JPH03155462A - Vacuum brazing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a vacuum brazing method.

[Conventional technology]

Conventionally, as a welding method for thin-walled metal articles, a metal base material and a metal member to be bonded are placed in a vacuum chamber with a welding member inserted, and the whole is heated to the melting temperature of the welding member. A so-called vacuum brazing method for welding the two is widely known.

As a heating means in this case, there are two methods: uniformly heating the entire object in a vacuum furnace, and heating locally by bringing a high-frequency induction heating coil close to the object [Problems with the prior art] By the way, Among the heating means mentioned above, the former means for heating the inside of a vacuum furnace to a uniform temperature is used when the base material or the adhered member contains a material that does not have heat resistance, or when the material has the property of being gasified by high-temperature heating. There is a problem that it cannot be applied in cases where the heating device is attached to a material that has internal residual stress and distortion occurs due to high-temperature heating, and the latter heating method using a high-frequency induction heating coil does not have the above-mentioned problems. However, there are problems in that the local heating zone is wide, considerable distortion occurs especially for thin objects, and it is not easy to control the heating conditions.

[Problem to be solved by the invention]

In view of the above-mentioned problems, the present invention has been made with the object of providing a vacuum brazing method in which the local heating zone is extremely narrow, thereby causing no distortion even for thin-walled objects, and in which temperature control is easy. It is something that

[Technology that led to solving the problem]

That is, in the vacuum brazing method of the present invention, a member to be bonded is placed with respect to a base material through a welding member under vacuum, and the base material and the member to be bonded in the vicinity of the welding member are exposed to a convergent state of electrons. This method is characterized in that the welding member is melted by heating with a beam.

[Effect]

In this invention, a convergent electron beam is used as a heating means for a welding member, that is, a brazing member.

The electron beam brought into this converged state is one whose converged state is defocused by 2 to 5 m.

This focused electron beam makes the heating zone extremely narrow, and since the beam irradiation position can be changed steplessly, it is possible to narrow down and heat only the necessary areas, so it is possible to heat thin objects that are prone to thermal distortion. This makes it possible to heat braze weld even objects in a stable state.

〔Example〕

Next, the present invention will be explained in detail.

[Example 1] As shown in Fig. 1 (a), a metal plate 3 with a thickness of 0.1 mm was used as a base material, and a circular hole 2 with a diameter of 30 fl was bored in the center of a disk 1 with a diameter of 100 mm. A disk 4 with a diameter of 34 cm is placed as a member to be bonded over the circular hole 2, and a brazing member 5 is placed around the disk 4 as shown in FIG. 1(b). After creating a vacuum state, an area S shown by a dashed line was uniformly irradiated and heated with an electron beam at a current value of 12 to 15 mA for an irradiation time of 40 to 55 seconds while visually observing the irradiation position.

At this time, the temperature rise state in the range S is as shown in the graph shown in FIG. When the temperature rose and reached the melting temperature of the brazed welding member 5, the surrounding area was uniformly welded.

Further, after welding, when the electron beam irradiation was stopped and the metal plate 3 was gradually cooled to room temperature, almost no distortion occurred in the metal plate 3.

[Example 2] Using the same metal plate 3, disk 4, and brazing welding member 5 as in Example 1, as shown in FIG. The area S was sandwiched between them in a sandwich-like manner and heated with an electron beam in the same manner as in the example.

The state of temperature rise in this case was also the same as in FIG. 2, and almost no distortion occurred after cooling.

[Example 3] Using the same metal plate 3, disk 4, and brazing welding member 5 as in Example 1, the circumference of the circular hole 2 of the metal plate 3 was pressed into a stepped shape as shown in FIG. , stress was applied thereto, a disk 4 was placed as shown in the figure, a braze welding member 5 was placed around it, and the area S was heated with an electron beam.

The state of temperature rise in this case was also the same as in FIG. 2, and almost no distortion occurred after cooling, including in the pressed portion.

[Comparative example]

In the welding method in Example 1, when heating was performed using a high frequency induction heating coil without using an electron beam,
As shown in Figure 5, there is a difference in the temperature rise between the metal plate 3 and the disc 4, and a gap occurs in the heating state before brazing is achieved, and it is confirmed that a slight distortion occurs in the surrounding area. It was done.

〔effect〕

As explained above, this invention uses a highly focused electron beam to locally heat only the necessary areas, making it possible to uniformly weld even materials that are prone to thermal distortion, such as thin metal plates. Because the part is locally limited, this may be the case even if the base material or the bonded member includes a material that does not have heat resistance, or a material that gasifies when heated to high temperatures. This has effects such as enabling patch welding.

[Brief explanation of the drawing]

Figures 1 (a) and (b) are a plan view and a sectional view of the first embodiment of the present invention, Figure 2 is a graph showing the heating state of the first embodiment, and Figure 3 is a diagram showing the second embodiment of the invention. FIG. 4 is a plan view and a sectional view of the third embodiment of the present invention;
Figure 5 shows the restraint r1 of the comparative example.

Claims (1)

[Claims] (1) A member to be bonded is placed with respect to the base metal through a welding member under vacuum, and the base metal and the member to be bonded near the welding member are heated with a tightly focused electron beam to heat the welding member. A vacuum brazing method characterized by melting.