JPS5918123B2 - Manufacturing method of ribbed H-beam steel - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The method of the present invention relates to a method for hot rolling a ribbed H-beam steel whose flange tip is bent inward at 90 degrees in order to improve the cross-sectional performance of the H-beam steel.

Conventionally, as shown in FIG. 1, as a manufacturing method of ribbed H-beam steel, both ends 1 of a steel plate 1 constituting the flange of the H-beam steel have been manufactured.
It was manufactured by bending forming a to 1d in advance and then welding the steel plate 2 constituting the web to the center portion of the formed flange steel plate 1.

Recently, a manufacturing method using roll forming has been proposed, and as shown in Fig. 2, an ultra-wide medium flange H-section steel 3 is rolled from a raw steel piece using ordinary H-section manufacturing equipment. After reheating the flange portion locally or as a whole, bending roller groups 4a to 4 of the rib forming equipment
By passing d through the flange tip rib equivalent portions 3a to 3
It was manufactured by bending d by 90 degrees to form ribs.

However, both methods have many problems as listed below. For example, in the case of the former, (1) high manufacturing cost, (2) low productivity, (3) low reliability of the strength of the welded part, (4) ) Residual stress is generated due to welding, and in the case of the latter roll forming method, (1) it is necessary to manufacture ultra-wide medium flange H-beam steel in advance, (2) it is expensive and requires a large number of bending roller groups. (3) A reheating device is required; (4) Rib and flange plates cannot be made thicker due to bending; and (5) The radius of the bent end of the flange is too thick. there were.

The method of the present invention solves the above-mentioned problems and provides a method for efficiently manufacturing ribbed H-section steel by a hot rolling method using a known H-shape rolling mill train.

The method of the present invention is a hot rolling method for manufacturing ribbed H-section steel, in which material steel pieces such as blooms are rolled into beam blanks of a predetermined shape using a rough rolling mill such as a double breakdown rolling mill, and then By performing reversible rolling multiple times using the universal rolling mill at the front stage of the rolling mill group, the thickness of the flange phase portion and the web-equivalent portion is reduced and stretched, and a bent portion (hereinafter referred to as the rib-equivalent portion) is formed near the tip of the flange. Product H-beam with flared flange (hereinafter referred to as open-legged H-beam)
At the same time, the end surface of the rib-equivalent part of the flange is shaped by a subsequent universal rolling machine, and in the final pass, while shaping the flange bending part, the rib-equivalent part is folded inward and formed, followed by a finishing universal rolling machine. A method for producing a ribbed H-beam steel, which comprises pressing and rolling the outer surface of the flange to make it straight, and lightly reducing the web and ribs to shape the fillet and the outer radius of the bent end of the flange. It is.

The method of the present invention will be explained in detail below with reference to FIGS. 3 to 8.

FIG. 3 shows the equipment arrangement for carrying out the method of the present invention, including a rough rolling mill 5 such as a double breakdown rolling mill, an intermediate rolling mill group 9 consisting of a front stage universal rolling mill 6 and a rear stage universal rolling mill 7, and a finishing universal mill. This is an H-shaped rolling equipment row consisting of rolling mills 8.

The heated material steel pieces such as blooms are passed through a rough rolling mill 5 having rolls with holes 10 to 13 carved therein as shown in FIG.
After being roughly rolled into a beam blank having a predetermined shape by multiple reversible rolling operations, the beam blank is led to an intermediate rolling mill group 9.

The intermediate rolling mill group 9 has horizontal rolls 16, 1 as shown in FIG.
6' and vertical rolls 15, 15' and a horizontal roll 17.1 as shown in FIG.
7' and a rear universal rolling mill 7 having vertical rolls 18, 18' as shown in FIG.

The side surfaces of the horizontal rolls 16, 16' of the front stage universal rolling mill 6 of the intermediate rolling mill group 9 are two stages A with different inclinations.

The flange leg angle θ1 formed by the body part C parallel to the axes of the rolls 16, 16' and the side face A adjacent to the body part C, the side face A and the side face B following the side face A, Assuming that the bending angle θ2 of the portion corresponding to the rib formed by the
0°〉θ1〉90°, 180°〉θ2〉270°-θ1
It is necessary to

In other words, the angle θ2 must be 180° or less because the ribs of the ribbed H-section steel are provided inside the H-section steel, and the horizontal roll sides A and B have an angle of 90° or more with respect to the roll axis. Rolling is not possible unless the surface is inclined.

In addition, a groove is provided near the center of the body C of the horizontal rolls 16, 16' to leave a convex portion in the web of the spread-legged H-section steel, thereby providing a shaping rolling type during finish rolling.

In addition, the vertical rolls 19 and 19 of the front stage universal rolling mill 6
The side surfaces of ' have parallel surfaces E and F corresponding to the sides A and B of the horizontal rolls 16 and 16'.

The horizontal rolls 17° and 17' of the rear universal rolling mill 7 are for shaping the end surface of the rib-corresponding part of the split-legged H-section steel 14.
Horizontal rolls 16.16 of the front stage universal rolling mill 6
The end surface of the rib-corresponding portion is shaped by a surface G having an angle θ with respect to the side surface B' from a predetermined position of the surface B corresponding to the side surface B.

Further, the flanges and ribs are folded inward by being pressed and rolled by the vertical rolls 18, 18', and the horizontal rolls 16.1 of the front stage universal rolling mill 6 are used.
The angle of the vertical roll 18.18' corresponding to the angle θ1° θ2 formed by the 6' side surfaces A to C is θ3. Let θ4 be the angle θ3
．． θ4 is 90°〈θ3×θ1.90°〈θ4〈θ2, θ
, <270°-θ3.

The beam blank obtained by rough rolling as described above is subjected to reversible rolling a plurality of times by the universal rolling mill 6 of the intermediate rolling mill group 9 to form a spread-legged shape H having a flange leg-spread angle θ1 and a rib-corresponding portion bending angle θ2. While being formed and stretched into a section steel 14, the horizontal roll 17 of the rear universal rolling mill 7
．． 17', the tip surface of the rib-corresponding part is shaped, and in the final pass of the intermediate rolling mill group 9, the flange leg angle is changed from θ1 to θ3 by the vertical D-rules 18 and 18' of the rear universal rolling mill 7. , and the rib bending angle is θ2→
θ4, the rib-equivalent portions are bent inward so as to face each other, and rolling is performed so that the outer surfaces of the curved portions of the flange and rib-equivalent portions are not rounded.

Note that the vertical rolls of the universal rolling mill used in the normal intermediate rolling mill group 9 do not have a drive device, so when rolling only the vertical rolls 18 and 18' of the rear stage universal rolling mill 7, the front stage universal rolling mill 6 opens the vertical rolls. Leg-shaped H-beam 1
4 transfers are performed.

Next, as shown in FIG. 8, the spread-legged H-beam 14 is rolled by the vertical rolls 19° 19' of the finishing universal rolling mill 8, which has horizontal rolls 24, 24' and vertical rolls 19, 19'. The fillet portion 22 is pressed and rolled into a straight shape, and the fillet portion 22 is shaped by the width direction thrust due to light reduction rolling of the central portion of the web by the horizontal rolls 24, 24' and the horizontal rolls 24, 24' and the vertical rolls 19, 19.
The corner portion 21 formed by the flange and the rib is shaped by light reduction rolling in the length direction of the rib portion (in a direction parallel to the roll axis), thereby forming the ribbed H-section steel 23.

Incidentally, the light reduction in the finishing universal rolling mill 8 is preferably performed at a rolling reduction rate of 2 to 5%, and the thickness tl of the convex portion provided during shaping by the intermediate rolling mill group 9 at the center of the web is equal to the finishing web thickness t.

It is preferable that it/1o=1.02 to 1.05 for the rib length l12, and the rib equivalent length 11 during shaping by the intermediate rolling mill group 9 is 11/1221.0.
It is preferable to set it to 2 to 1.05.

However, if the rolling reduction rate is 2% or less, the rolling blade is small and the effect of shaping the fillet portion 22, ribs, and flange corner portion 21 is reduced.

Next, the method of the present invention will be explained using examples.

(Example) Material steel slab 300mm thick, rectangular cross section bloom 1200mm wide, height 300run, width 300mm, web thickness t
.

= 9 mm, flange thickness tf = 15 mi, rib length l12 =
When manufacturing a ribbed H-section steel with 50 mrn and rib thickness tr = 15 mm, the rolling equipment row consists of a double breakdown rolling mill as a rough rolling mill 5, and an intermediate rolling mill group consisting of two universal rolling mills, a front stage and a rear stage. 9, and one finishing universal rolling mill 8. First, the raw steel billet is heated to 1280°C in a heating furnace (not shown), and then rolled through 15 passes including material turning in a double breakdown rolling mill. It is formed into a beam blank with a web thickness of 50 mm and a flange width of 430 mm by reversible rolling, and then simultaneously rolled and air rolled using the horizontal rolls 17 and 17' of the front universal rolling mill 6 and the rear universal rolling mill 7 of the intermediate rolling mill group 9. After 10 passes of reversible rolling, the web thickness was 1o==9. Q: Thickness t of the central convex part of the web is 9.35 mm, and flange thickness tf = 15r/L.
rft, the rib equivalent length l is 51.5 mm, the flange leg opening angle θ1 = 120°, and the rib bending angle θ2 = 155°. By one pass pressing of
After rolling the web at 5°, one-pass rolling is performed using the finishing universal rolling mill 8, so that the thickness of the central convex part of the web is t1 → t□ = 9.0 mm.
, the rib length 11→12=50.0 mm, the flange leg opening angle θ1 and the rib bending angle θ2 are each shaped to 90°.

The ribbed H-section steel manufactured by the above-mentioned rolling method has a rib thickness t.
r = = 15 mal, the outer R of the flange tip milling part = 5 mm, and the ribbed H has an extremely excellent shape.
We were able to manufacture shaped steel.

As shown in FIGS. 9 and 10, by the method of the present invention, when manufacturing a ribbed wire H-beam 25 with wavy projections on the web and a ribbed corrugated H-shape 26 with a wavy central part of the web, , the thickness tl of the central convex part of the web provided during forming in the intermediate rolling mill group 9 is increased, and the required grooves are formed on the horizontal roll 24.
, 24' can be manufactured by rolling the central convex portion of the web from t1 to to using a finishing universal rolling mill 8 provided on the body.

As mentioned above, the method of the present invention can produce ribbed H-beam steel by simply changing the rolling rolls of the known H-shape rolling equipment row, and in particular can produce flange-shaped steel without being limited by the flange thickness. Ribs can be formed by bending the portions corresponding to the ribs at the tip inward so that they face each other, and the cross-sectional performance of the H-section steel can be greatly improved, as well as the verticality of the rib tip surface and the flange. It is possible to manufacture a ribbed H-beam steel with an excellent outer radius of the tip milling part.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a ribbed H-section steel manufactured by a conventional welding method, Fig. 2 is a schematic cross-sectional view of a method for manufacturing a ribbed H-section steel by a conventional roll-forming method, and Fig. 3 is a cross-sectional view of the ribbed H-section steel manufactured by the conventional roll forming method. Fig. 4 to Fig. 8 are explanatory diagrams of the rolling roll shapes of each rolling mill for carrying out the method of the present invention, and Fig. 4 shows the horizontal roll holes of the rough rolling mill. diagram showing the shape,
Figure 5 is a diagram showing the horizontal and vertical roll shapes and rolled materials of the first stage universal rolling mill, Figure 6 is a diagram showing the horizontal roll shape and rolled materials of the second stage universal rolling mill, and Figure 7 is a diagram showing the vertical rolls of the second stage universal rolling mill. Figure 8 is a diagram showing the shape of the horizontal and vertical rolls of the finishing mill and the rolled material. Figures 9 and 10 are ribbed webs with wavy protrusions and corrugations in the center of the web. It is a sectional view showing a modification of H-beam steel. 1...flange, 1a-1d...rib, 2...web, 3...super wide medium flange leg angle, 3a-3d...・Rib equivalent part, 4a~
4d...forming roll, 5...rough rolling mill, 6...previous universal rolling mill, 7...
...Later stage universal rolling mill, 8...Finishing universal rolling mill, 9...Intermediate rolling mill group, 10
~13...Roll hole type, 14...Spread-legged H-shaped steel, 16.16', 17.17', 24,24'
...Horizontal roll, 15, 15', 18.18'
, 19, 19'... Vertical roll, 23...
... Ribbed H-beam steel, 25... Ribbed wire H-beam steel,
26... Ribbed corrugation H section steel, to...
... Web thickness, tf ... Flange thickness, t
r...Rib thickness, θ1. θ3...Flange leg opening angle, θ2. θ4... Rib bending angle.

Claims (1)

[Claims] 1 Roughly roll the raw steel billet into a beam blank using a rough rolling mill,
Then, by the universal rolling mill of the intermediate rolling mill group,
The web is formed into a split-legged H-beam steel having a predetermined thick wall portion at the center and rib-equivalent portions facing inward at a predetermined angle at both ends of the flange, and the rib-equivalent portions are formed by horizontal rolls of a subsequent universal rolling mill. After forming the end face of the web and reducing the spread of the flanges and ribs using vertical rolls, the web is pressed and rolled using a finishing universal rolling machine so that the opposing ribs and flanges are parallel to each other, and the thickness of the web is reduced. A method for manufacturing a ribbed H-beam steel, characterized by pressing and shaping the flesh part to the exact size.