JPS60184419A - Formation of square-shaped metallic blank pipe having embossed work - Google Patents

Abstract

PURPOSE:To form a titled square-shaped metallic blank pipe which is excellent in a collapse load strength by pinching the vicinity of the embossed end part by upper and lower rolls in a rough forming roll and setting it as a bending point, when obtaining a square-shaped blank pipe from a steel band on which an embossed pattern has been worked. CONSTITUTION:When an embossed pattern 30 is worked at an interval on a steel band, and a square-shaped blank pipe having a weld joint on one side is obtained by roll forming, the steel band is pressed by an upper roll 15-2 and a lower roll 15-1 in a rough forming roll 15. A caliber R is provided on the upper roll 15-2, and a part between the roll center and a width W2 is not subjected to the roll forming. A part of the steel band corresponding to a width W1 is pinched by the upper and the lower rolls 15-1, 15-2, and formed roughly by setting a point P as a bending point. This point P is made to coincide with the vicinity of the end part of the embossed pattern 30. In this way, a collapse load strength of the steel band can be increased by about 40%.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for forming a rectangular metal tube having an embossed pattern.

By applying equal pitch embossing on both sides of the rectangular metal pipe, the crushing load strength per unit area against vertical loads in the same direction as the embossed surface is higher than that of normal rectangular metal steel pipes of the same size. , it has been experimentally confirmed that the load strength is about three times as high.

Hereinafter, in the present invention, embossing refers to carving grooves at intervals on both side surfaces of a rectangular metal pipe adjacent to the welding surface.

FIG. 1 shows a metal tube 31 on which embossed patterns 30 are carved at equal pitches.

The applicant previously obtained the following through Japanese Patent Application No. 58-218686.
Incorporating an embossing roll into the pipe production line for square metal pipes,
A method for forming a rectangular blank tube with an embossed pattern by continuous roll forming was proposed.

That is, FIG. 2 is an example of a continuous pipe production line.

In the figure, an uncoiler 10, a strip material 11, an embossing roll 14, a pinch roll 13. Rough forming roll 15, fin pass roll 16. High frequency welding device 17, squeeze roll 1B, cooling zone 19. sizing roll 20,
The Radroll 21° shearing device 22 is shown in Turks.

The strip material used may be a strip, a slit coil, or a plate material, and the strip material has a predetermined width depending on the size of the rectangular metal tube to be manufactured.) Coiled materials such as IJ tubes are passed through an uncoiler and embossed. introduced into the role. Embossed patterns are formed at equal intervals on both sides of the square metal tube.

FIG. 3 is a flower diagram of roll forming of a rectangular blank pipe. It consists of a rough forming process 15 and a finishing forming process 16. 30 indicates an embossed pattern.

FIG. 4 is a partial schematic diagram of a rough forming roll 15 in a conventional method. The lower roll 15-1 and the upper roll 15-2 constitute a rough forming roll]5, and the upper roll 15-2 is provided with a caliber B. 11 is embossed pattern 3 with band material
0 is set. That is, in the conventional method, the profile of the upper and lower rolls of the belt was such that a point P at a length h from the end of the embossing 30 was the bending point of the strip material. Therefore, since the length hσ is not necessarily specified at the roll design stage, there is a disadvantage that a sufficient embossing effect cannot be expected.

An object of the present invention is to propose a method for continuously forming a rectangular metal tube having an embossed pattern with excellent crushing load strength.

That is, the gist of the present invention is to process a steel strip with embossed patterns at intervals, and then to roll form the steel strip to obtain a rectangular blank pipe having a welded seam on the - side. The purpose is to perform forming by inserting it at the bending point and forming it at the bending point.

The present invention will be explained in detail below with reference to the drawings.

FIG. 5 is a partial schematic diagram of the rough forming roll of the present invention.

In the figure, the rough forming roll 15 is composed of a lower roll [5-] and an upper roll 15-2. In the roll profile of the present invention, Caliber R is provided on the upper roll 15-2, but
Roll forming is not performed during roll center c and width w2. That is, the portion of the band material 11 corresponding to the width w1 is
It is sandwiched between the lower roll 15-1 and the first roll 15-2, and a bending point in rough forming is formed at point P. Therefore, the point P coincides with the closest end of the 3° embossed pattern formed on the strip material 11.

According to experiments, when the dimensions h2 between the end of the embossed pattern and the top and bottom corners exceed approximately 10m5, buckling occurs and the embossment does not work effectively.

FIG. 6 is a partial schematic diagram of the fin pass roll according to the present invention. In the figure, fin pass roll 1
6 is the lower roll 1.6-1. It is formed from the upper roll 16-2. In the present invention, the width W of the band material 11.

and W3 are each provided with a roll profile giving the curvature formula +R2. In other words, when forming a post-arc blank tube, the edges of the upper side are already bent to prevent green liquid during embossing, and by giving a curvature R to the lower side, it is possible to form with a well-balanced cross section. This makes it easy to adjust the rolls, which is convenient for finishing the shape after welding.

As described above, in the present invention, during rough forming, the area immediately adjacent to the embossed end is sandwiched between upper and lower rolls to form a bending point.
In order to form a band material embossed at equal pitches in the longitudinal direction of the band material 1], the upper roll corresponding to W2 of the band material 11 may be partially cut out.

Furthermore, the application of fin pass rolls to impart a desired curvature to the upper and lower sides of the blank tube during final forming may be employed at the appropriate time, taking into account the thickness, material, etc. of the strip material.

51 According to the present invention, since the bending point is formed near the end IN of the embossed pattern, the crushing load strength increases. Next, the test results will be shown.

According to the present invention, the thickness of the strip material is 1.6 mm, the material is 8841, the emboss depth is 5.0 mm, the emboss pitch is 40',
Emboss length 1150 (50/60 = 83 sections),
A load test was conducted on a rectangular steel pipe with a length of 240 cm, which was formed into a 60 x 60 mm shape as shown in Figure 9 by processing b, , h2 dimensions of 5.0 mm, and the crushing load was 10. It was '75t.

12 was set as 3.0 fights. Shows the welding position.

As a comparative example, the embossing length is 40 +ys (40/6
Assuming that the dimensions were 10.0 mm and the other specifications were the same, the crushing load was 7.70 tons.

As is clear from the above explanation, the crushing load strength can be increased by 40% in the above example depending on the distance from the embossed end to the bending point P, and the present invention is a rectangular steel pipe that fully utilizes the embossing effect. With the molding method, the industrial effect is a dog.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a square steel pipe with an embossed pattern, Fig. 2 is a forming process diagram of the square steel pipe, Fig. 5 is a flower diagram of roll forming, Fig. 4 is a schematic diagram of the roll arrangement of the conventional method, FIG. 5 is a schematic diagram of the roll arrangement of the present invention, FIG. 6 is a schematic diagram of the roll arrangement for finish forming of the present invention, and FIG. 7 is a schematic diagram of a cross section of a square steel pipe. 14; Embossing roll 15; Rough ffl-shaped roll] 6;
Shaping forming roll 20; Defined forming roll 71 Figure 1e Opening a6U-184419LOJ Figure 7

Claims (1)

[Claims] In this method, a copper strip is processed with embossed patterns at intervals, and then roll-formed to obtain a rectangular blank pipe with a welded seam on the - side.The area closest to the embossed end is sandwiched between upper and lower rolls to serve as the bending point. A method for forming a rectangular metal tube having an embossed pattern, which is characterized by performing rough forming.