JPS61232059A - Brazing method - Google Patents

Abstract

PURPOSE:To obtain a laser-brazed part without surface oxidation and to improve productivity and workability by providing a stage for preheating works by a reducing flame, brazing stage for melting a brazing filler metal by laser light and stage for cooling slowly the works with an inert gas after the end or from the mid-way of the two stages for preheating and brazing to the brazing stage. CONSTITUTION:The works 2, 3 are heated by the reducing flame 16 in such a manner that the flame covers the works to preheat the works. The laser light 10 for processing is then irradiated on the brazing filler metal 6 while the works are held heated by the flame 16 to braze the works. The irradiation of the laser light for processing is stopped and while a nozzle 15 is pulled up, the inert gas 8 is blown to the works 2, 3 from a supply pipe 7 in synchronization with said pulling up to cool slowly the works. Since the function to prevent oxidation is provided to the preheating stage, the uniform heating up to the substantial preheating temp. is made possible. The oxidation in the slow cooling stage is prevented by using the shielding by the inert gas and the heating by the reducing flame in conjunction with the slow cooling stage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a brazing method, and particularly to a brazing method using a laser in combination.

[Technical background of the invention and its problems]

In brazing performed by laser beam irradiation, it is necessary to create an atmosphere of inert gas or the like to prevent oxidation caused by heating. When brazing is performed in air, the surfaces of the brazing material and the parts to be brazed are oxidized, and this oxide film prevents the brazing material from being sufficiently wetted, resulting in poor brazing. Furthermore, when brazing ceramics and metals, it is necessary to perform preheating and slow cooling to prevent cracks from occurring in the ceramics.

FIG. 6 shows a conventional laser brazing method for ceramics and metal, which involves forming an inert gas atmosphere and performing preheating and slow cooling. That is, in FIG. 3, the processing table (1) K
One rod-shaped workpiece (2) made of a metal material and the other circular workpiece (3) made of ceramics and bonded thereto are placed in combination. Processing table (
1) K is equipped with a heater (4) for preheating. The heater (4) is connected to the power source (5) K.

Brazing metal (6) is used at the joint between workpieces (2) and (3).
are arranged. In the above, brazing is performed as follows. First, the heater (4) and the workpieces (2) and (3
) to moderate heat. Next, a cine active gas (8) is blown through the supply pipe (7) to form an inert gas atmosphere around the workpieces (2) and (3). In this state, brazing is performed by concentrating a comparatively high-energy processing laser beam transmitted by the optical 7 taper (9) onto the brazing material (6) with the condensing lens αυ. However, like this
.

In other methods, there was a problem in that the preheating temperature by the heater (4) did not rise sufficiently due to the cooling effect associated with the blowing of inert gas.There is also a method that uses a special container for creating an atmosphere. However, the workability was poor and it was not practical.

[Purpose of the invention]

Productivity 9 An object of the present invention is to provide a brazing method which can sufficiently prevent oxidation without reducing workability and can sufficiently perform preheating and gradual cooling.

[Summary of the invention]

In order to achieve the above purpose, there is a preheating process in which the parts to be joined are covered with a reducing flame and the workpieces are preheated, a brazing process in which the brazing metal placed on the parts to be joined is melted with a laser beam after this process, and a preheating and This method includes a slow cooling step in which an inert gas is sprayed onto the parts to be joined after or halfway through the two brazing steps.

[Embodiments of the invention]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on drawings showing embodiments. Note that parts common to those in FIG. 3 will be described with the same reference numerals.

That is, in Fig. 1, a nozzle CIG that supplies cyclogenic flame (IQ) such as oxygen/acetylene flame is arranged above the workpieces (2) and (3) placed on the processing table (1) K. In addition, a supply pipe ( 7) is arranged.In addition, a trap is formed so that the processing laser tip is focused and irradiated obliquely toward the brazing metal (6) arranged on the part to be joined.In the above, brazing is performed as follows. First, the workpieces (2) and (3) are heated and preheated by covering them with the annular flame α.Next.

Processing laser beam α is applied while still being heated due to cyclic flame α.
Irradiate the brazing material (6) with K and braze. Next, the irradiation of the laser beam for processing is stopped, and while the nozzle α0 is pulled up, the cine active gas (8) is sprayed through the supply pipe (7) to gradually cool the workpieces (2) and (3). .

The above three-stage process is shown in Figure 2. In the above slow cooling process, the cooling rate can be controlled by controlling the flow rate of the inert gas, the speed at which the annular flame (ll19) is moved away, etc. on the processing table (
There is no problem in embedding a heater (4) in 1) to further ensure sufficient preheating.

Furthermore, in the preheating process, it is effective to gradually bring the reducing flame closer while blowing inert gas, or to increase the size of the flame itself, and then preheat only with the reducing flame. .

〔Effect of the invention〕

Since a reducing flame is used as the preheating means and also has the function of preventing oxidation, it is possible to preheat to a sufficient preheating temperature without the cooling effect that occurs when an inert gas is used. Furthermore, there is little difference in heating temperature due to differences in the physical properties of the workpiece, such as in high-frequency heating, and uniform preheating can be achieved. The problem of oxidation during slow cooling is solved by combining shielding with an inert gas and heating with a reducing flame, making it possible to obtain a good laser-brazed part without 91 surface oxidation. Furthermore, the method according to the present invention does not require a dedicated chamber 4 for creating an atmosphere, so it is easy to automate and has excellent workability.

[Brief explanation of drawings]

Fig. 1 is a block diagram for explaining one embodiment of the present invention, Fig. 2 is a process diagram showing the process in terms of time and temperature factors, and Fig. 3 is a process diagram for explaining an embodiment of the present invention.
The figure is a configuration diagram for explaining a conventional example. (2), (3)... Workpiece (6)... Brazing material (8)... Inert gas a... Laser light for processing (ll19... Reducing flame agent Patent attorney) Kensuke Chika (and 1 other person)

Claims (1)

[Claims] A preheating process in which the workpiece is preheated by covering the part to be joined with a reducing flame, a brazing process in which the brazing material placed on the part to be joined is melted with a laser beam after this process, and two of the above preheating and brazing steps.
A brazing method characterized by comprising a slow cooling step of blowing an inert gas onto the parts to be joined after the completion of the step or in the middle of the step.