JPS60191716A - Cutting for casted pieces obtained through continuous casting - Google Patents

Abstract

PURPOSE:To prevent the generation of the cut iron loss and obtain the slab having the superior yield in hot rolling by cutting a casted piece obtained through continuous casting by using a pair of V-shaped cutters having the knife- edge surfaces asymmetrical in the lateral direction. CONSTITUTION:A pair of V-shaped cutters 10 are equipped with the knife-edge surfaces 11 and 12 asymmetrical in the lateral direction. A casted piece 14 obtained through continuous casting is interposed between a pair of V-shaped cutters 10, and the cutters are pushed into the casted piece 14 along the line 13 in the direction of advance of the knife edge, and the casted piece 14 is cut into a slab 21 by the contact of the knife edges 9 and 9. The slab 21 extends larger at the both edges in the direction of width in comparison with in the center part, and the amount of extension is larger on the rolled bottom side than on the rolled top side, and the yield in hot rolling is improved.

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to improving the shearing strength of continuously cast slabs (hereinafter referred to as continuous slabs), and particularly relates to improvement of the shearing strength of continuously cast slabs (hereinafter referred to as slabs). For 11th Run! Continuous slabs with no iron loss during UJ breakage and longed for hot rolling yields! ;IJ tFIi
It is about the method.

BACKGROUND TECHNOLOGY Conventionally, continuous slabs continuously cast by a continuous casting machine are cut into 111 rectangular slabs (hereinafter referred to as rectangular slabs) using a gas cutter installed at the rear of the machine end of the continuous casting machine. Rolled plate, hot strip: Rolled products. However, this method of cutting continuously cast slabs in the IJ direction using a gas cutter has the drawback of generating loss of fused iron.

On the other hand, in order to increase the operating rate of the continuous casting machine and operate it with high productivity, it is desirable to keep the cross-sectional size (width x thickness) of the continuous casting slab constant as much as possible. However, the width and thickness of the above-mentioned rolled products required by users vary widely, and in order to meet these requirements, the width of the slab does not change much during longitudinal rolling (thick rolling), so the width of the slab must be changed. It is safe to change the width of the rolled product to near the width of the rolled product by rolling in the IIJ direction.

For example, a rectangular slab 1 with a width W1 and a thickness T1 shown in FIG.
When producing a ring with width W3 (<W,) and thickness T3 (<Tl) by rolling in a hot rolling facility, slab 1 is subjected to width reduction rolling and thickness lower 1: rough rolling.
Figure 2 Figure 1
Yun Xiaoxiang JW (guw, Wu*WtsuA LiaoqλTu (ζT
．． ) is set to -2.

-1- Rough rolling is performed using a V-H rolling mill arrangement that combines a vertical roll mill and a horizontal roll mill, or a V-H-V mill arrangement that combines two vertical roll mills and a horizontal roll mill. This is carried out using a rolling mill arrangement, or a rolling mill arrangement in which a vertical roll mill exclusively for wide rolling is provided on the downstream side of the above rolling mill arrangement.

However, the rolling light of the roughly rolled bar 2, the rear end (
As shown in Fig. 2, 2<,
There is a problem that fish tails 3.4 occur due to width reduction rolling using vertical rolls in a rolling.

Such fishtail portions are not rolled products, and in order to prevent troubles during rolling by horizontal roll rolling mills, The crop shear installed on the entry side cuts and removes the material as crops, reducing yield. The rectangular par 5 with width W2 (medium W3) and thickness T2 shown in Figure 3, which has been enlarged by fishtail 3 and 4 with crop shear, is
Finish-F rolled by horizontal roll rolling mill group, width W3 (medium W2)
), resulting in a hot strip with a thickness of T3 (< T7 ).

When a rectangular slab is hot-rolled (width reduction rolling) in this manner, fishtails are formed at the top and bottom of the rolling, which has the disadvantage of reducing the hot rolling yield.

As a method for suppressing fishtail formation, for example, Japanese Patent Laid-Open No. 5 El-33159 proposes forming smooth curved constrictions in advance at both ends of the cut portion of the slab as a pre-process of oxygen gas cutting. However, this increases the number of steps and does not reduce loss due to oxygen gas cutting.

1.1 of the Invention The present invention provides a method for cutting continuous slabs that can prevent the above-mentioned cutting iron loss and obtain slabs with an excellent hot rolling yield.

Structure of the Invention The present invention has been made based on the results of the following investigation, study, and discussion. When a rectangular slab is rolled (width pressure)" J:E, both ends in the width direction of the slab extend more than the center, forming fishtails, so the slag 11
Formation of fishtails is suppressed by making the lengths of both end portions in the `` direction shorter than the length of the central portion in the +1 direction of the slab.

] The extension j11 noted in - on the rolling top side and the rolling bottom side of the 22 side rectangular rub is larger on the rolling bottom side than on the rolling top side due to metal flow characteristics.

Specifically, for example, the fishtail area ratio (rolled bottom side/rolled top side) is -1.5 to 3.0, and specifically, for example, 250 mm thickness, 1050.1300
．． A rectangular slab with a width of 1500 and 1700 mm is 4511
Sum J1.1350, 11+10. 1300.150
0rnII1 width (11200mm for IIJ river-redundant)
When parsed, the crop area on the rolling top side is 102
, 173, 248, 331 cm2 (slab area converted 'O,
'i+ei), whereas the crop area on the bottom side of rolling is 340, 520. 71[1,1143c
m2 (slab surface Ja exchanged q).

Therefore, in order to optimally suppress the formation of fishtails on the bottom side of the rolling drum and on each side, and to optimize the rolling yield, the longitudinal ends of the slab; l(fyyu1 +
j++ L,” L, 1.r: tct ty temple, 11
I Yama-rit +Fr+ 'IB l mouth F4R17'
+ The distance of the perpendicular line F from the tct point is the rolling top side (p
), it is sufficient to use a slab that is larger on the rolling bottom side (q).

Therefore, when cutting a continuous cast slab, the present invention uses a pair of V-shaped blades having blade surfaces that are asymmetrical with respect to the cutting edge advancing direction line to cut the continuous cast slab from the rl+ direction. It is characterized by forming a bulging surface asymmetrical with respect to the cutting edge advancing direction line on the cut surface of the slab.

action The wood invention will be explained in detail below.

FIG. 4(a) is a perspective view showing an example of a cutting device equipped with a V-shaped blade used in the present invention. The cutting tool can be obtained, for example, by cutting out the central part in the thickness direction of both corners of the tip of the rectangular parallelepiped 6, and between the pair of upper and lower parallel flanges 7.7, there is a cutout on the same level as the flange tip surface 8.8. This is formed by integrally forming a ■-shaped blade 10 with a V-shaped blade portion having a blade edge length H1 and a blade height B, and a .1.- row franchise 7. 11 and 12 are two side V
The blade surface of the mold blade 10 is shown, and 13 represents the advancing direction line of the cutting edge 9.

The length H and the blade height B of the cutting edge 9 are shown in FIG. 4(b).If the thickness and width of the 9 piece 14 are T and W,
=T+α, B=W/2+α, α=I0
It is approximately 0a1m. In addition, in Fig. 4(b), 15
and 1G indicate a long side surface and a short side surface of the continuously cast piece 14, respectively.

Fig. 5.6.7 shows an example of the shape of the L-cut, which is constructed from a V-shaped blade 10 formed integrally with the flange 7.7 between a pair of parallel flanges 7 to 7. In the cross-sectional view,
This figure shows the cross-sectional shape of the blade according to the plane rF perpendicular to the cutting edge line 9 constituting the cutting edge 9, and the V-shaped blade will be explained below based on the position of the drawing.

5 to 7 show cases in which the blade has a V-shaped blade surface that is bilaterally symmetrical with respect to a plane that passes through the cutting edge line and is parallel to the direction in which the blade advances.

Figure 5 shows the blade surface 11 at an angle θ4 on the left side of line 13, and line 1
A V-shaped blade is shown in which a blade surface 12 with an angle of 1 kOsC>θ, l) is formed on the right side of 3. FIG. 6 shows that from the cutting edge 9 to the W/4 position, blade surface portions from the cutting edge i9 to the corner 0 et al. From the position to the blade base, the angle change is OII, 0°,
(θ8>0.) blade surface? ) I (71 scraps. Figure 557 shows a curve that is asymmetrical with respect to the cutting edge advancing direction line 13, such as an elliptic curve, to create a blade +r+ilL)
71<' L, ii'f the v-shaped blade that formed 12
(X, Y) when the cutting edge 9 is the origin of the X-Y axis.
= 1(ll'- with (b+, r2) as the origin of the x-y axis
1f￥r'2, the blade surface 11 consisting of a circular curve of ellipse 1ir1 and the cutting edge 9 as the origin of the X-Y axis (X, Y) - (b+, r2') The blade surface 12 consists of an elliptical curve with a 1υ circle diameter r2' and an elliptical diameter rl, with the origin of the x'-y' axis
, , X=O, and a portion surrounded by four lines bl) is formed with a tapered blade portion. Note that r,>r,'.

The curve of a V-shaped blade with such a curved blade surface is 4.
ft Not limited to circular curves, but also hyperbolas, parabolas, cycloi I,
, involute, catenary, spiral line, line, Ninuke I, etc. can be adopted.

Next, attach the ■-shaped blade 10 as shown in Figs. 5 to 7 to the flange 7.
A procedure for cutting a continuous cast piece using a cutter formed integrally with the flange 7.7 will be described below.

As shown in FIGS. 8 to 10, both short sides 16 of the continuously cast piece 14.
Outside of 16, connect MJN4 symmetrically with I'I
The V-shaped blades 10 and 10 of the pair of cutting tools with Side face 16
．． A pair of V-shaped blades 10 and 10 marked with -L are pushed into the continuous casting J1 along the cutting edge advancing direction line 13, and a pair of cuts are made at the center of the continuous casting piece as shown in FIGS. 11 to 13. The parallel flange tip surfaces 8.8 and 8.8 of the tool come into contact with each other, and the cutting edge lines 9 and 9 come into contact with each other, and the pushing is completed. At the same time, the double-edged surfaces I1 of the V-shaped blades 1O1IO of a pair of cutting tools. +1.12.12 On the outside slab cut surface,
The widthwise cutting of the continuous slab 14 is performed by forming a V-shaped cutting surface 19, 20 that spans the metal peak with the central part protruding in the II] direction, which is asymmetrical with respect to the cutting edge advancement line 13! By carrying out the cutting operation at two locations in the longitudinal direction of the continuous casting hole 114 (lj-forming force direction), as shown in Figs. It is possible to create a slab 21 in which a V J (+7 cut surface 18.20 is formed and which has a different V-shaped protruding area at the front and rear ends in the rolling direction) over the entire IH with a protruding central part. The slab 21 in which the IIJ direction portion protrudes from the line connecting both inward ends of the slab 21 at different distances between the tip end and the rear end of the arrow [IJ A ] can be defined as 1;I.

When the slab shown in Figures 14 to 16 is subjected to rough rolling consisting of width rolling and thick rolling with the cut surface 20 side having the smaller distance as the rolling top, both ends in the width direction of the slab are compared to the center part. The extension: 1X is larger on the rolling bottom side than on the rolling top side, but the length in the rolling direction of both ends in the slab +1 direction is equal to the length in the rolling direction of the central part in the slab +l+ direction. In comparison, since the distance is larger on the rolling bottom side (q) than on the rolling top side (p), (
p<q), shape of fishtail on rolling top side and rolling bottom side, I+Ut car 1=-1, ++ number n+/
It is possible to improve the hot rolling yield by reducing the yield to 1 by 1.

Example 1 - The effect of suppressing fishtail production will be explained with reference to an example.

5.6.7 A continuous cast piece with a cross-sectional size of 250 mm in thickness and 17 QQ mm in width, and a uniform temperature of 1200°C in cross-section.
With the shape shown in the figure, under the conditions shown in Table 1 (7) H = 350
mm, B - V-shaped blade 10 having a left-right asymmetric blade + (+i 11 , 12 with respect to the cutting edge advancing direction line
8.11, 9.12 using a cutting tool formed with
With the cutting procedure shown in Figure 10.13! A slab having the shape shown in Figs. 14, 15, and 16 was obtained by cutting ilJ. In this case, there was almost no cutting loss.

Next, rough rolling is performed for 11 minutes with the cut surface 20 side as the rolling top.
Therefore, it was made into a par with a width of 1500III11 and a thickness of 45mm.

Table 2 shows the fishtail (crop) area at the front and rear ends of this par.

Incidentally, the percentage value shown in the column of fishtail (black, prosthesis) area in Table 2 is 25ofll11. @17ooII
The lffl rectangular slab is roughly rolled into a par with a thickness of 45+am and a width of 1500 mm, and the comparison number 4+tj is calculated when the fishtail (Kronpros) area of the leading and trailing ends of this par is taken as 100%. In both cases, the fishtail area was significantly reduced by rt+ compared to the conventional method.

Table-1 Table-2 Comparative Example Conditions of Table-3: H = 350mm, B = 950m
Blade surface I1 that is bilaterally symmetrical with respect to the blade edge hole 1J direction 13 of m
．． Using a cutting tool formed with a V-shaped blade 10 having +2, a 1LH6 piece under the same conditions as in the example was cut with the same hand 11'' to obtain a slab, and this slab was cut under the same conditions as in the example. Rough rolling was performed. Table 4 shows the fishtail (Klompros) area at the leading and trailing ends of the par.

Table 3 Table 4 Comparing Example 1 and Comparative Examples +a, b, c, Example 2 and Comparative Examples 2a, b, c, and Example 3 and Comparative Examples 3a, b, c, the asymmetric V Effects of the present invention on hot rolling yield of slabs obtained by the method of the present invention using mold blades As described above, according to the method of the present invention, slabs with excellent hot rolling yields without cutting iron loss can be obtained. can be easily obtained, and the present invention is extremely useful for industrial applications.

[Brief explanation of drawings]

Figure 1.2.3 is an explanatory diagram of the occurrence of fishtails due to rough rolling (lower rolling for width and thickness) during rolling production of real strips from rectangular slabs, and the reduction in hot rolling yield due to these fishtails. , FIG. 4 is a perspective view showing an example of a cutting tool with a V-shaped blade used in the method of the present invention, FIGS. 5 to 7 are illustrations of specific examples of the shape of the V-shaped blade, and FIG. 11
Figures 9.12 and 1O113 are illustrations of implementation of the cutting force method of the present invention]'-11ffi, Figures 14.15.16
The figure is a plan view showing the planar shape of a slab obtained by the cutting method of the present invention. l... Rectangular slab, 2 fists, e par, 3Φ, Φ fishtail, 4... volume fishtail, 5... rectangular par,
6...Rectangular parallelepiped, 7...Flan...V-shaped blade, 11.
Middle stand blade surface, I2...Blade surface, 13...Blade edge hole 1j direction line, 14...Continuous slab, 15...Long side surface, 16...
1υ side surface, 18... Cutting surface, 20... Cutting surface, 21
...Slab. Patent Applicant New I] Wooden Steel Co., Ltd. Representative Patent Attorney I - Ni Masao Figure 1 Figure 5 Figure 6 Figure 7 ×

Claims (1)

[Claims] Using a pair of V-shaped blades that have asymmetrical blade surfaces with respect to a plane that passes through the cutting edge line and is parallel to the direction of blade movement, I! 1! A method for cutting a continuously cast slab, characterized in that the continuously cast slab is cut from both sides in the 11'' direction, and the slab cut surfaces formed on both sides of the blade form an asymmetrical V-bulged surface.