JPS6192701A - Rolling method of rough h-shaped steel piece - Google Patents

Abstract

PURPOSE:To roll efficiently and stably a slab into a rough shaped slab by subjecting the slab to rolling reduction in conformity with the conditions of the slab by using specific calibers in edging the slab in its width direction into the rough shaped slab by using box calibers. CONSTITUTION:Double wedge calibers K1-K3 having each a projection with a multistepped slant face are used for calibers in edging. Plural calibers formed by keeping the dimensions of the 1st slant faces at their central pats constant, decreasing the angles theta1-theta3 from a roll axial-line to the 2nd slant faces adjoining to the 1st slant faces in sequence, and increasing their grooved-bottom widths B1-B3 in sequence are used. By edging a slab in accordance with the enlarging order of the grooved-bottom widths of these double-box calibers, a rough H-shaped steel piece is obtained by rolling the so-called dog-bone-shaped rough-shaped slab. In this way, the rolling is performed without leaving laps on the flange face and with rolls less damaged.

Description

DETAILED DESCRIPTION OF THE INVENTION ``Object B of the Invention'' The present invention relates to a method for rolling an H-shaped rough piece, in which a continuous cast slab is edge-rolled in the width direction, and a dog-bone-like rough piece is stably produced. The purpose is to obtain a method that allows efficient rolling.

Industrial applications Rolling technology for H-shaped rough shaped steel slabs to obtain H-shaped steel etc.

BACKGROUND OF THE INVENTION A considerable number of proposals have been made regarding obtaining rough-shaped steel slabs by edging rolling a slab-like material in the width direction using a box hole die. Among these methods, the basic method is to drill a flat index hole with a flat groove bottom and perform etching to gradually widen the width of the groove bottom.

In addition, as a method to solve the problems of such a basic method, there is a method in which the wedge box hole type with a tapered groove bottom in which the central part of the groove bottom of the box hole type protrudes is used to push and expand the width of the slab while cutting in the width end of the slab. A method of providing good centering property by providing a protrusion at the center of the groove bottom of a furan) yl-' tux hole type as in Japanese Publication No. 56-41002, and a method of improving centering property, and furthermore,
- Is there a method of providing a protrusion in the shape of a triangular hole like the one disclosed in Japanese Patent No. 18124, making the protrusion thicker and making a slit at the end of the slab? ;be.

Problems to be Solved by the Invention However, each of the above-mentioned conventional devices has its own problems. In other words, in the basic method described in MiJ, when a slab is etched into a so-called dog-bone shaped member, the build-up (dog-gone flange width widening) at the material width end is small, and unsteady deformation at the leading and trailing ends of the material occurs. The crop loss is large due to the narrowing of the flange width at the leading and trailing ends and the web thickening phenomenon (the web in the steady section is thinned by several inches), and when joining two thin-walled and wide slabs, the first
Buckling as shown in Figure 2 is likely to occur.

Chi 1 to take advantage of this disadvantage? In the method of splitting and pushing out the groove bottom with a web box hole type, the width of the dogbone flannel is large, but the centering properties of the material are poor, resulting in poor centering as shown in Figure 13. Although the product disclosed in Japanese Patent Publication No. 56-41002 has good centering properties, the width of the dogbone is insufficiently widened, and the crop loss at the leading and trailing ends is also large. In addition, the product disclosed in Japanese Patent Publication No. 59-18124 has good centering properties, but it is difficult to form a wide flange, the deformation is not smooth when flattening the slit surface, and the top of the triangular projection is difficult to form. It has disadvantages such as small corners and easy damage to the roll.

``Structure of the Invention'' Means for Solving the Problems The present invention is designed to solve the technical problems of the above-mentioned conventional products. In order to roll a dogbone-shaped rough-shaped steel piece into an H-shaped rough-shaped piece, a double box hole type having a protrusion with a multi-step slope is used in the above-mentioned edging rolling hole, and in the double box hole type. Central part 1
The dimensions of the slope are constant, and the angle from the roll axis of the second slope leading to this slope is made smaller by one step, while at the same time the width of the bottom of the bottom is sequentially increased.These double boxes An H-shaped gage characterized in that the copper piece is edge-rolled in the order in which the groove bottom width in the gutter increases;
→ Chilled by rolling method of rough shaped steel billet.

By rolling with a wedge hole type roll having a protrusion at the center of the action, the spread of 7 runs in the υ dog peen is made into a dog, but it is necessary to use a protrusion with multi-step slopes in such a hole type. This makes it possible to perform efficient rolling with a wide spread dog under conditions of large web and groove angles, with less crop loss and less edge rolling, and to ensure centering of the material, and with the double box hole type. The dimension of the first slope in the central part is constant, and the angle of the subsequent second fi surface from the roll axis is sequentially decreased, and the groove bottom width is sequentially expanded, and a plurality of hole types K%- are formed, and these double By edge-rolling the steel billet in the order in which the width of the bottom of the steel billet is increased in the box-hole die, no scratches are left on the sifting flange surface, and rolling is performed with less damage to the rolls.

EXAMPLE To explain in detail the present invention as described above, the present invention was devised to stably produce H-shaped rough shaped steel slabs from wide, thin-walled continuous casting slabs with high efficiency and high yield. First, to describe the basic characteristics when a slab is etched, a slab 1 with a thickness to and a width Ho as shown in Fig. 2 (,) is wedged with a wedge angle θ as shown in Fig. 2 (b). When the end face is flattened with a flat roll as shown in the same figure (C) after being etched with a roll, and when the slab is directly etched with a flat roll, the expansion of the dog bone flange base B of Quito is 9, that is, the dog bone protrusion. rate(
Bo to ) AH (However, here ΔH=Ho−
1() is, for example, Slavno♀t0=220! +II
I+1 slab @ HO = 900-1500 bait, etching amount ΔH = 300-460 group, roll diameter D = 1000-1
In the case of 100 plays, as summarized in Figure 3, the size is larger when using a wedge roll than when using a flat roll, and the edging under sheet pressure is larger at 1. Become.

Furthermore, a custom-made first shift of Nairao, in which the slab 1 was etched with a flat roll and a wedge roll with a different wedge angle, is as shown in the following first bag.

That is, the rolling conditions for this first category are: slab thickness 220++s, slab width 1200+n, wedge roll diameter 1100mm, 1/f square IE lower! It's 60m, but
The clog loss is the value in the final rough shape material of the shaped hole type roll rolling, and it is clear that the larger the wedge angle is, the more advantageous it is also regarding the characteristic value of inclination. It goes without saying that a small two-song load is also advantageous against buckling of the material.

The present invention was created based on these basic characteristic relationships, and after repeated practical studies and speculations. It summarizes the relationships. That is, the height H
The hole type for rolling a slab 1 with a thickness of 0 at 8 is as shown in Figures 1 (b) to (,), and the double wedge hole type with a two-stage ques- ing slope is formed in 1~. , and nine rolls having a flat ♂ tux hole WK4 for finishing the furan-zo surface.
, to θ, and the dimensions of the first protrusion in the center of these hole shapes are the same, and the width of the groove bottom of the box hole shape is gradually increased from B1 to B4. It is. However, these Figure 1(b)~
The material formed into a dog bean shape using the γg box hole die as shown in FIG. 2(e) is rolled into a final rough profile using the shaping hole die as shown in FIG. 1(f).

By the way, to explain the proper angle and dimensions of the double wedge, which is the important point of the present invention, Fig. 4 shows the symbols related to the dimensions of the hole-shaped valley.
When the material 10 hits eccentrically as shown in FIG.
Between 1FB, FA≧FB [-'4 section is required,
Considering this condition, FA=P1 (ha tanφL F2 =Pt (
tan79+-φ) (however, φ is Masen Kakutsuru-1μ
where μ is the thick part coefficient).

Generally p, >p! However, when P and = P, the centering condition F l:) F B is the plow α-bn /'
>2t,,Iφ.

b, nα:> 2tXIsφ+tanβ. Here, it may be considered that φ is 17° (that is, μ is 0.3).

Furthermore, in order to eliminate the resistance to the widening of the material 10, the average wedge angle θ is set to θ>φ in FIG.

On the other hand, as shown in Fig. 7, considering the deformation resistance of the material 10, it is necessary to set d>C between the height d of the central protrusion and the height C of both sides at the height of the double wedge. In relation to the wedge hole type, the position of the wedge tip at the time of biting must be g≧1/2·d.

In addition, the tip wedge height d should be larger from the point of view of material centering, but it should be noted that
In order to avoid leaving dents, it is better to make d smaller. According to the test results, the wedge height d is 0.25t0 in d with respect to the slab thickness t0, and the wedge width a is 0.25t0 in a.
．． An appropriate value is around 5.

Tests have confirmed that the tip wedge angle α should be α<60° in order to avoid leaving lap scratches on the 7-run surface, and it is better to have a smaller α in order to prevent roll damage.

In addition to the above conditions, in order to gradually reduce the average wedge angle θ as shown in FIG. Medium β weight, (θ is determined) and groove bottom width Bl+B of each caliber! v , B3 e B
4 is gradually expanded into equal parts, and the slab thickness is t.

= 220 rts to dog zone flange @B4=
An example of the results obtained when molding to 500 m+ is shown in Table 2 below.

Table 2 Note Bl”ldl α, β, θ are according to the quantitative symbols in FIG.

Next, to explain the optimization of the reduction schedule, as already explained with reference to Figs. 2 and 3, the flange width B of the dog zone material has a large wedge angle θ, so the edging due to one pass light reduction becomes large. . This indicates that for products with a large 7-lunge thickness, on the contrary, edging should be applied in one pass under heavy pressure using a hole type with a small wedge angle. This is because, as shown in Figure 9, the cross-sectional area PAs of the material reduced by △H by etching and the cross-sectional area S' of the flange portion of the dog zone material must be equal unless the longitudinal elongation of the material is taken into account. (S in S/), which means that under rolling conditions where the dog zone flange width B is small, the flange thickness t! indicates that it becomes thicker. However, even when considering the longitudinal elongation of the material,
The trend is the same.

Therefore, 7 lunge thickness t! For thick products, see Figure 1 (
After making an incision in the center of the cis slab in the wedge hole type 1 in b), a wedge hole type K with a small wedge angle is made without using the hole type in the same figure (c).

Or flat box hole type 4! In this case, if the wedge angle of the hole shape is small, unsteady parts at the rolling edge and trailing edge tend to increase, so it is better to use the method of edging with strong rolling pressure. Hole ff,
By rolling using K, it is possible to prevent an increase in crop loss. That is, for a relatively thin product with a 7-range thickness and a thick product, it is desirable to select the hole type and reduction amount as shown in Table 3 below.

Note that methods for rolling down only the leading and trailing ends of the rolled material include a method of changing the opening degree of the rolls during rolling, a method of stopping rolling halfway and returning the material, and the like.

The following Table 4 comparatively shows an example of a rolling schedule when thin and thick H-beam steels of 700 x 300 size are edge-rolled in a hole having the dimensions shown in FIG. 2. That is, for thin materials, the amount of reduction is 20 to 40 degrees, especially 30 degrees.
While light pressure is mainly applied to the throat, strong pressure of 50 to 60 m is generally used for thick materials.

The unit interval, Δh, is the reduction amount in one pass. FIG. 10 shows the tip shape of such an H-shaped rough shaped steel piece. Generally, the Franz width B of the tip, which is an unsteady part, is narrow and the web thickness is thick, but the double wedge of the present invention? It is clear that this unsteady part can be made smaller by using the Tuxhole type. In other words, Fig. 11 shows the tip end of a H700x300 thin-sized rough-shaped steel billet rolled using a hole with the dimensions shown in Table 2 and according to the rolling schedule shown in Table 4, and when it was rolled using a conventional flat roll hole. A comparison of flange width change and web thickness change is shown. In other words, according to the present invention, compared to the conventional method, the narrowing of the flange width is less than one-half, while the increase in nib thickness is less than one-third, and the effect of reducing unsteady parts is clear. .

``Effects of the Invention'' According to the present invention as explained above, a target rough-shaped steel billet can be efficiently stabilized by using a unique wedge roll hole shape and performing a reduction that responds immediately to the condition of the raw steel billet. It is obvious that this invention can be obtained by doing so, and it is an invention that has great industrial effects.

[Brief explanation of drawings]

The drawings are intended to illustrate the technical content of the present invention, and Figure 1 is an explanatory diagram showing the general relationship of the method of the present invention step by step with the roll hole arrangement and the cross-sectional deformation process of the material. A schematic explanatory diagram regarding roll shape and material deformation. Figure 3 is a diagram summarizing the relationship between the dog bone elevation rate and the amount of edging depending on the roll shape. Figure 4 is an explanation of the dimensions of the double wedge hole type according to the present invention. Figure 5 is an explanatory diagram of the relationship between eccentric contact with the groove shape of the material, Figure 6 is an explanatory diagram analytically showing the relationship between the wedge surface contact force, and Figure 7 is an explanatory diagram of the relationship between the groove shape and the front groove rolled material. FIG. 8 is an explanatory diagram summarizing the relationship of each roll hole type in the present invention. FIG. 9 is an explanatory diagram of the deformation relationship of the dogbone-like material from the raw slab. The figure is an explanatory view showing both the planar and lateral shapes of the tip end shape of a rolled rough-shaped steel piece, and Fig. 11 shows the flange width and web η of the inventive method and the conventional method. FIG. 12 is an explanatory diagram of the buckling state of the material during rolling, and FIG. 13 is an explanatory diagram of the state of poor centering of the material. In these drawings, 1 indicates the slab, 10 indicates the material, the double-dex hole type in 1 to 3 rolling rolls, and K4 the flat roll hole type. Patent controller: Nihon University Steel Tube Co., Ltd. Inventor: Takeshi Hirasawa
daytime twisting
Yoshiyuki Taka Shiima Mori
Kiyoshi Oka Takatoshi Suzuki
Daido Ide Tetsu Seiji 4 Enjun, 5' Endai I 1 7 to 0 (Genkui Ta V7'11 帛, r05J No.//'gom) L4 Toyo Makata-)

Claims (1)

[Claims] When edging a slab-shaped steel piece in the width direction and rolling a so-called dogbone-shaped coarse steel piece to form an H-shape steel piece, the edging rolling hole has a protrusion with a multi-stage slope. A double box hole type is used, and the dimension of the first slope in the center of the double box hole type is constant, and the angle of the second slope from the roll axis is gradually decreased, and at the same time, the groove bottom width is sequentially expanded. A method for rolling an H-shaped rough-shaped steel billet, characterized in that a plurality of double box pits are used, and the billet is edging-rolled in the order in which the groove bottom widths of these double box pits increase.