JPH09196836A - Thermal fatigue tester - Google Patents

Abstract

(57) Abstract: When performing temperature control by injecting a cooling gas onto a test piece in a thermal fatigue test in high frequency induction heating, there is a slight difference between the temperature raising process and the temperature lowering process. It is impossible to control the cooling gas injection by. Provided is a thermal fatigue testing machine, particularly a cooling gas injection control mechanism, which solves such a problem. SOLUTION: A test piece TP is heated by high frequency induction and a cooling gas is injected to cool the test piece TP, and the temperature of the test piece TP is controlled to a desired value while demonstrating thermal fatigue of the test piece TP. Two temperature cooling gas sources SE and temperature cooling gas sources CE are provided, and a temperature raising cooling gas control valve SV and a temperature lowering cooling gas control valve CV for controlling the injection amount of these gases are installed to increase the temperature. During cooling and cooling, the temperature of the test piece TP is controlled to a desired value with different cooling gases.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fatigue test for demonstrating thermal fatigue of a test piece while controlling the temperature of the test piece to a desired value by heating the test piece with high frequency induction and cooling it by injecting a cooling gas. It is about machines.

[0002]

2. Description of the Related Art In a fatigue tester of this type, a test piece TP is usually provided with a high frequency induction heating coil K as shown in FIG.
And the like, and the cooling gas is blown from the injection nozzle N to cool it, and the fatigue test is performed while controlling the temperature according to a desired program. As a heating method, there are a hot air blowing method, a resistance heating method, and an infrared heating method in addition to the high frequency induction heating method, but the high frequency induction heating method is often used to enable high-speed control. When the cooling gas is sprayed from the injection nozzle N, a plurality of cooling gas is arranged along the longitudinal direction of the test piece TP as shown in FIG. 6 so that the entire length of the test piece TP is uniformly cooled. . As the cooling gas, cooling air or nitrogen gas (N ² ) is used.

[0003]

In the above high frequency induction heating, the test piece TP is changed from the change of the magnetic field generated by the high frequency.
A current flows through the test piece TP itself, and the heat loss causes the test piece TP itself to generate heat. Therefore, this heat generation largely depends on the magnetic character of the test piece T. By the way, this magnetic character differs between the temperature raising process and the temperature lowering process. For example, in the martensitic structure of iron, magnetic transformation occurs between 670 degrees Celsius and 700 degrees Celsius. In that case, the temperature at which the magnetic transformation occurs differs between the temperature raising process and the temperature lowering process, and a so-called hysteresis phenomenon occurs. Therefore, the control in the high frequency induction heating is slightly different in the temperature raising process and the temperature lowering process, and therefore it is impossible to control one cooling gas injection system by the control program. In particular, in the fatigue test that requires high-speed and precise control according to the program, the thermal fatigue test with accurate control could not be realized. The present invention intends to provide a thermal fatigue tester that solves such problems.

[0004]

The thermal fatigue tester provided by the present invention performs a test while controlling the temperature of a test piece to a desired value by heating the test piece by high frequency induction heating and injecting a cooling gas to cool it. In a fatigue tester for demonstrating the thermal fatigue of a piece, a cooling gas control valve for heating and a cooling gas for cooling to control the injection amount of these gases are provided while providing two cooling gas sources for heating and cooling gas for cooling. A control valve is installed so that the temperature of the test piece is controlled to a desired value by different cooling gases at the time of temperature rise and at the time of temperature decrease.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing a schematic configuration for temperature control in a thermal fatigue tester provided by the present invention, where TP is a test piece, K is a high frequency induction heating coil, and N Indicates a cooling gas injection nozzle. Although not shown, the heating temperature of the test piece TP is measured by a temperature measuring means such as a thermocouple, and the signal is fed back to be controlled by the temperature controller TC. In this control method, for example, proportional / integral / derivative control, a so-called PID control method, is used. One of the output signals from the temperature control device TC becomes a control signal of the high frequency induction heating drive device KD, and the other one becomes a cooling gas injection type cooling control signal.

The present invention is characterized in that the control of the cooling gas injection is performed separately for the temperature raising and the temperature lowering purposes, and there are two of the temperature raising cooling gas source SE and the temperature lowering cooling gas source CE.
The individual cooling gas sources are installed, and control signals are input to the temperature increasing cooling gas control valve SV and the temperature decreasing cooling gas control valve CV installed corresponding to the respective gas sources SE and CE. It has become so. Then, the cooling gas that has passed through each control valve SV or CV is sprayed onto the test piece TP through the nozzle N. CR is a switching device, which is switched each time the temperature is raised or lowered. This switching is automatically performed by a signal from the temperature control device TC. In particular, for example, in the martensitic structure of iron, a magnetic transformation occurs between 670 ° C. and 700 ° C. Therefore, when the temperature is between 670 ° C. and 700 ° C., control is performed in the temperature rising process. When controlling in the temperature lowering process, the distinction is discriminated and a switching signal is issued from the temperature control device TC to switch the cooling gas supply.

The temperature raising cooling gas control system and the temperature lowering cooling gas control system are both configured to be the same.
Therefore, the cooling gas control system for cooling the temperature will be taken up and its configuration will be described below with reference to FIGS. 2 to 5. FIG. 2 shows a control unit UN equipped with a gas flow path system centering on the cooling gas control valve CV for temperature lowering. Gas from the cooling gas source CE for temperature reduction (not shown) is guided to the gas pressure reducing valve unit GV from the pipe L1, is supplied to the control valve CV via the filter F and the pipe L2. Here, the cooling gas for cooling the temperature of which the flow rate is controlled in a predetermined manner is guided to the gas branch manifold MH through the pipe L3. Then, the gas branch manifold MH is branched into four thin tubes P1 to P4 and pressure-fed to the respective nozzles N.

The structure of the control valve CV provided between the pipes L2 and L3 is shown in FIG. Fig. 3 shows control valve C
The cross-sectional view of V is shown, and the gas flow rate is controlled by the rotation control of a rotary flow control valve 2 rotatably provided in a valve housing 1 interposed between the pipes L2 and L3.
That is, the rotation control of the rotary flow control valve 2 is performed by the motor 3 which is operated by the control signal from the temperature control device TC, and the rotation amount of the rotary flow control valve 2 is detected by the rotary encoder 4 to detect the temperature. The feedback is made to the control device TC. The rotary flow control valve 2, the motor 3 and the rotary encoder 4 are connected and fixed to each other on one axis, and the rotation amount of the motor 3 is accurately transmitted to the rotary flow control valve 2 and the rotary encoder 4. It As shown in FIGS. 4 and 5, the rotary type flow control valve 2 has a cylindrical shape and a flow control channel 2 in the center thereof.
R is bored, and wedge-shaped grooves 2K for enabling fine flow rate control are formed at both ends of the flow path 2R. A plurality of sealing grooves are formed at both ends of the outer peripheral surface of the cylindrical body.

The cooling gas control valve CV for cooling the temperature is constructed as described above, and in consideration of the temperature characteristics due to the magnetic transformation occurring in the cooling process, the flow rate of the gas, that is, the precise control of the injection amount from the nozzle is finally controlled. Is guaranteed. As described above, the configuration of the temperature increasing cooling gas control valve SV is also the same as the configuration of the temperature decreasing cooling gas control valve CV, and the cooling gas control is appropriately performed by the operation of both control valves.

The thermal fatigue tester provided by the present invention, in particular, the cooling gas supply control mechanism for temperature control is as described above, but includes various modified embodiments utilizing this feature in addition to the above-mentioned or illustrated examples. To do. First, regarding the configuration of the gas supply control valve, in the illustrated example, the rotary type flow control valve that can be directly connected to the motor and has a simple structure was used, but it can be connected to an electro-hydraulic servo valve for a wide range of control. A displacement type spool valve can also be used. Further, in the above, the configuration of the cooling gas control valve for temperature increase SV is the same as that of the cooling gas control valve for temperature decrease CV, but the respective configurations are changed so that the temperature characteristics of temperature increase and temperature decrease are matched. It may be configured as follows. Further, in the illustrated example, various devices are interposed in the gas flow path system, but these are not essential devices,
It is also possible to appropriately change or omit. In the illustrated example, the number of nozzles is set to four so as to allow uniform cooling, but the structure is not limited to this, and it is possible to simplify the structure by providing one wide-width nozzle along the longitudinal direction of the test piece. is there.

Further, in the example shown in the drawings, the nozzle has an embodiment in which the same nozzle is used to inject the temperature rising cooling gas and the temperature lowering cooling gas, but the temperature rising cooling gas and the temperature lowering cooling gas are injected. It is also possible to adopt a system in which the nozzles are used separately. This method has the advantages that a flow path switching mechanism is not necessary and that the injection of the temperature rising cooling gas and the temperature lowering cooling gas onto the test piece can be completely switched. The present invention includes all these modifications.

The present invention is summarized as follows.

Supplementary Note 1 In a fatigue testing machine for demonstrating thermal fatigue of a test piece while controlling the temperature of the test piece to a desired value by heating the test piece by high frequency induction heating and cooling by cooling gas, A cooling gas source and a cooling gas source for cooling are provided, and a cooling gas control valve for heating and a cooling gas control valve for cooling are installed to control the injection amount of these gases, and they are different when heating and when cooling. A thermal fatigue tester characterized in that the temperature of a test piece is controlled to a desired value with a cooling gas.

Supplementary Note 2 In a fatigue tester for demonstrating thermal fatigue of a test piece while controlling the temperature of the test piece to a desired value by heating the test piece by high frequency induction heating and cooling by cooling gas, A cooling gas source and a cooling gas source for cooling the temperature are provided, and a cooling gas control valve for raising the temperature and a cooling gas control valve for cooling the temperature for controlling the injection amount of these gases, and a nozzle for injecting the cooling gas onto the test piece, A switching mechanism for selectively supplying the temperature-raising cooling gas and the temperature-cooling cooling gas to the nozzle is provided, and the temperature of the test piece is controlled to a desired value by using different cooling gases during temperature increase and temperature decrease. A thermal fatigue testing machine characterized by the above.

Supplementary Note 3 In a fatigue tester for demonstrating thermal fatigue of a test piece while controlling the temperature of the test piece to a desired value by heating the test piece by high frequency induction heating and cooling by cooling gas, A cooling gas source and a cooling gas source for cooling the temperature are provided, and a cooling gas control valve for temperature rising and a cooling gas control valve for cooling the temperature for controlling the injection amount of these gases, and a temperature rising connected to each of these gas control valves Each of the nozzles for injecting the cooling gas for cooling and the cooling gas for cooling to the test piece is provided, and the temperature of the test piece is controlled to a desired value by different cooling gas during temperature increase and temperature decrease. Characteristic thermal fatigue tester.

[0016]

The thermal fatigue tester provided by the present invention, especially the test piece temperature control mechanism, is as described above.
The advantage is that the cooling gas can be injected to sufficiently follow the special temperature change even with respect to the magnetic transformation of the test piece due to high-frequency induction heating, the desired control can be realized, and a highly accurate thermal fatigue test can be performed. Have.

[Brief description of drawings]

FIG. 1 is a diagram schematically showing a configuration of a thermal fatigue tester according to the present invention.

FIG. 2 is a diagram showing a configuration of a cooling gas supply mechanism of the thermal fatigue testing machine according to the present invention.

FIG. 3 is a diagram showing a configuration of a cooling gas supply control valve in the thermal fatigue tester of the present invention.

FIG. 4 is a diagram showing a configuration of a cooling gas supply control valve in the thermal fatigue tester of the present invention.

FIG. 5 is a diagram showing a configuration of a cooling gas supply control valve in the thermal fatigue tester of the present invention.

FIG. 6 is a diagram showing a configuration of a test piece heating mechanism in the thermal fatigue tester of the present invention.

[Explanation of symbols]

 TP ... Test piece K ... High frequency induction heating coil N ... Cooling gas injection nozzle TC ... Temperature control device KD ... High frequency induction heating drive device SE ... Temperature rising cooling gas source CE ... Temperature decreasing cooling gas source SV ... Temperature rising cooling gas Control valve CV ... Cooling gas control valve for cooling 1 ... Valve housing 2 ... Rotary flow control valve 3 ... Motor SG ... Marker 4 ... Rotary encoder

Claims (1)

[Claims] 1. A fatigue test machine for demonstrating thermal fatigue of a test piece while controlling the temperature of the test piece to a desired value by heating the test piece with high-frequency induction heating and cooling the test gas to cool the test piece. A cooling gas source and a cooling gas source for cooling are provided, and a cooling gas control valve for heating and a cooling gas control valve for cooling are installed to control the injection amount of these gases, and they are different when heating and when cooling. A thermal fatigue tester characterized in that the temperature of a test piece is controlled to a desired value with a cooling gas.