JPS5935802A - Production of rough shape billet for h-beam using flat billet as blank material - Google Patents

Abstract

PURPOSE:To produce a rough shape billet for an H-beam from a flat billet by forming a billet part of an H-shaped section having thick walled parts in a web in the longitudinal end of the flat billet and subjecting the same to broadside edging rolling and form-rolling thereby rolling the same to the rough shape billet. CONSTITUTION:The longitudinal end of a heated flat billet (a) is pressed with a pair of upper and lower plunger dies 9, 10 having a groove part 3 of a width W0 at the center and parallel projections 4 of a width W on both sides thereof, thereby forming a billet part A having an H-shaped section. The billet is passed successively between the upper and lower rolls (p) and (q) provided with broadside edging calibers I , II and forming calibers III, IV with the billet (a) held longitudinally whereby the billet is rolled to a rough shape billet for an H-beam. The formation of a long tongue in the end is obviated and the generation of crops is reduced, whereby the production of the rough shape for the H-beam from the flat billet in a high yield is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a rough-shaped H-shaped steel piece using a flat steel piece as a raw material.

In order to reduce the manufacturing cost of H-beam steel, conventionally, plumes (large rectangular cross-section steel slabs) or beam blanks (H-section enlarged large steel slabs) obtained from steel ingots through blooming rolling (hereinafter referred to as large-scale blooming steel slabs) are used. Rather than using a continuous casting method, plume or beam blanks or continuously cast flat steel slabs (hereinafter simply referred to as flat steel slabs) have begun to be used.

When this flat steel billet is used, in order to form a flange unique to H-beam steel, the flange is first edged and edged rolled in the rough rolling stage to make the rough shape steel billet. Although the tip and end in the length direction differ somewhat depending on the product size, it is difficult to form a flange between about 1 and 2 m, and a so-called "unsteady rolling part" is formed. The reason for this is that metal flow is likely to occur freely in the longitudinal direction at the tip and end of the rolled material due to rolling, but metal flow is difficult to occur in the width direction. And this “
``Unsteady rolling section'' refers to the so-called ``unsteady rolling section'' where even if the rough shaped steel slab is further subjected to intermediate rolling and finishing rolling, it no longer has the specified product width of 7 lunges.
Forming cropped parts such as flange width (→), ``flange selvedge width insufficient'', etc. In particular, the above-mentioned ``flange width (→''), that is, 7 flange width insufficient, may be used to determine the crop amount,
This cropping amount is larger than that made from the rough-shaped steel slab obtained from the above-mentioned large-scale bloomed steel slab, so the yield loss is large.

Therefore, in order to reduce the above-mentioned cropping amount, as shown in Fig. 1, the tip of the flat steel billet a is
, c, the so-called "pre-deformation rolling" is carried out in which the shape of the tip is prepared in advance by inserting the annular grooves e and f into the part where the flange part d is formed in the rolling machine. Although it is already a known method, it is difficult to transfer the groove shape (the annular grooves e and f) of the pre-deformation rolling into the existing rough rolling roll because of the limited roll body length. In addition, if the pre-deformation rolling roll is prepared separately and used in combination with the rough rolling roll, the flat steel billet a, which is the material to be rolled, will be subjected to rough rolling after pre-deformation rolling. , it has to be heated again, resulting in 2-heat heating, which not only has the drawbacks of large heat loss and large labor, but also flat steel that has been subjected to rough rolling after pre-deformation rolling as described above. Since piece a is rolled in a flat state from the beginning, as shown in Fig. 2, the tip 1 (the same goes for the end) of the rough-shaped steel piece formed by completing the rough rolling after the pre-deformation rolling.
The shape of the continuous cast flat steel slab shown by the solid line in Figure 2 is better than that obtained from the large-sized slab steel slab shown by the dotted line in Figure 2. Although the inner g is sufficient, the tank part 1 formed at the center of the web part becomes long, and there is a risk that the tongue part i will hit the guide during intermediate rolling, and the length of the tank part i will be reduced by the amount of elongation. This increases the amount of parts that are discarded, which is unfavorable in terms of yield.

The present invention can eliminate the above-mentioned drawbacks, especially the long tank part l.
To provide a method for producing a rough H-beam steel piece made from a flat steel piece, which does not cause the occurrence of cropping, minimizes the occurrence of cropped portions, and improves the yield.

In the method of manufacturing a rough H-beam steel slab made from a flat steel slab a according to the present invention, as shown in FIG. An H-shaped cross-sectional steel billet portion A having a thick wall portion 2 is formed therein, and then a rough shaped steel billet is obtained through edging application rolling and forming rolling.

The method for forming the above-mentioned H-shaped cross-section steel piece A is, for example, the fourth method.
Width W in the center as shown in the figure. upper and lower parts 1 having a groove part 3 and a jetty part 4 having a width W parallel to the groove part 3 on both sides of the groove part 3;
A pair of pressing dies 9 and 10 are used to press a preheated flat steel piece a. In addition, if an example of the dimensions of the press molds 9 and 10 is shown, h=H15-10n=0.2-2mw=01-0.2W.

(2w 10w. = 0.5 Wo~0.7 WQ), and as shown in Fig. 5, both sides of the flat steel slab a are fixed with fixtures 5 and 6, and as shown in Fig. 6. , the front and rear ends are regulated by fixtures 7 and 8, respectively, to prevent metal flow from occurring. As a result, the metal flow due to pre-deformation increases the slab thickness H at the unreduced surface 11 of the flat slab a, which contributes to shortening the length of the unsteady part of the flange width (→) mentioned above. Reduce the length of the cropped part.

In another method, as shown in Fig. 7, there are holes I, n (7th part) in the figure) and the molding hole mold I11. IV, (part in Figure 7)
Normally, as shown in FIGS. 8 and 9, the flat steel strip a is held vertically to form the above-mentioned etching proposal holes 1 and 2, and forming holes 2.

(2) is passed sequentially to make an H-shaped assembled steel piece, but the other method described above uses the hole shapes I and II and the forming hole (2) to form a flat piece, as shown in Figure 10. In this method, a steel slab A is inserted horizontally, that is, horizontally, between upper and lower rolls A and B, and a part of the tip is rolled to obtain an H-shaped cross-sectional steel slab part A shown in FIG. In addition, in order to adopt this method, as shown in FIG. must be made equal.

Although it may be made by any of the methods described above, the obtained flat steel billet a (see FIG. 3) having the H-shaped cross-sectional steel billet portion A is then made into a flat steel billet a as shown in FIG. 11. First, it is inserted vertically into holes I and II, and then sequentially passed through holes ① and ② shown in FIG. 10 to obtain a crude H-shaped steel piece B as shown in FIG. 11V.

The following is the result of an experiment in which an H-beam phase steel slab was made using rolls b and c having the shape shown in Fig. 1, and this rough-shape steel slab was then intermediately rolled and finished rolled to produce a product. We were able to confirm the effect of cropping improvement.

That is, 1. The size of the experiment; - The cross section of the flat steel piece (rectangular in cross section) a used is Wa = 11007 + 1 mHa = 250 as shown in Figure 1.
mm ・ Dimensions of the obtained H-beam final product 7 Lunge width = 400 Capacity height = 4oomm 11 Pre-deformation amount In Figure 3 h-20~80 1-1~3m Pulling = 800mm 111 Effect steel piece during experiment Yield p improvement effect of 1 to 2% on a 20-ton basis (including both tip and end effects) (this corresponds to the crop reduction amount e + p described later) 1. Tip and end shapes of rolled material by pre-deformation rolling Improvement effect The shape of the end of the rough-rolled final H-section steel slab produced by conventional pre-deformation rolling shown in Fig. 12 (a) is as shown in Fig. 12 (b), Products that are not preformed and rolled have shapes as shown by dotted lines, and products that are preformed and rolled have various shapes shown as solid lines. The shape is as shown in Fig. 12. Those that are not subjected to pre-deformation rolling are shown in dotted lines, and those that are subjected to pre-deformation rolling are as shown in solid lines. C
8 shows the crop length without pre-deforming rolling, C2 shows the crop length with pre-deforming rolling, and the crop length with pre-deforming rolling can be shortened by C, -C2=e. However, when the method of the present invention is implemented, that is, when the pre-deformation rolling shown by the solid line in FIG. 13(a) is changed to the pre-deformation rolling shown by the dotted line, the final H
The shape of the end of the shaped steel piece is as shown in Figure 13 (B), and the shape of the end of the product obtained from the rough shaped steel piece is as shown in Figure 13 (C). If C2 is the crop length of the rough-shaped steel billet that has been roughly rolled by the conventional pre-deformation rolling, then the crop length of the rough-shaped steel billet that has been pre-deformed and rolled according to the method of this invention is C8. The shortened length of the crop length caused by pre-deformation rolling is C2-C3-p.

Since this invention has the above-mentioned concept, it is possible not only to reduce the amount of cropping more than the conventional pre-deformation rolling, but also to improve workability when biting the rolled material after intermediate rolling. There is a remarkable effect that the predeformation rolling and the subsequent rough rolling can be carried out in one heat instead of multiple heats.

[Brief explanation of the drawing]

Figure 1 is an explanatory diagram of the conventional method of creating a pre-deformation rolled part at the tip of a flat steel billet, and Figure 2 is an illustration of the end of a finished rough-shaped steel billet with and without conventional pre-deformation rolling. FIG. 3 is an explanatory diagram of the shape, and FIG. The figure is an explanatory perspective view of one embodiment of the method for forming an H-shaped section steel piece according to the present invention, FIG. 5 is a front view when a fixture is used, FIG. 6 is a side view, and FIG. 7 is a rough view. A front view showing the hole shape of the shape rolling roll, FIGS. 8 and 9 are explanatory diagrams of a conventional method of rough rolling a flat steel billet, and FIG. 10 is a method of forming an H-shaped cross section steel billet according to the present invention. FIG. 11 is an explanatory diagram of a rough rolling method after forming an H-shaped cross-section steel billet in the method according to the present invention, and FIG. 12 is an illustration of a method in which a flat steel billet is subjected to conventional pre-deformation rolling. Fig. 13 is an explanatory diagram of the superiority and inferiority of the cropping amount between those subjected to cropping and those not subjected to cropping. Explanatory diagrams of the superiority and inferiority of the cropping amount of the pieces are shown respectively, where a is a flat steel piece, A is an H-shaped steel piece part, 1 is a web part,
2 indicates the thick portions. Patent Applicant Kawasaki Steel Corporation 9- C1 Taste Figure 12 (/1') (B) 0\) (C) 10-

Claims (1)

[Claims] An H-shaped cross-section steel billet portion A in which a thick wall portion 2 is formed on a web portion 1 at least at the tip or end in the length direction of the flat steel billet a.
A method for manufacturing an H-beam rough-shaped steel billet using a flat steel billet as a raw material, characterized in that the rough-shaped steel billet is obtained by forming a steel billet, and then undergoing edging application rolling and forming rolling.