JP3074811B2 - Vacuum aluminum brazing furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a vacuum aluminum brazing furnace for brazing aluminum products.

[0002]

2. Description of the Related Art As is well known, it is essential that a brazing material for brazing aluminum products contains magnesium as a getter material for oxygen. That is, when brazing aluminum products with a vacuum aluminum brazing furnace, if an oxygen gas or moisture is present in the furnace atmosphere, an aluminum oxide film is formed on a portion to be brazed and the brazing is performed. In order to prevent such a problem, the brazing material containing magnesium having a higher affinity for oxygen than aluminum is contained in the brazing material, and the magnesium is evaporated together with the brazing material during the treatment, and the Oxygen and moisture are combined with magnesium and removed as magnesium oxide.

[0003] Further, the amount of magnesium contained in the brazing material alone may be insufficient to sufficiently remove oxygen and moisture, and in such a case, pure magnesium or other magnesium may be used as another magnesium evaporation source. Brazing sheet (equivalent to brazing material containing magnesium)
Is placed in a furnace together with the object to be treated, called so-called magnesium storage.

[0004]

However, when the treatment is carried out by placing magnesium as described above, it is not possible to freely control the amount of magnesium evaporated from the magnesium evaporation source. In some cases, more magnesium than necessary for oxygen removal was evaporated. And if magnesium evaporates excessively, it will adhere to various parts in the furnace and contaminate the furnace, so not only frequent cleaning is required, but also
There has been a problem that excessively evaporated magnesium may melt into the molten brazing material and adversely affect the quality of the product.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide a vacuum aluminum brazing furnace capable of freely controlling the amount of evaporation from a magnesium evaporation source (placed magnesium). A magnesium body, a heating chamber provided inside the furnace body, and magnesium evaporation which is provided so as to be able to be taken in and out of the heating chamber and which is charged into the heating chamber during processing to evaporate magnesium. Source, a measuring device for measuring the magnesium concentration in the heating chamber, and a driving device for taking the magnesium evaporation source into and out of the heating chamber based on the measurement result of the measuring device, is there.

[0006]

In the vacuum aluminum brazing furnace of the present invention, a magnesium evaporating source, which is magnesium, is provided so as to be freely inserted into and removed from the heating chamber by a driving device. Measure, if the magnesium concentration is less than the predetermined value, charge the evaporation source into the heating chamber to evaporate the magnesium, and if the magnesium concentration in the heating chamber exceeds the predetermined value, remove the evaporation source from the heating chamber. By taking it out and suppressing further evaporation, the magnesium concentration in the heating chamber is maintained at a predetermined value.

[0007]

An embodiment of the present invention will be described below with reference to FIG. FIG. 1 is a schematic configuration diagram of a vacuum aluminum brazing furnace of the present embodiment. In the figure, reference numeral 1 denotes a furnace main body which is a vacuum vessel, 2 denotes a door thereof, and 3 denotes a heating chamber provided inside the furnace main body 1. Reference numeral 4 denotes its door, reference numeral 5 denotes an object to be processed, reference numeral 6 denotes a support base for supporting the object to be processed, and reference numeral 7 denotes a heater.

An opening 8 is provided at the center of the bottom of the heating chamber 3, and the opening 8 is opened and closed by a shutter 9 which slides in a horizontal direction (in the drawing, the front and back sides of the paper). A cylinder (driving device) that is operated by hydraulic pressure or pneumatic pressure to extend and retract the cylinder rod 11 in the furnace main body 1 at the center of the bottom surface of the furnace main body 1.
A magnesium evaporation source 12 (pure magnesium or magnesium such as a brazing sheet) is provided at the tip of a cylinder rod 11. Then, by extending the cylinder rod 11 upward, the evaporation source 12 passes through the opening 8 of the heating chamber 3 and enters the heating chamber 3 as shown by a chain line in the figure, and the cylinder rod 11 Is contracted downward, so that the evaporation source 12 is taken out of the heating chamber 3 as shown by a solid line in the figure. Further, a lid 13 that closes the opening 8 when the evaporation source 12 is loaded into the heating chamber 3 is attached to the cylinder rod 11.

Further, the furnace of the present embodiment has a measuring device 15 for measuring the concentration of magnesium vapor in the heating chamber 3.
Is provided. The measuring device 15 is composed of a measuring device main body 16 such as a mass spectrometer and a suction nozzle 17 for sucking a sample gas from the inside of the heating chamber 3, and the magnesium concentration in the heating chamber 3 during the brazing process. Is measured continuously or intermittently. And
The cylinder 10 is controlled by the control device 18 based on the measurement result.

That is, when the concentration measured by the measuring device 15 is less than a predetermined value in a state where the evaporation source 12 is outside the heating chamber 3, the control device 18 extends the cylinder rod 11. The cylinder 10 is operated so as to cause the evaporation source 12 to be charged into the heating chamber 3, and the evaporation of the magnesium from the evaporation source 12 is promoted to increase its concentration. Further, when the magnesium concentration in the heating chamber 3 exceeds a predetermined value in a state where the evaporation source 12 is loaded in the heating chamber 3, in order to prevent further evaporation and reduce the concentration. The control device 18 operates the cylinder 10 so as to retract the cylinder rod 11, and draws out the evaporation source 12 from the heating chamber 3. As a result, the magnesium concentration in the heating chamber 3 is maintained at a predetermined value.

When the evaporation source 12 is outside the heating chamber 3, the shutter 9 of the opening 8 is normally closed. The shutter 9 is opened when the evaporation source 12 is inserted into the heating chamber 3, but the opening 8 is closed by the lid 13 at the same time as the evaporation source 12 is inserted. Further, the evaporation source 12
It is necessary to close the shutter 9 promptly after taking out the heating unit 3 from the heating chamber 3.
8 to control.

An example of the operation procedure of the vacuum aluminum brazing furnace having the above configuration will be described below. First, the evaporation source 12 is disposed outside the heating chamber 3 and the shutter 9 is closed. In this state, the workpiece 5 is disposed in the heating chamber 3 and the doors 4 and 2 are closed. Thus, the entire inside of the furnace body 1 is evacuated, and when a predetermined degree of vacuum is reached, the heater 7 is energized to perform initial heating. At this stage, the moisture adhered to the processing object 5 evaporates, and the degree of vacuum temporarily decreases. Therefore, the evacuation is further continued until a predetermined degree of vacuum is reached. At this time, if the predetermined degree of vacuum cannot be reached only by performing evacuation, the evaporation source 12
Is preferably temporarily charged into the heating chamber 3 to evaporate magnesium, thereby removing water vapor in the heating chamber 3.

When the inside of the heating chamber 3 reaches a predetermined degree of vacuum, main heating is performed to further raise the temperature in the furnace, thereby melting the brazing material previously attached to the workpiece 5 to perform a brazing process. Perform At this time, as described above, the magnesium concentration in the heating chamber 3 is measured by the measuring device 15, and the cylinder 10 is operated based on the measurement result to move the evaporation source 12 into and out of the heating chamber 3. Maintain the magnesium concentration in 3 at a predetermined value.

By the above-described operation, the concentration of magnesium in the heating chamber 3 can be properly maintained. Therefore, not only can the water and oxygen in the furnace be reliably removed, but also the magnesium evaporates excessively. Can be prevented from occurring, that is, excessively evaporated magnesium adheres to the inside of the furnace, requiring frequent cleaning and adversely affecting product quality.

In the above embodiment, the evaporation source 12 is moved up and down by the cylinder 10 so as to be moved in and out of the heating chamber 3 from the bottom. However, a driving device for moving the evaporation source 12 in and out is as follows. It goes without saying that an appropriate mechanism can be adopted without being limited to the cylinder 10. Also,
In the above-described embodiment, the cylinder 10 is automatically controlled by the control device 18 based on the measurement result of the measurement device 15. However, the driving device such as the cylinder is manually operated by observing the measurement result. May be.

[0016]

As described in detail above, the vacuum aluminum brazing furnace of the present invention is configured so that the evaporation source is moved into and out of the heating chamber based on the magnesium concentration in the heating chamber. It is possible to maintain the concentration properly, so that it is possible to prevent the furnace inside from being contaminated by excessively evaporated magnesium and to prevent problems such as adversely affecting product quality.
It is extremely effective in terms of maintenance and quality control.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a vacuum aluminum brazing furnace according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace main body 3 Heating chamber 5 Object to be processed 10 Cylinder (drive device) 12 Magnesium evaporation source 15 Measurement device 18 Control device

Continuation of the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F27B 5/00-5/18 B23K 1/008 B23K 31/02 310

Claims (1)

(57) [Claims] 1. A furnace main body, a heating chamber provided inside the furnace main body, and a magnesium which is provided so as to be able to be taken in and out of the heating chamber and which evaporates when loaded into the heating chamber during processing. An evaporation source, a measuring device for measuring the magnesium concentration in the heating chamber, and a driving device for moving the magnesium evaporation source into and out of the heating chamber based on the measurement result of the measuring device. Aluminum brazing furnace.