JPS62227502A - Production of shape steel having web and flange such as h-steel - Google Patents

Abstract

PURPOSE:To improve efficiency and yield by subjecting an ingot which is formed to a plane or inward projecting shape on the long sides and is formed to a wedge shape in the central part on the short sides to wedge rolling by using a roll pair having a specific shape and successively expanding the surfaces corresponding to flanges. CONSTITUTION:The ingot 22 is cast by a continuous casting mold which is formed with the plane or the inward projecting curved surface in the transverse central part on the inside wall surfaces 3a of the casting mold on the diametrically opposed long sides 22 and is formed with the wedge-shaped projection in the transverse central part on the inside wall surfaces 32 of the diametrically opposed short sides 22a. The ingot 22 is subjected to wedge rolling by a pair of the rolls 4a, 4b, formed with caliber bottoms Ia larger by >=50mm than the thickness on the short sides of the ingot 22 and are formed with central bulging parts 41a in the transverse central part of the caliber bottoms Ia to successively expand the surfaces of the ingot corresponding to the flanges. The productivity and yield are improved by such method.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention involves continuous casting of a material for a section steel having a web and a flange, such as an H section steel, a ■ section steel, or a channel steel, and then rolling the cast slab. The present invention relates to a method for producing shaped steel.

[Conventional technology]

In recent years, slabs have come to be frequently used as the raw material for producing H-shaped steel, ■-shaped steel, channel steel, and other shaped steel having webs and flanges by the rolling method.

That is, in the past, either methods were adopted, such as blooming a steel ingot into a rough-shaped steel billet or continuous casting to produce a beam blank, but recently, methods have been adopted that allow for the omission of processes, energy saving, and Due to advantages such as ease of manufacturing, methods using slabs as materials have become mainstream.

A technique for roughly forming a rectangular steel piece such as a slab as a material is known, for example, as disclosed in Japanese Patent Publication No. 58-19361 or Japanese Patent Publication No. 58-37042, which was previously proposed by the applicant of the present application. In all of these methods, the Franz-equivalent surface of a slab material having a rectangular cross section is widened by a pair of rolls having a wedge-shaped central bulge portion, and edge rolling is performed. Fourth
Figure (A) shows a slab 2 with a rectangular cross section, and Figure 84 (Figure 84 shows a pair of rolling rolls 1a).

1b shows a hole type I in which the flange-equivalent surface 2a of the slab 2 is expanded by central bulges 11a and llb forming an apex angle α. Q→, 2) are the grooves ■, ■ and the rolled material 21 which are sequentially split and rolled at larger angles from the apex angle α to β and γ.
This shows the situation.

Note that the groove ■ shown in FIG. 4 (E) is a shaping hole type, and the posture of the material to be rolled is turned 90 degrees to the H posture in the final stage or in the middle of the edging rolling in the grooves ■ to m. Perform rough modeling finishing.

By the way, generally speaking, the hole bottom width m of the hole type (2) in which the edge rolling is first performed, as shown in Figure 4 (Diagram 1), is set approximately equal to the slab thickness t. In this way, since the hole bottom width m and the slab thickness t are related, the amount of flange widening by etching rolling in the groove I is naturally restricted by the groove width m.

In addition, if the center of the material to be rolled is not guided to the center of the groove I, the corner part 2 of the slab 2 is guided by the side surface 11m of the groove ■.
Along with the occurrence of scratches called bvC “scratching scratches”,
The distribution of the thickness of the upper and lower flanges was uneven, which caused a shape defect called ``web deviation'' in the final product. In addition, in order to obtain a final product with a constant thickness, the thicker the slab, the greater the stretching of the web compared to the stretching of the flange. It was also a factor in worsening the condition.

As a means to solve these difficulties, it is possible to provide as many expanded holes as possible on the mt-roll, but there is a limit to the number of holes that can be carved on one roll body length, especially when the web height In the case of H-beam steel with a large diameter or a large flange width,
There were problems in practical implementation.

[Problem that the invention seeks to solve]

The present invention uses a slab with a new shape and takes advantage of the conventional method of splitting and widening the flange-compatible side surface of a slab, making it possible to manufacture a section steel with a large cross-section, and also eliminating the occurrence of undercut flaws and web deviation. First, it provides a method for manufacturing a section steel having a flange and a web, such as an H section steel, which can shorten the clog length.

[Means for solving problems]

That is, the gist of the present invention is to cast a slab using a continuous casting mold in which the inner wall surfaces of the opposing long sides of the mold are formed flat, and a wedge-shaped protrusion is formed in the widthwise center of the inner wall surface of the opposing short side. After that, 50g from the short side thickness of the slab
Interrupt rolling the slab with a pair of rolls having a hole bottom with a width greater than m or more and a central bulge formed at the center of the hole bottom in the width direction;
This is a method for manufacturing a section steel having a web and a flange, such as an H section steel, characterized by sequentially widening the flange-equivalent surface of a slab.

The present invention will be explained in detail below based on embodiment examples shown in the drawings.

FIG. 1 (10 shows the configuration of the mold 3 used in the present invention,
The mold 3 is composed of opposing long sides 3a and opposing short sides 3b. The mold inner wall surface 31a of the long side 3a is formed into a flat surface, and the inner wall surface 31a of the mold inner wall surface 31a of the long side 3a is formed into a flat surface. A wedge-shaped protrusion 32 having a triangular cross section is provided on the wall surface and protrudes in the casting direction of the mold. The top angle θ of this wedge-shaped protrusion 32 can be set arbitrarily depending on the relationship between the thickness of the slab and the amount of expansion of the flange surface.
In the case of a typical slab having a slab thickness t of 200 to 300 m, the angle is preferably around 90 degrees. That is, if the top angle θ is too large, the guidance during rolling (described later) will be poor9, and if the height of the wedge-shaped protrusions 32 is constant, the amount of wall material in the flange-corresponding portion will be reduced, which is disadvantageous in terms of flange formation. becomes. On the other hand, if the top angle θ is too small, it will be difficult to cool the wedge-shaped protrusions of the mold, and there is a concern that the quality of the slab will suffer.

Although cooling means for the mold 3 is not particularly shown, a well-known structure in which cooling water is inserted into the inside of the mold may be adopted.

FIG. 1 (b) shows another embodiment of the mold used in the present invention,
The mold inner surface 31m of the mold long side portion 3a is formed with a convex surface that is curved in a gentle elliptical or circular arc shape along the entire long side width direction and protrudes most at the center portion in the width direction. Providing the wedge-shaped protrusion 32 at the widthwise central portion of the short side portion 3b is the same as the above-mentioned first aspect.
It is the same as figure (a).

FIG. 1(c) shows a further different example of the long side part 3a of the mold, in which a convex surface is formed only in the center of the long side by an ellipse or a complex circular arc surface with a different radius of curvature, and a flat surface is formed at both ends of the long side. This is what is left of the rest. Fig. 1) shows an example in which a convex surface is formed by a bent surface of a combination of planes. The convex curved surface in the present invention refers to a curved surface formed by a combination of an elliptical or arcuate curved surface and a flat surface. As shown in FIG. 2G, the slab 22 cast using the mold having such a configuration has a long side 22a that is flat, and a short piece 22b that has a Vc@-shaped concave groove 2.
2 (B) shows a piece cast using the mold shown in FIG. 1 (C), the long side 22a is curved inward, and the short piece 22b has a wedge-shaped A slab having a unique shape having a concave m23 is obtained.

Note that by using a well-known width changing means that moves the opposing short pieces 22b toward or away from each other in the width direction of the mold, it is possible to obtain any desired cast pieces with a constant thickness and different widths.

After casting, the slab 22 is subjected to a cutting process of cutting it into slabs of arbitrary length, a flaw inspection process, etc., and is then heated as a hot slab or subjected to appropriate intermediate heating, as shown in FIG. 3 (A). It is rolled by a pair of rolling rolls 4a and 4b.

This pair of rolling rolls is provided with a groove 1a having almost the same shape as the conventional edging hole type (2) explained in FIG.

41b is preferably formed to have a top angle θ approximately equal to that of the wedge-shaped protrusion 32 of the mold. In other words, the accuracy of the conventional guidance guide is not sufficient to align the center of the slab correctly with the center of the groove during rolling, and in the present invention, the concave groove 2 of the slab is
By configuring the angle 3 and the top angle θ of the hole mold 1a to be approximately equal, the precision of guidance can be made extremely high. Next, in the present invention, the hole bottom @m1 of the hole type Ia is the thickness tl of the slab.
The reason for setting such a dimensional relationship is as follows.

The above-mentioned through hole guides the slab to the center of the hole 1a with high precision, so the width of the flange-equivalent part in the hole 1a can be made considerably larger than in the past. This is because the required width of one flange (172 degrees of the total width of the flange) at the end of rolling the gill song is 25 degrees or more. In addition,
In the case of the slab shown in Fig. 2 (B), the thickness tl of the slab referred to in the present invention refers to the thickness at the end in the width direction; In the case of a slab cast using the mold described above, this refers to the widthwise end portion of the slab, that is, the portion where the thickness of the slab is maximum. In FIG. 3, the second edging I [a] following the hole pattern 1a shows the roughly formed hole pattern I[1a].

[Function and Examples]

A slab 22 having a wedge-shaped groove formed in the short piece is subjected to interruption rolling using a groove mold 1m having a central bulge having an apex angle approximately equal to the angle θ of the groove. At this time, since the angle of the concave groove of the slab and the apex angle of the central bulge of the hole mold are set to be approximately equal, the slab is guided to the center of the width direction of the hole mold 1a with high accuracy, resulting in smooth edging. Rolling is performed. Therefore, the thickness of the flange-equivalent portion of the slab 22 is expanded evenly symmetrically, and as shown in FIG. It fills the mold bottom width ml.After this, the flange part is further widened and rolled using the edging hole mold 11a shown in FIG.
Roughly model at 1m. Note that the hole shape na may be omitted depending on the depth of the depression in the slab.

Table 1 shows the relationship between the slab manufactured by the present invention with a long side of 7 lats and a wedge-shaped groove formed on the short side (Figure 2 (a)) and a conventional slab with a rectangular cross section. This is a comparison of The final product is a 400 x 300 H-shaped steel, and the slab size of the present invention is 250 m short piece thickness, 1150 + m long side width, and 65-m groove depth, while the conventional comparison slab is a short piece. 250m thick.

It is a slab with a long side width of 1150m11+.

As is clear from Table 1, when the slab of the present invention is used, the number of passes is reduced by 2.42 compared to the conventional method, and the number of holes can be saved by one. In addition, in the case of slabs whose long sides are curved inward, the effect of reducing the number of filings and the number of holes is the same as above 2. In addition to omitting the file, web rolling in the forming holes depending on the degree of concavity on the long sides. Since the amount is reduced, an additional 4 noses can be omitted, and the effect of reducing the clog length is also large. FIG. 5 shows the relationship between the thickness t2 of the concave portion on the long side of the slab and the ratio of the clog length to the thickness tl of both ends. In this case, the clog length is also based on the value measured after finishing the edging rolling and rough shape rolling and passing the product through three chairs in the next stage universal rolling mill. It can be seen from FIG. 5(f) that the larger the concave scale, the shorter the crop length can be. However, when actually setting the amount h of recess in the slab (Figure 5 (b)), it goes without saying that care should be taken to ensure that the thickness of the slab at the recessed portion is such that it will not buckle during edging rolling. .

Table 1 [Effects] According to the present invention, when the slab is first rolled in the first edging hole mold, it is accurately guided to the center in the width direction of the hole, so that there is no slippage and no web deviation 9 occurs. In addition, since the number of times of rolling can be reduced by 41 times, the efficiency of rolling is improved, and furthermore, since the clog length is shortened, the rolling yield is greatly improved.

[Brief explanation of drawings]

Fig. 1 is a schematic cross-sectional view of an example of a mold used in the present invention. ((A) and (B) are partially cutaway perspective views of slabs cast by the method of the present invention, Figure 3 (A),
(B), H, and B) are schematic explanatory diagrams showing the relationship between the etching hole type used in the present invention and the rolled material; FIGS. 4H) and (B); (C), (B) and (E) are schematic diagrams illustrating the conventional means for inserting and rolling a rectangular steel billet;
B) is a graph showing a decrease in clog length according to the present invention and an explanatory diagram of concavities in slabs. la, lb: rolling roll pair 2; slab 22; slab 11 m + 11'b; central bulge 3: mold
3a; Long side portion 3b; Short piece portion 32; Wedge-shaped protrusion 23; Concave groove Honda Kodaira f, - Masayuki Kishida Yasu 2nd drawing 3: Concave 3rd figure

Claims (1)

[Scope of Claims] 1. After casting a slab using a continuous casting mold in which the inner wall surfaces of the opposing long sides of the mold are formed flat, and the inner wall surfaces of the opposing short sides are formed with a wedge-shaped protrusion in the center in the width direction. , the slab is rolled with a pair of rolls having a hole bottom with a width 50 mm or more larger than the thickness of the short side of the slab and a central bulge in the center of the hole bottom in the width direction, and the flange-equivalent surface of the slab is rolled. A method for manufacturing a section steel having a web and a flange, such as an H section steel, characterized by sequentially widening the width of the section steel. 2. A shape having a web and a flange, such as an H-shaped steel according to claim 1, characterized in that a mold is used in which the inner wall surface of the long side of the mold is formed into a curved surface that is convex inward at the center in the width direction. Method of manufacturing steel. 3. Claims 1 or 2, characterized in that a mold is used in which the shorter sides of opposing molds can be expanded and contracted in the width direction.
A method for manufacturing a section steel having a web and a flange, such as the H-section steel described in 2.