JPS6372425A - Metal tube manufacturing method - Google Patents

Abstract

(57) [Abstract] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for manufacturing a metal tube, and in particular, a metal strip slit to a width corresponding to the diameter of the metal tube to be formed is formed into a tube shape, and The present invention relates to a method of manufacturing a metal tube in which the end faces of the metal tube are welded to form a tube body.

(Prior art) Generally, metal tubes are made by cutting a wide metal strip into a predetermined width according to the tube diameter, forming a narrow metal strip 1 into a tubular shape, and then forming the narrow metal strip 1 into a tubular shape, as shown in FIG. A metal tube 2 is formed by welding 1a and 1a. In this way, a long metal tube with a desired outer diameter and wall thickness is produced.

Next, this long metal tube 2 is cut into lengths according to the purpose and used, thereby improving productivity.

(Problems to be Solved by the Invention) However, in the above-mentioned conventional metal tube manufacturing method, when forming the metal strip 1 into a tube shape, slitting occurs on each end surface 1a, 1a. Since the metal strip 1 is supplied and formed so that the metal strips 1b, 1b formed on the inside of the metal tube 2, the metal strips 1b, 1b melt during welding and the metal is spattered. The spatter tends to fly off into the tube 2, and the scattered spatter remains inside the metal tube 2 or adheres to the inner surface, becoming residual spatter. When the metal tube 2 with such residual spatter is used as a fluid passage, for example, a fuel passage in an automobile, the spatter may gradually peel off due to the flow of fuel and be carried into the engine with the fuel, causing damage. There is a problem.

In addition, in some cases, as shown in FIG. 5, these metal tubes 1b, 1b may solidify as they are and become protrusions 1d, and when such a metal tube 2 is bent, the protrusions are formed. There is a problem in that cracks are likely to occur in the welded portion 3 due to the influence of 1d.

Further, when fluid is caused to flow into the metal tube 2, there is a problem that the inner surface of the metal tube 2 is easily oxidized due to the protrusion 1d.

Furthermore, for example, as shown in FIG.
(If large spatter (about 0.6 tm) 6 occurs when forming a metal band into a tube shape and welding it while wrapping the flux 5, draw the welding wire 4 even thinner after forming the tube. When making a thin welding wire with an outer diameter of about 1.2 fins, the flux 5 may be interrupted at that part due to the spatter 6. When such a welding wire is used, the flux 5 may be interrupted. There are problems such as the arc becoming unstable or poor welding occurring at the locations where the welding occurs.

The occurrence of spatter can be suppressed by removing the burrs and burrs that were present during slinting of the metal strip before forming the metal pipe, but the work of removing burrs and burrs reduces the number of man-hours required for pipe manufacturing. Not only will there be an increase in
There are problems such as decreased productivity and increased costs.

The present invention was made in order to solve the above-mentioned problems, and it is possible to significantly suppress the occurrence of spatter inside a metal tube without being affected by the cracks and burrs that occur when slitting a metal strip. The purpose of the present invention is to provide a method for manufacturing a metal tube.

(Means for Solving the Problems) In order to achieve the above object, according to the present invention, a narrow metal band is formed by slitting the metal tube to a width corresponding to the diameter of the metal tube to be formed. In the method of manufacturing a metal tube, the narrow metal band is formed into a tubular shape and the opposing end faces are welded. A method for manufacturing a metal tube is provided, which supplies and shapes the narrow metal strip to form the metal tube.

(Function) When forming a narrow metal band from a wide metal band, there is a gap caused by slitting on both end faces of the narrow metal band.
The metal strip is supplied and formed so that the burr is on the outside of the metal tube to be formed, and the opposing end surfaces are welded.

This greatly suppresses the scattering of spatter into the metal tube during welding. After the pipe is formed, any cracks, burrs, etc. remaining on the outer surface of the metal pipe are removed by beet cutting, etc., if necessary.

(Example) An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

In FIGS. 1 and 2, the metal band 10 is slit from a wide metal band with a wall thickness corresponding to the wall thickness of the metal tube to be formed to a narrow width according to the outer diameter of the metal tube. It is a metal plate made into a metal band, and burrs (including burrs) 10c and 10c produced during the slitting protrude from both slitted end surfaces 10a and one surface 10b of IQa. After the metal strip 10 is slit, it is formed 8! t (not shown) and is formed into a tubular shape of a predetermined diameter. When forming this into a tubular shape, as shown in FIG.
The metal strip 10 is supplied to the molding machine so that the burrs 10c and 10c are on the outside of the tube. A metal tube 11 formed into a tubular shape from this metal band 10 is formed into a substantially ■-shape with its groove 12 expanding outward, and ridges 10c and 10c protrude from the outer ends of the groove 12, respectively. ing.

The metal tube 11 is conveyed while being applied with an appropriate pressure by a squeeze roll (not shown) and welded, for example, by high-frequency induction welding, to the opposing end surfaces 10a, 1 of the groove 12.
0a is welded. During this welding, the end face 10a,
10a paris 10c.

Since the groove 10c protrudes from the outer end of the groove 12, scattering of sputter inside the metal tube 11 is extremely small, and as a result, the amount of sputter remaining inside the metal tube 11 is greatly reduced. Furthermore, no protrusions are formed on the inner surface of the metal tube 11 at the groove 12 positions due to the sputtering, and the inner surface of the metal tube 11 becomes substantially smooth.

In addition, after forming the metal pipe 11, the metal! The above-mentioned Paris IOC remaining on the welded portion of the outer surface of -11 is removed and shaped by a beat cut or the like, if necessary. Such beet cutting is easy. In this way, the metal tube 11 is formed.

(Example) Examples of the present invention will be described below.

Example 1 As a metal strip, the wall thickness t = 1. Q x votes, width W=36.
Using 81 heavy mild steel (SPCC), the outer diameter is φ-1 by high frequency induction welding method (150Kw x 400kHz).
A metal pipe with a length of 2.71 m and a wall thickness L = 1.0 mm was produced.

Table 1 shows the method of the present invention in which the metal strip is supplied and formed so that the edges and burrs are on the outside of the metal tube, and the conventional method in which the metal strip is fed and formed so that the edges and burrs are on the inside of the metal tube.
00 kg (about 350 m in length) are manufactured in groups of 5 each and each is wound into a coil shape, and each of these metal tubes is filled with a pressurized fluid, such as a fluid that dries easily and does not cause rust on the metal tubes. Contains a solvent (triclene) that does not have any negative effects.
The results are shown in which the spatter remaining inside each metal tube was collected by flowing it under pressure of +r/- from 6 to 6 and filtering with a filter paper.

(Margins below) As is clear from Table 1, the average amount of residual sputter in the method of the present invention is 0.010 g, which is about 1 liter compared to the average amount of residual sputter in the conventional method, which is 0.114 g. /10, making it possible to significantly reduce the amount of residual sputtering. Furthermore, according to the method of the present invention, the protrusion of all five inner bead shapes is very small and is good (◯), and the overall evaluation is good (0) for all five bead shapes. On the other hand, the inner bead shape of the metal tubes obtained by the conventional method has a large protrusion amount (, (△) or (x)) and is poor, as indicated by (△) or (x), and the overall evaluation is that all five pipes are poor (x).

Example 2 As a metal band, meat f'lt = 0.8 m fat, width W =
Using 28.91 stainless steel (SUS304),
TrG? 8 welding method (welding current 15 (IA), outer diameter Φ
-10,011, metal tubes with wall thickness t=0.8 mm are shown in Table 2.

In the case of the method of the present invention in which the metal strip is supplied and formed so that the edges and edges are on the outside of the metal tube as in Example 1, and the metal strip is fed and formed so that the edges and edges are on the inside of the metal tube. Five 100 kg (approximately 550 m long) metal tubes were manufactured using a conventional method, each of which was wound into a coil shape, and an organic solvent (triclene) was poured into the tube under pressure of 4 to 6 kg/aJ, and each tube was filtered through a filter paper. Table 2 shows the collected spatter remaining inside the metal tube.

(Margin below) As is clear from Table 2, the average value of the amount of residual sputter in the method of the present invention is 0.009 g, which is about 1 /10, making it possible to significantly reduce the amount of residual sputtering. In addition, the inner bead shape of the five pipes has a very small amount of protrusion and is good (○), and the overall evaluation is good (0) for all five pipes.On the other hand, the inner bead shape of the metal pipe made by the conventional method has a very small amount of protrusion. is large and is defective as indicated by (Δ) or (×), and the overall evaluation is (Δ) for all five pieces.
Or it is defective as indicated by (×).

As is clear from Examples 1 and 2 above, the amount of residual spatter in the metal tube formed by the method of the present invention was significantly reduced compared to the amount of residual spatter in the metal tube formed by the conventional method.

(Effects of the Invention) As explained above, according to the present invention, a narrow metal band is formed by slitting to a width corresponding to the diameter of the metal tube in which the wide metal band is to be formed. In a method of manufacturing a metal tube in which a metal strip is formed into a tubular shape and the opposing end faces are welded, the narrow metal strip is formed so that the edges and burrs caused by slitting the narrow metal strip are on the outside of the metal tube. Since the metal tube is formed by supplying and forming the metal strip, it is possible to greatly reduce the amount of residual spatter remaining inside the metal tube after forming it, and it is easy to fit. A good metal pipe can be formed, and it is extremely effective when used for fluid passages, fuel pipes, etc. Further, there is an excellent effect that burrs, burrs, etc. remaining on the outer surface of the metal pipe after pipe production can be easily removed by beat cutting or the like, if necessary.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view showing a state in which a metal band is formed into a tubular shape by the method of manufacturing a metal tube according to the present invention, Fig. 2 is an enlarged view of the main part of Fig. Between the cross sections showing the state formed into a tubular shape, Figure 4 is an enlarged view of the main part of Figure 3,
FIG. 5 is an enlarged sectional view of a welded portion of a metal tube formed by a conventional method, and FIG. 6 is a sectional view of a welding wire formed by a conventional method. DESCRIPTION OF SYMBOLS 10...Metal band, 10a... End surface, 10e... Nomali, 11... Metal tube, 12... Bevel.

Claims (1)

[Claims] Metal in which a narrow metal band is formed by slitting to a width corresponding to the diameter of the metal tube to form the wide metal band, the narrow metal band is formed into a tubular shape, and the opposing end faces are welded. In the pipe manufacturing method, the metal tube is formed by supplying and forming the narrow metal band so that burrs and burrs caused by slitting the narrow metal band are on the outside of the metal tube. Characteristic method for manufacturing metal tubes.