JPH09182906A - Roll stand of round tube stretch reducer and rolling method of round tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce inner face angularness of a product by rotating a roll stand in the plane orthogonal crossing to a rolling pass line at a specified angle. SOLUTION: A housing 1 is fixed on a rotatable cradle 2. A moving cradle 2 is fixed on a fixed cradle 4, by rotating a lead screw 5 arranged on the fixed cradle 4, the moving cradle 2 is rotatable in a range of -15 deg. to 15 deg. around a pass line. That is, by a simple operation of rotating the lead screw 5, each roll is arranged while having a specified angular displacement in the peripheral direction of a rolling pass line. Accordingly, while a base tube to be stretch- reduced by each stand is advancing, it is subjected to plastic deformation from directions different by, e.g. 15 deg., a tube thickness and a roundness of inner face are improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roll stand of a squeeze rolling mill for reducing the internal surface squeezing of a product generated during a squeeze rolling process.

[0002]

2. Description of the Related Art Drawing rolling of a metal tube is carried out by a drawing rolling machine in an important manufacturing process for determining the tube dimensions such as the outer diameter and the tube thickness of a product. This squeeze rolling mill is one in which a plurality of roll stands having three rolls arranged at intervals of 120 degrees in a circumferential direction of a surface orthogonal to the rolling direction are continuously arranged on a rolling pass line. Shown in.

Conventionally, in the case of a three-roll type reduction rolling mill, the rolls of the roll stand are arranged with an angular displacement of 60 degrees in a plane orthogonal to the rolling pass line as shown in FIG. For this reason, a circular pipe is 6
Since the plastic working is repeatedly performed in the divided areas, as a result, a hexagonal inner surface tension is formed as shown in FIG. 9A, and the dimensional accuracy of the inner diameter and the thickness of the circular pipe is reduced.

As a method for improving this, Japanese Patent Laid-Open No. 58-25
Japanese Patent No. 805 proposes a squeeze rolling mill in which three rolls of a roll stand are arranged with an angular displacement of 30 degrees in a plane orthogonal to the rolling pass line, as shown in FIG.

Further, as disclosed in Japanese Unexamined Patent Publication No. 62-187507, one kind of roll stand is rotated in the front and back and in the circumferential direction as a reduction rolling apparatus having the features of low cost and easy remodeling of equipment. A rolling mill having an arrangement of a roll stand having an angular displacement of 30 degrees in a plane orthogonal to the rolling pass line, and the roll stand used upside down as described in JP-A-62-199210. However, there has been proposed a squeeze rolling mill that realizes an arrangement of roll stands having an angular displacement of 30 degrees in a plane orthogonal to a rolling pass line by changing the arrangement reference line of the roll stands by a certain angle.

[0006]

However, all of these improvement methods have problems and are not sufficient solutions.

Each item will be described below. First, the method disclosed in Japanese Patent Laid-Open No. 58-25805 is a method of arranging rolls of a roll stand with an angular displacement of 30 degrees in a plane orthogonal to the rolling pass line. Since rolling of the outer diameter and tube thickness of the pipe is repeated on each roll stand on the roll surface that divides the circumferential direction into 12 equal parts, it is possible to avoid the formation of a dodecagonal inner surface in the circumferential direction of the product as shown in FIG. 10b. There wasn't. The dodecagonal tension is an improvement over the hexagonal tension, but it was not a complete solution.

According to the method disclosed in Japanese Patent Laid-Open No. 62-187507, one type of roll stand is rotated in the front and back and in the circumferential direction, and 30 rolls are formed in a plane orthogonal to the rolling pass line.
There is a roll stand with a degree of angular displacement,
The problem of dodecagonal inner surface has not been solved yet.

The method disclosed in Japanese Patent Laid-Open No. 62-199210 has not yet solved the problem of dodecagonal inner surface.

[0010]

According to a first aspect of the present invention, there is provided a roll housing having three squeeze rolls installed at an angle of 120 ° in the circumferential direction in a plane perpendicular to the rolling direction. A roll stand for a circular pipe rolling mill comprising a movable cradle with a gear for rotating the movable cradle in a circumferential direction orthogonal to the rolling direction and a fixed cradle having a means for supporting and rotating the movable cradle. .

According to a second aspect of the present invention, there is provided a roll stand for a circular pipe reduction rolling machine according to the first aspect, wherein the means for rotating the movable cradle is a lead screw with a gear.

According to a third aspect of the invention, the basic arrangement of the three drawing rolls is (0 °, 120 °, 240 °), (30 °, 150
°, 270 °), (60 °, 180 °, 300 °),
(90 °, 210 °, 330 °) is installed, and the roll stand of the circular pipe reduction mill according to claim 1 or 2 is combined to perform reduction rolling.
This is a method of rolling a circular pipe. The roll stand of the circular tube drawing and rolling mill, which is the basis of the present invention, has three drawing rolls whose basic arrangement is installed at an angle of 120 ° in the circumferential direction in a plane perpendicular to the rolling direction. A diaphragm for a circular pipe comprising a roll housing, a movable cradle with a gear for rotating the movable housing in the circumferential direction of a surface orthogonal to the rolling direction by 0 to 15 °, and a cradle table having means for supporting and rotating the movable cradle. It is a roll stand of a rolling mill.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a vertical sectional view of a cradle of a housing which is a basic type of a roll stand of a circular tube drawing and rolling mill according to the present invention.

In the housing 1, three rolls 3a, 3b, 3c for drawing and rolling a circular tube are provided in a plane perpendicular to the rolling direction (0 °, 120 °, 240) with respect to an arbitrary reference axis.
°), (30 °, 150 °, 270 °), (60 °, 1
80 °, 300 °), (90 °, 210 °, 330 °)
And the stand is arranged with an angle difference of 120 °.

The housing 1 is fixed on a rotatable movable cradle 2. The movable cradle 2 is movably supported on the fixed cradle 4. The movable cradle 2 can be rotated about the pass line in the range of −15 to 15 ° by rotating the lead screw 5 installed on the fixed cradle 4.

FIG. 2 is a schematic view of equipment according to the embodiment of the present invention. The steel strip 6 is heated to 1200 ° C. or more in the heating furnace 7, and then both ends (edge portions) of the steel strip 6 are heated to about 1380 ° by the edge heaters 8. Then the pipe making machine 9
By forging both ends of the steel strip 6, the mother tube 10 is formed. A roll stand 11 in which the mother tube 10 is a set of three rolls is arranged on the rolling pass line.

After being drawn and rolled to a predetermined outer diameter and tube thickness by a squeeze rolling mill 12, it is cut into a predetermined size by a cutting saw 13, and then a product 14 is obtained, which is then conveyed to a cooling floor 15.

[0019]

EXAMPLE FIG. 4 shows the roll stand of the reduction rolling mill of the present invention arranged with an angular displacement of 0 to 15 degrees in the circumferential direction around the rolling pass line.

FIG. 3 is a schematic view of the apparatus around the roll stand.
Shown in The roll drive system is a system in which the power from the motor 16 is distributed to predetermined angles via the speed reducer 17.
Angle change gear 1 to accommodate finer angular displacement
Power is transmitted to one roll shaft 19 of the roll stand through 8 as required.

The other rolls 20 in the roll stand are driven by gears 21 inside the roll stand and transmitted to the respective rolls (internal drive system).

Although the 15-degree phase difference rolling is carried out in the present invention, as described above, the roll stand must be rotated by 15 degrees in the plane perpendicular to the rolling pass line to set the angular displacement of the roll stand. For that purpose, it was rotated to a predetermined angle by a rotating device of a roll stand as shown in FIG.

In this rotating device, the movable cradle 2 attached to the roll stand holder is rotated by rotating the lead screw 5 attached to the roll stand holder, so that the roll stand can be moved in a plane perpendicular to the rolling pass line. It is possible to rotate the rolls by a certain angle, and the rolls can be arranged with a predetermined angular displacement in the circumferential direction of the rolling pass line by a simple operation.

As shown in FIG. 5, the circular tube drawing and rolling mill according to the present invention in which the basic arrangement of the three rolls is 0 °, 120 °, and 240 ° is No. 1 stand, No. 2 stand, and the basic arrangement is 30 °. No.3 stand and No.4 stand for 150 ° and 270 °, and 60 °, 180 ° and 3
No. 5 stand, No. 6 stand for 00 °, 9
0 °, 210 °, 330 ° with No7 stand, N
It is arranged on an o8 stand, and even-numbered rolls are rotated by 15 ° in the clockwise direction by the rotating device according to the present invention. FIG. 5 shows an arrangement pattern of rolls having an angular displacement of 30 degrees on a roll stand of a conventional reduction rolling mill and an arrangement pattern of rolls having an angular displacement of 15 degrees on a roll stand of a drawing rolling mill of the present invention. As is apparent from this figure, the mother pipes drawn and rolled by the stands arranged are subjected to plastic working from 24 directions different by 15 °, so that the pipe thickness and the circularity of the inner surface are also improved.

[0025]

According to the roll stand of the squeeze rolling mill of the present invention, the roll stand and the roll stand stand are not complicated and the roll stand is provided in the circumferential direction around the rolling pass line with a simple structure. It can be arranged with an arbitrary angular displacement.

As a result, since the rolling can be performed with an angular displacement (for example, 15 degrees) smaller than that of the conventional 30 and 60 degree phase angle rolling, the roundness of the pipe is improved.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a roll stand rotation device and a roll stand of a reduction rolling mill used in an embodiment of the present invention.

FIG. 2 is a schematic diagram of equipment according to the present invention.

FIG. 3 is a configuration diagram in the vicinity of a roll stand of a reduction rolling mill used in an example of the present invention.

[Fig. 4] Angular displacement 15 of the roll stand of the reduction rolling mill
It is a layout drawing of a degree roll.

FIG. 5 is a layout view of a method of setting an angle of a 15-degree roll stand in the reduction rolling mill of the present invention.

FIG. 6 is a perspective view of a roll stand of the reduction rolling mill.

FIG. 7: Angular displacement 60 of the roll stand of the reduction rolling mill
It is a layout drawing of a degree roll.

FIG. 8: Angular displacement 30 of the roll stand of the reduction rolling mill
It is a layout drawing of a degree roll.

FIG. 9 is a schematic diagram showing the relationship between the angular displacement of the roll of the roll stand and the angular tension of the inner surface of the product.

[Explanation of symbols]

 1 Housing 2 Movable Cradle 3 Squeezing Roll 4 Fixed Cradle 5 Reed Screw 6 Strip Steel, 7 Heating Furnace, 8 Edge Heater 9 Pipe Making Machine 10 Mother Tube 11 Roll Stand 12 Squeezing Rolling Machine 13 Cutting Machine 14 Product 15 Cooling Floor 16 Motor 17 Speed reducer 18 Angle change gear 19 Power transmission shaft 20 Roll shaft 21 Gear

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshiyuki Kurosawa 1-2, Marunouchi, Chiyoda-ku, Tokyo Japan Steel Pipe Co., Ltd. (72) Yuji Sugimoto 1-2-1 Marunouchi, Chiyoda-ku, Tokyo Date Main Steel Pipe Co., Ltd.

Claims (3)

[Claims] 1. A roll housing having three drawing rolls installed at an angle of 120 ° in the circumferential direction in a plane perpendicular to the rolling direction and a circumference of a plane orthogonal to the rolling direction. A roll stand for a circular tube drawing and rolling machine comprising a movable cradle with a gear that rotates in a predetermined direction and a fixed cradle that has a means for supporting and rotating the movable cradle. 2. The lead screw with a gear is used as the means for rotating the movable cradle.
Roll stand of the described circular pipe drawing and rolling mill. 3. The basic arrangement of the three drawing rolls is (0 °, 12) with respect to an arbitrary reference axis in a plane perpendicular to the rolling direction.
0 °, 240 °), (30 °, 150 °, 270 °),
(60 °, 180 °, 300 °), (90 °, 210
3. The rolling method of a circular pipe, characterized in that the rolling process is carried out in combination with the roll stand of the circular pipe rolling mill according to claim 1 or 2, which is installed at an angle of 330 °.