JPS60108118A - Fin pass roll forming method of blank pipe for electric welded steel pipe - Google Patents

Abstract

PURPOSE:To obtain an electric welded steel pipe which is excellent in a material yield and a quality of a weld zone by executing a forming for obtaining a forming flower blank pipe being approximate to a U-shape in the initial stage, subsequently, performing a rolling reduction in the direction for reducing a longitudinal diameter of its blank pipe, and also advancing partially an unbending forming. CONSTITUTION:When forming the first fin pass roll 1F, a bending of a blank pipe side part is suppressed intentionally. As a result, a reaction force f3 from the roll becomes larger than usual, and an inclination of the edge is large, therefore, thetaF can be made small. Accordingly, a component of force f1 of a rolling down force F is reduced and a component of force f2 in the radial direction is increased. As a result, a thickness increase of the edge is decreased and the rolling down force is reduced. In the subsequent forming process, a rolling reduction is executed in the direction for reducing a longitudinal diameter of the blank pipe, and also the blank pipe side part and a boundary part B of the edge part are brought to unbending. According to this method, welding is stabilized, and also an electric welded steel pipe whose material yield has been improved is obtained.

Description

Detailed Description of the Invention (Technical Field) The present invention starts with a strip, roll-forms it into an annular shape in an intermediate forming process, and then finishes it with a fin bath roll.
In the field of welding the edges of the obtained blank pipes to form Wi-sewn AW4 pipes, we propose a new technique for finishing forming using fin bath rolls.

(Conventional technology and one point in between) The general method for manufacturing ERW steel pipes with seam lines extending parallel to the pipe axis is to first cut a strip to the developed size of the ERW steel pipe to be manufactured. The plate is first formed into a predetermined shape, that is, a circular cross section, using various forming rolls in the rough and intermediate forming processes, and then the joint edges are stably formed using finned rolls in the final forming process, and then the forming process is performed. The barber tube of the predetermined shape and size is guided to a squeeze roll,
Finally, the seam edge is bath-welded. In the production of such re-seamed steel pipes, the pre-forming of the raw pipe is important for the bath-welding quality, forming yield, productivity, and mill G is an important factor that directly affects the rate of body movement, and therefore the suitability of the forming method is extremely important. In general, ? -4 Steel pipe forming method uses software technology to form a coil cross section in the forming process, i.e. forming flower, and no-ware forming step weight 1i.
We select 4t and 4 specific forming methods and perform the desired forming process by combining them. A diagram showing the process in which the ':#'f plate is sequentially formed by each roll as the J plate progresses, using the cross-sectional shape of the forming band)0. In order to reduce the forming process and forming load in fin bath roll forming, is it necessary to perform 'ilk & overall bending in advance during the rough and intermediate forming processes? It was a slow process, and it was rough.

Examples of intermediate forming methods include the circular bend method shown in Figure 1 (4), the combination molding method of circular bend and edge bend shown in Figure 1 CB), and the W-bend and circular molding method shown in Figure 1 (OJ). -Bend combination forming method, circular bend, edge bend and center pen shown in Figure 1) Also, as a conventional fin bath forming flower in the fin bath roll forming process which corresponds to the finishing process of J The molding methods shown in 5) and 2) are known. Figure 2 (4)
The method shown in Fig. 1 is a forming method that is generally referred to as Yoder and Matsukei molding flowers, and is an overall width bending method in which the entire raw pipe is rolled up while sequentially forming the width bends. . In addition, the forming method shown in ) in Fig. 2 is a forming method called Etna-type forming flower, in which the lower half of the blank tube is previously formed in the intermediate forming area to the final forming cylindrical curvature. 5 of the final molded cylindrical curvature of the upper part of the raw pipe
It is formed to a curvature of about 0 to 70 inches, and the upper part of the raw pipe is formed in the fin bath forming process. The +J curve is formed by forming, and the partial width curve where the edge part is formed by J is a processing method.

Figure 3 (4) and CB) are the above Yoder,
FIG. 2 is a diagram showing a projection locus change in the process of forming a fin bath of a raw pipe edge portion based on the idea of a Matsukei molded flower and an Etna molded flower. According to this Fig. 3, the thread tube side part σ month l'i+f
Is the directional projection locus change a gradual decrease type or constant type, and what is the crystallization direction projection locus of the raw pipe edge? It is recognized that it is a lji-reduced type. From this, it can be said that in the conventional fin bath forming method, the l1ij and l bending of the yarn tube can be achieved by the reso-use type forming method, which mainly focuses on forming.

By the way, in this Yoder/Matsukei type J7Sc type fan, since it is necessary to form the entire blank tube in each fin bath, the fin bath forming load is relatively large. Moreover, the +ii+J on the side part of the raw pipe is 4r.
As a result, roll flaws are likely to occur, and the edge opening distance of the yarn tube edges gradually becomes narrower, and the edge I/Ei distance of the winter fin bath reed becomes smaller. For this reason, the V-shape angle of the s7Lr contact portion becomes too small, causing problems such as the occurrence of type 8 welding phenomena, the occurrence of edge sparks in the ■ shape, and the occurrence of edge waves. Furthermore, since the fin angle of the upstream fin bath roll is relatively large, there is a problem that edges tend to occur.On the other hand, the Etna-type molded flour described above has a relatively large fin angle, so the Etna-type molded flour has a relatively large fin angle when compared to the Yoter-type and Matsukei-type molded flour. Although the load is reduced and the occurrence of roll defects is suppressed, the bending process of the entire strip in the intermediate forming process, especially the "A"
Finishing bends equivalent to 1,000 minutes under the tube require molding. Therefore, there was a drawback that forming a mold during the intermediate forming process was difficult. Furthermore, there is the problem of narrowing of the bath contact part V shape angle due to the narrowing of the edge interval after film force i-miffin bath forming, and the generation of edge ^ and a thickening due to the fin angle of the upstream fin bath and a size. , Yoder, and Matsukei had similar problems with molded flowers. In particular, there is a risk that the edge term will become even larger than the Yoder and Matsukei types.

In summary, there are six methods for forming conventional ERW FiA tubes, especially for processing fin bath rolls.
■The curved cross-section of the raw pipe is defective in shape, ■Poor forming at the tip and rear end of the stack, ■Insertion of fin bus forming load, ■Narrowing of the final fin width ζ
゛Decrease in the shape angle of the d-contact area, ■Occurrence of sinking at the edge of the raw pipe, ■Need to adjust the fin bus reduction due to changes in plate thickness and grade, ■N large residual stress in the circumferential direction of the raw pipe, etc. There was a 1d point in between.

(Aim of the invention [1'J and fly J 戊] The purpose of the present invention is to improve the fin bath roll forming process, which is the finish forming process, compared to the conventional lf'ij japling process. By twisting, the formability of fine large molding is completely improved, and the 43-size yield, tube shape and welding quality are excellent. An object of the present invention is to provide a method for forming an electric resistance welded 111 il tube into a fin bath roll.For this purpose, the present invention is to form a strip plate into a plate shape sequentially in an intermediate coloring process, and then to apply a fin bath. Finishing is carried out with the roll in mind - 1... and then the edges of the obtained raw pipe are welded together to form 'dih Ki'D B',... → In the process of manufacturing the pipe. For forming fin bath rolls.

First, at least by the end of the initial stage 2 of fin bath roll forming, forming is performed to obtain a formed flower tube approximately in a U-shape in which the bending process of the side part is suppressed, and in the next successive step, the longitudinal direction is By applying pressure in the direction of reducing the diameter, the side portion of the yarn tube is formed so that it gradually extends in the width direction, and only its lateral diameter is different. The above-mentioned prior art has been achieved by adopting a fin bath roll forming method for a raw pipe for ERW steel pipes, which is characterized by simultaneously bending the edge portion of the raw pipe and partially unbending the circumferential portion of the raw pipe. [Part 1] I tried to overcome point d.

(11'q composition of the invention) Fig. 4 shows the projection locus of the blank tube in the fin bath roll forming process according to the present invention. This is an example of a molded flower showing the process of forming a yarn tube in the large forming process. Figure 5 shows the shape of each stand in the case of molding using an 8-stand fimbus roll. Next, a specific example of the fin bath roll forming process according to the present invention will be explained. In the fin bath roll forming of the present invention, the forming process in the initial and intermediate forming areas, [
After that, in the first fin roll forming area, 1□lid: 1 oval flower sparrow ゛ is fυ
1% 1iii. Then, in the present invention, the yarn tube side nlsσ is
) We will achieve the functions and effects that will be explained below. First, we will explain the processing during the molding process. 〕Shin) 1 In the fimbus roll (IF), the yarn tube size vfsisσ) is used to suppress the bending process in a value diagram (final forming opening ↑n). 1. Due to this bending process in the fimbath forming process, the edge part of the raw pipe is first bent to a curvature of 80 inches or more of the curvature of the final formed cylindrical pipe, while the side part of the raw pipe, the edge part of the raw pipe, and Each boundary between the yarn tube side portion and the base tube bottom portion is formed by a first fimbath roll (IF) that can be overbended to a degree greater than the final forming cylindrical tube curvature.
The advantage of using the molding process is that the edges of the raw pipe can be easily curved, and in addition, the fiber reduction is
As the V is reduced, the horizontal type of fin bath molding becomes smaller.

In addition, FIG. 6 is a model diagram showing the system pipe forming state in the first fimbath roll and the force acting on Mif. FIG. 6 (N shows the case of fin bath roll forming according to the present invention, and FIG. 6 (J3) shows the case of forming according to the conventional forming process.

For example, as shown in No. 611, when the same rolling blade F acts in the fin bath in both the definition 3b process, in the case of the method of the present invention, the curve of the i-side portion C suppresses forming, so the roll The reaction force f8 from the blade becomes larger than that of the conventional forming/shaping blade method. Furthermore, the boundary part B between the side part C of the main pipe and the back edge part A, which has been suppressed in shaping, is overbended in the curve of the main pipe edge part A, which is larger than the curvature. Therefore, compared to conventional fin bath roll forming, the edges can be tilted, and the fin angle θF of the first fin bath roll can be made smaller. As a result, the circumferential component □, which is the component force of the fin bath reduction blade F, decreases,
The radial component element 2 increases. In addition, in the forming method of the present invention, the edge term is reduced by 1 by decreasing the circumferential direction component 1, and the bending of the edge portion of the raw pipe is radial direction component 2/, C and uiJ roll. The reaction force f8 from
・By increasing a, the moment that acts on the edge portion becomes larger, making it easier to achieve %W. Therefore, in the l-th fin bath forming process in the method of the present invention, compared to the conventional forming process, the one term of the base edge is reduced n1 and the fin bath reduction blade can be reduced.

Next, the 2nd finbath roll (2F) at f5° to the 1st finbath roll (CIF), and the 43rd finbath roll (
In the forming process in step 3F), the side part C of the raw pipe is restrained from being bent by the first fimbath roll (IF) by mainly applying a reduction in the direction of reducing the vertical diameter of the raw pipe.
The pipes are sequentially stretched in the width direction and formed so that the horizontally assembled pipe is the front layer. If this side part 9-extrusion forming process is carried out, the bending process of the side part of the raw pipe and the first
The curves of the side part of the raw tube, the edge part of the purple tube, and each boundary part B between the side part of the raw tube and the bottom part of the raw tube, which have been overbend formed with a fimbath roll (IF), are returned to the original shape.

In addition, for the fluorescent molding of the base pipe site part on the second fimbus roll, the entire part where the first fimbus roll was formed was gradually exposed and curved until the predetermined opening is reached. Also, similar to the m-shaped process using Hz fin bath rolls, it is possible to suppress the bending of the side part of the raw pipe and gradually reduce the bending acceptance area, and perform overhang bending, 〇In the fin bath roll forming according to the present invention, forming is performed such that the side part of the blank tube is gradually increased by rolling out the side portion of the blank tube, so that the final fin bath roll is Edge spacing (
It is possible to increase the external degree of sieving (θV) of the WaF and bath contact portions. Therefore, welding with squeeze rolls becomes stable and quality improves.

In addition, according to the method of the present invention, since the overbend-formed area with the first fimbus roll is bent back and formed after the second fimbus roll, the formed part is formed as shown in FIG. The direction of the moment in the circumferential component of the processed part is different from that of the conventional molded element a' shown in Figure 7 (■), and the moment B is in the direction of rounding the nest. Therefore, the height of the product surface in the bath contact area is stepped.

Figure 8 shows an example of the flower-shaped shape of the finn bath roll to make the finn bath method of the present invention effective. roll hole, profile dimensions Ri and θ1 (i-1 to 5), vertical diameter (H), horizontal writing (tv
), fin 1IIIi (WF), fin angle (θk・
) may be changed sequentially. For example, H, WF.

θB= r RB , θ8 is reduced to the A order, W +
R2+θ2 + R4+θ.

There is a way to make it into a 4+1 hole V shape that allows for the addition of a solid base.

In addition, as another embodiment of the present invention, 19! !
Instead, it is also possible to extend the hole to the squeeze roll at the stage of forming the fin bath roll of the present invention, and to form a polygonal squeeze roll hole shape as shown in FIG. 8, for example. In this case, the fin bath roll forming in the present invention is reduced, and the tlh Irf forming control part of the raw tg sa() part is maintained until the squeeze roll forming or the pull-out roll after squeeze roll forming, The above-mentioned 5Ji extrusion molding process will be performed in the later process of sizer molding. As described above, by applying the method of the present invention to the fin bath and squeeze roll forming regions, rotation of the raw tube in the circumferential direction is prevented, and twisting of the welded portion of the yarn tube in the circumferential direction can be prevented. This makes it possible to stabilize bead cutting, seam annealing, and bath welding conditions. It becomes possible to manufacture Lu-sewn pipes with the shape quality of the '64 bulge shape.

Furthermore, in the above description, three-stand fin bath roll forming was explained as an example, but the present invention is applicable to fin bath roll forming Jlt using other stands. Furthermore, the present invention is not limited to the dividing method of the Finno-crusted roll, ie, the 20-le type or the 40-le type, and any shape or shape of the black can be used as long as it achieves the object 11'J of the present invention. It may also be possible to use rolls and devices that provide reliable construction.

Furthermore, in the above-mentioned specific example of the method of the present invention, an example was shown in which the blank tube and pop-out molding were applied to the bales after the second fimbus. It is also possible to apply this method to the case where the molding process is carried out at an early stage of υ1d, and then the entire molding process is performed by extruding from the first fimba roll.

・(Example) The "A" tube forming in the rough and intermediate forming areas was carried out by the cage roll forming method using the combination forming method of circular bend and edge bend as shown in Section IIA), and the fin bath roll forming was performed using the conventional method. The molding method, for example, is shown in Figure 2 (4
) and the molding method using the one-way molding flower method shown in the specific example of the present invention, the outer diameter of 24
inch, wall thickness 16.0”sW standard API 5LX -X
60 and 26 inch outer diameter, 6.36 mm wall thickness, and pipe standard API5LX-X56 electric resistance welded steel pipes. Shape load, td
A comparison and trial sale of each product was conducted regarding the occurrence of V-shape sparks during contact. The results are shown in Table 1.

According to Table 1, the forming method according to the present invention achieves light reduction forming of two-in-bath rolls, reduces the fin path total reduction by 50 to 70 inches, and reduces the fin path reduction compared to the conventional method. 85-50 of space forming/load
% reduction is achieved. In addition, the 5-edge Rinku skewer is less than 50 tib of the garden tree, which stabilizes the cutting of the inner bead and prevents defects in wall thickness due to edge ^ and d thickness in thick materials. Figure 9 is shown above. This figure compares the pulp-like bulge (at the edge part of the raw pipe after fin bath forming in 24-inch material) with that obtained by the conventional method. It is recognized that the method of the present invention has the ability to significantly reduce the amount of ↓ and d meat in the meat. In addition, according to the method of the present invention, the open length due to poor molding of the tip and rear end of the yarn tube was reduced by 50% compared to the conventional method.
The passing rate of the super vinegar wave test at the bath contact area was also improved by 5%. Furthermore, since the direction of the residual bending moment in the circumferential direction of the filament tube after fin bath roll forming is improved, the springback of the yarn tube is 1.
It is LJJ to directly reduce and obtain a welded pipe with a predetermined shape and size.
Becomes Noh.

Moreover, in the method of the present invention, manufacturing is difficult in terms of formability l and strength with Niwagi's fin bath roll forming method.
Equivalent to 26 inches x 6.0 mm (X60), then t
/, D - 4,3 multi-411 20 inch x 22 space (X
The stable production of 5B) resulted in uJ's ability. Furthermore, the roll tit:j adjustment time was reduced by 40 times compared to the conventional forming method due to the change in the pipe forming diameter.

Note that the present invention is applicable not only to circular tubes but also to the manufacture and construction of square tubes.
The bending of the edge part of the raw pipe during the roll forming stage can be formed, and the force that can prevent the edge part from forming), the reduction of the forming load by +NI OR of fin bus reduction, and the reduction by +1 by changing the plate thickness grade! This eliminates the need for maintenance. In addition, it is possible to enlarge the V-shave angle of the bath contact part by increasing the fin 'l'i+f^''d of the final fin bath roll, and to reduce the residual 11L1 force in the circumferential direction of the raw pipe. Due to material yield,
ERW with superior pipe shape and weld quality: 1.・It is possible to manufacture i-tubes. Furthermore, it is possible to improve the mill operation rate and expand the production area.

[Brief explanation of drawings]

Figures 1 (4) to (D) are model diagrams showing molded flowers in the conventional molding method, Figures 2 (5) and (B) are model diagrams showing conventional fimbass molded flowers, and Figure 3 ( A) and (J3) are conventional fin bath formation J
FIG. 4 is a projected locus line showing the process of forming a raw tube by the lj method, and FIG.
Figure 6 (g) is a model diagram showing the molded flower of the raw tube edge parting and raw tube hole forming processes in fin bath forming that replaces the fin bath roll according to the present invention. Figure 7 (g) is a model diagram showing the moment of residual bending in the circumferential direction of the welded pipe formed according to the present invention; Figure 7 (B)
is a model diagram showing the moment of residual bending in the circumferential direction of t6-a formed by a conventional forming method. Figure 8 is a line diagram showing an example of the hole shape of a fin bath roll in which the fin bath forming process according to the present invention can be performed. This is a diagram comparing the wall thickness distribution of the edge part of the raw pipe after rolling. ...
Fin angle W8F of fin bath roll...Edge spacing IF of fin bath roll...41 Fin bath roll forming 2F...Second fin bath roll forming 8F...Eighth fin bath roll forming W. ...Horizontal set H...Vertical diameter θi, Ri...Roll hole J and shape dimension A...Edge part B...Boundary part C...Side part. Figure 1 rA> Figure 1 CC) Figure 1 CD) Figure 2 (A) Figure 2 (B) lFfii'+ fF 2F 3F SQ Figure 3 (B) Figure 4 Figure 5 rA> 7 <A) Figure 6rB) Figure <B)

Claims (1)

[Claims] L @ The board is formed into a clay shape in the rough and intermediate forming process, then guided to a fin bath roll and processed for finishing.
The end faces of the edge portions of the obtained raw pipe are welded to each other for fin bath roll forming in the process of manufacturing ERW steel pipes. First, the side portions are welded together at least until the initial stage of fin bath roll forming is completed. Forming was carried out to obtain a molded 7-flour blank tube with a U-shaped approximation that had undergone bending process, and in the next successive step, a pressure reduction was applied to the tjU-marked blank in the direction of reducing its longitudinal diameter. System pipe side part is 'I'l+1
Forming is carried out so that only the narrow diameter of the tube gradually protrudes in the direction of 73L, which is characterized in that the surface undergoes back molding at the same time.
A method for forming fin bath rolls for sewn steel pipes.