JP2692543B2 - Chamfering rolling mill and corner chamfering method of continuously cast slab - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention is, for example, for hot rolling a continuously cast slab to obtain a hot rolled steel plate or a thick steel plate.
The present invention relates to a chamfering rolling mill capable of preventing the occurrence of wrinkle-shaped flaws and folding flaws generated at the end of a product, and a method for chamfering the corner portion of a continuously cast slab using the chamfering rolling mill.

[0002]

2. Description of the Related Art When a steel sheet is hot-rolled, a flaw occurs in the steel sheet due to an oscillation mark at an edge portion of the rolled material, supercooling, and nonuniform elongation. This is because at the time of hot rolling, the rolling material widens due to the thickness reduction by the horizontal rolls, and at the short side surface which is the side surface of the rolling material, wrinkle-like flaws are generated due to compression deformation due to the initial reduction. This is because the width of the rolled material causes it to wrap around the front and back surfaces of the rolled material.

That is, as shown in FIG. 10, as the rolling pass progresses, the rolled material 1 widens, and as described above, the wrinkled portion 1a formed on the side surface of the rolled material gradually becomes flat on the front and back surfaces. Come around.

In this way, the wrinkled portion 1a wrapping around the front and back flat surfaces remains at the product stage, and the wrinkled portion at this product stage is generally called a seam flaw.
When this seam flaw occurs, this portion must be removed (hereinafter referred to as "trim"), and the yield loss due to this trim reaches several percent, which is the main cause of the yield loss. .

Therefore, conventionally, before performing rough rolling, a vertical roll mill equipped with a hole-type roll or the like is used to chamfer the corner portion of the side surface of the rolled material, thereby causing the initial side surface of the rolled material. Wrinkles have been reduced. For example, the presentation material "CAMP-" by the 119th Spring Steel Association
ISIJ, Vol. 3 (1990) "p. 1346 discloses a technique of forming a side surface shape of a rolled material before rough rolling in advance by using a box hole type having a double radius collar capable of preventing the rolled material from being dogbone-deformed for the purpose of improving metal flow. Has been done. Further, according to this technique, since the side surface of the rolled material is directly rolled down by the hole-shaped roll, no wrinkled portion is generated on the side surface of the rolled material.

[0006]

However, when the rolled material is width-reduced, the compression due to the reduction occurs only at the end portion of the rolled material, so that the end portion of the rolled material 1 is as shown in FIG. , Rises like a dog bone, and wrinkles 1a are generated in this portion. In this case, the wrinkled portion 1a remarkably occurs at the boundary between the hole-type roll and the material,
Since the position of the seam flaw thus generated enters the width center direction of the rolled material as compared with the conventional seam flaw, the trim margin may be further increased.

Further, according to the above-mentioned technique, when the thickness of the rolled material to be used is different, it is necessary to prepare the hole die to be used according to the thickness of the rolled material. As shown in FIG. 3, it is necessary to install a large number of hole dies 2a on the pair of rolls 2 and move them up and down in synchronization with each other to change the size of the hole dies 2a to be used. This leads to a decrease in operating rate.

The present invention has been made in view of the above-mentioned problems in the prior art. The side edge of a steel sheet after hot rolling and An object of the present invention is to provide a chamfering rolling mill capable of significantly reducing seam flaws and the like generated at the front and rear ends, and a method of chamfering a corner portion of a continuously cast slab using the chamfering rolling mill.

[0009]

In order to achieve the above-mentioned object, the first rolling mill for chamfering of the present invention is a double type horizontal rolling mill, in which a fixing sleeve is attached to one side of the body of the roll arbor. A movable sleeve that is fitted and fixed and that is movable toward and away from the fixed sleeve is externally arranged on the other side of the body portion, and chamfering holes of the rolled material corner portion are provided at the outer peripheral corners on the inner surface side opposite to each other. The rolling rolls provided with the molds are arranged one above the other, and the second rolling mill for chamfering of the present invention has a pair of stands equipped with cantilevered horizontal rolls at the top and bottom of each roll end. Is a rolling mill arranged so as to face each other, and with a chamfering hole type of the rolled material corner portion at the inner peripheral side outer peripheral corners of the horizontal rolls installed in the respective stands, one of the stands. Or both The with each other to configured to be move toward and away relative stand.

Further, in the corner chamfering method of the continuously cast slab of the present invention, the corner portion of the continuous cast slab is chamfered by using the above-described first or second chamfering rolling mill of the present invention. .

[0011]

In the chamfering mill of the first aspect of the present invention, the moving sleeve is moved toward and away from the fixed sleeve, and in the chamfering mill of the second aspect of the present invention, the stand is moved toward and away from the stationary sleeve. The chamfering hole die is positioned at a predetermined position according to the width of the slab to be tried. Further, it is possible to cope with various slab thicknesses and intermediate rolled materials by changing the opening degree of the rolling rolls arranged above and below.

[0012]

EXAMPLES A chamfering rolling mill of the present invention will be described below with reference to the examples shown in FIGS. FIG. 1 is a front view showing a structure of rolling rolls arranged vertically, which is a main part of a chamfering mill of the first invention, and FIG. 2 is a slab chamfered by using the chamfering mill of the first invention. 3 is a cross-sectional view showing the strain distribution in the corner portion, FIG. 3 is a view showing an example of the installation position of the chamfering rolling mill of the first present invention, and FIG. 4 is a chamfering hole type 1
The figure which shows an example, FIG. 5 is a front view of the rolling mill for chamfering of 2nd this invention, FIG. 6 is a figure which shows an example of the installation position of the rolling mill for chamfering of 2nd this invention, FIG. 7 is 2nd. FIG. 8 is a diagram showing an example of rolling using the chamfering rolling mill of the present invention, and FIG. 8 is an explanation of the installation position of the chamfering rolling mill in the continuous casting line when the corner chamfering method of the continuously cast slab of the present invention is carried out. FIG. 9 and FIG. 9 are views showing another example of the chamfering hole type.

In FIG. 1, reference numeral 11 is a rolling roll of the first rolling mill for chamfering of the present invention, which comprises a roll arbor 11a,
The fixed sleeve 11b shrink-fitted to one side of the roll arbor 11a and the shrink-fitted sleeve 11b of the roll arbor 11a prevent axial movement, and the key prevents relative rotation with the roll arbor 11a. The intermediate sleeve 11c includes an adjusting sleeve 11d that is loosely fitted in the other shaft end of the roll arbor 11a, and a moving sleeve 11e that is shrink-fitted to a position near the other end of the intermediate sleeve 11c.

An oil hole 11f is formed at the center of the shaft of the roll arbor 11a from the other end, which is the working side, and the oil hole 11f is radially arranged to reach the outer fitting portion of the moving sleeve 11e in the intermediate sleeve 11c. Penetrates.

Further, in the outer peripheral corners of the fixed sleeve 11b and the movable sleeve 11e which face each other, chamfering hole dies 11g of a symmetrical shape, such as a taper or a corner, for chamfering a rolled material corner are provided. A female screw 11h is provided on the inner peripheral surface of the other end of the intermediate sleeve 11c, and the female screw 11h is provided on the outer peripheral surface of the adjusting sleeve 11d on the body side end.
Is provided with a male screw 11i.

With the above construction, when rolling is performed, both the fixed sleeve 11b and the moving sleeve 11e are fixed to the roll arbor 11a, and when changing the interval between the hole dies 11g, first, the oil holes The intermediate sleeve 11c is floated from the roll arbor 11a by applying hydraulic pressure via 11f. Next, when the main motor is rotated by a set amount while the adjustment sleeve 11d is fixed to the chock by the operation of the clutch 11j installed on the other shaft end of the roll arbor 11a, the moving sleeve 11e and the intermediate sleeve 11c pass through the key. Rotating and adjusting sleeve 11d
It moves by a predetermined amount in the axial direction by screwing with.

When the interval between the hole dies 11g reaches a predetermined interval, the hydraulic load is stopped, the moving sleeve 11e and the intermediate sleeve 11c are fixed to the roll arbor 11a, and rolling is started. Then, in the case where the rolling is performed using the horizontal hole type roll as in the first rolling mill for chamfering of the present invention, as shown in FIG. 2, in the vicinity of the contact point with the rolling roll 11 on the upper and lower surfaces of the rolled material 1. Unlike the case where the conventional vertical roll is used, the tensile stress state is reversed, and the wrinkle portion does not occur. On the other hand, the left and right surfaces of the rolled material 1 are in a state of compressive stress, and wrinkle-like portions are likely to occur. However, by reducing the thickness of the outermost end, it is possible to prevent the wraparound to the upper and lower surfaces of the steel sheet.

The first chamfering rolling mill of the present invention provided with the rolling roll 11 having the above-described structure is, for example, in a hot strip mill facility as shown in FIG. 3, a rough rolling tandem mill 12 and a heating mill. It is installed between the furnaces 13.

Incidentally, in the position shown in FIG.
Continuous casting slab heated to 1250 ° C. in the heating furnace 13 using the hot strip mill equipment in which the chamfering rolling mill of the present invention is installed [thickness 200 mm, width 1200 mm, length 10000 mm, material; SUS304 stainless steel]
4C was chamfered by a chamfering rolling mill provided with a rolling roll 11 provided with a hole die 11g having a size shown in FIG.
Then, the rough rolling tandem mill 12 consisting of 6 stands was rolled down to a thickness of 20 mm according to the pass schedule shown in Table 1, and then the finish rolling tandem mill 14 consisting of 6 stands was further rolled down to a thickness of 6 mm according to the pass schedule shown in Table 2, It was wound into a coil.

[0020]

[Table 1]

[0021]

[Table 2]

As a result, when chamfering was not performed, seam flaws were generated at the widthwise end of the product over a width of about 40 mm, but when chamfering was performed by the first rolling mill for chamfering of the present invention, seam flaws were found. The width has been reduced to about 5 mm.

Next, the second inventive chamfering mill shown in FIG. 5 will be described. In FIG. 5, reference numeral 15 is a stand provided with cantilevered horizontal rolls 15a and 15b at the top and bottom. Two of these stands 15 are provided for each horizontal roll 1.
The rolls 5a and 15b are arranged so that their roll ends face each other, and these stands 15 are configured to be movable toward and away from each other. Reference numeral 15e in FIG. 5 is a drive motor for the horizontal roll 15b, 15f is a screw shaft for moving the stand 15 in and out,
15g is also a nut body, and the nut body 1 is screwed onto the screw shaft 15f by rotating the screw shaft 15f in the forward and reverse directions with a motor (not shown).
By moving 5 g, the stand 15 is moved integrally with the nut body 15 g.

Also in the chamfering rolling mill of the second aspect of the present invention, the chamfering hole dies 15c for the corners of the rolled material are provided at the outer peripheral corners of the horizontal rolls 15a and 15b, which are installed on the respective stands 15, which face each other.・ 15d is provided.

When the spacing between the hole dies 15c and 15c and 15d and 15d is changed by using the chamfering rolling mill of the second aspect of the present invention having the above-mentioned construction, the respective motors of both stands 15 are driven to drive the screw shaft 15f. Rotate forward and backward to stand 15
The nut body 15g integrally attached to the lower part of the stand is moved to move both stands 15 apart from each other. Then, when the hole-shaped space becomes a predetermined space, the driving of the motor is stopped and the rolling is started.

Even when the chamfering mill of the second aspect of the present invention is used, the horizontal rolls 15a on the upper and lower surfaces of the rolled material 1 are the same as when the chamfering mill of the first aspect of the present invention is used.
It goes without saying that no wrinkled portion is formed near the contact point with 15b.

A heating furnace 13 is equipped with the second rolling mill for chamfering of the present invention having the above-described structure, using equipment installed between a vertical mill 16 and a 1st mill 17 as shown in FIG. 6, for example.
Continuous casting slab heated to 1230 ° C [250m thick
m, width 1300 mm, length 10000 mm, material: SS
41], a horizontal roll 15a having a 60 ° tapered hole mold 15c, 15d shown in FIG.
Rolling mill for chamfering equipped with 15b, the thickness at the end is 40 m
Chamfering was performed so that the thickness became m, and then it was pressed by a 1st mill 17 to a thickness of 100 mm.

Here, the rolled material 1 is rotated by 90 °, and the rolled material 1 is returned to the second rolling mill for chamfering of the present invention. Here, the portion corresponding to the original front / rear end face corner portion is chamfered, and then, It was rolled down to a thickness of 20 mm with a 2nd mill 18 to form a thick plate. As a result, almost no seam flaws were found on the corners of each surface.

Needless to say, the chamfering mill of the present invention shown in FIGS. 1 and 5 may be of a non-driving type in addition to the roll-driving type of this embodiment. Further, these rolling mills for chamfering of the present invention may be arranged in tandem so as to gradually increase the chamfering amount.

FIG. 8 shows the straightener 2 after the bending process of the continuous casting line equipped with the BV type continuous casting machine 19 is completed.
At the position where 0 is straight, 30R as shown in Fig. 9 (a)
And a chamfering mill of the present invention shown in FIG. 5 having a hole shape on a 40R quarter arc as shown in FIG.
With a base tandem arrangement and a surface temperature of about 1000 ° C,
Continuously cast slab produced in hot coil [thickness 200m
m, width 1200 mm, material; SUS304 stainless steel] corner portion is first chamfered to 30R, then 50
Chamfered to R.

Thereafter, this continuously cast slab is transported to the hot rolling plant shown in FIG. 3 and, after reheating, it is 20 m in the rough rolling tandem mill 12 consisting of 6 stands according to the pass schedule of Table 3.
The thickness was further reduced to a thickness of m, then further reduced by a finish rolling tandem mill 14 consisting of 6 stands to a thickness of 6 mm according to the pass schedule of Table 4, and wound into a coil.

[0032]

[Table 3]

[0033]

[Table 4]

As a result, when chamfering was not carried out, seam flaws were generated over the width of about 40 mm at the edges in the width direction of the product, but when chamfering was carried out by the method of the present invention, the width of the seam flaw was reduced to about 5 mm. did.

[0035]

As described above, according to the present invention,
In the hot rolling of steel sheets, the yield of products can be significantly improved, and the facility does not require a large number of hole rolls, and the hole interval can be easily changed in a short time.

[Brief description of the drawings]

FIG. 1 is a front view showing a structure of vertically arranged rolling rolls, which is a main part of a chamfering rolling mill of the first present invention.

FIG. 2 is a sectional view showing a strain distribution in a corner portion of a slab chamfered by using the chamfering mill of the first invention.

FIG. 3 is an installation position 1 of the chamfering mill of the first invention.
It is a figure showing an example.

FIG. 4 is a view showing an example of a chamfering hole die.

FIG. 5 is a front view of a chamfering rolling mill of the second present invention.

FIG. 6 is an installation position 1 of the rolling mill for chamfering of the second invention.
It is a figure showing an example.

FIG. 7 is a diagram showing an example of rolling using the chamfering mill of the second present invention.

FIG. 8 is an explanatory view of the installation position of the chamfering rolling mill in the continuous casting line when the corner chamfering method of the continuously cast slab of the present invention is carried out.

FIG. 9 is a diagram showing another example of a chamfering hole die.

FIG. 10 is an explanatory diagram of a state of occurrence of seam flaws during conventional rolling.

FIG. 11 is an explanatory diagram of a situation of occurrence of seam flaws when a vertical roll is used.

FIG. 12 is an explanatory view of a lifting hole type of a conventional vertical roll.

[Explanation of symbols]

 11 Rolling Roll 11a Roll Arbor 11b Fixed Sleeve 11e Moving Sleeve 11g Hole Type 15 Stand 15a Horizontal Roll 15b Horizontal Roll 15c Hole Type 15d Hole Type 15e Motor 15f Screw Shaft 15g Nut Body

Claims (3)

(57) [Claims] 1. A double horizontal rolling mill, wherein a fixed sleeve is externally fitted and fixed to one side of a body of a roll arbor, and a moving sleeve which is movable toward and away from the fixed sleeve on the other side of the body. And a rolling mill having chamfering hole dies for the corners of the rolled material at the outer peripheral corners of the two sleeves facing each other, and the rolling rolls are vertically arranged. 2. A rolling mill in which a pair of stands equipped with cantilevered horizontal rolls at the top and bottom are arranged so that the respective roll ends face each other, and the horizontal rolls installed at the respective stands are opposed to each other. A chamfering hole die of the rolled material corner portion is provided at the outer peripheral corner of the inner surface side, and one or both of the stands is configured to be movable toward and away from the opposing stand. Machine. 3. A method for chamfering a corner of a continuously cast slab using the chamfering mill according to claim 1 or 2.