JPS6046885A - Press welding method of galvanized steel sheet by resistance heating - Google Patents

Abstract

PURPOSE:To join galvanized sheets to each other with low current without using solder and flux by subjecting the zinc coated on the galvanized sheets and copper to contact heating. CONSTITUTION:Copper foil 3 is held in place between galvanized iron sheets 1 and 2 and the iron sheets are electrically heated by upper and lower electrodes 6, 7 attached with heating plates 4, 5 at the top ends. The foil 3 which is resistance-heated by the current conducted thereto forms the molten alloy phase of Cu-Zn on the contact surface and acts said phase as a brazing material. Both sheets are press-welded via said phase. The joining is accomplished in extremely short time and the need for a flux necessary for general brazing is eliminated by such joining coupled with the effect of exerting pressure to the molten part.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a method for joining galvanized steel sheets to each other and a method for joining zinc steel sheets and copper alloy parts. The present invention relates to a simple joining method characterized by forming and press-welding.

[Prior art]

Conventionally, galvanized steel sheets are joined together mainly by resistance welding or caulking, and joined to copper alloy parts mainly by silver brazing, but both methods are extremely difficult to connect and have the following drawbacks. Ta.

(1) Resistance welding requires relatively high current and high temperature, requires a welding machine with high capacity, and the electrode tip is subject to rapid wear.

(2) Caulking lacks joint stability, flexibility, and leak resistance.

(31&H brazing requires an expensive brazing cost and requires a lot of man-hours because it is manual work. In particular, it requires a lot of man-hours to remove flux, making the joints expensive.

[Purpose of the invention]

An object of the present invention is to provide a method for easily manufacturing a structure of galvanized steel sheets with low current and for directly joining copper alloy parts to galvanized steel sheets without using wax or flux.

[Summary of the invention]

The feature of the present invention is that a Cu--Zn alloy molten phase is produced by contact heating the zinc and copper coated on a galvanized steel sheet, and this is used as a brazing material to join the two. When joining galvanized steel sheets, a copper foil is sandwiched between the points to be joined, and electricity is applied and pressure is applied using upper and lower electrodes with iron-based heating plates attached to the tips. CLI-Zn alloy is formed by heat conduction from the heating plates and resistance heating. A molten phase is generated and the parts are pressure-welded.

If you want to make a structure by joining galvanized steel sheets of various shapes together, you can sandwich thin rod-shaped copper or apply paste-like copper, and apply pressure to the parts to make the joints.

If you want to join a copper alloy part to a zinc steel plate, the joint is directly sandwiched between the -1 lower electrodes, which are also equipped with iron-based heating plates, and the CLI-Zn alloying reaction is caused by applying current and pressure. Both can be completely joined without a brazing material.

The joining described in 2.2 is extremely short (17υ), and combined with the effect of applying pressure to the molten part, there is no need for the flux required for general brazing.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to FIG. 1st
The figure shows an example of joining galvanized steel sheets in the simplest form.
A copper foil 3 is sandwiched between the galvanized steel plates 1 and 2, and a heat generating plate 4 is placed at the tip.
．． This figure shows the state in which electrical heating is performed using the lower electrodes 6.7 marked with 5. When the copper foil is resistively heated by electricity, a molten Cu--Zn alloy phase is generated on the contact surface, and the two plates are pressed together through this.

Figure 2 shows an example of joining a copper alloy part to a galvanized steel plate, in which a hole is made in the galvanized steel plate 1, a flanged copper pipe 3 is fitted into the hole, and the lower surface of the flange of the copper pipe and the galvanized steel plate are brought into direct contact. The figure shows the situation where heating plate 4 is attached to a part of the flange of the copper pipe with electrode 6 holding down the 2 side, and galvanized steel plate is being heated by holding down the zinc steel plate with lower electrode 7 to which heating plate 5 is attached. It is. On the contact surface of the art material, the zinc and copper of the coated galvanized steel sheet react with each other when energized, forming a C11-Zn alloy phase similar to the example shown in Figure 1, and this is then separated between the galvanized steel sheet and the copper pipe. , it is completely joined without brazing filler metal or flux. When the galvanized steel plate is 1°Qt, the copper pipe has an outer diameter of 12.7φ, and a wall thickness of 0.8t, the resistance heating conditions are: current 10.0OOA, energization time 120, and pressure 3.
Approximately 50 Ky is appropriate.

In addition, by using a heating plate at the tip of the electrode.

There is no problem of copper electrode wear, which is a drawback in welding galvanized steel sheets, and since it is a high-resistance material, it takes advantage of the ability to generate high heat with a relatively low current. If there is no heating plate, copper has extremely high electrical conductivity, so heat concentration is poor, and the required temperature is often not achieved even if the current is increased.

According to this embodiment, a zinc steel plate and a copper pipe can be easily joined by directly fitting the copper pipe without using a brazing material, applying an electrode, and applying electricity.

〔Effect of the invention〕

According to the present invention, by utilizing the reaction of zinc and copper due to heat,
Resistance heating enables the joining of zinc steel sheets and the joining of zinc steel sheets and copper alloy parts, and has the effect of being simple and inexpensive with a low-capacity resistance welding machine.

[Brief explanation of drawings]

FIGS. 1 and 2 are sectional views of essential parts for explaining one embodiment of the present invention. 1.2... Galvanized steel plate, 3... Copper foil, 3'... Copper pipe, 4.5... Heat generating plate, 6.7... Upper and lower electrodes.

Claims (1)

[Claims] 1. Using a resistance welding machine as a means for joining galvanized steel plates,
A copper foil is sandwiched between the points to be joined, and electrical current is applied through the lower electrode to form a Cu-7,N alloy molten phase at the interface through resistance heating, which acts as a brazing filler metal to join the galvanized steel sheets by pressure welding. resistance heating pressure welding method. 2. Resistance heating pressure welding of galvanized steel sheets according to claim 1, in which structures of various shapes of galvanized steel sheets are created by sandwiching and press-welding thin rod-shaped or paste-like copper in addition to copper foil at the joint part. Law. 3. As a method for directly joining copper alloy parts to galvanized steel sheets,
- Resistance heating pressure welding method of the front plate of the resistor by directly sandwiching the joint between the lower electrodes. 4. During resistance heating, a heat generating plate with high electrical resistance is attached to the tip of the electrode, and when electricity is applied and pressure is applied, heating by heat conduction from the heat generating plate is used in combination with resistance heating.
The described resistance heating pressure welding method of galvanized steel sheets.