JPH0221882B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for manufacturing a long steel bar by tearing a multi-strip material, and a method for producing a long steel bar by tearing a multi-strip material, by which at least three bars can be simultaneously produced from one billet with high efficiency. The present invention relates to a cutting device.

As a method for simultaneously producing long steel bars such as steel bars and sections with high efficiency from one billet, the following method for producing long steel bars by cutting a multi-strip material is known.

A billet heated to a predetermined temperature is rolled by slotted rolls of a plurality of rolling mills arranged in tandem, and a plurality of strips of material connected in parallel by a plurality of thin knots are formed from the billet. A multi-strip material of a book is prepared, the one multi-strip material is cut in the length direction from the node using a cutting device to form a plurality of intermediate steel bars, and then the plurality of intermediate steel bars are are finished rolled by a finishing rolling mill group consisting of a plurality of finishing rolling mills arranged in tandem, thus producing a plurality of bars of a predetermined shape.

FIG. 1 is an explanatory diagram showing an example of the conventional method described above. In FIG. 1, A is a rolling mill group consisting of 11 rolling mills No. 1 to No. 11 arranged in tandem at predetermined intervals, and on the exit side of the No. 11 rolling mill, A tearing device 1 is provided. B is
This is a finishing rolling mill group consisting of two finishing rolling mills No. 12 and No. 13 arranged in tandem at a predetermined interval on the exit side of the cutting device 1.

A billet heated to a predetermined temperature by a heating furnace (not shown) is passed through grooved rolls of rolling mill group A, and rolled by rolling mill group A, thereby converting the billet into, for example, the shape shown in FIG. One multi-strip material 3 is prepared, which is shown in cross-sectional view in FIG. 1A and consists of three strips of material 3a, 3b, and 3c connected in parallel to each other by thin nodes 3d and 3e.

Next, one multi-thread material 3 is guided to the tearing device 1, and the multi-thread material 3 is cut lengthwise from its thin knots 3d and 3e by the tearing device 1, so that it is cut into the shape shown in the cross-sectional view of FIG. 2b. Three intermediate steel bars 4, 4'4'' shown are prepared.

Next, each of the three intermediate steel strips 4, 4', 4'' is passed through the grooved rolls of finishing mill group B at the same time.
By finishing rolling in finishing mill group B, three round bars 5, 5', 5'' shown in cross section in FIG. 2c are manufactured.

As an example of the above-mentioned tearing device 1, there is known a device as shown in a schematic front view in FIG. 3, which is disclosed in Japanese Patent Publication No. 56-25881, for example.
In FIG. 3, reference numeral 6 denotes a pair of circular slit rollers that are rotatably provided vertically facing each other with a slight gap between them. Each of the pair of upper and lower slitting rollers 6 consists of two adjacent disk knives 8, 8' fixed to a shaft 7. Each of the disk knives 8, 8' has inclined shoulders 8b, 8b and 8b', 8b' inclined at a predetermined angle, respectively, on both sides of the circumference around the apex 8a, 8a'. .

A multi-strip material consisting of three strips of material 3a, 3b, and 3c connected in parallel to each other by thin nodes 3d and 3e is guided by the slitting device 1 having the above-described structure and passes through a gap between a pair of upper and lower slitting rollers 6. 3 is
It comes into contact with the inclined shoulders 8b, 8b and 8b', 8b' of the disc knives 8, 8', and is torn left and right from the thin nodes 3d, 3e by the inclined shoulders 8b, 8b and 8b', 8b', Three intermediate steel bars 4, 4',
It becomes 4″.

According to the above-mentioned method, compared to the conventional method of rolling one billet into a predetermined shape through multiple rolling mills arranged in tandem, multiple billets can be rolled with fewer rolling mills. can be manufactured with high efficiency.

Further, the cutting of the multi-thread material 3 by the cutting device 1 is performed by the inclined shoulders 8b, 8b and 8b', 8b' of the disk knives 8, 8', as described above. Since the shearing is not performed by the top portions 8a and 8a', the disk knife 8,
There is little wear and tear on 8' and it is economical.

However, the above-mentioned method has the following problem when cutting one multi-strip material into three or more strips. That is, three strips of material 3a, 3b, which are connected in parallel to each other by thin nodes 3d and 3e.
As shown in FIG. 3, when a single multi-thread material 3 consisting of 3c is cut with a pair of upper and lower slitting rollers 6 consisting of two disk knives 8 and 8', the material 3a and the material 3a on both sides of the torn 3c can each escape to the outside, but since the central material 3b is sandwiched between the materials 3a and 3c on both sides, there is no place for it to escape. As a result, when the multi-strip material 3 is cut, the central material 3b rises, causing deformation and flaws in the material 3b, degrading the dimensional accuracy and surface quality of the product.

Solved the above problem and made 3 billets from 1 billet.
As a method for simultaneously producing more than one bar with high efficiency, the following method of producing a bar by cutting a multi-strip material is known.

A billet heated to a predetermined temperature is rolled by a first rolling mill group consisting of a plurality of rolling mills arranged in tandem, and two strips of material are produced from the billet, which are connected to each other by, for example, one thin joint. A first multi-thread material is prepared, and the first multi-thread material is cut into two in the length direction from the node using a first tearing device, thereby forming two first multi-thread materials. A first intermediate steel bar is prepared. Next, each of the two first intermediate steel strips is rolled by a second group of rolling mills arranged in tandem to form two strips of material each connected to each other by one thin node.
by preparing a second multi-strip material of the book, and then cutting each of the two second multi-strip materials into two in the length direction thereof from the node with a second tearing device;
A total of four second intermediate steel bars are prepared. Then,
Each of the four second intermediate steel bars is finish-rolled by a group of finish rolling mills arranged in tandem, thus producing four bars having a predetermined shape.

FIG. 4 is an explanatory diagram showing one embodiment of the method described above. In FIG. 4, A1 is the first rolling mill group consisting of 11 rolling mills No. 1 to No. 11 arranged in tandem at predetermined intervals, and is located on the exit side of the No. 11 rolling mill. A first tearing device 1 is provided. A2 refers to four pieces No. 12 to No. 15 arranged in tandem at a predetermined interval on the exit side of the first tearing device 1.
The second rolling mill group consists of the No. 15 rolling mill.
A second tearing device 2 is provided on the exit side of the rolling mill. B is No. 16 and No. 17 arranged in tandem at a predetermined interval on the exit side of the second tearing device 2.
This is a finishing rolling mill group consisting of two finishing rolling mills.

The billet heated to a predetermined temperature by a heating furnace (not shown) is passed through the grooved rolls of the first rolling mill group A1 and rolled by the first rolling mill group A1 to produce the billet shown in FIG. One first multi-strip material 9 is prepared, which is shown in cross-sectional view in FIG.

Next, one first multi-thread material 9 is guided to the first tearing device 1 equipped with a pair of upper and lower slitting rollers having the above-described structure, and the first tearing device 1 cuts the thin knot 9c into two pieces in the length direction. By cutting the first intermediate steel bar into two pieces, two first intermediate steel bars 10 and 10' shown in cross section in FIG. 5b are prepared.

Next, each of the two first intermediate steel strips 10, 10' is simultaneously passed through the slotted rolls of the second rolling mill group A2 and rolled by the second rolling mill group A2, thereby producing the shape shown in FIG. Two strips of material 11a, 11b connected to each other by a thin node 11c shown in a cross-sectional view,
Two second multi-strip materials 11, 11' are prepared, each consisting of two strips of material 11a', 11b' which are also connected to each other by a thin joint 11c'.

Next, each of the two second multi-thread materials 11, 11' is guided to a second tearing device 2 equipped with two pairs of upper and lower slitting rollers having the above-described structure, and
By cutting each thin section 11c, 11c' into two pieces in the length direction with the cutting device 2, the fifth
Four second intermediate steel bars 12 shown in cross section in Figure d,
Prepare 12', 12'', 12.

Next, the four second intermediate steel bars 12, 12',
12″ and 12 at the same time, finish rolling mill group B
The four round bars 13, 13', 13'', and 13 of the predetermined shape shown in the cross-sectional view in FIG. Ru.

According to the method described above, from one billet,
Although it is possible to manufacture a plurality of bars with high efficiency without causing deformation or flaws when cutting them, the above-mentioned method has the following problems.

The forming to prepare the first multi-strip material 9 shown in FIG. Further, the forming process for preparing the second multi-thread material 11, 11' shown in FIG.
This is done by a standard rolling mill.

As mentioned above, the four rolling mills No. 10, 11, 14, and No. 15 mainly form the rolled material, so the area reduction rate of the rolled material in each of the above rolling mills is , which is quite low compared to other rolling mills.The method described above requires a rolling mill with a reduced area ratio of at least 4 to form the rolled material.
Since the average area reduction rate of the entire rolling mill group is low, as in the past, one billet is passed through multiple rolling mills arranged in tandem to form a single bar of a predetermined shape. Compared to the rolling method, the number of rolling mills cannot be reduced.

In continuous rolling of long steel, free tension rolling is usually performed in which a loop is formed between each of a plurality of rolling mills arranged in tandem and the amount of the loop is adjusted. If there are three rolling mills, this free tension rolling requires one-stage control in which the roll rotation speed of the central rolling mill is controlled, and the roll rotation speeds of the other two rolling mills are controlled using this as a reference. However, in the case of the method described above, since the rolling mills constituting the second rolling mill group A2 consist of four rolling mills No. 12 to 15, for example, based on the No. 13 rolling mill, the No. 13 rolling mill To control the loop amount between rolling mill and No.14 rolling mill
When the roll rotation speed of No. 13 rolling mill is changed, No. 14
This affects the loop amount between the rolling mill and No. 15 rolling mill, and requires two-stage control to separately control the roll rotation speed of No. 15 rolling mill. As a result, control becomes complicated and it becomes difficult to perform appropriate free tension rolling.

In the rolling line, there are two cutting devices and two
4 for simultaneously rolling the first intermediate steel bar
The configuration of the rolling line is complicated because it incorporates a first rolling mill group and two second rolling mill groups for rolling four second intermediate steel strips at the same time.

From the above-mentioned viewpoint, the present invention provides a multi-strip material that can simultaneously produce at least three strips from one billet without causing any flaws or deformation, using highly efficient and simple equipment. The present invention provides a method for manufacturing a long steel bar by cutting it, and an apparatus for cutting a multi-strip material.

A billet heated to a predetermined temperature is rolled by grooved rolls of a rolling mill to prepare one multi-strip material consisting of at least three strips of material connected in parallel to each other by at least two thin knots. Then, the one multi-thread material is guided to a cutting device having a pair of upper and lower slitting rollers, and the one multi-thread material is cut in the length direction from its thin joints by the pair of slitting rollers. A multi-strip material is prepared by preparing a plurality of intermediate steel strips, and then finish rolling each of the intermediate steel strips with groove rolls of a finishing rolling mill, thus producing a steel strip of a predetermined shape. In the method for manufacturing a bar by slitting, the slitting device includes a pair of upper and lower first slit rollers, and at least a pair of upper and lower slit rollers provided on an exit side of the first slit roller in close proximity to the first slit roller. a set of second slitting rollers, the first slitting roller slits the one multi-thread material into two pieces in the length direction from one of the thin joints, and then the first slitting roller Twisted and torn to pieces, at least one
By the second slitting roller, at least one intermediate multi-strip material consisting of at least two strips of material connected in parallel to each other by two thin knots,
Cutting one of the thin joints into two in the length direction to prepare at least three intermediate steel bars,
Next, each of the at least three intermediate steel strips is finish rolled by groove rolls of the finish rolling mill.

Next, this invention will be explained based on the drawings.

FIG. 6 is an explanatory diagram showing one embodiment of the method of this invention. In FIG. 6, A is a first rolling mill group consisting of 11 rolling mills No. 1 to No. 11 arranged in tandem at predetermined intervals. On the exit side of the No. 11 rolling mill, there is a pair of upper and lower first slitting rollers having a structure to be described later, and on the exit side of the first slitting roller, there is a pair of upper and lower slitting rollers arranged in parallel adjacent to the first slitting roller. A tearing device 14 is provided which includes two sets of second slitting rollers. B is a finishing rolling mill group consisting of two rolling mills No. 12 and No. 13 arranged in tandem at a predetermined interval on the exit side of the tearing device 14.

By passing the billet heated to a predetermined temperature in a heating furnace (not shown) through the grooved rolls of the first rolling mill group A and rolling it in the first rolling mill group A,
For example, the thin node 15e shown in cross-section in FIG. 7a,
4 connected in parallel with each other with 15f and 15g
One multi-strip material 15 consisting of strip materials 15a, 15b, 15c, and 15d is prepared.

Next, the single multi-thread material 15 is cut by the device 1.
4, and the first slit roller of the cutting device 14 first slits the center thin knot 15f into two in the length direction, thereby forming a thin knot 15e as shown in the cross-sectional view in FIG. 7b. One intermediate multi-strip material 15A consisting of two strips of material 15a and 15b connected to each other, and one consisting of two strips of material 15c and 15d connected to each other by a thin knot 15g.
The intermediate multi-strip material 15B of the book is divided into two. continue,
Two sets of second slitting rollers arranged in parallel close to the first slitting roller cut the two intermediate multi-strip materials 15A and 15B into knots 15e and 1, respectively.
Four intermediate steel bars 16, 16', 16'', and 16 shown in cross-sectional view in FIG. 7c are prepared by cutting each of the 5g pieces into two in the length direction.

Next, four intermediate steel bars 16, 16', 1
6" and 16 at the same time through the slotted rolls of finish rolling mill group B and finish rolling in finishing mill B, four circles of a predetermined shape shown in the cross-sectional view in FIG. 7d are formed. Steel 17, 17', 17'', 17 is produced.

FIG. 8 is a partially cutaway schematic plan view showing one embodiment of the tearing device of the present invention, and FIG. 9 is a schematic side view. The tearing device 14 is shown in FIG.
A thin knot 1 in the center of one multi-thread material 15 shown in
A pair of upper and lower first slit rollers 19 are supported horizontally along the path C of the multi-striped material 15 to cut it into two lengthwise from 5f, and on the exit side of the first slit roller 19, Each of the two intermediate multi-strip materials 15A and 15B shown in FIG. 7b, which are arranged in parallel close to the first slitting roller 19, is cut into two pieces in the length direction from the central thin knots 15e and 15g. It consists of two sets of second slit rollers 20, an upper and a lower pair, which are supported horizontally.

The first slitting roller 19 and the second slitting roller 20 have inclined shoulder portions 19b and 2 inclined at a predetermined angle on both sides of the circumference centered on the top portions 19a and 20a, respectively, for cutting the multi-thread material.
It has 0b.

The first slitting roller 19 is rotatably supported by the frame 18 by a horizontal shaft 21.
The frame 18 is provided with two sub-frames 23 whose base ends are pivoted by two vertical shafts 22, and the two sets of second slitting rollers 20 are
Each subframe 23 is rotatably supported by horizontal shafts 24 . As described above, since the base ends of the two subframes 23 are each pivoted to the frame 18 by the vertical shaft 22, the subframes 23 are rotated about the vertical shaft 22.
By rotating the second slitting roller 2
0 position can be adjusted.

The frame 18 has 1 rolled by the rolling mill group A.
A first guide member 25 is provided for guiding the multi-strip book material 15 to the first slitting roller 19. The first guide member 25 includes a tunnel-shaped passage 25
a, and a bolt 2 attached to the upper bracket 26 is attached to an upper bracket 26 and a lower bracket 27 fixed to the frame 18.
8.

The frame 18 includes two intermediate multi-strip materials 15A and 1 which are divided into two by the first slit roller 19.
Two second guide members 29 are provided for guiding each of the rollers 5B to the second slit roller 20. The second guide member 29 includes two intermediate multi-strip materials 1
A tunnel-shaped passage 2 for guiding each of 5A and 15B to two sets of second slit rollers 20
9a, and an upper bracket 30 and a lower bracket 31 fixed to the frame 18.
It is fixed by a bolt 32 attached to the upper bracket 30.

Each of the two subframes 23 has two rollers for guiding each of the four intermediate steel bars 16, 16', 16'', and 16 cut by the two sets of second slitting rollers 20 to the finishing rolling mill group B. Third guide member 33
is provided. Each of the two third guide members 33 has tunnel-shaped passages 33a, 33a, as shown in the cross-sectional view taken along the line II in FIG. 8 in FIG. The upper bracket 34 and the lower bracket 35,
It is fixed by a bolt 36 attached to an upper bracket 34.

FIG. 11 is a partially cutaway schematic plan view showing another embodiment of the tearing device of the present invention. In this embodiment, two sets of second slit rollers 20 are provided on the exit side of the first slit roller 19.
With a slight gap between the slit roller 19 and the first
It is provided very close to the slit roller 19. Therefore, the second guide member 29 as shown in FIGS. 8 and 9 is not provided between the first slit roller 19 and the two sets of second slit rollers 20.

Further, in this embodiment, the subframe 23 as shown in FIGS. 8 and 9 is not provided, and the two sets of second slitting rollers 20 are fixed to the frame 18. Therefore, the second set of two
A third guide member 33 having four tunnel-shaped passages 33a for guiding each of the two intermediate steel bars cut by the slitting roller 20 to the finishing rolling mill group B is fixed to the frame 18. The rest of the structure is almost the same as the tearing device shown in FIGS. 8 and 9, so a description thereof will be omitted.

FIG. 12 is an explanatory diagram showing a state in which the multi-strip material 15 described above is torn by the tearing device 14 described above. 1 guided by the cutting device 14
The multi-strip material 15 of the book is torn into two in the length direction from a thin node 15f at the center by a set of first slitting rollers 19, and two strips of material 15a are connected to each other by a thin node 15e. 1 consisting of 15b
It is divided into an intermediate multi-strip material 15A of a book and one intermediate multi-strip material 15B consisting of two material strips 15c and 15d connected to each other by a thin knot 15g.

Next, each of the two intermediate multi-strip materials 15A and 15B divided in the above manner is cut into two pieces each from the central thin knots 15e and 15f by two sets of second slitting rollers 20, and then cut into four pieces. It is divided into intermediate steel strips 16, 16', and 16''16.

FIG. 13 shows, as another embodiment of this invention,
FIG. 2 is an explanatory diagram showing a state in which a single multi-thread material consisting of three material strips connected in parallel with each other by two thin joints is torn. In this embodiment, the tearing device 14 has thin sections 15e' and 1
Three strips of material 1 connected in parallel to each other at 5f'
One multi-strip material 1 consisting of 5a', 15b', 15c'
5' is cut into two lengthwise from one thin node 15e', and one intermediate steel bar 16 and two strips of material 1 are connected to each other by a thin node 15f'.
One intermediate multi-strip material 1 consisting of 5b' and 15c'
A set of first slitting rollers 19 for dividing the intermediate multi-strip material 15A' into two intermediate strips 15A' are used to cut the intermediate multi-strip material 15A' into two in the length direction from the thin node 15f'. Steel material 16' and 1
First slitting roller 19 for dividing into 6"
A pair of second slit rollers 20 are provided adjacent to the first slit rollers 19 on the exit side of the slit rollers.

One multi-thread material 1 guided to a tearing device 14
5', one intermediate strip steel material 16 and one intermediate multi-strip material 15 are removed by the first slitting roller 19.
Then, one intermediate multi-strip material 15A' is torn into two intermediate steel strips 16' and 16'' by a pair of second slitting rollers 20'.

As described above, according to the present invention, one multi-thread material 15 or one
5' is the first slit roller 19 and the first slit roller 19 on the exit side of the first slit roller 19;
A second slitting roller 20 provided adjacent to the slit roller 20 sequentially slits each piece into two pieces. Therefore, when the material is torn, the torn material can escape to both sides, so that the torn material can be smoothly torn, and no deformation or flaws will occur in the torn material.

Next, the present invention will be explained with reference to examples.

One side heated to a predetermined temperature by a heating furnace
A 135mm square billet is shown in Figure 6.
Rolling mill group A consisting of 11 rolling mills No. 1 to No. 11
By passing it through a grooved roll and rolling it in rolling mill group A, it is rolled into a shape shown in Fig. 7a with a thickness of 0.5~
Since they are connected in parallel to each other by thin nodes 15e, 15f, and 15g each having a diameter of 1 mm, four strips of material 15a, 15b, 15c, each having a circular cross section and a diameter of 11 mm are formed.
One multi-thread material 15 consisting of 15d was prepared.

Next, one multi-strip material 15 is guided to a tearing device 14 having the structure shown in FIGS.
By first cutting one multi-thread material 15 into two in the length direction from the central thin node 15f using the first slitting rollers 19 of No. One intermediate multi-strip material 15A consisting of two strips of material 15a, 15b connected to each other by a node 15e, and one intermediate multi-strip material 15A consisting of two strips of material 15c, 15d connected to each other by a thin node 15g. Then, two sets of second slitting rollers 20 are used to divide the intermediate multi-strip material 15B into strip material 15B.
A and its node 15e, and the intermediate multi-strand material 1
By cutting 5B into two lengthwise from the joint 15g, four intermediate steel bars 16, 16', 16'', 16 as shown in the cross-sectional view in FIG. 7c are obtained.
was prepared.

Next, four intermediate steel bars 16, 16', 16'',
16 to the slotted rolls of the finish rolling mill group B provided on the exit side of the cutting device 14, and are finished rolled by the finish rolling mill group B.
Four round bars 17, 17', 17'', 17, each having a diameter of 10 mm, as shown in the cross-sectional view in Figure d, were manufactured. There were no scratches or defects and the quality was excellent.

Next, the effects of this invention will be listed.

At least three bars can be produced simultaneously from one billet with high efficiency and without deformation or flaws.

There are 2 rolling mills for forming multi-strip materials.
Since only one rolling mill is required, the average area reduction rate of the entire rolling mill group can be increased, and the number of rolling mills in the entire line can be made smaller than before.

Only one cutting device is required, instead of two as in the past.
Since there is no need to provide a second rolling mill group consisting of four rolling mills between the base cutting devices, it is easier to perform free tension rolling than before, and as a result, the dimensional accuracy of the product is better than before. .

The equipment for the entire rolling line is simpler than before.

As described above, according to the present invention, at least three bars can be produced from one billet simultaneously without any flaws or deformation, and with high efficiency and simple equipment. is brought about.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram showing an example of a conventional method for simultaneously manufacturing multiple bars from one billet;
The figure is a cross-sectional view showing the manufacturing process of a bar manufactured by the method shown in Figure 1, Figure 3 is a schematic front view showing an example of a conventional cutting device, and Figure 4 is a cross-sectional view showing the process of manufacturing a long bar manufactured by the method shown in Figure 1. FIG. 5 is a cross-sectional view showing the manufacturing process of a bar manufactured by the method shown in FIG. 4, and FIG. FIG. 7 is a sectional view showing the manufacturing process of a bar manufactured by the method shown in FIG. 6, and FIG. 8 is a partially cutaway view showing one embodiment of the cutting device of the present invention. The schematic plan view, Figure 9, is the same schematic side view, Figure 10.
The figure is a sectional view taken along the line I--I of FIG. 8, FIG. 11 is a partially cutaway schematic plan view showing another embodiment of the tearing device of the present invention, and FIGS. It is an explanatory view showing a state of tearing a strip material. In the drawings, A, A1, A2...rolling mill group, B...finishing rolling mill group, 1, 2...conventional tearing device, 3...multi-strip material, 3a, 3b, 3c...material, 3d, 3e...section,
4, 4', 4''... intermediate bar steel, 5, 5', 5''... round steel, 6... slitting roller, 7... shaft, 8, 8'... disc knife, 8a, 8a'... top, 8b, 8b' …Slanted shoulder portion, 9…First multi-strip material, 9a, 9b…Material, 9
c... Node, 10, 10'... First intermediate bar steel material, 11,
11'...Second multi-strip material, 11a, 11a', 11b,
11b'...Material, 11c, 11c'...Section, 12,1
2', 12'', 12...Second intermediate bar steel material, 13,1
3', 13'', 13... Round steel, 14... Cutting device of the present invention, 15... Multi-strip material, 15A, 15B...
Intermediate multi-strip material, 15a, 15b, 15c, 15d
...Material, 15e, 15f, 15g...Section, 16,1
6', 16'', 16... intermediate bar steel material, 17, 17',
17″, 17…round steel, 18…frame, 19…
First slit roller, 19a...top, 19b...slanted shoulder, 20...second slit roller, 20a...top, 20b...slanted shoulder, 21, 24...horizontal shaft,
23... Subframe, 22... Vertical shaft, 25... First guide member, 26, 30, 34... Upper bracket, 27, 31, 35... Lower bracket, 28,
32, 36... Bolt, 29... Second guide member, 33
...Third guide member.

Claims (1)

[Scope of Claims] 1 A billet heated to a predetermined temperature is rolled by a grooved roll of a rolling mill, and is made up of at least three strips of material connected in parallel to each other by at least two thin joints. Prepare the multi-strip material of the book, then
The one multi-thread material is guided to a cutting device having a pair of upper and lower slit rollers, and the one multi-thread material is cut in the length direction from its thin joints by the pair of slit rollers. Preparing a plurality of intermediate steel bars, and then finishing rolling each of the intermediate steel bars with groove rolls of a finish rolling mill, thus producing a bar of a predetermined shape. In the manufacturing method, the slitting device includes a pair of upper and lower first slit rollers, and at least one pair of upper and lower slit rollers provided close to the first slit roller on the exit side of the first slit roller. two slitting rollers, the one multi-thread material is slit into two in the length direction from one of the thin nodes by the first slitting roller, and then the first slitting roller slits the material into two pieces. The second slitting roller slits at least one intermediate multi-strip material consisting of at least two strips of material connected in parallel to each other by at least one thin knot from one of the thin knots. At least three intermediate steel strips are prepared by cutting into two in the width direction, and each of the at least three intermediate steel strips is then finish rolled by groove rolls of the finishing mill. A method of manufacturing long steel by cutting a multi-strip material. 2 A billet heated to a predetermined temperature is rolled by a slotted roll of a rolling mill to form at least three billets connected in parallel to each other by at least two thin joints.
a plurality of rolling mills arranged in tandem at predetermined intervals for preparing one multi-strip material made of strip material; and at least two rolling mills provided on the outlet side of the plurality of rolling mills. A horizontally rotatably supported material for cutting a multi-strip material consisting of at least three strips of material connected in parallel to each other at thin joints into two longitudinally from one of the thin joints. a pair of upper and lower first slit rollers;
At least one intermediate multi-strip material consisting of at least two strips of material connected in parallel to each other by at least one thin knot, cut by a slitting roller, longitudinally from one of the thin knots. At least one pair of upper and lower second slit rollers, which are horizontally rotatably supported and are provided on the exit side of the first slit roller and close to the first slit roller, for cutting into two pieces. A device for tearing a multi-strip material, comprising: a tearing device; and a finishing rolling machine provided on the exit side of the tearing device.