JP3341666B2 - Diameter stand of steel pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates generally to a constant diameter stand for finishing a steel pipe, particularly an ERW steel pipe, to a predetermined outer diameter, and more particularly to a two-roll type constant diameter stand.

[0002]

2. Description of the Related Art Generally, in a constant diameter stand, a steel pipe is finished to a perfect circle so that an outer diameter of the steel pipe falls within a predetermined range.
Therefore, the structure of the constant diameter stand is required to have high mechanical precision and fine adjustment. In production facilities for ERW steel pipes and the like, two rolls are usually used.

That is, a seamless steel pipe rolled by a plug mill, a pilga mill or the like, or a welded steel pipe manufactured by high-frequency electric resistance welding, forging, or the like is used in a fixed diameter stand comprising a plurality of roll stands each having a pair of rolls. , Finished into a perfect circular tube of a predetermined outer diameter. FIG. 1 shows a conventional constant diameter stand. In FIG. 1, four horizontal roll stands 2 having a pair of horizontal rolls 3 whose axes are arranged in a horizontal direction are provided. Further, on the entry side of each horizontal roll stand 2, four pairs of vertical rolls 4 whose axes are arranged in a vertical direction are provided.

As shown in FIG. 1, a conventional fixed diameter stand 1 is generally composed of two to five stages of driving horizontal roll stands 2 provided with steel pipes to be fixed in diameter in the vertical direction; It is constituted by one series of stand composed of a non-driving vertical roll 4 provided on the entry side of each of the driving roll stands of the step with a steel pipe sandwiched in the left-right direction.

[0005] In the conventional constant diameter stand 1, the steel pipe is drawn down by a driving horizontal roll stand 2 of two to five stages provided so as to vertically sandwich a steel pipe to be fixed in diameter. The non-driven vertical rolls 4 that sandwich the steel pipe in the left-right direction suppress springback in the horizontal elliptical direction of the steel pipe.

[0006]

In the above-described prior art, as described above, the steel pipe is drawn by the driving horizontal roll stand. for that reason,
The rigidity of the horizontal roll stand is strong enough to give the steel pipe a restriction for a constant diameter. However, the non-driven vertical roll does not have the function of drawing the steel pipe, but has only the function of suppressing springback in the horizontal elliptical direction of the steel pipe. That is, the non-driven vertical roll has low rigidity including the shaft and yoke,
There was not enough force to apply enough drawing to the steel pipe for constant diameter, and it could only be used to narrow the pipe diameter.

Further, in the prior art, as described above, since the steel pipe is drawn only by the upper and lower rolls of the driving horizontal roll stand, the drawing direction is limited to the vertical direction, and the strain distribution in the circumferential direction of the steel pipe is not uniform. There was a problem. Further, since the steel pipe is constricted only by the driving horizontal roll stand, a large number of driving horizontal roll stands are required, and it takes a long time to adjust them.

Accordingly, the present invention has been made in order to solve the above-mentioned conventional problems, and reduces the number of steps of a fixed-diameter roll stand, and has a uniform circular pipe strain distribution in a circumferential direction, and has a circular accuracy. High ERW steel pipe can be manufactured,
An object of the present invention is to provide a steel pipe fixed diameter stand.

[0009]

Means for Solving the Problems In order to achieve the above object, the inventor has conducted intensive studies. As a result, by strengthening the shaft system and bearing system of the non-driven vertical roll, the vertical roll is configured as a vertical roll stand, and by making the rigidity of the vertical roll stand approximately the same as that of the driven horizontal roll stand, In the horizontal roll stand, the steel pipe can be given a vertical contraction, and in the vertical roll stand, the steel pipe can be given the horizontal contraction, so that the number of steps of the fixed diameter roll stand can be reduced and the steel pipe circumferential strain distribution can be reduced. It has been found that a uniform, highly accurate ERW steel pipe with perfect circularity can be manufactured.

[0010] The steel pipe constant diameter stand according to the present invention is based on the above-mentioned knowledge, and is provided with a plurality of steel pipes to be fixed in diameter in order to perform the constant diameter of the steel pipe. Drive horizontal roll stand, and
On the entry side of each of the plurality of driving horizontal roll stands, a two-roll type fixed diameter stand including a plurality of sets of non-driving vertical rolls provided so as to sandwich the steel pipe in the left-right direction. The non-driven vertical roll stand has a rigidity that is substantially the same as the rigidity of the driven horizontal roll stand.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An example of a steel pipe constant diameter stand according to the present invention is shown in FIGS. The constant diameter stand of the present invention will be described in detail with reference to these figures.

As shown in FIG. 2, the fixed diameter stand of the present invention includes a two-stage drive horizontal roll stand 12 provided with a steel pipe to be fixed in a vertical direction, and each of the drive horizontal roll stand. Is a two-roll type constant diameter stand 11 composed of a two-stage non-driven vertical roll stand 14 provided on the entry side of the steel tube with the steel pipe sandwiched in the left-right direction. Each drive horizontal roll stand 1
2 comprises a pair of rolls 13 whose axes are horizontal and each non-driven vertical roll stand 14
Consists of a pair of rolls whose axes are perpendicular.

In the constant diameter stand of the present invention, as shown in the schematic diagram of FIG. 3, driving horizontal rolls 13 and non-driving vertical rolls 14 having substantially the same rigidity are alternately arranged. The steel pipe to be fixed in diameter is firstly constricted in the left-right direction by the non-driving vertical roll 14, and then constricted in the vertical direction by the driving horizontal roll 13. At this time, the adjacent non-driving vertical roll 14 and the driving horizontal roll 13 apply the same amount of drawing to the steel pipe. Therefore, in the constant-diameter stand of the present invention including the two-stage driven horizontal roll stand and the two-stage non-driven vertical roll stand, when a predetermined restriction is given to the steel pipe, an equal amount of each of the horizontal roll and the vertical roll is provided. Since the restriction is given to the steel pipe, it is 1/4 of the predetermined amount of restriction.
Each amount of aperture can be set to give. For example, when a steel pipe is given a 2% reduction, a 0.5% reduction is given per stand for each of the horizontal roll and the vertical roll.
Note that the amount of reduction of the horizontal roll and the vertical roll of the first stage and the amount of reduction of the horizontal roll and the vertical roll of the second stage may be set to different amounts. However, even in this case, the horizontal roll of the first stage and the vertical roll of the first stage have the same amount of reduction, and the horizontal roll of the second stage and the vertical roll of the second stage have the same amount of reduction. To be configured.

In the present invention, it is necessary that the driving horizontal roll stand and the non-driving vertical roll stand have substantially the same rigidity. In one embodiment of the present invention, in order to make the rigidity of the driving horizontal roll stand and the non-driving vertical roll stand approximately the same, the non-driving vertical roll is strengthened with the shaft system and bearing system of the non-driving vertical roll. Although the vertical roll is configured as a vertical roll stand, other means may be used to make the rigidity of the non-driven vertical roll stand the same as that of the driven horizontal roll stand.

[0015] As described above, according to the constant diameter stand of the present invention, in each of the driven horizontal roll stand and the non-driven vertical roll stand, substantially the same constriction is given to the steel pipe. , And a steel pipe with high roundness accuracy with uniform steel pipe circumferential strain distribution can be manufactured.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a steel pipe constant diameter stand according to the present invention will be described below with reference to the drawings. The constant diameter stand shown in FIGS. 2 and 3 was applied to a real line (not shown). φ165.
Two types of ERW steel pipes of 2 × 12.5 and φ139.8 × 4.5
Using the constant-diameter stand of the present invention, a constant-diameter was performed by giving an aperture. FIG. 4 shows the results. In FIG. 4, the vertical axis indicates the amount of reduction (%), and the horizontal axis indicates each roll. In the figure, $ 1S
Z, # 3SZ indicates a non-driven vertical roll, and # 2SZ, # 4SZ indicates a driven horizontal roll.

As is apparent from FIG. 4, the non-driving vertical rolls # 1SZ and # 3SZ gave approximately the same amount of reduction to the steel pipe as the driving horizontal rolls # 2SZ and # 4SZ. That is, in the case of φ165.2 × 12.5 steel pipe, about 0.4% reduction was given in each SZ. For φ139.8 × 4.5 steel pipe, ♯1SZ and ♯2SZ
At about 0.24% aperture is given, and 与 え
At 3SZ and # 4SZ, an aperture of about 0.25% was provided. Therefore, φ passing through ♯1SZ to ♯4SZ
The 165.2 x 12.5 steel pipe was given a total of 1.6% drawing and was φ139.8 x which passed through # 1SZ to # 4SZ.
4.5 The steel pipe was given a total reduction of about 1.0%.

At this time, as a result of examining the strain distribution in the circumferential direction of the steel pipe, as described above, the 絞 り 1SZ and ♯3SZ provide the left-right iris, and the ♯2SZ and ♯4SZ provide the vertical iris. , $ 1SZ and $ 2S
In Z, and in the 絞 り 3SZ and ♯4SZ, the same value of restriction was given, so that the circumferential strain distribution in the steel pipe was uniform,
A steel pipe with high roundness accuracy could be manufactured.

As is apparent from the above description, the number of stages of the driving horizontal roll stand in the conventional constant diameter stand can be reduced to half. as a result,
The time required to adjust each drive horizontal roll stand was significantly reduced.

[0020]

According to the steel pipe fixed diameter stand of the present invention,
It is possible to provide a steel pipe constant diameter stand capable of reducing the number of steps of the constant diameter roll stand and producing an ERW steel pipe having a uniform circular strain distribution and a high roundness accuracy. A more useful effect is brought about.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing a conventional constant diameter stand.

FIG. 2 is a schematic side view showing one embodiment of the constant diameter stand of the present invention.

FIG. 3 is a schematic view showing an arrangement of rolls of the constant diameter stand of the present invention.

FIG. 4 is a schematic explanatory view showing the aperture amount of each stand in the constant diameter stand of the present invention.

[Explanation of symbols]

 1. Fixed diameter stand 2. Driven horizontal roll stand 3. Horizontal roll 4. Non-driven vertical roll 11. Fixed diameter stand 12. Driven horizontal roll stand 13. Horizontal roll 14. Non-driven vertical roll -Stand

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-7-32010 (JP, A) JP-A-59-179208 (JP, A) JP-A-2-63603 (JP, A) 60634 (JP, U) (58) Field surveyed (Int. Cl. ⁷ , DB name) B21B 17/14

Claims (1)

(57) [Claims] 1. A plurality of drive horizontal roll stands, each of which is provided with a steel pipe to be reduced in diameter in a vertical direction, and each of the plurality of drive horizontal roll stands is provided for performing a constant diameter of the steel pipe. On the side, in a two-roll type constant diameter stand composed of a plurality of sets of non-driving vertical rolls provided so as to sandwich the steel pipe in the left-right direction, the non-driving vertical rolls are constituted by a plurality of simple stands, and A fixed diameter stand for a steel pipe, wherein the rigidity of the non-driven vertical roll stand is substantially equal to the rigidity of the driven horizontal roll stand.