JP3951391B2 - Manufacturing method of solid-phase bonded tube - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing a solid-phase bonded tube , and more specifically, a steel strip is pressure-formed into a tubular shape by a forming roll, and the whole of the belt plate and / or the tubular body and both edges are heated and then solidified. Equipped with a solid-phase bonded pipe production line for phase joining, a plurality of squeeze rolls with caliber are arranged in the circumferential direction, and each squeeze roll narrows the outer diameter of the tubular body and presses both edges to seam The present invention relates to a method for manufacturing a solid-phase bonded tube using a squeeze device for forming a squeeze.
[0002]
[Prior art]
An example of a conventional squeeze device is shown in FIG. The tubular body (band steel) 1 is in a state where both edges 2 and 2 are abutted and heated to a temperature range where welding or solid phase bonding can be performed by a heating means (not shown). An arrangement configuration in which two squeeze rolls 3 and 3 having a mold or a groove shape are pressed against the outer periphery of the tubular body 1 from both sides of both edges 2 and 2 to generate a pressing force in the direction of the arrow. Hold in. This type of squeeze device is called a horizontal squeeze device.
[0003]
Due to the circumferential direction component of the pressing force, both edge portions 2 and 2 are pressed (upset) to form a seam portion (joint portion). However, since the horizontal squeeze device does not have means for restraining the periphery of both edges 2 and 2 in the thickness direction, as shown in FIG. 4) Sedimental deformation of the periphery of the tube 4 toward the inner surface of the tube, or (b) Uplifted deformation to the outer surface of the tube, and (c) Both edges of the molten state or the solid phase immediately before melting are brought to the inner and outer surfaces by upsetting. Shape defects such as swell and thickening tend to occur alone or in combination.
[0004]
These shape defects require corrections such as cross-section correction for deformation and smoothing by rolling or cutting for increased thickness in the post-process, which hinders productivity and increases the equipment costs and This also increases the cost associated with the addition of work costs.
[0005]
[Problems to be solved by the invention]
The deformation of (a) and (b) and the outer wall thickness increase in (c) are, for example, as shown in FIG. 6, two squeeze rolls 3 and 3, one of which is a seam of the pipe 10 According to the squeeze device that is held in an arrangement form that abuts against the portion 4, it can be suppressed. In this case, since the acting direction of the pressing force by the squeeze rolls 3 and 3 indicated by the arrows is substantially perpendicular to that of the horizontal squeeze device, this form of squeeze device is referred to as a saddle type squeeze device. According to this saddle type squeeze device, the squeeze roll (seam contact roll 3A) that contacts the seam portion 4 presses and restrains the outer surface of the pipe around the seam portion, so that the settling deformation and the bulge deformation are eliminated, and the outer surface side It is expected that there will be no increase in thickness.
[0006]
On the other hand, as shown in FIG. 2 , for example, as shown in FIG. 2 , the inner surface side thickening is performed on the inner surface of the tube 10 at the outlet side of the squeeze device to roll a hot inner surface side thickening immediately after formation. 5 can be erased.
However, in the saddle type squeeze device, the seam contact roll 3A is in contact with the welding point in the immediate vicinity, so that the joining current to the roll side (directly energized to heat the part from both edges to the welding point intensively) In order to prevent leakage loss of the high-frequency current flowing through the tubular body by induction), the seam contact roll 3A needs to be formed of a nonmagnetic and insulating material, such as silicon nitride (Si3O4) or alumina. Ceramic materials such as (Al2O3) are suitable for this, but these ceramic materials are excellent in heat resistance and wear resistance, but there are many problems in impact resistance or thermal shock resistance. It may break due to impact from a defective part, contact with a high temperature seam part during pipe making, or sudden temperature fluctuation due to repeated cooling, that is, thermal shock.
[0007]
When roll breakage occurs, downtime for replacement occurs and productivity is impaired. In general, ceramic rolls are more expensive than commonly used iron-based rolls, leading to increased unit consumption and production cost.
Accordingly, an object of the present invention is to provide a method of manufacturing a solid-phase bonded tube that can prevent the breakage of a roll while preventing the occurrence of a shape defect around a seam portion during bonding in the manufacture of a solid-phase bonded tube. .
[0008]
[Means for Solving the Problems]
INDUSTRIAL APPLICABILITY The present invention is deployed in a solid-phase bonded pipe manufacturing line in which a steel strip is pressure-formed into a tube shape by a forming roll, and the entire band plate and / or tubular body and both edges are heated and then solid-phase bonded. A solid-phase bonded tube using a squeeze device in which a plurality of squeeze rolls having a caliber are arranged in the circumferential direction, and each squeeze roll narrows the outer diameter of the tubular body and presses both edges to form a seam portion . in the manufacturing method, one of the squeeze roll is made of a nonmagnetic material, it is disposed to include seam passing range to the caliber range, 5 to width to the seam passing range of tube outer diameter Using a seam pass roll provided with a recess having a depth of 30% to 100% of the thickness of the strip, and further using a thickening roll disposed on the exit side of the squeeze device, the thickness is increased by the pressure welding. Is the meat seam inside or outside the pipe? It is a manufacturing method of solid phase bonding tube, wherein the benzalkonium be rolled across al.
[0009]
The seam pass roll is preferably a roll formed of a ceramic material having a bending strength of 15 kgf / mm ² or more and a thermal shock temperature difference of 150 ° C. or more. In addition, it is more preferable that the thickening roll is a roll formed of the same ceramic material.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
An example of a solid-phase bonded tube manufacturing line to which the present invention is applied is shown in FIG. The strip 1 is heated by heating means such as a heating furnace 15 and is formed into a tubular shape by the forming rolls 7 to 7 and further joined together. Is heated and pressed by the squeeze device 8. The squeeze device 8 of this example has four squeeze rolls, and on the exit side of the squeeze device 8, thickening rolling rolls 6A and 6B are arranged inside and outside the pipe. The steel strip may be heated after the tubular molding, or it may be heated at both stages before and after the tubular molding. In that case, heating means such as a heating furnace is provided on both the exit side or the entrance / exit side of the forming roll group.
[0012]
An example of the squeeze device used in the present invention is shown in FIG. In FIG. 1, (a) is a plan view, (b) is a partially cutaway side view, (c) is a view taken along arrow AA in (b), 3C is a seam path roll, 9 is a roll carriage, and 11 is a reverse side. A force receiving roll, 30 is a recess. In addition, the same code | symbol is attached | subjected to the same or equivalent part as each figure mentioned above, and description is abbreviate | omitted.
As shown in the figure, the squeeze device 8 used in the present invention is similar to the saddle type squeeze device, but one of the squeeze rolls 3 to 3 is arranged so that the seam portion 4 passing range is included in the caliber range. It is a seam pass roll 3C made of a nonmagnetic insulating material, and the seam pass roll 3C has a width of 5 to 30% of the outer diameter of the pipe and a depth of the pipe 10 (that is, an increased thickness seam part 4). 20 to 100% of the recess 30 is provided to such an extent that a gap is formed between the base material and the thickness of the base material (the thickness of the strip).
[0013]
By providing such a recess 30, repeated contact with the periphery of the high temperature seam portion (referred to as a high temperature portion for convenience) can be avoided, and the thermal shock to the non-magnetic insulating material such as a ceramic material is alleviated and the roll Breakage can be prevented. When the width of the concave portion 30 is less than 5% of the outer diameter of the tube 10, it is difficult to avoid contact with the high temperature portion. Further, when the width of the recess 30 exceeds 30% of the outer diameter of the tube 10, the action of restraining the periphery of the seam portion is weakened to prevent the settling deformation and the bulging deformation shown in FIGS. 5 (a) and 5 (b). It becomes difficult .
[0014]
On the other hand, for the thickening of the seam portion shown in FIG. 5 (c), the thickening rolls 6A and 6B are provided on the inner and outer surface sides of the squeeze device 8 so that the seam portion 4 is sandwiched therebetween. This increase in thickness can be eliminated by rolling at. The thickening roll 6A on the inner surface side can be supported by a roll carriage 9 that can be inserted into the tube 10 as shown in FIG. If necessary, a reaction force receiving roll 11 that receives a rolling reaction force exerted on the roll carriage 9 may be provided on the outer surface side of the tube 10.
[0015]
Further, according to the investigation by the present inventors, a bending stress of 15 kgf / mm ² or more is generated in the seam path roll by the reaction force from the pipe body, and the seam path roll has a recess in the seam by heat radiation from the high temperature part. In other words, the same temperature and the temperature higher by 150 ° C or more are repeated with respect to the other caliber ranges, and the state changes abruptly. Therefore, in order to prevent breakage of the roll, a roll formed of a nonmagnetic insulating material, particularly a ceramic material, having a bending strength of 15 kgf / mm ² or more and a thermal shock temperature difference of 150 ° C. or more is preferable. In the present invention, the thermal shock temperature difference means that a 3 mm x 4 mm x 40 mm square bar test piece (spec for JIS 4-point bending test) is heated to a predetermined temperature and then dropped into water. It means the temperature difference (difference between heating temperature and water temperature) that does not occur. In light of the current technical level, such ceramic materials include silicon nitride (Si ₃ N ₄ ), silicon carbide (SiC), zirconia (ZrO ₂ ), and alumina (Al ₂ O ₃ ). It is desirable to choose one of these because it fits.
[0016]
In addition, when the distance between the thickening roll and the squeeze device is short and the leakage loss of the junction current to the thickening roll cannot be ignored, the thickening roll needs to be formed of a ceramic material. In that case, it is considered that the thickening roll is subjected to the same stress load and heat load as the seam pass roll, so it is desirable to use the same material as the seam pass roll material. .
[0017]
【Example】
The present invention was carried out in a process of manufacturing a pipe having an outer diameter of 60.5 mm from a 0.08% C steel strip (thickness 3.2 mm) in the solid-phase bonded pipe manufacturing line shown in FIG. In this embodiment , the apparatus shown in FIG. 1 is used for the squeeze apparatus, a silicon nitride-based ceramic roll is used for the seam pass roll and the thickening roll, and the width of the recess of the seam pass roll is 0.20 D, The depth was 0.5 t (D: pipe outer diameter, t: base metal thickness). The squeeze roll has a throat diameter of 160 mmφ. Moreover, the pipe making by the comparative example which carried out the same conditions as an Example was also performed except having replaced the seam pass roll with the squeeze roll (seam contact roll) without a recessed part.
[0018]
As a result, in the comparative example, a tortoiseshell-shaped microcrack was generated on the seam abutting roll at a total tube length of about 600 m, and when the tube was further formed, the roll surface chipped off at a total tube length of 950 m. In the example, cracks were not seen on the surface of the seam path roll even when the total pipe length reached 3000 m, whereas the outer pipe had to be interrupted to replace the roll because wrinkles occurred on the outer surface. It was confirmed that the squeeze device used in the present invention is excellent in durability.
[0019]
It should be noted that the occurrence of deformation in the vicinity of the seam portion in the steady pipe-forming state and shape defects due to thickening could be effectively suppressed in both the comparative example and the example.
[0020]
【The invention's effect】
Thus, according to the present invention, an excellent effect called Ru it can be prevented roll split loss while preventing the shape defect occurrence of seams around the time of joining in the manufacture of solid phase bonding tube.
[Brief description of the drawings]
FIG. 1A is a plan view showing an example of a squeeze device used in the present invention , FIG. 1B is a partially cutaway side view, and FIG.
FIG. 2 is a cross-sectional view showing an inner surface rolling roll .
FIG. 3 is a schematic view showing an example of a solid-phase bonded tube production line to which the present invention is applied.
FIG. 4 is a cross-sectional view showing a horizontal squeeze device.
FIG. 5 is a cross-sectional view showing a shape defect of a pipe joined by a horizontal squeeze device.
FIG. 6 is a cross-sectional view showing a saddle type squeeze device .
[Explanation of symbols]
1 Tubular body (band steel)
2 Edge part 3 Squeeze roll 3A Seam contact roll 3C Seam pass roll 4 Joint part (Seam part)
5 Internal Rolling Rolls 6A, 6B Thickening Rolling Roll 7 Forming Roll 8 Squeeze Device 9 Roll Cart
10 tubes
11 Reaction force receiving roll
15 Heating furnace
20 Electric heating device
21 Induction heating device
30 recess

Claims (3)

The steel strip is press-formed into a tubular shape by a forming roll, and the whole of the strip and / or the tubular body and both edges are heated and then placed on a solid-phase joining pipe manufacturing line for solid-phase joining, and has a caliber. In the method for producing a solid-phase bonded tube using a squeeze device in which a plurality of squeeze rolls are arranged in the circumferential direction, and each squeeze roll narrows the outer diameter of the tubular body and presses both edges to form a seam portion. to one of the squeeze roll is made of a nonmagnetic material, it is disposed to include seam passing range to the caliber range width to the seam passing range 5 to 30% of the tube outer diameter, the depth Using a seam path roll provided with a recess having a thickness of 20 to 100% of the thickness of the strip, and further using a thickening roll disposed on the exit side of the squeeze device, the seam portion increased in thickness by the pressure welding Pressure from inside and outside the tube Method for producing a solid phase joint tube, wherein the prolong Turkey. The method for producing a solid-phase bonded tube according to claim 1, wherein the seam pass roll is formed of a ceramic material having a bending strength of 15 kgf / mm ² or more and a thermal shock temperature difference of 150 ° C or more. The method for producing a solid-phase bonded tube according to claim 1, wherein the seam pass roll and the thickening roll are formed of a ceramic material having a bending strength of 15 kgf / mm ² or more and a thermal shock temperature difference of 150 ° C or more.

Images