JPH0718825B2 - Radiant heat insulation method in high temperature test equipment - Google Patents

Description

[Detailed Description of the Invention] A. Field of Industrial Application This invention shuts off radiant heat emitted from a test piece when measuring the elongation of a test piece heated by a high-frequency heating device provided in a high-temperature test device. The present invention relates to a method for blocking radiant heat in a high temperature test device for performing the above.

B. Conventional Technology A high-temperature test device is known that measures the elongation of a test piece heated by using a high-frequency heating device that utilizes the skin effect and proximity effect of a high-frequency current. In this type of device, for example, an elongation measuring device, a test piece is placed in the center of a high-frequency heating coil provided in a furnace, and a contact point constituting an extensometer is abutted and locked at a gauge point position of the test piece. The extent to which the contact of the extensometer is expanded by the elongation of the test piece is measured by the displacement detection unit including a differential transformer. In such a high-temperature test, in a test using a large test piece or a test in which a soaking range is wide, the radiant heat from the test piece increases, and equipment such as an extensometer or a vacuum chamber installed in the surroundings increases. The temperature may rise abnormally under the influence of radiant heat.

Such an increase in radiant heat exerts a particularly serious influence when the high temperature test apparatus is an extensometer, and the temperature drift becomes large so that accurate elongation cannot be measured. There is a risk that the extensometer may be destroyed by exceeding the service temperature of the displacement detector such as a differential transformer.

Therefore, in order to prevent the influence of radiant heat as described above on surrounding equipment as much as possible, conventionally, a radiant plate is provided on the extensometer to prevent radiant heat from the test piece, and the length of the contact of the extensometer is reduced. The main body of the extensometer, such as a differential transformer, is installed separately from the heat source, or the extensometer and vacuum chamber are water-cooled.

C. Problems to be Solved by the Invention However, in the conventional method of reducing the influence of radiant heat on surrounding equipment as much as possible, the structure of the high temperature test apparatus becomes complicated and the contactor becomes long. There is a problem that the reliability of the measured value is reduced.

An object of the present invention is to propose a method for shielding radiant heat in a high-temperature test device, which reduces radiant heat itself emitted from a test piece heated by a high-frequency heating device.

D. Means for solving the problem The present invention is a high-frequency heating device for heating a test piece, and a radiant heat blocking method in a high-temperature test apparatus comprising a measuring device for measuring the physical quantity of the test piece, wherein A pair of contacts that make up the measuring device contact the test piece,
A method for blocking radiant heat in a high-temperature test apparatus, characterized in that the surface of this test piece is covered with a heat-resistant blocking member having low thermal conductivity that is not subjected to high-frequency induction, in addition to the portion where the pair of contacts come into contact with each other. .

E. Function The radiant heat from the test piece heated by the high-frequency heating device provided in the high-temperature test device is blocked by the function of the blocking member coated on the test piece.

F. Example As shown in FIG. 1, the test piece 1 is positioned in a high frequency heating coil 3 provided inside a furnace 2. At the gauge point position of this test piece 1, a pair of contacts penetrating the furnace wall 2a
The detection ends 5a, 5b of the 4a, 4b are abutted and locked by a predetermined contact pressure. In the high-temperature test apparatus, the other ends of the pair of contacts 4a, 4b forming the extensometer are inserted into the holders 6a, 6b, and the springs 7 provided in the holders 6a, 6b prevent the contacts 4a, 4b from moving. During elongation measurement, the test piece 1 is brought into contact with and locked by the predetermined contact pressure as described above.
The holders 6a and 6b are connected to each other by a leaf spring 9 fixed to a fixing portion 8 by a bar 7. In addition, the housing 10a on the coil side of the differential transformer 10 is attached to the holder 6a,
A core 10b is attached to the holder 6b.

Then, the test piece 1 does not receive high frequency induction by the high frequency heating coil 3 and is made of a heat-resistant material as a blocking member 11
The wire material or cloth material is wound around the portions other than the portions in contact with the detection ends 5a, 5b of the contacts 4a, 4b without any gap. The material of the blocking member 11 is preferably glass wool, asbestos or the like, but any material may be used as long as it does not receive high frequency induction and has low heat conductivity and heat resistance.

In the high temperature test apparatus, in order to measure the elongation of the test piece 1, a high frequency current is passed through a high frequency heating coil 3 from a power source (not shown) to heat the test piece 1. When the test piece 1 extends, the detection ends 5a, 5b locked at the gauge point position of the test piece 1
The expansion is allowed by the leaf spring 9 being convex toward the test piece 1 and curved. On the other hand, the displacements at the ends of the holders 6a and 6b which are brought closer to each other due to the expansion of the detection ends 5a and 5b are detected by the differential transformer 10 in the form of an electric signal, and therefore, they follow the mounting position of the differential transformer 10. The elongation of the test piece 1 is measured by performing a calculation on the electric signal.

The test piece 1 thus heated does not receive high frequency induction and is made of a heat-resistant material having a low thermal conductivity.
Since the test piece 1 is wound, the radiant heat of the test piece 1 is blocked by the wound blocking member 11 even though the test piece 1 is heated to a high temperature by the high frequency current during the high temperature test. The radiant heat to the differential transformer 10 and the like forming the extensometer is reduced as compared with the conventional one. Although the temperature of the blocking member 11 also rises due to the heat conduction from the test piece 1, the radiant heat from the blocking member 11 is slightly smaller than the radiant heat emitted from the test piece 1 itself described in the conventional technique, which causes a problem. I won't.

The experimental results comparing the case where the blocking member 11 is wound and the case where it is not wound under the same test conditions are shown below. The material of the blocking member 11 is glass wool,
The test piece was a plate-shaped test piece with protrusions, and the test piece was heated to 800 ° C. for an experiment.

(1) When the blocking member is not wound It took about 4 hours for the output of the differential transformer 10 to reach a steady state, and the temperature of the differential transformer 10 rose to 95 ° C.

(2) When the blocking member is wound The output of the differential transformer 10 becomes steady within 1 hour,
The temperature of the differential transformer 10 only rose to 70 ° C.

Although the case where the method of the present invention is applied to the extensometer has been described above, the method of the present invention can be applied to not only the extensometer but also a measuring device that measures various physical quantities that change due to heating of the test piece.

When the extensometer is housed in the vacuum chamber in which the cooling water passage is arranged and the high temperature elongation test is performed, the volume of the cooling water passage can be reduced as much as the radiant heat is reduced, and the vacuum chamber can be downsized.

G. Effect of the Invention According to the present invention, since the radiant heat emitted from the test piece is cut off only by covering the test piece with the blocking member, a radiant plate is provided as in the conventional case, and the length of the contact is increased. And so on
The effect of radiant heat can be prevented very effectively without complicating the structure of the high temperature test device or deteriorating the measurement performance. Further, according to the present invention, since the heat of the test piece does not escape by the blocking member, the time for heating to the same temperature is shortened, and the output of the high frequency heating device can be reduced by about 30 to 40% compared to the conventional case, and the effect of energy saving. Also has.

[Brief description of drawings]

FIG. 1 is a schematic sectional view when the method of the present invention is applied to an extensometer, and FIG. 2 is a sectional view taken along the line II-II in FIG. 1: Test piece, 2: Furnace, 2a: Furnace wall 3: High frequency heating coil 4a, 4b: Contact, 5a, 5b: Detection end 6a, 6b: Holder, 7: Compression spring 8: Fixed part, 9: Leaf spring 10: Differential transformer, 11: Breaking member

Claims (1)

[Claims] 1. A radiant heat blocking method in a high-temperature test apparatus comprising a high-frequency heating device for heating a test piece and a measuring device for measuring a physical quantity of the test piece, the pair of contacts constituting the measuring device. While contacting the test piece, the surface of the test piece is covered with a heat-resistant blocking member having a low thermal conductivity that is not subjected to high frequency induction, in addition to the portions where the pair of contacts come into contact with each other. Radiant heat insulation method in high temperature test equipment.