JPH02305951A - Method and device for cooling after vacuum thermal spraying - Google Patents

Abstract

PURPOSE:To execute cooling in an extremely short period of time and to improve productivity by successively cooling a work after a vacuum thermal spraying to cooling by using a water cooling means, inert gas cooling means and spray cooling means in a reduced pressure chamber. CONSTITUTION:The work 8 with which the thermal spraying is completed is brought into contact with the base of a water cooling box 2a of the water cooling means 2 while the work is rotated on a turn table 7 in the reduced pressure chamber. The water in the box 2a is replaced by a hose 11 and the cooling of the work is executed. A temp. measuring control panel 19 blows the inert gas from the nozzles 3a of the inert gas cooling means 3 in place of the water cooling means 2 and cools the work in a contactless state when the temp. of the work 8 measured by a radiation thermometer 18 attains a prescribed temp. The control panel 19 supplies a refrigerant 16 to the nozzles 3a of the spray cooling means 4 and cools the work 8 down to the prescribed temp. by the refrigerant 16 when the work 8 cools down to the prescribed temp. The cooling of the work 8 is thus executed by successively changing the cooling means according to the temp. thereof, by which the cooling of the work 8 is executed in an extremely short period of time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to processing processes performed under reduced pressure, such as reduced pressure plasma spraying and electron beam welding, and particularly relates to a cooling method and apparatus for cooling after reduced pressure spraying.

(Prior Art) For example, the process for plasma spraying is to first set up a workpiece in a thermal spraying chamber, then evacuate the chamber, perform plasma preheating and surface Bonibird treatment, and then perform plasma spraying. After thermal spraying, the workpiece is left to cool and then vacuum depacked to remove the workpiece, thereby completing the thermal spraying process.

Therefore, for example, low pressure plasma spraying of 30 to 100't b
When performing r r, 400 to 5
Thermal spraying is performed after preheating to 00°C and cleaning the surface with plasma flame, but if the film is exposed to the atmosphere immediately after spraying, oxidation will occur and the film will not be able to fully demonstrate its properties. Therefore, until the above-mentioned influence disappears, it is left to cool under reduced pressure and then cooled by sealing in gas.

(Problems to be Solved by the Invention) However, when a large-capacity workpiece such as a large roll is thermally sprayed using a reduced-pressure thermal spraying process, the temperature of the workpiece reaches 600 to 700° C. due to preheating and long-term thermal spraying heat. Therefore, it is desirable to move on to the next process immediately after thermal spraying, but in order to avoid problems such as oxidation of the coating, it is not possible to expose it to the atmosphere until the temperature falls below a predetermined temperature.

Therefore, cooling under reduced pressure cannot be expected to rely on radiant heat and partial heat conduction through jigs, etc., and cooling takes a very long time.

In view of this, the present invention aims to eliminate the drawbacks of the prior art by providing a cooling method and device for cooling the workpiece after vacuum spraying, which efficiently lowers the temperature of a heated workpiece under reduced pressure. It is.

(Means for Solving the Problems) In order to achieve the above object, claim 1 of the present invention provides a cooling method after finishing a processing process such as reduced pressure plasma spraying or electron beam welding that is carried out under vacuum or reduced pressure. Contact cooling by cooling means, direct cooling by gas cooling,
Claim 2 is characterized in that the spray cooling is selected depending on the temperature of the workpiece to sequentially perform specific cooling. The apparatus is characterized in that a water cooling means, an inert gas cooling means, a spray cooling means, and a measuring means are provided in the reduced pressure chamber.

(Function) By using the apparatus of claim 2, the effect of claim 1 can be achieved, and thereby the cooling time can be significantly shortened compared to the conventional method.

(Example) The present invention will be described below with reference to the example shown in FIGS. 1 to 5.

The cooling method after vacuum spraying according to claim 1 of the present invention is carried out using the cooling device after vacuum spraying according to claim 2.

That is, the cooling device includes a water cooling means 2 in the decompression chamber 1,
It is comprised of an inert gas cooling means 3, a spray cooling means 4, and a measuring means 5.

The decompression chamber 1 is depressurized to a vacuum state by a vacuum pump 6 or the like, and therein are a water cooling means 2 consisting of a water cooling box 2a etc. and an inert gas cooling means 3 consisting of a nozzle 3a etc.
A spray cooling means 4 and a measuring means 5 such as a radiation thermometer are built in, and a rotary table 7 on which a thermal spray work 8 is placed is provided below these.

The water cooling means 2 includes a water cooling means positioner 9 provided on the side wall surface inside the decompression chamber 1, and is supported by this, and this positioner 9 is supported by a water cooling means w provided outside the decompression chamber 1.
The water cooling box 2a is raised and lowered by being activated by a signal from the zio.

Cooling water is introduced into the cooling box 2a of the water cooling means 2 from outside the decompression chamber 1 through a hose 11, and is discharged outside the cooling decompression chamber 1 as heated hot water.

The bottom surface of this water-cooled box 2a is brought into contact with the top surface of the thermal spraying wire 28 to cool the spraying wire 28.

In this case, the temperature of the workpiece 8 is measured by a contact thermometer sensor 12 provided in the water-cooled box 2a.

The inert gas cooling means 3 includes a gas cooling positioner 1 provided on the side wall surface of the decompression chamber 1 in the same manner as the cooling means 2.
The positioner 13 is also operated by a signal from a gas cooling control block 14 provided outside the decompression chamber 1 to move the nozzle 3a of the inert gas cooling means 3 up and down and horizontally. It is something. Gas is supplied to this nozzle 3a from outside the decompression chamber 1 through a hose 15 or the like.

The spray cooling means 4 has the same equipment as the nozzle 3a, but is functionally different.
In addition to the inert gas, water or other refrigerant 16 is supplied from outside the decompression chamber 1 to a.

Therefore, as shown in FIG. 3, this control is activated by a signal from a spray cooling chamber 91 board 17 provided outside the decompression chamber 1 to move the gas cooling positioner 13 up and down.

The measuring means 5 consists of the contact thermometer sensor 12, the non-contact radiation thermometer 18, and the like, and these are connected to the water cooling control plate 10. It is connected to a gas cooling control panel 14 and a spray cooling control panel 17.

Further, the temperature measurement control panel 19 is connected to the vacuum system control of the plasma device 20 and the vacuum pump 6, and is further connected to a drive source 21 for rotating the rotary table 7 of the workpiece 28.

As a result, the bottom surface of the water cooling box 2a of the water cooling means 2 is brought into contact with the workpiece 28 that has been thermally sprayed, and when the workpiece temperature at that time is detected by one of the contact type thermometer sensors 11 of the measuring means 5, the temperature is measured. In FIGS. 4 and 5, the control g119 is T>T, (700 to 300 in the embodiment
℃), a signal is sent to the water cooling control panel 10 to operate the water cooling means 2 to replace the water in the water cooling box 2a, and as a result, the temperature of the workpiece 8 is TNT, (3 in the embodiment).
00℃), temperature measurement control! ! 19
releases the water cooling means 2, sends a signal to the gas cooling control panel 14, and sprays the inert gas supplied to the nozzle 3a to cool the workpiece 8 in a non-contact manner.

When the temperature of the workpiece 8 is detected by the other radiation thermometer 18 of the measuring means 5 and a signal is sent to the temperature measurement control panel 19, and as a result T<72 (lower than 200°C in the example), The temperature measurement control panel 19 releases the inert gas cooling means 3 and sends a signal to the spray cooling control panel 17 to control the nozzle 3a.
In addition to the inert gas, water or other refrigerant 16 is supplied to the spray cooling means 4 for cooling. As a result, when the temperature of the workpiece 8 reaches T3 (60° C. or lower in the embodiment), the operation of the spray cooling means 4 is stopped by the spray cooling control panel 17.

In this way, the temperature of the workpiece 8 after the machining process is constantly measured and cooling is performed in accordance with the workpiece temperature.

Note that each of the above-mentioned cooling operations is performed while the workpiece 8 is rotated by the drive source 21.

Further, in the embodiment, the case of plasma spraying has been described, but similar cooling can be performed also in the case of electron beam.

FIG. 5 shows a graph of experimental data comparing the cooling processing time in the case of the conventional process and the process of the present invention.
It took 4 hours to lower the temperature from 00°C to 300°C and 15 minutes to lower the temperature from 300°C to 150°C, but in the case of the present invention, it took 30 minutes to lower the temperature from 700°C to 300°C, and 30 minutes to lower the temperature from 300°C to 200°C. 10 minutes to cool down to 200℃
The result was that it took 5 minutes to lower the temperature from ℃ to 150℃.

(Effects of the Invention) As explained above, the present invention uses the cooling device of claim 2 to cool the workpiece by the cooling method of claim 1. This can be done on time, improving productivity.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an overview of the cooling device after reduced pressure thermal spraying according to the present invention, Fig. 2 is an explanatory diagram of the operating sequence of the cooling method of the present invention, and Fig. 3 is a diagram showing each cooling means and control panel of the present invention. FIG. 4 is a block diagram of the cooling operation path of the present invention, and FIG. 5 is a graph showing a comparison between the conventional cooling time and the cooling time using the cooling method of the present invention. DESCRIPTION OF SYMBOLS 1... Decompression chamber, 2... Water cooling means, 2a... Water cooling box, 3... Inert gas cooling means, 3a... Nozzle, 4... Spray cooling means, 5... Measuring means, 6.
...Vacuum pump, 7. Rotating table, 8. Workpiece, 9. Positioner for water cooling means, 10. Control panel for water cooling, 12. Sensor for contact type thermometer, 13.・
... Gas cooling positioner, 14... Gas cooling control panel, 17... Spray cooling control panel, 18... Radiation thermometer, 19... Temperature measurement control panel, 20... Plasma device Control panel, 21... Drive source. Applicant Komatsu Ltd. (b) (C) Figure 3 Figure 4 □ Haruma Figure 5

Claims (1)

[Claims] 1) A cooling method after the completion of a processing process performed in vacuum or under reduced pressure, such as reduced pressure plasma spraying or electron beam welding, which includes contact cooling using water cooling means in a reduced pressure chamber and direct cooling using gas cooling. A cooling method after reduced-pressure thermal spraying, characterized in that different types of cooling are sequentially performed by selecting , spray cooling, and spray cooling depending on the temperature of the workpiece. 2) In a cooling device after the completion of a processing process performed under vacuum or reduced pressure such as reduced pressure plasma spraying or electron beam welding, a water cooling means and an inert gas cooling means are provided in the reduced pressure chamber.
A cooling device after reduced pressure thermal spraying, characterized by comprising a spray cooling means and a measuring means.