JPH02182334A - Manufacture of short tube - Google Patents

Abstract

PURPOSE:To manufacture a short tube having an excellent strength and a nice appearance by forming a short tube member into a bent short tube, upset-butt- welding this bent tube by a projection welding machine to obtain a welded short tube and removing swells on the inner and outer peripheral surfaces. CONSTITUTION:Material such as steel plate is blanked to obtain a short tube member. This is formed into a bent short tube 2 having dimensions required by a bending roll etc. The bent short tube 2 is set between the electrodes 3, 4 of the projection welding machine. The gap part (bent ends 5, 6) of the bent short tube 2 undergoes upset butt welding. The swell parts on the inner and outer peripheral surfaces of the welds of this welded short tube is removed. By this method, the quality of the short tube can be stabilized and the welding time can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for manufacturing short tubes that are used as structural members of industrial products and are required to have relatively thin walls and sufficient strength.

Conventional technology Conventionally, relatively thin steel short pipes that require sufficient strength have been produced by cutting long steel pipes produced by drawing into desired dimensions, or by using steel pipes produced by TEG welding. It was used by cutting it to size.

, Problems to be Solved by this Invention Using drawn long steel pipes is not only expensive, but also
The disadvantage is that cutting, processing, and finishing are time consuming and costly. In addition, when manufacturing by TEG welding, melt drips on the welded surface, and the welding strength varies, making the quality unstable. Moreover, the welding speed is slow and the equipment cost is expensive.

Means for Solving the Problems A material such as a steel plate is punched out according to the required dimensions of the tube, a short tube member is provided, and this short tube member is used to bend a short tube (bending) of the required dimensions using a penden roller machine or other bending machine. This curved short tube is placed between the electrodes of a projection welding machine, the gap part (curved end) of the curved short tube is upset spot welded, a welded short tube is provided, and this welded short tube is welded. There is a method of manufacturing a short pipe that eliminates the raised ridges on the inner and outer circumferential surfaces of the part.

The working short pipe member is provided by instantly punching out a material such as a steel plate using a press machine according to the required dimensions for forming the tube, etc. This is then formed into a curve using a penden roller machine etc. to provide a curved short pipe. The gap part of the pipe is placed between the electrodes of a general projection welding machine, and the welding is carried out in about 2 seconds, the entire width of the gap part is securely connected, and the slight bulge on the inner and outer circumferential surfaces created during welding is removed using a tool or device. The purpose is to manufacture short tubes (square tubes) whose connecting parts have the same strength as the members and whose appearance is beautiful.

Embodiments Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
As shown in the figure, a flat steel plate is punched out using a press machine to provide a short pipe member 1 having the required short pipe diameter, length, and wall thickness. Next, this short tube member 1 is applied to a pending roller machine, and as shown in FIG. 2, it is curved into a circular shape to form a curved short tube 2. Next, as shown in FIG. 3, the short curved tube 2 is placed between the electrodes 3 and 4 of a conventional projection welding machine, and energized in the same manner as in ordinary spot welding.

The curved end 5.6 of the short curved tube 2 is heated by resistance heat and simultaneously swaged and welded to form the welded tube 7. A slight embankment 8.9 is formed on the inner and outer peripheral surfaces of the welded portion of this welded pipe. This bulge υ8.9 is crushed or scraped off using a suitable tool or device to produce an integrally joined short pipe 10 as shown in FIG.

The electrode 3.4 of the projection welding machine is constructed as shown in FIG. The curved end corresponds to 5.6 circles with the short tube 2, and when a voltage is applied and current flows, the welded part is effectively heated and melted, and the remaining outer peripheral surface of the curved short tube 2 is an electrical insulator. When 13 and 14 are brought into contact and pressure is applied, the circular shape of the short curved tube 2 is maintained and the curved ends 5 and 6 are welded.

Effects of the Invention Conventionally, general projection welding machines have performed spot welding where the welding area is limited to a certain part, and it is not possible to weld and manufacture plates that are relatively thin and require sufficient strength. It is thought that it was a material, and TEG welding was performed. However, TEG welding has a drawback in terms of productivity, and when we conducted research to improve this, we found that the shrinkage that occurs during welding with projection welders falls within a certain range, which was previously thought to be the case. A method of manufacturing short tubes that can be used as a standard was completed.

The manufacturing method of this invention is extremely general and can be easily mass-produced without any technical difficulty using inexpensive equipment, and can reduce the cost of manufacturing short tubes by four times compared to conventional short tube manufacturing costs. In particular, compared to the TEG welding method that is generally used to obtain sufficient strength with relatively thin walls, the welding strength is uniform, the quality is stable, the welding time is shortened to less than A, and the production capacity is reduced. I can get e6.

With simple finishing operations, it is possible to produce short pipes with an appearance comparable to continuous integrally formed pipes, such as drawn steel pipes, and with the required dimensions.

Therefore, there is a great deal of inconvenience in manufacturing methods for industrial product parts that are required to be relatively thin, have sufficient strength, and have a beautiful appearance.

[Brief explanation of the drawing]

The drawings show an embodiment of the short pipe manufacturing method of the present invention, in which Fig. 1 is a plan view of a member for a short pipe punched out of a plate material adapted to the necessary dimensions of the short pipe, and Fig. A perspective view of the appearance of a short pipe member in a circularly curved state by a pending roller, Fig. 3 is an explanatory diagram of an example in which the joining end surfaces of the curved short pipe member are welded, and Fig. 4 is an appearance of the welded short pipe before finishing. The perspective view and FIG. 5 are similarly external perspective views after finishing. 1-.- Short pipe member, 2- Curved short pipe, 3- Electrode, 4- Electrode, 5.6- Curved end, 7- Welded pipe, 8.9- Swelling, 10- Short pipe, 11. 12-...-Electrifying surface, 13.14
- Electrical insulator.

Claims (1)

[Claims] A process of punching out a material such as a steel plate according to the required dimensions of the tube to provide a short pipe member, a process of forming this short pipe member into a curved short pipe of the required dimensions using a pending roller or other forming machine, and The process of placing the pipe between the electrodes of a projection welding machine and upset-welding the gap part (curved end) of the short pipe to form a welded short pipe; A method for manufacturing short pipes, which is characterized by comprising a processing step that eliminates rising.