JPS58215204A - Rolling method of h-shaped steel - Google Patents

Abstract

PURPOSE:To reduce the crops to be produced at the front and rear ends of an H-shaped steel product in universal rolling of a rough shape steel by using the rough shape steel which is specified in the coefft. of universal rolling down balance and the leg length of the flange thereof. CONSTITUTION:A rough shape steel of which the coefft. K of universal rolling down balance expressed by the equation I is in the range expressed by the equation II and the leg length E of the flange satisfies the equation III or the equation IV is used in the stage of universal rolling of an H-shaped steel. In the equations I , II, III, IV, H: the web height of the product, B: the flange width of the product, f1: the flange area of the rough shape steel, f0: the flange area of the product, w1: the web area of the rough shape steel, w0: the web area of the product, C: the leg length of the flange of the product. The amt. of the crops to be produced is thus suppressed to the flange width of the product or below, and the yield is improved.

Description

Detailed Description of the Invention Regarding the FiH shape rolling method of the present invention, in particular, when a rough shaped steel piece is universally rolled to obtain a product, by using a rough shaped steel piece having a specific size and shape, The present invention relates to an H-shape rolling method for reducing crop occurring at the front and rear ends of an H-shape steel.

As is well known, H-shaped steel e, as shown in Figure 1 (5) to (F), is made of mosquito reheated material 1 such as plume 1A, beam blank IB, straddle slab IC, etc. by continuous casting.
This is roughly rolled using a breakdown rolling mill or the like to form a rough shaped steel piece 2, and then manufactured through universal rolling as shown in FIGS. 10 to 1(E). Figure 1 (
(D) is a diagram showing an H-section steel as a product.

In the universal rolling process, the rough universal rolling mill 3 shown in FIG. 1(C) and the edging rolling mill 4 shown in FIG.
After continuous shape rolling in the finishing universal rolling mill 5 shown in FIG.

FIG. 2 (5) and FIG. 2) are diagrams in which the shapes and dimensions of the rough-shaped steel piece 2 and the H-shaped steel (product) 6 are indicated by symbols. In Figures 2 and below, the web height of the product is indicated by H, and the flange width is indicated by B.

When producing H-section steel by the method described above, cropped portions 7 as shown in FIG. 3 are inevitably generated at the front and rear ends of the rolled material. This crop 7 must be cut and removed in the middle or in the final process, and its amount corresponds to 1 to 5 inches of the rolled material, which is the largest loss in H-shape rolling. Therefore, reducing the crop length by shortening the length of the shape defects that occur at the head (tip) and tail (rear end) of the rolled material is the biggest challenge for improving the rolling yield. be.

In order to reduce the crop occurring at the front and rear ends of the rolled material, the above-mentioned rolling process, that is, the rough rolling process of forming the rough-shaped steel piece 2 from the material 1 in FIG. It is necessary to take measures at each step of the universal rolling process up to product 6. The present invention aims to reduce cropping at the front and rear ends of the rolled material that occurs during the universal rolling process from the latter rough shaped steel billet 2 to the product 6.
A shape shaping rolling method is provided.

The cropping of the front and rear ends of the rolled material that occurs during the universal rolling process is caused by the relative elongation of the flange to the web due to the difference in reduction between the flange area f1 of the rough shaped steel slab 2 and the web area Wl, as shown in Fig. 2 (5). Based on the difference between It includes a minus part (F in Fig. 3) in the flange which is generated by the flange.

First, cropping based on the difference in flange and web elongation due to the difference in rolling reduction of the 7 langes and web in universal rolling has conventionally been dealt with as follows.

For the rolling reduction ratio of the 7-lunge and web in universal rolling, the universal rolling reduction lance coefficient K shown in the following formula is used, mainly due to modeling issues, and the value of K is empirically determined from 1 to 2. I was doing it.

K2 (f1/fo)/(W+/wo) where '1 is the flange area of the rough-shaped steel billet, fO is the flange area of the product, Wl is the web area of the rough-shaped billet, and WO is the web of the product. The area is shown for each.

The above-mentioned modeling problem is that if the value of K is too small and the web stretches too much, web waves will occur, and if the value of K is too large and the flange stretches too much, flange waves will occur. This means that the phenomenon of web puncture (see Fig. 4 (g)) occurs.

In the conventional technology, the reduction ratio (lance coefficient K is set to 1 to
They were appropriately selected within the range of 2 based on experience or through trial and error. Therefore, it is extremely unsatisfactory from the viewpoint of suppressing the crop length at the front and rear ends of the rolled material to a predetermined value or less and improving the yield.

For example, when rolling is performed with a reduction balance coefficient of 1.90, which is a range in which flange waves can be formed without causing flange waves, the fourth
As shown in FIG. 5 and FIG. 4(b), the flange 9 is more elongated than the web 8, and a shape-deficient portion 7 is generated at the front and rear ends of the rolled material. This cropped portion (crop) 7 includes a web rib portion 10 and a rim width minus portion 11. On the other hand, when rolling is performed under the rolling balance coefficient i < = 1.0, which is near the lower limit value at which web waves do not occur, as shown in Fig. 5 (5) and in Fig. 5),
The web 8 is more elongated than the flange 9, and similarly, shape-deficient portions 7 are generated at the front and rear ends of the rolled material. This shaped recessed portion 7 includes a tongue 122 and a flange width minus portion 11.

This figure 4 (5), (8) and figure 5 (5), (B
) As explained above, even if the value of K is within a range that poses no problem in terms of modeling, the length of the shape cutout 7 is quite long and the cropping length is considerably larger than the flange width B.

Next, the flange root part (
The occurrence of the flange width minus portion (F in FIG. 3) caused by the difference in the amount of elongation between the flange tip (N in FIG. 2) and the flange tip (S in FIG. 2) will be explained.

This 7 flange width minus part is the flange tip of the rough shaped steel piece 2 in Fig. 2 (5) with a plate thickness of 1. and 7 lange root plate thickness 1.
The flange root N caused by the difference in rolling reduction based on the difference between
This is due to the difference in elongation of the tip S.

In the prior art, the outer oblique angle α of the flange in FIG. It was determined based on the relationship between the shaping problem in rough rolling and the horizontal roll shape of the rough universal mill following rough rolling (Figure 1 (shape to roll 3 in Q). In other words, in the conventional technology, The magnitude of the inclination angles α and 0 on the outside and inside of the flanges of the rough-shaped steel billet are the main causes of the negative flange width part F as shown in Fig. 3, and are closely related to the crop length. Nevertheless, it was determined only from the above viewpoint.Therefore, it was extremely unsatisfactory from the viewpoint of shortening the length of the cropped part (crop) that occurs at the front and rear ends of the rolled material.

The present invention has been made in view of the current state of the prior art as described above, and is intended to minimize the occurrence of shape defects before and after the rolled material in H-shape rolling (for example, from flange RLJB onward). The purpose of this invention is to improve the rolling yield by minimizing the amount of crop 9j discarded during rolling or rolling acid.

The present invention is concerned with the universal reduction balance coefficient K, which is determined as the ratio of the flange reduction ratio to the web reduction ratio, the edging reduction amount, which indicates the relationship between the flange leg length of the rough-shaped steel billet and the product, and the outer side of the flange of the rough-shaped steel billet. After confirming that the size of the inner ILji bevel is closely related to the length of the shape gap and the minus flange width portion at the front and rear ends of the rolled material, we conducted repeated experiments and analyzes. By limiting these values to specific ranges, we can calculate the length of the shape gap caused by the difference in elongation between the web and seven flanges during universal rolling, and the minus width part of the flanges caused by the difference in elongation between the tip and root of the flange. The objective is to minimize the amount of cropping and thereby improve the rolling yield by reducing the amount of crop truncation.

The present invention provides the following (
The universal reduction balance coefficient K shown in formula 1) is as follows (
The above objective is achieved by using a rough shaped steel piece that is within the range shown by formula 2) and whose flange leg length E satisfies formula (3) or (4) below.

K-(f+/fo)/(W+/Wo)
-----(1) When B≦-; E≧0.8X
C-4,0・・・・・・・・・・・・(4) Here, K: Univeral printing balance coefficient ■I; Web height of product B: Fludge width of product fl: Coarse Flange area fG of the shaped steel piece: Flange area Wl of the product; Web area Wo of the rough shaped steel piece; Web area E of the product; Flange leg length of the rough shaped steel piece C; Flange leg length of the product. Examples of the present invention will be described below. do.

In Fig. 6, the ratio H/B between the web height H and the flange width B of the product is plotted on the horizontal axis, the universal reduction balance coefficient K defined by the above formula (1) is plotted, and the product It is a figure showing the clog generation situation of. In FIG. 6, the mark X indicates a case where web flesh pricking (see FIG. 4) occurs and the length t of the cropped portion is larger than the 7 flange width B, so the cropping amount is also larger than the flange width B. The square mark indicates a case where web tongs (see FIG. 5) occur, and the square mark indicates a case where the clog length t is smaller than the 7 lunge width B, and therefore, the amount of truncation may be less than 7 lunges. Further, the range of K according to the above equation (2) is represented by the area between the upper limit line A and the lower limit line B in FIG.

According to FIG. 6, the crop length t of the product can be reduced to 7; It can be seen that the cropping amount can be suppressed to below, and the cropping amount can be reliably reduced and the rolling yield can be improved.

Furthermore, according to Fig. 6, if a rough shaped steel slab with a universal reduction balance coefficient K exceeding the upper limit of the above-mentioned equation (1) is used, the 7 langes will extend too much with respect to the web, and K will be
If a rough shaped steel piece smaller than the lower limit of the formula is used, the web will elongate too much for 7 mm/d, making it impossible to control the crop length as a whole, and the crop length will be too short for the product. It can be seen that the width exceeds the flange width B, leading to a decrease in rolling yield.

Next, regarding the edging curve, which is the ratio of the flange leg length E of the rough-shaped steel piece to the 7 flange leg length C of the product, in Fig. 2 (g) and proviso, the larger it is within the moldable range, the better.
To shorten the flange width minus part (see F in Figure 3) (
= is preferable. However, there are restrictions due to the biting of the edger roll (roll 4 in Figure 1 0), and the results of actual machine tests show that the value of the flange leg length E of the rough shaped steel piece is
It is preferable to set the range of formula 3) or formula (4).If set within this range, by selecting the balance coefficient K within the range of formula (2), the length of the flange width insufficient portion can be shortened and crop truncation can be performed. It was confirmed that the amount could be suppressed to less than the product 7 lunge width B.

Figure 7 shows the 7-lung leg length C of the product on the horizontal axis, the 7-lung leg length E of the rough shaped steel piece on the vertical axis, and the H
It is a graph in which the line X indicates the lower limit of the equation (3) for a section steel, and the line Y indicates the lower limit of the equation (4) for a narrow width H section steel. In other words, for products with a wide intermediate size, that is, a flange width B from 1/2 to the same value as the web height H, use a rough-shaped steel piece with a leg length E in the area exceeding the line B is web height H
For products with a size of 1/2 or less, the length of the flange width minus part can be shortened by using a rough-shaped steel piece with a leg length E exceeding line Y, and the crop cut amount can be reduced to 7 flange width B or less. It can definitely be suppressed.

If the flange leg length E of the rough shaped steel piece is smaller than the lower limit of formula (3) or (4), the flange width minus part becomes long, and the amount of cropping cannot be suppressed, and its value becomes the product flange width B. This results in a decrease in yield.

Finally, regarding the outer inclination angle α and inner inclination angle θ of the 7 flanges of the rough shaped steel slab 2 in Fig. 2 (5), the smaller these values are made to make the cross section square, the shorter the minus part in the flange becomes. It is preferable for

However, there are problems with wear and shaping of the rolls that form the rough-shaped steel billet, and furthermore, there are problems with the horizontal rolls of the rough universal rolling mill (
Due to the relationship with FIG. 1 (roll 3A in q), it cannot be made extremely small.

From the results of the actual machine test and its analysis by the inventor,
By using a rough shaped steel piece whose inclination angles α and θ are within the range shown in Table 1 below, and by setting the reduction balance coefficient K within the range of equation (2) above, the length of the minus part of the flange can be adjusted. It was found that the length of the cropped portion as a whole could be suppressed to a value smaller than the product flange width B.

Note that if the flange inclination angles α and θ are larger than the values in Table 1, the length of the flange width minus part (F in Figure 3) becomes too long, making it possible to suppress the overall length of the cropped part. It was confirmed that the value became larger than the product 7 lunge width B, leading to a decrease in yield.

The results of a comparison between an example in which the present invention described below is actually applied and a conventional method will be described below.

To roll and form a narrow product (product web height H = 200 m, flange width B = 100 + m, leg length C = 47.25 m), maf, 160 rtan x 210
From the tag (') plume, a rough-shaped steel billet suitable for carrying out the present invention was formed. This rough shaped steel piece had a leg length E of 36, an outer flange inclination angle α of 1 degree, and a flange inner inclination angle θ of 6.

The measurement results of the crop length according to the method of the present invention and the crop length according to the conventional method when such a rough shaped steel piece is used are shown in Table 2 below.

As shown in Table 2, by implementing the present invention, as shown in Table 2, by implementing the present invention, the total length of the product is 70? For y+, the conventional crop of 330 mm was shortened to 180 m7, and the crop length was reduced by the difference of 150+ m, achieving a yield improvement of 0.2 inches.

Figures 8 to 10 show that a rough shaped steel slab with the same specifications as described above is used to roll the same narrow product as described above, and the value of the universal rolling balance coefficient is set to the upper limit value according to the method of the present invention (
=1.60), is the median value (=1.45), and is the lower limit value (=
1.30) is a diagram showing the cropping occurrence situation in each case. That is, Fig. 8 (5), (
B) shows the case when = 1.60, Figure 9 (G), however, shows the case when = 1.45, Figure 10 (B) shows the case where = 1.3
The case of 0 is shown respectively.

As is clear from the above description, according to the present invention, it is possible to obtain an H-shape rolling method that can suppress the crop generation amount during the universal rolling process to less than the product 7 lunge width and improve the yield.

[Brief explanation of the drawing]

FIG. 1 (8) to ■ are explanatory diagrams illustrating the H-section steel rolling process;
Fig. 2 (5), @ is an explanatory diagram showing the cross-sectional shape and dimensions of the product with symbols, Fig. 3 is a perspective view illustrating the cropped part and the minus flange width part of the product, and Fig. 4 ( 5)
, @ is a diagram illustrating the shape of the shape notch at the end when the 7 langes are stretched too much against the web, Figure 5 (G), 03
) is a diagram illustrating the shape of the shape gap at the end when the web is stretched too much with respect to the flange, Figure 6 is a graph illustrating the correlation between the universal reduction balance coefficient and the cropping situation, and Figure 7 is a graph illustrating the correlation between the universal reduction balance coefficient and the cropping situation Graphs illustrating the influence of the relationship between the flange leg length of the product and the flange leg length of the rough-shaped steel piece on the length of the minus 7 flange width section, and FIGS. This is a diagram illustrating the shape of the product end when fiK is changed.IA, IB, IC...Material, 2...Rough shaped steel piece, 3.
...Roughing universal rolling mill, 4.Edging rolling mill, 5.Finishing universal rolling mill, 6.Product (
H-shaped steel), 7... Shape notch part (crop part), 8.
...Product web, 9...Product flange, 1o...
・Web meat stabbing, 11...7 lunge middle minus part, 1
2... Web tongs, H... Product web height, B
...Product flange width, F...7 lange r1j minus part long. Agent Tatsuyuki Unuma (and 2 others)

Claims (2)

[Claims] (1) In universal rolling of H-beam steel, the following (1)
The universal reduction balance coefficient K shown by the formula is as follows (2)
is within the range shown by the formula, and the flange leg length E is as follows (3
) or formula (4) = (ft/fo)/(t/Wo)
------(1) 1 When B≦-; E≧0.8 X C-4,0...
・・・・・・・・・(4) Here, K: Universal reduction balance coefficient 1 (; Product web height B; Product flange width fI; Flange area of rough shaped steel piece fo; Product flange area Wl ; Web area Wo of the rough-shaped steel piece; Web area E of the product; flange leg length of the rough-shaped steel piece C: flange leg length of the product. (2) In universal rolling of H-beam steel, a rough-shaped steel piece whose flange outer inclination angle α and inner inclination angle θ are in the following ranges is used, as claimed in claim 1. 11 shape adjustment rolling method described