JPH044902A - Hot rolling method of h-shape steel - Google Patents

Abstract

PURPOSE:To roll H-shape steel with the section of high rigidity by properly adjusting the three elements of the shape of horizontal roll, shrinkage and thickness of web and rolling reduction for flange. CONSTITUTION:Using horizontal rolls 6B which the position in the axial direction of roll is variable and which is divided into at least two for a finishing universal mill, the thickness of flange is reduced and simultaneously the height of the web 11w is compressed while the web 11b of an intermediate rolled stock 11 to be rolled which is restrained by setting the dimension of the outside width smaller than the dimension of the outside width of horizontal rolls 4b of a roughing universal mill 4 and while raising up the angle of the flange 11f with vertical rolls 6A. The H-shape steel with the section of high rigidity is obtained by thickening the vicinity of the joint part R of the flange with the web according to the compressing quantity of web height, rolling reduction balance of flange thickness and web thickness and shape of roll at this time.

Description

[Detailed description of the invention] <Industrial application field> The present invention relates to a method for hot rolling I (section steel).

<Prior art> In the conventional hot rolling method for H-beam steel, as shown in FIG. After being roughly rolled in a mill 2, it is sent to a transfer 3, and then rolled in multiple passes in a rough universal rolling mill 4 and an edger rolling mill 5 to form an intermediate rolled material 11 with approximately predetermined dimensions, and then transferred to a finishing universal rolling mill. Finish rolling is performed in step 6 to produce 1 (shape steel 12) having the final dimensions and shape.
In some cases, another rough universal rolling mill is installed downstream of the rolling mill.

At that time, rough universal rolling 4! The shape of the intermediate rolled material 11 that is rolled at g4 is as shown in FIG. from,
In finish universal rolling R6, as shown in FIG. 9(b), when finish rolling is performed using a pair of upper and lower horizontal rolls 6a and a pair of left and right vertical rolls 6b, the flange portion 11
f is rolled down into a vertical shape by a vertical roll 6b.

Once the dimensions of the product to be rolled are determined in this way, the dimensions of the rolls of the finishing universal rolling mill 6 and the rolls of the previous rolling mills are determined.

By the way, ■1 section steel has many sizes of flange thickness in the same designation series, for example, web height: 600 m.
Regarding the X flange radius of 300 m5, the difference between the maximum and minimum flange thickness is usually around 16 mm, and the web height changes by 32 fi, which is twice that.

Therefore, as a means to classify the differences in web height in several groups in such conventional rolling methods, for example, Japanese Patent Application Laid-Open No. 2-60
As disclosed in Publication No. 01, normal universal rolling is performed up to the rough universal rolling stage, and then, in the finishing universal rolling stage, a horizontal roll having at least two split rolls whose position in the roll axis direction can be changed is a horizontal roll with a side surface and a vertical roll. A method for manufacturing a so-called H-beam steel with constant web height has been developed and put into practical use, in which the thickness of the flange is reduced using rolls, and the web height is simultaneously reduced.

On the other hand, recently, there has been an increasing demand for H-section steel having high bending rigidity. To explain the bending rigidity of this H-section steel in a little more detail, as shown in Fig. 10, an H-section steel 12 with a flange width of B, a flange thickness of T, and a web height of H and thickness is L-shaped. The bending rigidity 1 when used in is as follows (11 Formula % Formula % Sl ; flange cross-sectional area Szi + cross-sectional area of web root R; distance from x-axis to flange center, Hx-axis to web root R) The distance to the center of gravity is 1, the moment of inertia around the Bx axis is
As shown in Figure (a), an H-section steel 12A with flange width: B, flange thickness: T, web height: H, the web thickness is uniform at LA, and the cross-sectional area is SA; 1st
As shown in Figure 1 (b), the thickness of the central part of the web is ts
(However, 1A > 1.), the root part is thick, and its cross-sectional area S is equal to the cross-sectional area S of the H-shape 1112A.
, Im are compared, the bending rigidity of the H-section steel 12B, which has a thinner web at the center and thicker at the base, is 1. Therefore, it is known that even if the weight of the H-section steel is the same, a high-strength steel can be obtained.

<Invention tries to solve! ! l! Subject: However,
It is not possible to simply reduce the web height using the manufacturing method of H-beam steel with a constant web height in JP-A No. 2-6001 mentioned above. There was a problem in that it was not possible to manufacture H-beam steel with high bending rigidity.

An object of the present invention is to provide a method for hot rolling steel section 11 that solves the above-mentioned problems.

<! ! l! Means for Solving the Problem> The present invention reduces the web thickness, flange thickness, and flange width of a rough-shaped steel piece during the rough rolling stage in a rough universal mill when hot rolling an H-section steel, and then In the finish rolling stage of the finishing universal mill, the outer width dimension of a horizontal roll divided into at least two parts whose position in the roll axis direction can be made variable is set smaller than the outer width dimension of the horizontal roll of the roughing universal mill used for rough rolling. The horizontal roll and vertical roll of the finishing universal mill are used to reduce the thickness of two langes and raise the angle, and at the same time reduce the web height to balance the amount of compression of the web height, the flange thickness, and the amount of reduction of the web thickness. This is a hot rolling method for H-section steel, which is characterized by increasing the thickness of the web and the base of the flange depending on the roll shape.

<Function> According to the present invention, when manufacturing H-beam steel with a constant outer diameter by reducing the web height using a finishing Uniper roll mill, the shape of the horizontal roll, the amount of reduction of the web, and the thickness Furthermore, since the three elements of the reduction amount of the flange are appropriately adjusted, it is possible to roll an H-section steel having a highly rigid cross section.

<Examples> Examples of the present invention will be described in detail below with reference to the drawings.

As shown in FIG. 1(a), finishing universal rolling 11
16 is a horizontal roll 6B divided into at least two parts whose position in the roll axis direction can be varied,
The outer width dimension of the horizontal roll 4b of the rough universal mill 4
Intermediate rolled material 1 that is rolled with the outer width dimension set smaller than that of
While restraining the web l1w of No. 1, as shown in FIG. 1(b), the thickness of the flange Ilf is reduced while raising the angle of the flange Ilf with the vertical roll 6Δ, and at the same time the height of the web I1w is compressed.

At this time, the thickness of the base of the web and flange is increased depending on the balance between the compression amount of the web height, the flange thickness, the reduction amount of the web thickness, and the roll shape.

In this case, it is sufficient if all of the reduced part of the web becomes elongated in the longitudinal direction of the rolled material, but in reality, even if the balance of the reduction ratio between the web and the flange is changed, the elongation in the longitudinal direction can be achieved in one pass of rolling. As shown in FIG. 2, the limit is about 60%, and the rest consists of partially increasing the thickness of the flange or web or expanding the flange width by using the metal 70-. The basic principle of the present invention is that an H-section steel with a highly rigid cross section can be obtained by actively utilizing this increased thickness in the cross section and increasing the thickness near the root R of the flange and web. This is a great idea.

Therefore, the cross-sectional size of the H-shaped steel is web height: 60 (]
m x flange width; 200 m x web thickness; 12 rolls x flange thickness; 25 m When manufacturing a product size of 11, each of the intermediate rolled materials 11 on the exit side of the rough universal rolling mill 4 is The cross-sectional shape is Wl; 586 m
, h, ;19B cabinet, R section;18gn
, t+ ; 12.2 kaku, f+ ; 25.8
−2θ; 51, and as shown in FIG. 3(b),
The cross-sectional shape of the H-shaped steel 12 at the exit side of the finishing universal rolling l116 is Wl; 554 mm ht; 202 m
Rg; 15m, tt; 12. Om fz
; 25.0 yen θ; 01.

Then, experiments were conducted for each of the following cases: ■ changing the roll shape, ■ changing the amount of web height reduction, and ■ changing the amount of flange reduction. .

First, regarding the roll shape, the roll surface is normal as shown in Figure 4 (al), and the part where the web root R is rolled down is pre-shaving by 31 in cross-sectional area as shown in Figure 4 (b). The two cases were rolled with other rolling reduction conditions being the same.

At that time, the cross-sectional area corresponding to the increased thickness near the R portion of the finished product is, assuming that the web height reduction IS is ΔhXt as shown in FIG. , St =0.3 (Δh x t, ) / 2
--In the case of the roll shape of (31 and Fig. 4 Φ), S
t' = 0.6 (△h x t + ) / 2-
(It became 41. Most of the difference between these two appeared as an increase in the overall web thickness, and the difference was also recognized in the rolling load of the horizontal roll 6A. At this time, the difference between the two (S
! 'St) is approximately equal to the cross-sectional area difference S1 of the roll shape.

Next, roll-shaped horizontal roll 6A in FIG. 4(b)
FIG. 6 shows the relationship between the ratio of the maximum reduction amount S, that is, the reduction ratio α, and the thickness increase ratio at the R portion in the case where the amount of web reduction is changed using '. From this figure, it can be seen that the larger the reduction ratio, the more the thickness increases.

Further, FIG. 7 shows the rate of increase in thickness when the web reduction amount is the same and the flange reduction amount is changed at the same reduction ratio. As can be seen from this figure, there is an optimum point for the reduction ratio between the flange and the web, and it also shows that the amount of flange reduction influences the thickness increase near the R section.

In this way, by controlling the shape of the horizontal roll, the web reduction, and the amount of flange reduction, the increase in thickness near the web base R can be adjusted arbitrarily, and the H of the same cross-sectional area can be adjusted as desired.
It is also possible to manufacture products with excellent bending properties in shaped steel.

<Effects of the Invention> As explained above, according to the present invention, it is possible to manufacture a highly rigid H-section steel product, which can greatly contribute to improving the performance of the product.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are front views partially showing the outline of the horizontal roll of a finishing universal rolling mill used to carry out the method of the present invention, and Figure 2 shows the reduction ratio and longitudinal direction of the web flange. FIG. 3(a) is a front view showing the shape of the intermediate rolled material used in the implementation of the present invention, and FIG. 3(b) is a characteristic diagram showing the relationship between the elongation rate and the 4(a) and 4(b) are front views showing the shape of the horizontal roll used in the experiments of the present invention, and FIG. 5 is a front view showing the shape of the web base. An explanatory diagram of the state of the meat. Figure 6 is a characteristic diagram showing the relationship between the reduction rate and the R section thickness increase rate. Figure 7 is a characteristic diagram showing the relationship between the flange reduction amount and the thickness increase rate. , l] A plan view showing a conventional example of a hot rolling line for section steel, FIGS.
FIG. 10 is an explanatory diagram of rolling of H-section steel, FIG. 10 is an explanatory diagram of bending rigidity, and FIGS. 11(a) and 11(b) are front views showing the shape of H-section steel. 4... Rough universal rolling mill, 4a... Vertical roll, 4b... Horizontal roll, 6... Finishing universal rolling mill, 6A... Vertical roll,
6B...Horizontal roll 511...Intermediate rolling material, 1
2...H-shaped steel.

Claims (1)

[Claims] When hot rolling a section, the web thickness, flange thickness, and flange width of the rough section are reduced in the rough rolling stage with a rough universal mill, and the roll axial direction is reduced in the subsequent finish rolling stage with a finishing universal mill. The outer width of the horizontal roll divided into at least two parts whose position can be varied is set smaller than the outer width of the horizontal roll of the roughing universal mill used for rough rolling, and the horizontal roll and vertical roll of the finishing universal mill are used to roll the flange. Raise the angle while reducing the thickness and simultaneously reduce the web height to increase the thickness at the base of the web and flange by adjusting the amount of web height compression and flange thickness, the balance of web thickness reduction, and the roll shape. A method for hot rolling H-section steel, characterized by: