means for Solving the Problems The present invention was devised to solve the problems of the conventional products as described above. When manufacturing H-beams by rough rolling, web expansion rolling, and universal rolling using calibers, the smallest size product among multiple types of H-beams with different web heights from continuous cast slabs of the same size. The H-shape is characterized in that it is a roughly formed material with a web inside method smaller than that of the web inside method, and in subsequent web expansion rolling, it can immediately correspond to the product dimensions of the above-mentioned plural types of H-beam steels, and the web inside method is expanded respectively. It is a method of manufacturing steel.

Among the multiple types of H-section steel dimensions that are intended for operation, by using a web-shaped material that is smaller than the web-in-web method for the smallest dimension product, it is possible to subsequently web expand and roll to produce products of any size. You can also get exactly what you want. When obtaining a raw material slab by continuous casting, several sizes of H-beams with the same dimensions are used, which improves the workability of continuous casting and simplifies slab management. Adoption of web expansion rolling enables the use of narrow width slabs, avoids collapse and buckling during etching, improves the shape of the leading and trailing edges of the material, improves both rolling workability and yield, and reduces crop loss. , it is possible to obtain rolling with an advantageous roll unit consumption.

EXAMPLE To further explain the present invention as described above, the present invention generally has a relatively thinner wall than the conventional one.

A narrow width continuous casting slab is used, and the width of the slab is etched using an etching caliher installed on a horizontal roll or a vertical roll. After being formed into a roughly shaped material with a small internal web dogbone shape, the web thickness is reduced using caliber rolls.Furthermore, several calibers are used to lightly reduce the web thickness and at the same time perform web internal processing. is enlarged and finally finished into predetermined types of H-beam steel by universal rolling. That is, as mentioned above, it is rolled as a rough-shaped material, and in this way, in the present invention, it is possible to roll several types of rough-shaped steel slabs for 4-shaped steel using the same shaping roll from a slab of the same size. That is.

To explain these relationships in more detail with reference to the drawings, there are various possible configurations of the mill line to which the method of the present invention is applied, and FIG. 2 shows the line configuration actually applied. 2H
The i-breakdown mill BD is provided with several calibers for slab etching and a caliber for rough forming, and performs reverse rolling. 2 The Hi shaping mill R1 is equipped with several calibers for enlarging the inner web of the material, and by rolling 1 to 2 baths with each caliber, at the same time as expanding the inner web, slight reduction of the web thickness and flange Shape the area. After that, several 1M passes of stretching and rolling are carried out in the rough universal mills U3 and El, and finally the universal finishing mill U
Rolling is completed by F.

The caliber applied to this rolling line configuration and the process of changing the cross-sectional shape of the rolled material are shown in FIG. That is, the thickness t. A slab 1 with a width H8 is etched as shown in the same figure (bl, fc) and (d) using three calibers for etching to form a dogbone-shaped material 2 with a web height H3 and a flange width B3. The web is rolled down using a rough forming caliber until the web thickness is t, as shown in FIG. 2(e). Next, using the web internal method enlarging caliber, the web internal methods 6, L8, and L corresponding to the product size are expanded (fl, (g
), (hl). After that, each rolled material 11, 12, 13 is rolled by a conventional universal mill as shown in (f'), (g'), and (h'). Products 21, 22, and 23 of each standard are finished.

Now, to explain the relationship between the internal dimensions of the web,
The web-equivalent inner diameter L3 of the dogbone-like material is shown in Figure 1(e).
It is approximately equal to the web length L4 of the rough forming caliber, that is, #L, and the web length L of the web expansion caliber is approximately equal to #L.
4 to L7, LA<LS<l, 6<1. , and for the inner law of products 11a, 12a, 13a, Ls ”LA
, Lb #Ls, 1.7=Lc is one of the characteristics of the method of the present invention.

Next, Figure 3 (a) shows the state of material collapse during etching, which tends to occur when using thin wide slabs. This causes a lack of width. FIG. 3(b) shows the buckling state of the material. / to is 6
This may cause buckling of the front and rear ends of the material. In the test results, Ho/t.

It is practical to set < [i, 5, and the material buckling is
This can lead to fatal defects such as insufficient flange width and bite flaws during caliber molding.

Furthermore, FIG. 4 (al) and FIG. 4 (b) schematically show the relationship between the shapes of slabs, dogbone-shaped materials, and caliber shaped materials in the conventional general method and the method of the present invention. As shown in Figure 4 (a), the more the web expansion rolling is carried out, the more the elongation of the web part during shaping rolling is reduced, and the tongue-like extension of the end shape shown in the lower part of Fig. 4 (a) is improved. In addition, the amount of etching ΔH for forming the flange portion is small in the method of the present invention because there is less “whisker” on the flange during shape rolling. This aspect also makes it possible to apply narrow width slabs, prevent material collapse and buckling, and reduce crop loss.

In addition, it is possible to apply a narrow slab to prevent buckling and reduce crop loss. Furthermore, the application of such narrow width slabs means that thin slabs can be used in terms of buckling limits.

Figure 6 summarizes the scope of application of the thin-walled, narrow-width slabs of the present invention and those of the conventional method. This is the area where buckling occurs, and the applicable range of the conventional method is generally when the slab get-to is 250 to 300 mm and the slab width is 1 mm.
350 to 1780 am, whereas in the case of the method of the present invention, the slab thickness is 200 to 220 μm, and the slab width is 1
100 to 1400 mm, and the diagonal line ■...
・It is higher than ■. For example, from the viewpoint of buckling, the practical limit of the ratio of the scrubbing width H0 to the slab thickness t0 is I]. /
Since 10 < 6.5, as will be specifically explained in the manufacturing example below, in contrast to the case where a slab with a thickness of to-220 mj and a width Ho = 1450 to 1730 inches is used in the conventional method, in the method of the present invention, the thickness is At Lo-2201, the width H = 1350 1, and this relationship is concretely shown in Fig. 6 as points a, b, c (conventional method) and point d (invention method). It is clear that the material slabs differ considerably.

The characteristics of the method of the present invention as described above are summarized as follows.

■ Workability and efficiency of continuous casting are improved, and slab management is simplified.

As mentioned above, continuous casting slabs of the same size can be applied to several sizes of H-section steel, and therefore the workability of continuous casting,
It is clear that efficiency is improved and slab management is simplified.

■ Improve rolling workability and improve rolling yield.

Since it is possible to use narrow width slabs, it is possible to prevent the material from collapsing and buckling during etching, and it is also possible to prevent bite defects during caliber molding and improve the shape of the leading and trailing ends, which improves rolling workability (stability). In addition to improving the rolling yield, the rolling yield can be improved.

■ Improved rolling efficiency and energy saving.

The ratio of slab width H0 to slab thickness t0 is Ho/L.

<6.5, thin slabs can be used, so the number of shaping rolling passes is shortened and rolling efficiency is improved. Furthermore, since the temperature drop during rolling is reduced, low temperature heating is possible and an energy saving effect can be obtained.

■ Crop loss is reduced.

In a thin slab, the amount of reduction in web thickness is reduced, resulting in a so-called short tongue, which reduces crop loss.

Note that since web expansion rolling is performed after the web width of the roughly shaped material is made smaller than that of the smallest product, the shape of the leading and trailing ends of the material is improved and the rolling yield is improved.

■ Improve the roll consumption rate.

Because several sizes (series) of H-beam steel are shared, the number of rolls owned is reduced and the roll consumption rate is improved. Note that by reducing the number of roll changes, workability (rolling efficiency) is improved from this point as well.

A specific manufacturing example of the product according to the present invention will be described below.

Table 1 below shows the main dimensions of specific manufacturing examples according to the present invention, which are shown in Figure 2. This is a case where the method of the present invention is implemented on a rolling line consisting of V, , E, , V, and the symbol dimensions are indicated according to the dimension symbols shown in the material cross-sectional change process diagram in Figure 1, and the target size (series)
is H700X300, H800X300. )H900X
This is the case of 300.

Table 1 (Unit capacity) The following Table 2 shows a comparison between the method of the present invention and the conventional method as described above. In other words, in the conventional method, the roll lift of the breakdown mill is approximately 1400°C, so the etching is performed using a blooming mill, but even if it is directly rolled with a high-lift breakdown mill, basically remains unchanged.

The above explanation was basically applied to the line configuration shown in Figure 2, but it is also applicable to a semi-continuous mill line that performs etching with vertical rolls as shown in Figure 5. It is clear that the method of the present invention is equally applicable.

"Effects of the Invention" According to the present invention as explained above, a continuous cast slab is rolled (edged) in the width direction to form a so-called dogbone shape, and then rolled to expand the web height by reducing the web thickness using a caliber roll. After that, when creating the desired product using a universal mill, it prevents slab buckling during etching and reduces crop loss during the shaping process.
In addition, it is possible to share shaping rolls for several sizes of H-beam steel, which simplifies slab management, improves rolling workability, improves rolling yield, and saves energy, making it efficient and economical. This invention is industrially very effective because it enables the production of H-beam steel.

[Brief explanation of drawings]

The drawings show the technical contents of the present invention, and FIG. 1 shows a caliber and a rolling machine for an example of carrying out the present invention.
FIG. 2 is a general explanatory diagram showing an example of a rolling line in which the method of the present invention can be applied; FIG. 4 is an explanatory diagram showing the state of rubbing and buckling of the rolled material during etching, and FIG. The explanatory diagram shown in Fig. 5 is an explanatory diagram of a semi-continuous mill line to which the method of the present invention can be applied;
The figure is a table summarizing the applicable range of slab dimensions according to the conventional method and the method of the present invention. In these drawings, 1 is a slab, 2 is a dogball-shaped material, 11, 12, and 13 are intermediate rolled materials, and 21, 22, and 23 are products.

Claims (1)

[Claims] After edging a continuous cast slab to form a dog ball shape, the web height is changed from continuous cast slabs of the same size to produce H-section steel by rough rolling, web expansion rolling and universal rolling using a caliber. The web is made into a rough shaped material using the web inner method smaller than the smallest dimension product of the plurality of types of H-beams, and is immediately adapted to the product dimensions of the above-mentioned plurality of H-beams in subsequent web expansion rolling. A method for manufacturing H-beam steel, characterized by expanding the inner diameter of each.