JPS6018202A - Method for rolling nonsymmetrical rough-shaped billet - Google Patents

Abstract

PURPOSE:To roll efficiently and advantageously a billet into a nonsymmetrical rough- shaped billet free from camber and bend by changing from each other the diameters of a pair of rolls used for edging repeatedly a flat billet having a large widththickness ratio, and rolling the billet into a nonsymmetrical dog-bone-shaped billet by driving the roll of one side only. CONSTITUTION:A flat steel billet 1 is rolled in the width direction by the calibers I , IIIprovided respectively to the small diametral part 4 of an upper roll 2 and a lower roll 3, to deform it into a primary dog-bone-shaped billet 1a having the bulged thicknesses at its side edges. At that time, as the root diam. D, of caliber I is different from the root diam. D2 of caliber III, the thicknesses W1, W2 at the upper and lower side-edges of billet 1a are made different from each other to be W1>W2. After being rolled by the calibers I and III through prescribed passes, the billet 1a is roll-formed repeatedly through prescribed passes by the roll-forming calibers II, IV, having respectively body- diameters D3, D4 and provided to the small diametral part 4 of upper roll 2 and the lower roll 3, while roll-forming the side-end faces of billet 1a at the same time. Further, the billet 1 is rolled for finish forming by roll-forming calibers V, V having the same shapes and provided respectively to the rolls 2, 3, to obtain a nonsymmetrical rough- shaped steel 1c having flanges different from each other in shape dimensions such as F1, F3.

Description

[Detailed description of the invention] Technical field A so-called rough shaped steel slab, which is a rolled stock of shaped steel, is subjected to repeated width reduction using a pair of slotted rolls to a flat steel slab with a large width-to-thickness ratio, such as a continuous casting slab. The technical content described in this specification relates to advantageously obtaining an asymmetric rough-shaped steel piece by unevenly guiding this dogbone deformation when processing is performed through dogbone deformation that forces the side edge thickness to become enlarged. is positioned in the technical field to which section steel rolling belongs.

Problem: When rolling an irregularly shaped H section steel (hereinafter referred to as asymmetric section steel), which has a pair of flanges at both ends of the web, but whose flange width or flange thickness is different, using a universal mill or groove mill. In particular, in order to properly balance the rolling load on both flanges and prevent longitudinal deformation (bending, warping, etc.) of the rolled material, the material to be rolled, that is, the rough-shaped steel piece, must have an asymmetrical curved surface. In order to prepare this asymmetric rough-shaped steel slab, which needs to have the following shape: (1) Obtain an asymmetric slab using a continuous casting mold with an asymmetric shape.

■ An ingot or steel material with a rectangular cross section is rolled with asymmetrically slotted rolls and processed into an asymmetrical rough shape steel piece.

■ Obtain an asymmetrical steel billet by cutting off part of the flange on one side of a symmetrical steel billet.

As for method 8, it is not only uneconomical to prepare a separate mold for each size of asymmetric section steel, but also to remove and replace it. It is technically difficult and not common because it tends to cause defects such as cracking.

Regarding ■, due to the different reduction ratio of each flange,
It is easy to bend during rolling, which causes problems during transportation or handling as a rough shaped steel billet.

Regarding (2), since the good quality part of the copper piece is removed as a waste, it is uneconomical and the load for cutting is heavy.

Furthermore, in any of the above cases, since the asymmetric rough shape + ¥4 piece has an irregular cross section before rolling the asymmetric section steel, it is difficult to store, transport, or heat the asymmetric section, and the link method and equipment 6 used therefor are difficult. There are also notable drawbacks to the complexity.

OBJECT OF THE INVENTION It is an object of the present invention to advantageously solve the above-mentioned problems specific to obtaining an asymmetric rough-shaped steel piece.

42 of invention. The above objectives are suitably achieved by process steps which consist of the following:

Repeatedly applying width reduction to a flat steel piece with a large width-thickness ratio,
During the rolling process to obtain a roughly shaped steel billet through dogbone-like deformation that forces the side edge thickness to enlarge, a pair of rolls used for width reduction are made to have different diameters, and rolling is performed with one of the rolls not being driven.
A method of rolling an asymmetric rough-shaped steel billet comprising inducing a non-force first-order dogbone-like deformation.

Here, flat steel pieces with a large width-to-thickness ratio, such as continuous cast slabs, are used as asymmetric rough-shaped steel pieces to produce asymmetric steel sections by universal mill or groove mill rolling, and a dogbone shape is created by width reduction. By asymmetrically guiding the deformation, a complementary piece of asymmetrical section steel can be advantageously obtained.
In this case, by performing asymmetric rolling of the rough shaped steel pieces in a rough rolling mill on the upstream side of the asymmetric shaped steel rolling line,
By heating a flat 41 piece only once, it is possible to manufacture an asymmetric shaped steel from a rough shaped steel piece through rolling processing, which is not only economical but also free of disadvantages and inconveniences in terms of handling. It can be resolved.

This invention is based on the operational experience of the dogbone deformation process behavior due to width reduction of continuously cast slabs mentioned at the beginning. The idea is to utilize the fact that the expansion rate of dogbone deformation is different and the expansion becomes more significant on the smaller roll diameter side to induce asymmetric dogbone deformation.

Figure 1 shows the groove rolling process of an asymmetric coarse copper piece.
The front view of the pair of hole-shaped rolls is also shown in a hypothetical shape. 1 in the diagram
Although it is a flat steel piece, the deformation process is distinguished by subscripts -a'-c. 2.8 is a pair of upper and lower rolls, and 4 is a small diameter portion of the upper roll 2.

In the figure, the steel billet f1' l is rolled down in the width direction by the hole I provided in the small diameter part 4 and the hole type II provided in the Far 8, and as a result, the thickness of the side edge becomes enormous. The primary dogbone-shaped steel piece 1aK is deformed.

In this case, the valley diameter D□ of the hole type ■ and the valley diameter D8 of the hole type nt are different 1
Therefore, as shown in Fig. 2, a primary dogbone steel piece 1 is
The side edge thicknesses W, , and W2 of a are different on the upper and lower sides.

That is, the green thickness W is larger than W2 when rolled with a small diameter roll 4 (1ill).

For example, one piece of hemlock with a thickness of 250 mm is
When the width is rolled down in one pass using a pair of rolls with different diameters of o mm (D3) and 500 mrn (Dl), w2 is approximately 260.
W□ was 266°9'lrnm for 7mm.

After passing through a predetermined bath in hole types I and m, the side end face of the primary dowel and bone-shaped steel slab 11 is shaped, and the diameter of the small diameter part of the upper roll 2 and the body diameter provided on the lower roll 3 are respectively D2.
．． D, orthopedic hole: 'l'! Repeat the predetermined pass with It, tv, Sarashu, upper roll 2 and lower roll 8
Finish forming and rolling is performed using forming holes V and V of the same shape provided in the respective holes to obtain asymmetric rough-shaped steel pieces 1c having different flange shapes and dimensions as F□ and F2 as shown in FIG.

In particular, for convenience of illustration, only one set of each hole type of the upper and lower roll pairs 2 and 8 is shown, but it is of course possible to increase the number of 11.M to multiple sets if necessary. , and hole type I for shaping the end of a dog-bone steel piece.
If necessary, rolling using T, A' and finishing forming hole V alternately may be carried out.

In rolling with different diameters using a pair of upper and lower rolls, one roll is not driven in order to prevent the steel material from slipping during rolling and from warping on the rolling exit side.

[In other words, the sleeve is fitted as a small diameter portion 4 via a bearing 5 to the shaft 6 which is integrated with the upper roll 2 in FIG. It is a non-driven roll that can rotate.

Although I have explained that Naorol 2.4 is the upper roll and Roll 8 is the lower roll, if necessary, you can use the 2nd and lower rolls of these rolls.

The dimensions and shape of the forming hole die (■) are as follows: 1. When a dog-bone shaped steel piece 1a or lb is rolled with this hole die (■), the dimensions and shape of the forming hole (1) shall be determined as appropriate to prevent distortion (bending, warping), etc. from occurring in the rolled material on the rolling exit side. All you have to do is

Note that the flange II of the asymmetrical coarse piece 1c shown in FIG.
If you want to change the ratio of @ F By changing the ratio of the side edge thicknesses W□ and W2 of the dogbone-shaped steel piece 1a, rolling can be carried out using a modified dogbone shape (1) suitable for rolling 1 piece lb of dogbone-shaped steel piece 1a accordingly.

In order to cover the side edge thicknesses W□ and W2 of the dogbone-shaped steel piece, as shown in Fig. 4, a difference in shape is made between the bottom surface of the hole pattern ■ and the bottom surface of the hole pattern ■.For example, the hole pattern ■ is 1. Make it with Berry Ia, but make the hole type ■ flat, or do the reverse arrangement IJ-I
There is a method of changing the enlarged deformation at the side edges of the flat steel billet l by changing the size of a, or by creating a temperature difference on both sides of the flat steel billet 1 or the primary doghorn shaped billet 1a.
For example, it is possible to apply a combination of a method of giving enlarged deformation in the form of a one-sided cooling dogbone to produce an asymmetrical steel section IC having a constant size and shape.

Effects of the Invention This invention provides an asymmetrical rough shape KiJ that is free from warping, warping, and bending.
The i-piece can be rolled efficiently and advantageously.

[Brief explanation of drawings]

Fig. 11g1 is a front view of the main part of a slotted roll showing the procedure for rolling an asymmetric rough-shaped steel piece, Fig. 2 is a sectional view of a primary asymmetric dogbone-shaped steel piece, and Fig. 8 is an asymmetrical steel piece rolled by the method of the present invention. of rough shaped steel billet (
Figure 4 is an explanatory diagram showing the difference in expansion deformation effect due to changes in the hole shape of the roll pair. Figure 1 fi IV V Figure 2 Vt Ki W2 Figure 4

Claims (1)

[Claims] L The width reduction is repeatedly applied to a large flat steel piece with a large width-to-thickness ratio to obtain a rough-shaped copper piece through a dragon-bone deformation that forces the side edge thickness to increase. A method for rolling an asymmetrical A'-shaped steel piece, characterized by rolling a pair of rolls of different sizes and rolling with one of the rolls not being driven to induce an asymmetrical dogbone-like deformation.