JPH04162956A - Method for brazing faucet joint of pipe - Google Patents

Abstract

PURPOSE:To improve flow of brazer and joining ratio by generating rotating magnetic field at the joining part in a brazing joint for doubling pipes and acting electromagnetic force in the circular direction to molten brazing filler metal in a joint gap. CONSTITUTION:An electromagnetic coil 4 is concentrically set to outer periphery of doubled part between an inside pipe 1 and an outside pipe 2 and the brazing filler metal 3 receives the electromagnetic force to shifting direction 5 of magnetic field. The rotating magnetic fields of three-phase three-poles and three- phase two-poles are rotated by changing over directions of the electromagnetic coil 5 conducting current and the current 6 in order, respectively. The molten brazing filler metal flows to the circular direction in the joint gap with this rotating magnetic field, and as the flow of the brazer is improved, the joining ratio is improved. By this method, i.e., by flowing the molten brazing filler metal in the doubled joint gap with the rotating magnetic field, the method for brazing faucet joint having high joining ratio without any defect, can be obtd.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for brazing a spigot joint for pipes.

[Conventional technology]

When brazing pipes with lap joints, the joining rate of the joints depends on the brazing filler metal supply method and the shape of the joints.

It is controlled by construction conditions such as the gap between joints and heating temperature.

[The present invention aims to solve the problem of reducing defects that occur in joints and improving the joining rate when brazing pipes with overlap joints, and in particular,
For joints that require leak resistance, the axial direction of the joint @
It is very important to prevent the occurrence of linear defects.

The present invention was proposed in view of these circumstances, and
The purpose of the present invention is to provide a method for brazing a pipe spigot joint with no defects and a high joining rate.

[Means to solve the problem]

To this end, the present invention generates a rotating magnetic field in the lap joint when inserting the tube end of the inner tube into the tube end of the outer tube and brazing the two, thereby directing the molten brazing material into the gap between the lap joints. It is characterized by being made to flow.

[Effect]

According to such a method, in a spigot joint of overlapping pipes, a rotating magnetic field is generated at the joint, and a tMi force in the circumferential direction is applied to the brazing filler metal melted within the gap between the joints.

This electromagnetic force causes the melted filler metal to flow in the circumferential direction within the joint gap, improving the swirling flow of the filler metal.
The joining rate is the same as above.

〔Example〕

An embodiment of the present invention will be explained with reference to the drawings. FIG. 1 is a partial longitudinal sectional perspective view thereof, FIGS. 2 and 3 are explanatory diagrams showing the rotating magnetic field by the electromagnetic coil of FIG. 1, and FIG. FIG. 1 is a cross-sectional view showing a modification of the coil shown in FIG.

As shown in FIG. 1, the inner tube 1. An electromagnetic coil 4 is disposed coaxially around the outer periphery of the overlapping portion of the outer tube 2, and the brazing filler metal 3 receives an electromagnetic force in a direction 5 of movement of the magnetic field.

FIG. 2 shows a three-phase, three-pole rotating magnetic field, and FIG. 3 shows a three-phase, two-pole rotating magnetic field. The magnetic field is rotated by sequentially switching the direction of the tIIMi11M microcoil 6 through which current flows.

Then, the molten brazing filler metal 3 will be directed in the same direction as the rotational direction of the magnetic field! Rotates due to magnetic force.

As shown in FIG. 4, the rotating magnetic field is generated by rotating a soft iron 7 to which two sets of permanent magnets 8 of N and S poles are alternately arranged on the inner surface of the inner tube 1. It is also possible to apply a magnetic force of 1 it to the melted brazing filler metal 3 in the same direction as the rotational direction of the magnetic field.

The joint can be heated by high frequency heating if it is from the outside of the outer tube 2, or by high frequency heating or heating using an electric heater if it is from the inside of the inner tube 1.

〔Effect of the invention〕

According to this method, in a pipe-to-pipe overlap brazed joint, a rotating magnetic field is generated at the joint, and a circumferential electromagnetic force is applied to the melted filler metal within the joint gap, thereby eliminating this electromagnetic force. The force causes the melted brazing filler metal to flow in the circumferential direction within the joint gap, improving the vortex flow of the brazing filler metal, thereby improving the joining rate.

In short, according to the present invention, when the tube end of the inner tube is inserted into the tube end of the outer tube and the two are brazed, a rotating magnetic field is generated in the lap joint, and the molten brazing material is poured into the gap between the lap joints. The present invention is industrially extremely useful because it provides a method for brazing a pipe spigot joint with no defects and a high joining rate by allowing the fluid to flow within the tube.

[Brief explanation of the drawing]

FIG. 1 is a partial longitudinal sectional side view showing one embodiment of the present invention, and FIG.
3 and 3 are explanatory diagrams showing a rotating magnetic field caused by the electromagnetic coil shown in FIG. 1, respectively, and FIG. 4 is a cross-sectional view showing a modification of the electromagnetic coil shown in FIG. 1. 1... Inner tube, 2... Outer tube, 3... Brazing metal, 4
... Electromagnetic coil, 5... Direction of movement of magnetic field, 6...
Current, 7...Soft iron, 8...Permanent magnet, Agent: Masa Tsukamoto, patent attorney Figure 1 Figure 2

Claims (1)

[Claims] When the end of the inner tube is inserted into the end of the outer tube and the two are brazed, a rotating magnetic field is generated at the lap joint, causing the molten brazing filler metal to flow within the gap between the lap joints. A method for brazing spigot joints for pipes.