JPH0677761B2 - Bar mill - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a strip rolling mill used in a row of rough rolling rolling mills arranged horizontally in a strip rolling mill, for example.

1 to 4 show a part of this type of rolling mill train, in which a twisting device 23 is arranged between a first-row steel rolling mill 21 and a second-row steel rolling mill 22 and has a rectangular cross section. The rolled steel 7 is twisted 90 ° by both rolling mills 21 and 22 and rolled.

The first steel rolling mill 21 has a pair of upper and lower first rolling rolls 25 and 26 which horizontally support the roll shaft. The first rolling rolls 25, 26 have an appropriate number of V grooves 27, over the entire circumference of the surface.
It has 28, and V groove 27, 28 above and below forms a pair and caliber 2
Forming a nine.

In addition, since the caliber 29 is overlapped with the steel strip 7 in the drawing, its label number is also shown next to the label number of the steel strip 7.

The twist device 23 includes a twisting roller portion 31 having two cylindrical rollers 30 which are rotatably supported in parallel at appropriate intervals.
It is formed so that it can be tilted at an appropriate angle on the pass line. Further, the interval between the cylindrical rollers 30, 30 can be adjusted appropriately.

The 2nd steel rolling mill 22 is similar to the 1st steel rolling mill 21 described above.
It has a pair of upper and lower second rolling rolls 32, 33 supported horizontally. However, the caliber (not shown) formed by the second rolling rolls 32 and 33 is specifically (i +) when the i-stand is a diamond-shaped caliber when, for example, a diamond-square path is adopted.
1) Square-shaped caliber is used for the stand,
The caliber size in the (i + 1) stand is determined so that the required reduction rate (reduction rate) can be obtained during that period (rolling technology, published by Nikkan Kogyo Shimbun by Kanichi Katsura).
242).

Then, the steel strip 7 that has entered from the left side in FIG. 1 is formed into a rhombus cross-sectional shape having a long axis in the horizontal direction (indicated by a chain line a in FIG. 3 and subsequent figures) by the first steel strip rolling mill 21. It is rolled (see FIG. 3) and sent to the twist device 23. In the twist device 23, the steel strip 7 is passed between the two cylindrical rollers 30, 30 of the twisting roller portion 31 to be twisted by the inclination angle of the roller shaft and sent to the second steel strip rolling mill 22.

As a result, the steel strip 7 increases its twist angle in the process from the twisting device 23 to the second steel strip rolling mill 22, and the first steel strip rolling mill 21 shown in FIG. It will be twisted 90 degrees from the exit side. The second strip rolling mill 22 smoothly rolls the strip 7 from a direction different by 90 ° from the case of the first strip rolling mill 21.

By the way, as shown in FIG. 4, in the above rolling, from the state in which the long axis of the rhombus is horizontal (immediately after the exit from the first strip rolling mill 21 (indicated by rhombus b in FIG. 4), the second grade steel is shown. Rolling mill 22
The twisting roller portion 31 is used to change the state of turning 90 ° on the entrance side of the sheet (shown by a diamond c in the figure).
Here, it is performed only by twisting the bar 7 by a predetermined angle (the twisted state is shown by a rhombus d in the figure).

Therefore, the bar steel 7 is 2 with respect to the rhombus b immediately after rolling.
The twist angle of the rhombus d when passing between the two cylindrical rollers 30, 30 is large.

In this twist, the steel strip 7 is the first steel strip rolling mill during rolling.
Immediately after exiting from 21, the twisting roller portion 31 receives a force to continuously twist the diamond roller into a diamond-shaped d state.
There is no problem because it passes smoothly between 30 and 30, but there is a problem when the tip of the steel strip 7 reaches the twisting roller portion 31 at the start of rolling.

That is, at this time, the steel bar 7 is not receiving the force from the twist roller portion 31, and the tip end thereof moves forward in the state of the rhombus b immediately after rolling, as shown by the rhombus e in FIG. The two horizontal corners of the two cylindrical rollers 30
(The collision part is indicated by B in the figure). Then, after this collision, the tip is instantly greatly twisted along the surface of the cylindrical roller 30 from the state of the diamond e to the state of the diamond d, and passes there.

For this reason, at the time of this passage, the collision portion B at the tip receives a large impact, and a flaw 34 is generated after passage, and this phenomenon is remarkable especially as the sectional size of the steel strip 7 increases and its linear velocity increases. As a result of drawing the flaw 34 along with rolling, a problem arises in that the flaw must be cut off due to a surface flaw over a considerably long range of the tip of the product of the steel strip 7.

Furthermore, the impact given to the twist device 23 at the time of the above-mentioned collision is large, and the device is damaged, resulting in a problem that the operation is stopped.

The present invention has been made in view of the above conventional problems,
The center line connecting the vertices of the caliber formed on the upper and lower rolls with respect to the center line of the caliber orthogonal to the roll axis is twisted at the required angle of inclination to form the caliber, which causes flaws in the leading end of the steel strip. The present invention intends to provide a steel strip rolling mill capable of eliminating the above-mentioned problem and reducing the load on the twisting device.

Next, the present invention will be described with reference to the drawings which are one embodiment.

The steel strip rolling mill 1 according to the present invention is the first steel strip rolling mill of FIG.
It corresponds to 21 and is substantially the same as that shown in FIGS. 1 and 2 in the drawings, and these drawings are shared and each part thereof, that is, the rolling rolls 2, 3, V grooves 4, 5, caliber Each number of 6
Display with (). The details of the caliber 6 are shown in FIGS. 5 and 6.

In FIG. 5, O is the center of the caliber 6, and the roll diameter of the V groove 4 portion of the rolling roll 2 at a position separated from the vertical line C passing through the center point O by the equal distance 1 to the left and right is D1.
(Right side), D2 (Left side) V so that D1> D2
The groove 4 is formed. On the other hand, in the case of the rolling roll 3, the V groove 5 is formed so that the roll diameter of the portion of the V groove 5 at the position separated by the distance l is D1 on the left side and D2 on the right side, contrary to the above. is there.

That is, in the example of FIG. 5, the rhombus short axis E which is the center line connecting the vertices of the caliber 6 is twisted from the vertical line C which is the caliber center line orthogonal to the roll axis by an inclination angle θ (1 to 3 °). ing.

As a result, the steel bar 7 rolled by this caliber 6
Receives a twisting moment by the caliber 6 and travels in a twisted state symmetrical with respect to the vertical line C.

When the rolled steel strip rolling machine 1 is fed in this twisted state, as shown by an arrow F in FIG. 5 due to the difference in roll peripheral speed caused by the difference in roll diameters D1 and D2. The twist increases further in the clockwise direction. This twist and the twist by the caliber 6 increase in proportion to the distance traveled by the steel strip 7, and ensure smooth guidance to the subsequent guide device.

Therefore, at the start of rolling, as shown in FIG. 6, the strip 7 exits the strip rolling mill 1 in the state of the rhombus g, which is twisted by an angle θ from the state of the rhombus f, which shows the state on the rolling mill entrance side. At the same time, the twist is slightly increased so that the twisted rhombus h comes into contact with the cylindrical roller 30 of the twist roller portion 31 in a substantially twisted rhombus h state, that is, in a state close to the above rhombus d. For this reason, the steel strip 7 is in the above-mentioned rhombus d state by only a slight twist, and can pass between the two cylindrical rollers 30, 30 as shown by the solid line in the figure. The impact on the collision part G is reduced, and no flaw is generated in this part.

Even during rolling, the twisting roller portion 31 has a diamond shape e.
Since it does not have to be in the state of (see FIG. 4), it is necessary to slightly twist from the rhombus h immediately after rolling to the state of the rhombus d.
The load on the device is reduced. It should be noted that the present invention does not limit the direction of the twist angle, but may be any of the left and right directions (clockwise, counterclockwise).

Further, the present invention does not limit the shape of the caliber at all, and the ones shown in the above-mentioned embodiments are merely examples.

As is apparent from the above description, according to the present invention, the center line connecting the vertices of the caliber formed in the upper and lower rolls with respect to the caliber center line orthogonal to the roll axis has a twist angle that is a required inclination angle. To form the caliber. For this reason, the steel strip comes out of the rolling mill and enters the twisting device in an appropriately twisted state, and even at the start of rolling, the tip of the steel strip does not receive a large impact and the twisting device is twisted. You can pass while. As a result, flaws do not occur at the tip portion, and the yield of rolled products can be improved.

Further, since the twist angle of the steel strip in the twisting device is reduced as described above, the load on the device is reduced accordingly, the damage to the device is reduced, and the productivity is improved by reducing the defective suspension of the device. it can.

[Brief description of drawings]

FIG. 1 is a side view showing a part of a steel strip rolling line, FIG. 2 is a sectional view taken along the line I-I showing only the rolling roll portion of FIG. 1, and FIG.
Figures and 4 show a conventional bar mill,
FIG. 6 shows a bar mill according to the present invention.
Of these, FIGS. 3 and 5 are enlarged views of a portion A of FIG.
Figures and 6 are perspective views showing the twisted state of the steel bar. 1 ... Strip rolling machine, 2, 3 ... Rolling rolls, 4,5 ... V groove, 6 ... Caliber, 7 ... Strip, 23 ... Twist device.

Claims (1)

[Claims] 1. The caliber is characterized in that the center line connecting the vertices of the caliber formed on the upper and lower rolls with respect to the center line of the caliber orthogonal to the roll axis has a twist angle that is a required inclination angle. A steel strip rolling machine.