JPS5921716B2 - Electromagnetic solid phase joining method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an electromagnetic solid phase joining method for joining a metal member mainly composed of aluminum to another metal member.

Regarding the electromagnetic solid phase bonding method, for example, Japanese Patent Publication No. 47-39
It is shown in the No. 825 publication.

The method shown in the publication is to butt a pair of pipe members together,
After heating the abutting portion by passing a high-frequency heating current through a high-frequency induction coil, a forming current consisting of large current pulses larger than the above-mentioned high-frequency heating current is passed through the coil, and an electromagnetic attractive force is generated between the pair of tube members. This method can be applied to the production of a heavy D-joint 3 in which a pair of pipe members 1 and 2 are partially overlapped, as shown in FIG. 1A or B. That is, in manufacturing the heavy joint 3, the pair of pipe members 1 and 2 are first overlapped with their joining surfaces thoroughly treated chemically, and then the overlapping portion is heated by a high-frequency induction coil until it reaches an appropriate temperature. A heating current is passed through the coil to heat it, and then a forming current consisting of a large current pulse larger than the above-mentioned high-frequency heating current is passed through the coil, and the induced electromagnetic force causes pressure contact. Induction coil and outer tube member 1
They are joined by an electromagnetic repulsion force generated between the tube members 1 and 2 in the tube diameter direction and an electromagnetic attraction force generated between the pair of tube members 1 and 2 in the tube axis direction.

By the way, when it comes to joining ordinary metal members that maintain a relatively large tensile strength when in a liquid phase, it is possible to produce a nearly satisfactory joined member using the above method, but aluminum or a metal whose main component is aluminum When joining parts (in the present invention, these are collectively referred to as metal parts whose main component is aluminum), it is necessary to stably produce the required joined parts, since aluminum rapidly decreases its tensile strength near its melting point. difficult to do.

For example, even in the prescribed crushing test, the bonded portion often peels and a strong bond cannot be obtained. Furthermore, in joining an aluminum pipe and a copper pipe, intermetallic compounds between aluminum and copper are likely to be formed at the joint interface, and the formation of this excessive intermetallic compound further reduces the joint strength. In order to prevent such a decrease in joint strength, especially when joining aluminum pipes and copper pipes, we apply nickel plating to the copper pipes to suppress the formation of intermetallic compounds between the two metals at the interface of the weight part. However, this method requires more processing before joining than the normal electromagnetic solid phase joining method, and also has a high melting point metal layer interposed in the overlapping part during joining, so This requires a large electromagnetic force.

In addition, due to the large electromagnetic force, the aluminum tends to melt and scatter, and furthermore, the pressure contact force decreases due to the loss of the θ pincher, and a good bond cannot necessarily be obtained. In order to solve the above-mentioned problems, the present invention provides a method for joining a metal member whose main component is aluminum and a metal member made of a different material from this metal member by electromagnetic solid-phase joining. By arranging the aluminum pressing flux, it is possible to easily obtain a bond with the required strength.

Hereinafter, the present invention will be described by way of examples with reference to the drawings. FIG. 2 shows a heavy joint 12 in which one end of a pipe member 10 made of aluminum is expanded and joined to the outer surface of one end of a pipe member 11 made of copper, and the joint interface between both members 10 and 11 is shown. A breathing flux 14 is involved.

The weight joint 12 is manufactured by chemically treating the copper pipe member 11 and the aluminum pipe member 10, which has one end enlarged to have an inner diameter slightly larger than the outer diameter of the copper pipe member 11, to clean the surface. , Aluminum brazing flux 14 (for example, Nihon Alumitsu DM-055) used at a low temperature of about 500 to 600° C. is applied to the outer surface of one end of the copper tubes 11 or the inner surface of the expanded portion of the aluminum tube 10 that are joined to each other. Apply.

The presizing flux 14 is preferably applied by pulverizing a commercially available flux and suspending it in water. Next, as shown in FIG. 3, both members 10 and 11 are overlapped, and a high-frequency heating current is passed through the high-frequency induction coil 15 installed outside the overlapped part to heat the overlapped part. The coil 15 is manufactured in such a way that a forming current consisting of large current pulses, such as the above-mentioned high-frequency heating current, is passed through the coil 15, and the coils 15 are brought into pressure contact with each other by the induced electromagnetic force. By joining by such a method, members whose main component is aluminum can be joined at a low temperature, and a good joined member can be obtained.

In other words, since the tensile strength of members whose main component is aluminum rapidly decreases near their melting point, in the normal electromagnetic solid-phase welding method, the electromagnetic force induced by the forming current flowing through the high-frequency induction coil 15 during pressure welding is reduced. However, according to the method of the present invention, aluminum with reduced tensile strength scatters, and if the forming current is weakened, the bond becomes insufficient, making it difficult to produce a good bonded member. By using a low-temperature aluminum brazing flux interposed at the interface, welding can be performed at a lower temperature than conventional methods, and in addition to the bonding force of this brazing flux, the electromagnetic force of electromagnetic solid phase bonding can also be applied. It can be added to create a strong bond. Moreover, since the joined parts are joined at a relatively low temperature, the constituent parts whose main component is aluminum will not melt and become deformed, and processing is easier than in the method of plating the constituent parts. This has advantages such as low production costs. Table 1 shows outer diameter 6wnφ and wall thickness 1? When one end of the aluminum tube is expanded to fit a copper tube with an outer diameter of 61φ, and brazing flux for aluminum (Nippon Alumito DM-055) is applied to the inner surface of the expanded portion and joined. This figure shows the joint strength and appearance defect incidence rate compared to when no brazing flux is used.

Next, other embodiments will be described.

FIG. 4 shows that the outer surface of a copper tube 11 and the inner surface of an aluminum tube 10 having the same diameter are cut and overlapped, a presizing flux 14 for aluminum is interposed in the overlapped part, and electromagnetic solid contact is made in the same way. It was produced legally.

Such a joining method also produces effects similar to those of the above embodiment. In FIG. 5, an annular groove 17 is provided on the outer surface of the joint part of the copper pipe member 11 which becomes the inside of the weight joint 12, and an aluminum brazing flux 14 is applied inside the groove 17.
They were joined by electromagnetic solid phase joining method.

In addition to the above method, the groove 17 may be formed by, for example, the fourth method.
Corresponding to the weight joint 12 shown in the figure, as shown in FIG. When the members 10 and 11 are overlapped, a groove 17 may be formed between the base end 18 and the distal end 19.

Further, the shape of the groove 17 is not limited to the rectangular cross-section shown in FIGS. 5 and 6, but may be triangular as shown in FIG. 7, and the shape is not limited. However, the size of the groove should normally be such that it does not cause a structural defect. The manufacturing method of these weight joints 12 is the same as that of the previous embodiment except that the machining process for forming the groove 17 in the copper tube member 11 before joining the two members 10 and 11 is slightly different.

For joining, when the overlapping portion of the two members 10 and 11 is heated by the high-frequency induction coil 15, the brazing flux applied in the groove 17 is first melted, and this melted brazing flux is applied by capillary action, etc. By leaching it to the bonding interface between both members 10, a bond similar to that of the previous embodiment can be obtained.

The effects of the bonding methods of these embodiments are almost the same as those of the previous embodiments, but in addition, the supply amount of brazing flux can be kept constant, and variations in bonding strength due to excess or deficiency of flux can be reduced. be able to. In addition, there is less leakage of other parts of the flux, and post-processing of the bonded members is facilitated. As described above, the present invention provides a brazing flux for aluminum that can be used at low temperatures when joining a metal member whose main component is aluminum to another member made of a different material by electromagnetic solid-phase joining. By bonding by flux and pressure welding by electromagnetic force,
This ensures strong bonding.

In addition, particularly in the case where grooves are formed in the joining portion of both members, the amount of flux supplied can be made appropriate and a joining with little variation can be achieved at all times.

[Brief explanation of the drawing]

Figures 1A and B are cross-sectional views of a heavy weight joint manufactured by the conventional electromagnetic solid phase joining method, Figure 2 is a cross-sectional view of a weight joint manufactured by the method of the present invention, and Figure 3 is a cross-sectional view of a weight joint manufactured by the method of the present invention. 4 to 7 are cross-sectional views showing different shapes of weight joints manufactured according to the present invention. 10: aluminum pipe member, 11: copper pipe member, 12: weight joint, 14: brazing flux for aluminum,
17: Concave groove.

Claims (1)

[Scope of Claims] 1 A metal member whose main component is aluminum and a metal member made of a different material from this metal member are heated by passing a high-frequency heating current through a high-frequency induction coil, and then the high-frequency heating current is applied to the high-frequency induction coil. In the electromagnetic solid phase welding method in which a forming current consisting of a larger current pulse is applied and the two members are pressed together by electromagnetic force, brazing flux for aluminum is placed at the joint of the above two members, heated, and pressed together by electromagnetic force. Characteristic electromagnetic solid phase joining method. 2. After heating a metal member whose main component is aluminum and a metal member made of a material different from this metal member by passing a high-frequency heating current through a high-frequency induction coil, a large current pulse larger than the high-frequency heating current is applied to the high-frequency induction coil. In the electromagnetic solid-phase joining method, in which a molding current is passed through and the parts are pressed together by electromagnetic force, a concave groove is provided at the joining part of the above two members, and brazing flux for aluminum is placed in this concave groove, heated, and pressed by electromagnetic force. An electromagnetic solid phase bonding method characterized by