JPH07100528A - Production of special shaped tube excellent in shape property - Google Patents

Abstract

PURPOSE:To obtain a special shaped tube whose dimensions of corner parts are smaller and which is excellent in flatness in planar parts. CONSTITUTION:By rolling using a grooving roll and grinding, Vgrooves G1-G8 which are extended in the longitudinal direction are formed on a strip material S. The strip material S is bent in the width direction taking the V-grooves G1-G8 as valley bending lines, butt welding J or lap welding H is executed in both end parts in the width direction. Then, the V-grooves G1-G8 are preferentially crooked at the time of bending, so the dimensions of the corner parts are smaller and straight-line-like corner parts C1-C8 along the longitudinal direction of the strip material S is obtained. And, since bending stresses that act on the planar parts P1-P8 are mitigated, the planar parts P1-P8 after bending have higher flatness, groove shape or overlapping state is unified and welding condition is stabilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a deformed pipe such as a square pipe having excellent flatness in a flat portion and small corner portions.

[0002]

2. Description of the Related Art Square tubes having a rectangular cross section are used as columns, fences, handrails, etc. that give a sense of mass. Further, in sashes for window frames and the like, deformed pipes having various modified cross sections are used. This type of deformed pipe is a method of bending a long material with a broken line in the longitudinal direction and butt-welding or overlapping welding both ends in the width direction, and a deformed shape such as a rectangular shape of a pipe-shaped ERW steel pipe with a forming roll. It is manufactured by the method of processing the cross section. For example, the actual exploitation Sho 63-11122
No. 0 gazette discloses that a square tube is manufactured by processing a cylindrical electric resistance welded steel tube with a forming roll.
In addition, Japanese Patent Publication No. 60-199523 discloses a method of bending a strip into a substantially rectangular cross-section and then butt-welding both ends. At this time, the rigidity in the longitudinal direction of the strip is increased by the formation of the welding line, and a rectangular tube having a desired rectangular cross section is obtained while suppressing the occurrence of waviness at the edge. Further, Japanese Patent Publication No. 58-500511 discloses a method of manufacturing a deformed tube by bending with a groove formed by an etching press inside.

[0003]

When manufacturing a square tube from a round tube such as an electric resistance welded steel tube, the material strength is different between the welded portion and the base material portion, and therefore uniform work deformation in the circumferential direction is required. Difficult to do. Therefore, the molded square tube is
It tends to have a cross-sectional shape displaced from the target rectangular cross-section. On the other hand, when manufacturing a square tube by butt-welding or superposing-welding the width direction both ends of the strip material bent at right angles with respect to the width direction, the groove shape is apt to change in the longitudinal direction of the strip material. Therefore, it becomes difficult to weld both widthwise end portions under constant welding conditions, which causes burn-through,
Weld defects such as insufficient penetration are likely to occur. In addition, since the groove bottom formed by the edge-pressing is flattened or rounded, the linearity of the corner formed when the strip is bent in the width direction is poor. In either method, the flat surface of the obtained rectangular tube does not have sufficient flatness. Therefore, the flatness of the flat surface portion is improved by partially grinding the convex portion. However, grinding may take a lot of time. Also, there are some which cannot be ground after molding. As a result, the flatness of the flat portion is poor, and the commercial value is reduced.

In addition, in the use as a decorative building material, in order to have harmony with other building materials and to improve the appearance,
Small corner dimensions are required. However, when a rectangular cross-section is formed by using a forming roll or the like, a relatively large radius is generated at the corner. Even when the size of the corner portion is reduced, the formed square tube is subjected to cutting work or the like. If good shape characteristics can be obtained at the manufacturing stage of the deformed pipe, cutting work for improving the flatness of the flat surface portion or reducing the corner portion size can be reduced or omitted. However, so far, no practical method has been proposed for forming a target shape or a shape close to the target shape at the manufacturing stage. The present invention has been devised in order to solve such a problem, and by bending the strip material with the V groove, the bent portion is concentrated at the tip of the V groove, and the linearity of the corner portion is excellent. The object of the present invention is to obtain a deformed pipe having a flat portion with high flatness and a small corner portion size.

[0005]

In order to achieve the object, the method for manufacturing a deformed pipe according to the present invention comprises forming three or more V-grooves extending in the longitudinal direction on a strip and using the V-grooves as valley fold lines. After bending the strip in the width direction with a forming roll to form a profiled tube, the widthwise ends of the strip located in the plane of the profiled pipe are abutted or the widthwise opposite planes are overlapped and welded. It is characterized by The V groove is formed by rolling a strip between a grooving roll having a plurality of protrusions that circulate around the roll body and a flat roll, or between a pair of grooving rolls. Alternatively, the V groove can be formed by cutting the strip in the longitudinal direction. Further, the formation of the V groove, the shaping of the deformed pipe, and the welding can be continued in one production line.

In the following description, a deformed tube having a rectangular cross section as a basis and a concave portion formed in a part thereof is taken as an example.
However, the present invention is not restricted to this, and is similarly applied to a deformed pipe having a cross-sectional shape based on a triangle, a hexagon, etc. as long as the bending deformation is concentrated in the V groove. The modified pipe used as the sash for the window frame has a modified cross-sectional shape as shown in FIG. In order to obtain the flat portions P _{1 to} P ₈ having excellent flatness, the widthwise end portions of the strip material bent in the width direction by the forming rolls are more than the method of forming a round pipe such as an electric resistance welded steel pipe into a deformed pipe. Butt welding or superposition welding are suitable. As shown in FIG. 2, V grooves G _{1 to} G ₈ along the longitudinal direction of the strip S are formed in the inner corner portions when the strip is bent in the width direction with a forming roll. The rigid body strength of the bent portion is locally reduced by the V grooves G _{1 to} G ₈ . Therefore, when the strip S is bent in the width direction by the forming roll, the force is concentrated on the corners C _{1 to} C ₈ in preference to the flat portions P _{1 to} P ₈ . As a result, the flat portions P _{1 to} P ₈ having a high degree of flatness as well as the corner portions C _{1 to} C _{8 having} a small dimension are formed.
Is formed. Moreover, the corners C _{1 to} C ₈ have excellent linearity in the longitudinal direction of the strip S.

The V-grooves G _{1 to} G ₈ are preferably V-grooves having a shape such that the flat portions P _{1 to} P ₈ adjacent to each other when the strip material S is formed by a forming roll do not interfere with each other. .
To form the V-grooves G _{1 to} G ₈ , for example, as shown in FIG. 3, a grooved roll W ₁ having protrusions T _{2 to} T ₇ formed in the circumferential direction around the roll body is formed by using a similar protrusion T _1. , opposite placed grooving roll W ₂ with T _8, grooving roll W ₁ and W
_The method of passing the strip S between the _two and the _two is adopted. When the strip S passes through the roll gap between the grooving rolls W ₁ and W ₂ , the protrusions T _{1 to} T ₈ form V grooves G _{1 to} G ₈ extending in the longitudinal direction of the strip S. In the case of FIG. 3, since V grooves G _{1 to} G ₈ are formed on both surfaces of the strip S, grooved rolls W ₁ and W ₂ having protrusions T _{1 to} T ₈ formed on both work rolls are used. are doing. However, when the V groove is formed only on one surface of the strip S, a flat roll is used as one of the work rolls. Alternatively, the same V grooves G _{1 to} G ₈ are formed by cutting a part of the surface of the strip S in the longitudinal direction with a cutting tool.

The roll pair shown in FIG. 3 is incorporated in the rolling apparatus 10 of the profiled pipe manufacturing line shown in FIG. The rolling apparatus 10 includes the strip material S ₀ unwound from the payoff reel 11.
Is sent to the rolling roll 13 by the deflector roll 12. The rolling roll 13 includes a pair of grooving rolls W ₁ and W ₂ shown in FIG. 3, and either one or both can be moved so that the roll gap can be adjusted. Strip S ₀ is grooved when passing through the roll gap of the roll W _1, W _2, projections T ₁ through T ₈ V grooves G ₁ ~G ₈ grooved strip S ₁ which is attached extending in the longitudinal direction by Becomes The grooved strip S ₁ is continuously fed to the subsequent profiled pipe forming apparatus 20. In the layout of FIG. 4A, the grooved strip S ₁ is fed to the bridle roll 15 via the deflector roll 14 and given an appropriate tension. By applying the tension by the bridle roll 15, the strip S ₀ being rolled is maintained in the tension applied state. The tension can be applied not only by the bridle roll 15 but also by the take-up reel 16 as shown in FIG. Figure 4
In the layout of (b), the grooved strip S ₁ is once wound on the take-up reel 16 and then the grooved strip S ₁ is unwound from the payoff reel 17 again.
Send to.

The deformed tube forming apparatus 20 comprises a deflector roll 21, a pinch roll 22, a leveler 23, and a shear 2.
4, forming roll stand 25, welding machine 26 and shear 2
It is composed of 7. The grooved strip S ₁ delivered by the pinch roll 22 has its curl corrected by the leveler 23,
The shear 24 cuts the strip material S ₂ . The constant length strip S ₂ is bent in the width direction while passing through the plurality of forming roll stands 25 along the V grooves G _{1 to} G ₈ as valley fold lines, and becomes a deformed pipe S ₃ having a predetermined cross-sectional shape. In the present invention, it is also possible to use the standard length strip S ₂ as a starting material. In this case, as shown in the layout of FIG. 4C, one by one is taken out from the stocked standard length strip S ₂ by the feeder 28, passed through the deflector roll 21, the pinch roll 22 and the leveler 23, and then formed. The roll stand 25 is formed into a predetermined sectional shape.

The forming roll stand 25 has a V inside G from the V grooves G ₁ and G ₈ near both ends in the width direction of the grooved standard length strip S _2.
V-groove G _{1 in} the order of grooves G ₂ , G ₇ → G ₄ , G ₅
Bend in a stepwise manner using G ₈ as a valley line. At this time, the constant length strip material S ₂ with grooves is accurately bent along the V grooves G _{1 to} G ₈ and the bending stress acting on the flat portions P _{1 to} P ₈ is relaxed. Therefore, in the deformed tube S ₃ , the flat portions P _{1 to} P ₈ are excellent in flatness, and the corner portion C has a small corner portion size.
_{It has 1 to} C ₈ . Further, since the widthwise edges and the flat portions at both ends in the width direction of the standard length strip S ₂ do not deform irregularly, when the widthwise ends are abutted or overlapped with each other as shown in FIG. The groove shape or the superposed state is obtained. Therefore, the welding conditions by the welder 26 are stabilized, and the welded portions H and J having uniform beads can be obtained. After being welded by the welder 26, the welded profile pipe S ₄ is
Then, it is cut to a fixed length to form the product deformed tube S ₅ . In addition, welding machine 2
It is also possible to employ a method in which 6 is arranged on the downstream side of the shear 27, and the widthwise both ends of the strip material cut by the shear 27 to a constant length are butt-welded or superposed and welded.

[0011]

According to the present invention, after forming the V grooves G ₁ ~G ₈ extending in the longitudinal direction of the strip S, folding the strip S in the width direction along the V groove G ₁ ~G _8, deformed cross It is assumed to be a deformed tube with. The V-grooves G _{1 to} G ₈ act as valley crease lines during bending with a forming roll, and the bent strip S
The corners C _{1 to} C ₈ of the strip are regulated linearly along the longitudinal direction of the strip S. Therefore, accurate bending along the V grooves G _{1 to} G ₈ is possible. The V grooves G _{1 to} G ₈ apply the force applied to the strip S during bending to the groove tips, that is, the corners C ₁ to C.
₈ to reduce the bending stress acting on the plane portions P _{1 to} P ₈ . Therefore, the flatness of the plane portions P _{1 to} P ₈ is maintained as it is. In particular, since the widthwise edges of the strip S and the flat portions P ₁ and P _{8 at} both ends do not change irregularly, a constant groove shape or a superposed portion can be obtained and welding conditions are stabilized. Thus, according to the present invention, the corner C ₁
Excellent flatness linearity and flat portions P ₁ to P ₈ of -C _8,
A deformed pipe such as a square pipe having a small corner size and a sound weld can be obtained. Further, since the formation of the V grooves G _{1 to} G ₈ and the bending / welding to the deformed pipe can be performed in a consistent line, a highly efficient and highly productive production line is constructed.

[0012]

EXAMPLES As a grooved roll W ₁ , a body having an outer diameter of 400 mm and a body length of 300 mm was formed, and projections T _{2 to} T ₇ were formed at positions 26 mm, 58 mm and 74 mm apart from the center of the body in both end directions. Used a roll. Protrusion T ₂ ~ T
₇ had a tip angle of 90 degrees and a height of 1 mm, and had a pointed triangular cross section. The other grooved roll W
_{For No. 2} , a roll having a body portion having an outer diameter of 400 mm and a body length of 300 mm and having similar protrusions T ₁ and T ₈ formed at positions 89 mm apart from the center of the body portion in both end directions was used. With a rolling stand incorporating the grooved rolls W ₁ and W ₂ as a pair of work rolls, a plate thickness of 1.5 mm and a plate width of 2
A 04 mm stainless steel strip was rolled. The grooved rolls W ₁ and W _{2 have} a peripheral speed of 2 m / sec, a rolling reduction of 50% in one pass, and a V-groove G _{1 on the} strip S by one-pass rolling without using rolling oil. to form a ~G _8. When the surface of the rolled strip S was observed, V grooves G _{1 to} G
₈ had a uniform shape with a width of 0.8 mm and a depth of 0.4 mm.

The strip material S having the V grooves G _{1 to} G ₈ is
It was bent in the width direction with a forming roll stand 25 of steps. Bending at this time is performed by V-grooves G ₁ and G near both ends in the width direction.
_{From 8} to the inner V-grooves G ₂ , G ₇ → G ₄ , G ₅ were successively carried out in each stand, and molded into a deformed pipe having a cross-sectional shape shown in FIG. Both ends of the bent width direction were butted against each other and continuously TIG welded. The welded deformed pipe was cut with a shear 27 at intervals of 3 m to obtain a product deformed pipe of a fixed length. When the cross section of the product profiled tube was observed, as shown in FIG. 5A, plane parts P _{1 to} P ₈ having extremely high flatness were formed. Further, the corner portions C _{1 to} C ₈ located between the adjacent flat surface portions P _{1 to} P ₈ are linear, have a constant angle along the longitudinal direction of the strip S, and have a small corner radius. there were.

For comparison, a flat stainless steel strip was similarly bent without forming a V groove. The obtained profiled tube has flat portions P _{1 to} P _{8 as} shown in FIG.
Was inferior in flatness. Further, as shown by the flat portion P ₅ located between the corner portion C ₄ and the corner portion C _5, greater curvature in the vicinity of due to the spring back caused by bending the corners C _4, C ₅ occurs It was a flat part that was slightly receded from the rectangular cross section. In addition, a waviness of ± 0.05 mm was generated in the plane portions P _{1 to} P ₈ in the longitudinal direction, and the angles of the corner portions C _{1 to} C ₈ also changed irregularly. For each of the bent deformed pipes, the flat surface portions P _{1 to} P ₈
The length from the radius start position to the radius end position, that is, the corner size was measured. According to the present invention, V-grooves G ₁ -G
_{In the case} of bending after forming ₈ (FIG. 5 a), the corner size remains about 1.1 mm, and the corners C _{1 to} C ₈
The Earl had an irregular cross section that gave an inconspicuous and sharp impression. On the other hand, in the case where the stainless steel strip was bent without forming the V grooves G _{1 to} G ₈ (FIG. 5b), the corner size was as large as about 2.6 mm.

In the case of bending after forming the V grooves G _{1 to} G ₈ (FIG. 5A), a constant groove shape was obtained after molding. Therefore, when the both ends in the width direction were butt-welded by TIG welding, welding could be performed under stable conditions without causing welding defects such as burn-through and insufficient penetration. Also,
The welds formed exhibited great joint strength. The obtained product deformed pipe did not require grinding for reducing the corner size, and could be used as a sash in the as-welded state. On the other hand, in the case where the stainless steel strip is bent without forming the V-grooves G _{1 to} G ₈ (FIG. 5 b), since waviness is generated in the flat surfaces at both ends in the width direction, both ends in the width direction are parted. When they were butted, the groove gap was fluctuating. Due to this fluctuation, the welding conditions became unstable and welding defects such as burn-through and insufficient penetration occurred. Moreover, in the deformed tube obtained after welding, it was necessary to cut the corners and their periphery in order to reduce the size of the corners and give a sharp impression.

[0016]

As described above, according to the present invention, a V-shaped groove in the longitudinal direction is formed in the strip, and the strip is continuously bent along the V-shaped groove to form a deformed shape such as a square tube. Manufactured into tubes. Since the V groove acts as a valley fold line, the strip can be bent at a right angle with a small corner size, and the flatness of the flat surface facing the corner can be increased. Therefore, the deformed pipe manufactured by welding the bent strip material has excellent shape characteristics, and the grinding process can be reduced or omitted.
In addition, since the straightness of the corners and the flatness of the flat surface are high, a constant groove shape or a superposed state is obtained when the widthwise both ends are abutted or overlapped, and welding under stable conditions is performed. Is possible. Further, when the V-groove forming, roll forming, and welding processes are successively performed in sequence, various deformed pipes are manufactured in an integrated line, so that productivity can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of a deformed pipe to which the present invention is applied.

[Fig. 2] A process of bending the strip into an irregular cross-sectional shape.

FIG. 3 is a strip material threaded between a pair of grooved rolls.

FIG. 4 is a modified pipe manufacturing line, in which (a) is a continuous modified pipe forming line in which a V-groove forming and rolling line and a modified pipe forming line are directly connected, and (b) shows V-groove forming and deforming pipe forming independently. Line, (c) is a line for continuously forming deformed pipes from cut plate-shaped strips

FIG. 5 shows a cross-sectional shape of a bent strip material,
(A) shows a V-groove formed after bending, and (b) shows a flat band formed by bending.

[Explanation of symbols]

S: strip material, S ₀ : strip material (material), S ₁ : grooved strip material, S ₂ : standard length strip material, S ₃ : deformed pipe, S ₄ : welded deformed pipe, S ₅ : product deformed pipe G _{1 to} G ₈ : V groove, P _{1 to} P ₈ : flat surface portion, C _{1 to} C
₈ : Corner W ₁ , W ₂ : Grooving roll, T _{1 to} T ₈ : V-groove forming protrusion H: Overlap portion, J: Butt portion

Claims (3)

[Claims] 1. After forming three or more V-grooves extending in the longitudinal direction in a strip, and bending the strip in the width direction with a forming roll to form a deformed tube, the V-grooves serving as valley fold lines. A method for producing a deformed pipe, characterized in that the widthwise ends of the strip located in the flat portion of the deformed pipe are abutted with each other or the flat portions at both widthwise ends are overlapped and welded. 2. The deformed pipe manufacturing method according to claim 1, wherein the V groove is formed by a grooved roll having a plurality of protrusions that circulate around a roll body. 3. The method for manufacturing a deformed pipe according to claim 1, wherein the V groove is formed by cutting a strip material in a longitudinal direction.