JP3375486B2 - Squeeze roll stand - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a squeeze roll stand, and more particularly to a squeeze roll stand suitable for forming a pipe by abutting and joining both edges of an open pipe in a proper solid pressure welding proper temperature range.

[0002]

2. Description of the Related Art Welded steel pipe is made by forming a steel plate or steel strip (steel strip) into a tubular shape and welding its joints, and is manufactured by various manufacturing methods from small diameter to large diameter. Examples thereof include electric resistance welding (electric resistance welding), forge welding, and electric arc welding. For small to medium diameter steel pipes, an electric resistance welding method using high frequency induction heating (electric resistance welded steel pipe, electric resistance welded pipe) is mainly used. This method
Continuously feed the strip steel and form it into a tubular shape with a forming roll to form an open tube, and then use high frequency induction heating to heat both edge parts of the open tube above the melting point of the steel and then use a squeeze roll to form both edge parts. This is a method of manufacturing a steel pipe by butt welding the end faces (for example, the 3rd edition of the Iron and Steel Handbook, Volume III (2)).
1056-1092).

In the above-mentioned method for manufacturing an electric resistance welded pipe using high frequency induction heating, the end faces of both edge portions of the open pipe are heated above the melting point of the steel, so that the molten steel flows due to the influence of the electromagnetic force and the generated oxidation occurs. The object is caught in the abutting weld, welding defects such as penetrator or molten steel scattering (flash)
There is a problem that is likely to occur. For this problem,
For example, Japanese Patent Laid-Open No. 2-299782 proposes a method for manufacturing an electric resistance welded steel pipe having two heating devices. That is,
The first heating device heats the temperature of both edges of the open pipe above the Curie point, the second heating device further heats above the melting point, and both edges are butt welded with a squeeze roll installed immediately downstream. To manufacture a steel pipe. In addition, Japanese Patent Laid-Open No. 2-299783
In the publication, a current of 45 to 250 kHz is applied in the first heating device to preheat both side edge parts, and the second heating device further heats to a melting point or higher, and both edge parts are butt welded with a squeeze roll. An electric resistance welded pipe manufacturing apparatus for manufacturing a steel pipe has been proposed.

However, although these electric resistance welded pipe manufacturing techniques suggest that the edge portions are uniformly heated, both edge portions are heated to a temperature higher than the melting point of the steel, so that molten steel is struck during butt welding. Are discharged to the inner and outer surfaces of the pipe to form beads (overfill). Therefore, it is necessary to remove the weld beads on the inner and outer surfaces of the pipe after the abutting welding, and most of them are cut and removed by a bead cutting tool.

For this reason, in this method, adjustment of the cutting amount of the bead cutting tool causes a loss of material and time. Since the bead cutting tool is a consumable item, it varies depending on the pipe making speed, but it is necessary to replace the tool every bead cutting length of 3000 to 4000 m. Therefore, it is necessary to replace the tool every 3 hours for 3 to 5 minutes. Forcing you to stop the line.

Particularly, in high-speed pipe forming at a pipe forming speed exceeding 100 m / min, the bead cutting bite has a short life and is frequently replaced. However, there was a problem that productivity was low because bead cutting became a bottleneck and high-speed pipe making was not possible. On the other hand, there is a forged steel pipe manufacturing method having extremely high productivity for relatively small diameter steel pipes. In this method, the continuously supplied strip steel is heated to approximately 1300 ° C in a heating furnace, then formed into a tubular shape by a forming roll to form an open tube, and then high-pressure air is blown to both edges of the open tube to form an end surface. After doing the scale-off of
It is a method of manufacturing a steel pipe by blowing oxygen to the end surface with a welding horn, heating the end surface to about 1400 ° C. with the heat of oxidation, and then abutting the end surfaces of both edge parts with a forge roll to perform solid phase joining ( For example, 3rd Edition Iron and Steel Handbook, Vol. III (2), 1056-1092).

However, in this method of manufacturing a forged steel pipe, the scale-off of the end face is not perfect, so that scale entrapment occurs in the forged abutting portion, and the strength of the seam portion is considerably inferior to that of the base metal portion. For this reason, in the flatness test, the flat height ratio h / D = 2t / D (t: plate thickness) can be achieved in the case of ERW steel pipe, whereas the flatness height ratio h / D is inferior to approximately 0.5 in the forged steel pipe. Will be things.

Since the steel strip is heated to a high temperature, scale is generated on the surface of the pipe and the surface texture is poor. Although the pipe making speed is as high as 300 m / min or more and the productivity is high, the seam quality and surface texture are poor, and there is a problem that it is impossible to manufacture JIS STK etc. that require strength reliability and surface quality. . To advantageously solve the above problems,
It is preferable to use the solid-state pressure welding method which is the idea of the present inventors. This is an unprecedented pipe making method in which the edge part of an open pipe is induction-heated and pressure-welded to a solid phase pressure proper temperature range (1300 ° C to 1500 ° C) below the melting point. Steel pipes manufactured by this solid pressure welding method do not require bead cutting unlike conventional welded tubes, so high-speed pipe manufacturing is possible and high productivity is achieved.
Moreover, there is no deterioration of seam quality and surface skin due to oxidation, which is a drawback of the conventional forged tube.

However, the conventional squeeze roll stand used for manufacturing a welded pipe has the following drawbacks, and there is a problem in applying it to the solid pressure welding process. Figure 3
Of the conventional squeeze roll stand, (a) is a side view, (b) is a plan view, (c) and (d) are AA and BB arrow views of (a), and 1 is a tubular body. 1A is an open pipe, 1B is a pipe, 2 is an edge part, 3 is a pressure contact, 4 is a seam part, 4A is an outer bead, 5 is a squeeze roll, 6 and 7 are the direction of the passing material and the direction of the pressing force, respectively. Indicated arrows, 12 is an outer bead cutting device, and 50 is a squeeze roll stand. In addition, the tube body 1 continuously threaded in the direction of the arrow 6,
An open pipe 1A is provided upstream of the pressure contact 3, and a pipe 1 is provided downstream thereof.
I will call it B.

As shown in FIG. 3, a conventional squeeze roll stand 50 is provided with a pair of squeeze rolls 5 whose roll surface is a caliber, and these are symmetric with respect to a plane formed by the pressure contact 3 and the central axis of the tubular body 1. It will be arranged in. Tube 1
Is drawn into the squeeze roll stand 50 as the open pipe 1A in the direction of arrow 6, and the outer peripheral surfaces on both sides are pressed by the squeeze rolls 5 in the direction of arrow 7. At this time, the two edge portions 2 are pressed into contact with each other to form the pressure contact 3, and the tube 1B is delivered. The seam 4 on the tube 1B has a pressure contact 3
Is the trajectory of.

FIG. 4 is a cross-sectional view showing a seam portion shape defect that tends to occur in a conventional squeeze roll stand. In FIG. 4, reference numeral 8 denotes a press contact thickening portion, the same members as those in FIG. In the conventional squeeze roll stand, as shown in FIG. 3, both side surfaces are pushed in the vicinity of the pressure contact 3 without being constrained in the pipe radial direction, and as a result, as shown in FIGS. 4 (a) and 4 (b). As shown in (3), a shape defect in which the seam portion 4 is recessed inside the tube (referred to as “seam part recess”) or projected outside the tube (referred to as “seam part sharpness”) is likely to occur. For this reason, cross-section correction is required in a later process, which hinders high-speed pipe making.

In addition to these, the seam portion 4 is upset to increase the thickness of the seam, so that the pressure contact thickened portion 8 as shown in FIG. 4C is easily formed. In the welded pipe forming method in which the edges are melt-bonded, the press-welding thickened portion 8 is a weld bead having oxide slag further adhered to the surface thereof, so that the bead cutting process is indispensable as described above. On the street. However, bead cutting is not necessary in the solid-state pressure welding method.The smoothing of the pressure-increasing thickened portion 8 depends on the bead cutting process that is still in the old state. I can't expect at all.

[0013]

SUMMARY OF THE INVENTION In view of the problems of the prior art described above, the present invention provides solid pressure welding capable of producing a steel pipe which does not require bead cutting and can ensure high productivity and is excellent in seam quality and surface texture. An object of the present invention is to provide a squeeze roll stand capable of realizing a pipe making method.

[0014]

SUMMARY OF THE INVENTION The present invention comprises a plurality of squeeze rolls having a caliber roll surface, and the squeeze rolls are rotated to draw the formed tube into the open tube so that both edge portions of the open tube are removed. Solid-state pressure welding is necessary for bead cutting.
A squeeze roll stand that sends out as a pipe joined at the seam, which is the locus of the pressure contact of the steel pipe ,
The gist is that one of the squeeze rolls is a seam shaping roll that abuts the seam portion within the caliber range.

[0015] The present invention is made et al., Abstract, further comprising a thickened portion rolling rolls against phase to said seam shaping rolls across the seam from the tube body, rolling the pressed thickening unit generated in the seam portion And The seam shaping roll and the thickened part rolling roll have a bending strength of 15 kg / mm ² or more and a thermal shock temperature difference of 1
It is preferable to use a material having a characteristic of 50 ° C. or higher as a raw material.

As such a material, silicon nitride-based, silicon carbide-based, zirconia-based or alumina-based ceramics are most suitable.

[0017]

1 shows an example of a squeeze roll stand of the present invention, (a) is a side view and (b) is a plan view (thickness increasing roll is not shown) . In FIG. 1, 5A is a seam shaping roll, the same members as in FIG. As shown in Figure 1,
In this example , one of the squeeze rolls 5 is
The seam shaping roll 5A is arranged so that the seam portion 4 is brought into contact with the caliber range. Although only one squeeze roll 5 is shown in FIG. 1, the present invention is not limited to this. For example, as shown in FIG. 5, a plurality of squeeze rolls 5 (in FIG. Seam shaping roll 5A
A total of four examples including the above are shown. ) The form provided can also be adopted. Note that, in FIG. 5, the same members as those in FIG. 1 are denoted by the same reference numerals, and the description thereof will be omitted.

With this structure, both edge portions 2 in the vicinity of the pressure contact 3 are constrained in the pipe radial direction by the seam shaping rolls 5A, so that the seam portion depressions as shown in FIGS. No seam sharpness occurs. In addition, FIG.
It is also possible to prevent the protrusion of the press contact thickened portion 8 on the outer surface of the pipe.
Therefore, the cross-section straightening and the pipe outer surface smoothing processing, which are conventionally required to be performed, are not required, and high-speed pipe making can be realized.

2A and 2B show an example of the squeeze roll stand of the present invention. FIG. 2A is a partially cutaway side view, and FIG.
FIG. In FIG. 2, reference numeral 9 is a thickening portion rolling roll, 10 is a roller, and 11 is a dolly, and the same members as those in FIG. As shown in FIG. 2, in the present <br/> invention, against phase seam shaping rolls 5A across the seam portion 4 from the tube inside 1, by rolling press thickening unit generated in the seam portion 4 pipe A roll for increasing thickness 9 for smoothing the surface was provided. In addition, although the supporting form of the thickening portion rolling roll 9 is not particularly limited, in FIG. 2, a trolley 11 having a roller 10 which is in contact with the inner surface of the pipe body 1 other than the seam portion 4 and is movable in the pipe axial direction is used. The form to be installed is adopted.

As a result, it becomes possible to roll and easily crush the pressure-increased portion of the seam portion 4 near the pressure contact 3 while it is still in the hot temperature range of about 900 ° C. or higher, and the high-grade steel pipe can be crushed. Since the smoothing treatment of the inner surface of the pipe, which is often required in the above, can be performed much more efficiently, it is possible to further speed up the pipe making process. The seam shaping roll according to the first aspect of the present invention and the thickening portion rolling roll according to the second aspect of the present invention generate a bending stress of 15 kg / mm ² or more due to the reaction force from the tubular body, and the tubular body of the roll. The temperature difference between the vicinity of the pressure contact on the contact surface and the other area is steep and often reaches 150 ° C or more.

Therefore, in order to extend the service life of these rolls, it is preferable to select the material of the rolls from those having a bending strength of 15 kg / mm ² or more and a thermal shock resistance difference of 150 ° C. or more. The thermal shock temperature difference used in the evaluation here is 3 mm x 4 mm x 40 mm as a material test piece.
After the test piece is heated to a predetermined temperature using a rectangular rod (specification for JIS 4-point bending test), the temperature difference (between heating temperature and water temperature) does not cause cracks in the test piece when dropped in water. Difference). In view of the current state of the art, silicon nitride (Si ₃ N ₄ ) based, silicon carbide (SiC) based, zirconia (ZrO ₂ ) based or alumina (Al ₂ O ₃ ) based ceramics are the most suitable materials. is there.

[0022]

EXAMPLE A squeeze roll stand of the present invention shown in FIG. 2 was used as a material for a seam shaping roll and a thickening part rolling roll as a silicon nitride ceramic having a bending strength of 85 kg / mm ² and a thermal shock resistance difference of 800 ° C. Installed in the steel pipe production line,
After molding by the solid pressure welding method, the pipe diameter is φ25 ~ 60 mm x wall thickness
Carbon steel pipe for general structures (2.0 mm to 4.5 mm) (JIS G
3452 SGP, G3444 STK equivalent) were manufactured.

As a result, in the past, the conventional squeeze roll stand shown in FIG. 3 was installed, and the steel pipe of the same standard and the same size was trial manufactured by the solid pressure welding process while the seam portion was straightened and smoothed downstream. 100m during production
The maximum molding speed, which was the limit value of / min, was significantly increased to 150 m / min, and it was clearly demonstrated that the effect of the present invention was exceptional.

[0024]

As described above, according to the present invention, the solid-state pressure welding method capable of producing a steel pipe which does not require bead cutting, can ensure high productivity and is excellent in seam quality and surface texture is realized. There is a marked effect of doing.

[Brief description of drawings]

FIG. 1 shows an example of a squeeze roll stand of the present invention,
(A) is a side view and (b) is a plan view (thickened portion rolling roll).
(Not shown) .

FIG. 2 shows an example of a squeeze roll stand of the present invention,
(A) is a partially cutaway side view, and (b) is a view on arrow AA of (a).

FIG. 3A is a side view, FIG. 3B is a plan view, and FIGS. 3C and 3D are views of a conventional squeeze roll stand.
FIG. 3 is an AA, BB arrow view of FIG.

FIG. 4 is a cross-sectional view showing a seam portion shape defect that is likely to occur in a conventional squeeze roll stand.

5A and 5B show an example in which the number of rolls of the squeeze roll stand of the present invention is four; FIG. 5A is a plan view and FIG. 5B is a sectional view taken along the line AA of FIG.

[Explanation of symbols]

1 tube 1A open pipe 1B tube 2 Edge part 3 pressure contact 4 seam section 4A outer bead 5 squeeze rolls 5A seam shaping roll Arrows showing the 6 and 7 directions 8 Pressure welding thickened part 9 Rolls for thickening part 10 rolls 11 dolly 12 External bead cutting device 50 squeeze roll stand

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification symbol FI B23K 103: 04 B23K 103: 04 (72) Inventor Akira Ito 1-1 Kawasaki-cho, Handa-shi, Aichi Kawasaki Steel Co., Ltd. Chita Works (72) Yuji Hashimoto, 1-1, Kawasaki-cho, Handa-shi, Aichi Prefecture, Chita Works, Kawasaki Steel Co., Ltd. (72) Nobuki Tanaka, 1-1, Kawasaki-cho, Handa-shi, Aichi, Chita Works, Kawasaki Steel Co., Ltd. ) Reference JP-A-5-212555 (JP, A) JP-A-4-270077 (JP, A) JP-A-8-103815 (JP, A) JP-A-4-118114 (JP, A) JP-A 9-277068 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B23K 20/00 B23K 13/00

Claims (4)

(57) [Claims] 1. A plurality of squeeze rolls each having a caliber roll surface are provided, and by rotating the squeeze rolls, the formed pipe body is drawn into the open pipe, and both edges of the open pipe are solid-state pressure-welded to bead cutting is required. A squeeze roll stand that sends out as a pipe joined at the seam part which is the trajectory of the pressure contact of a steel pipe, one of the squeeze rolls is a seam shaping roll that abuts the seam part within its caliber range, and A squeeze roll stand, further comprising a thickening portion rolling roll that faces the seam shaping roll across the seam portion and that rolls the press-contacted thickening portion generated in the seam portion. 2. The seam shaping roll has a bending strength of 15
The squeeze roll stand according to claim 1, which is made of a material having characteristics of a kg / mm ² or more and a thermal shock resistance difference of 150 ° C or more. 3. The seam shaping roll and the thickening part rolling roll have a bending strength of 15 kg / mm ² or more and a thermal shock temperature difference of 1.
The squeeze roll stand according to claim 1, which is made of a material having a characteristic of 50 ° C or higher. 4. The squeeze roll stand according to claim 2, wherein the material is a silicon nitride-based, silicon carbide-based, zirconia-based, or alumina-based ceramics.