JPS58125383A - Eutectic pressure welding method - Google Patents

Abstract

PURPOSE:To execute eutectic pressure welding at a high speed and with high mass-producing properties, and to remarkably reduce the number of man-hours, by thermally spraying fine particles of an inserting material to a joined surface of one metal, and executing eutectic pressure welding together with the other nonreacted metal. CONSTITUTION:With a lower side pipe 2 which has formed a covered layer 1 by fine particles of an aluminum-silicon alloy on a flange surface by plasma thermal spraying, a flange surface 4 of an upper side pipe 3 is brought into contact. Both the pipes 3, 2 are pinched by upper and lower electrodes 6, 7, and are electrically conducted and heated by a resistance welding machine. An aluminum-silicon eutectic molten phase 5 generated on the joined surface by heating is discharged by pressure together with a broken oxide film and others, and at the same time, complete metallic coupling is obtained.

Description

[Detailed Description of the Invention] When joining metals, the present invention generates a eutectic molten phase at the interface when it comes into contact with the metal base material and heats it. - Fine particles of insert material are placed on the joining surface of one of the metals. It relates to a method of applying a thin coating such as by thermal spraying and eutectic pressure bonding with another untreated metal.

The eutectic pressure welding method is characterized by sandwiching an insert material that causes a eutectic reaction with the metal base metals to be joined, and heating and pressurizing the joint, but the use of insert materials has the following drawbacks. Ta.

(1) Generally, a micron-sized thin plate, ie, foil, is used as the insert material, but the method of manufacturing this foil requires advanced technology and equipment, and therefore is not easy to handle.

(2) Because it is easy to break and is brittle, it is difficult to handle and automatic feeding to joints is difficult, making it difficult to automate pressure welding equipment.

(3) It is difficult to sandwich the foil and it tends to slip off easily. For example, when joining at the end of a pipe, use foil on the inner surface.

This will cause inconvenience in taking out the product.

(4) There are limits to the material and size of the insert foil that can be manufactured.

The purpose of the present invention is to eliminate the drawbacks of the eutectic pressure welding method using insert materials for joining similar or dissimilar metals, since there are difficulties in the production and supply methods of the insert material foil that is sandwiched between the joints. The aim is to expand the scope of application of eutectic pressure welding.

The main points of the present invention are as follows.

(1) It is sufficient to thinly coat the bonding surface with fine particles of the insert material on only one metal base material, and the one that is easier to coat in terms of shape and material can be selected.

(2) A metal coated with fine particles of insert material and an untreated metal are brought into contact with each other and heated and pressurized to form a eutectic molten phase on the joint surface and perform pressure welding.

(3) Since there is no need for man-hours such as supplying the insert material and inserting it between the base materials, the structure of the pressure welding equipment becomes simpler and automation becomes easier.

(4) The number of post-processing steps is reduced because there is no protrusion of the insert material as would be the case when foil is sandwiched.

(5) Methods for coating the joint surface with fine particles of insert material can be broadly divided into thermal spraying and painting methods. Thermal spraying uses combustion gas, plasma, etc. to spray fine particles onto the joint surface, and the coating method involves spraying the fine particles mixed with a volatile solvent into a liquid state, and then heating the mixture to form a solution. is removed to form a fine grain layer.

Hereinafter, the present invention will be explained in detail by way of an example.

Figure 1 shows an example of eutectic pressure welding of aluminum pipes together on the 7-rank surface.A coating layer 1 of aluminum-silicon alloy fine particles is formed on the 7-rank surface by plasma spraying on the lower pipe 2, and the upper pipe 3 is attached to the lower pipe 2. It is a figure in which the flange surfaces 4 are about to be brought into contact.

B shows a state of eutectic pressure welding in which both pipes are sandwiched between lower electrodes 6.7 and heated with electricity using a resistance welding machine. , the destroyed oxide coating etc. are discharged under pressure, and at the same time a complete metal bond is obtained. There are various heating methods such as high frequency heating and furnace heating.
In either method, there is almost no change in the properties of the press-welded portion.

FIG. 2 is a diagram showing fine aluminum-silicon alloy particles as an insert material being thermally sprayed onto the flange joint surface of the aluminum pipe 2 by a thermal spray gun 8.

There are two main types of thermal spraying methods for powder materials:
Select a method that is more suitable for the combination of metal base material and powder material.

■There are cases in which combustion gas is used to melt and spray the fine particles, and cases in which they are not melted, but this is determined by considering adhesion, etc.

■Plasma is used as a heat source, and a mixed gas of nitrogen, hydrogen, argon, helium, etc. is used as the plasma gas.

In addition, in the painting method, a volatile solvent and insert material particles are mixed and applied to the joint surface by spraying, but the solvent is removed by subsequent heating and a caking agent is added to accelerate curing. This may improve adhesion.

Which method should be used to coat the joint surface with fine particles of insert material depends on the material and shape of the metal base material, the form of the joint surface, and the properties of the insert material. However, if the eutectic pressure bonding conditions such as heating temperature and pressure are appropriate, simple and stable bonding is possible.

According to the present invention, the problems associated with the use of conventional insert materials are solved, and the advantages of eutectic pressure welding, which is faster and more easily mass-produced than other joining methods, are utilized, and in particular, automation is possible and the number of work hours is reduced. This has the effect of significantly reducing

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the present invention, and is a schematic cross-sectional view of eutectic pressure welding using an aluminum pipe as an example, and FIG. 2 is a diagram showing insert particles being sprayed onto the joining surface of the pipe by a thermal spray gun. 1... Coating layer of aluminum-silicon alloy fine particles, 2
...Lower aluminum pipe, 3...Upper aluminum pipe,
4... Upper aluminum pipe flange joint surface, 5...
Ejected eutectic melt, 6.7... Upper and lower electrodes, and...
Thermal spray gun. Representative Patent Attorney Susuki 1) UnIJ9. ．． iF1Figure 5F32■ /Small\

Claims (1)

[Claims] 1. A thin plate of insert powder, which has a melting point lower than that of the metal base material and which forms a eutectic melt phase with the base metal, is sandwiched between the base metals, and that part is heated and pressurized to form a eutectic phase in the contact area. In the eutectic pressure welding method, in which metals of the same or different types are bonded together by generating a molten phase, the bonding surface of the base metal on which the insert material is more likely to adhere is thinly coated with insert material fine particles, and the untreated base metal is coated with a thin layer of fine particles of insert material. The eutectic pressure welding method is characterized by joining metals by heating and pressurizing them by bringing them into contact with each other to generate a eutectic molten phase on the joint surfaces. 2. The eutectic pressure welding method according to claim 1, in which the insert material is coated by spraying fine particles of the insert material onto the bonding surface of the base material using combustion gas spray, plasma, or the like. 3. To coat the insert material, fine particles of the insert material mixed with a solvent are applied to the joining surface of the base material, and then heated to remove the solvent and fix the fine particles - Claim 1
Eutectic pressure welding method described in section.