JP3264050B2 - Material testing machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a material testing machine for evaluating characteristics in a process of melting and solidifying a test piece.

[0002]

2. Description of the Related Art From the viewpoint of resource recycling, used metals are recovered, melted, solidified, and reused. At this time, it is necessary to know how the characteristics of the metal change due to the process of melting and solidifying the metal.

[0003] Conventionally, as a material tester for measuring a change in characteristics due to the melting and solidifying processes of a metal, a plurality of turns (corresponding to the length to be melted and solidified) of a metal test piece held by the material tester are used. winding a coil having turns) around the specimen, negative cooling, the specimens were allowed to clot test piece by applying a high frequency voltage to the coil heating, after melt
There was something to load .

[0004]

However, in the above-mentioned conventional material testing machine, the test piece is melted by a coil having a plurality of turns corresponding to the length to be melted and solidified. There is a possibility that the area to be melted at a time is so large that the melted portion flows down, making it impossible to evaluate the characteristics thereafter.

An object of the present invention is to provide a material testing machine capable of dissolving and coagulating a test specimen in a desired range to evaluate characteristics.

The present invention is applied to a material testing machine for evaluating characteristics in a process of melting and solidifying a test piece, and an object of the present invention is to provide a load means for loading a test piece, Heating means for heating and melting a predetermined area,
Move the heating means along the specimen to heat and melt the specimen.
Control means for sequentially performing melting and solidification from one end to the other end of a predetermined range.

[0007]

The heating means heats and melts a predetermined area of the test piece, and the control means moves the heating means along the test piece , thereby heating, melting and solidifying the test piece from one end of the predetermined range . It is performed in order to the other end . Thereby, it is possible to heat, melt , and solidify the test piece over a desired range while limiting the range of melting at a time to a predetermined range.

[0008]

FIG. 1 is a schematic view showing the overall configuration of an embodiment of a material testing machine according to the present invention, FIG. 2 is a partially cutaway front view of the testing machine main body, and FIG. FIG.
In these figures, reference numeral 10 denotes a tester main body for loading a test piece TP, and the tester main body 10 includes a load frame LF. The load frame LF is configured by horizontally extending a yoke 13 on the upper ends of a pair of screw rods 12a and 12b erected on the table 11, and screwing a crosshead 14 to the screw rods 12a and 12b.

The table 11 is provided with a load motor 15, and the rotation of the motor 15 is transmitted to a pair of screw rods 12 a and 12 b via a transmission 16.
The crosshead 14 is moved up and down by the rotation of 12b. The cross head 14 is provided with an upper grip 18a via a load cell 17, and the table 11 is provided with a lower grip 18b. The test piece TP is provided with these upper and lower grips 18a, 18b.
It is loaded in the state where it was grasped.

Reference numeral 20 denotes a table 11, screw rods 12a and 12
The vacuum furnace is disposed in a space surrounded by “b” and the crosshead 14, and is placed on the table 11 via the fixing member 21. The inside of the vacuum furnace 20 is maintained at a predetermined degree of vacuum by an exhaust means (not shown), and the atmosphere in the vacuum furnace 20 is replaced with an inert gas by introducing an inert gas after the vacuum. Is done.

In the vacuum furnace 20, the above-mentioned upper grip 18
a, 18b and the test piece TP are accommodated, and airtight holding means (not shown) is interposed between the upper and lower grips 18a, 18b and the vacuum furnace 20, so that the inside of the vacuum furnace 20 is airtight. Is held. The reason why the periphery of the test piece TP is held in a vacuum state or an inert gas atmosphere is that the test piece TP is not oxidized when the test piece TP is melted in a vacuum state or an inert gas atmosphere. It is not necessary to provide the vacuum furnace 20 as long as the substance does not easily oxidize.

As shown in FIGS. 1 to 4, a screw rod 22 parallel to the screw rod 12a is provided in the vacuum furnace 20, and the screw rod 22 is fixed to the vacuum furnace 20. It is rotationally driven by a motor 23 (only schematically shown in FIG. 1).

As shown in FIGS. 4 and 5, reference numeral 25 denotes a high-frequency heating coil, which is fixed to a coil holder 26 provided on the upper part of the vacuum furnace 20 so as to penetrate the vacuum furnace 20. It is arranged to. The tip 25a of the coil 25 is wound only once around the test piece TP as shown in FIG. That is, the number of turns of the coil 25 is one. 4 and 5, only the load axis AX of the test piece TP is illustrated, and the grippers 18a and 18b are not illustrated.

The base 25b of the coil 25 is supported by a fixing member 27 as shown in FIGS. 4 and 5, and at the side of the fixing member 27, a female screw portion 27a screwed to the screw rod 22 is formed. Have been. Therefore, the screw rod 22
The coil 25 moves up and down along the load axis AX together with the coil holder 26 and the fixing member 27 by the rotation of. Therefore, a metal bellows 28 is interposed between the coil holder 26 and the vacuum furnace 20, and the airtightness of the vacuum furnace 20 is maintained even if the coil holder 26 moves as the coil 25 moves up and down. Configuration is maintained. In FIG. 5, reference numeral 29 denotes a stopper bar for preventing the coil holder 26 from rising above the vacuum furnace 20 at a certain height.

Returning to FIG. 1, reference numeral 30 denotes a thermocouple attached to the test piece TP. The thermocouple 30 is disposed at a position avoiding a range where the test piece TP is melted and solidified as described later, and more specifically, a minute distance ( (For example, about 1 mm).

Reference numeral 40 denotes a control device for controlling each part of the tester main body 10, and is constituted by, for example, a programmable controller or the like. The control device 40 includes the load cell 1
7. Input a signal from the thermocouple 30 to control the driving of the motors 15 and 23 and the voltage and current applied to the coil 25 according to a predetermined program pattern.

Next, the operation of the material testing machine of this embodiment will be described with reference to FIGS. First, the motor 15 is controlled to adjust the position of the crosshead 14, and
After holding the test piece TP by 8a and 18b, the vacuum furnace 2
The test is started by evacuating the inside of 0 or replacing with an inert gas.

Next, the control device 40 controls the driving of the motor 23, and as shown in FIG. 6 (a), the coil 25 is provided at the lower end of the melting and solidifying range (indicated by R in the figure, 20 mm long as an example). The position of the coil 25 is adjusted by moving the coil 25 up and down so that the tip 25a of the coil 25 is located. In this state, the control device 40 applies a high-frequency voltage to the coil 25 to inductively heat the test piece TP.

The test piece TP heated by the coil 25 expands due to a rise in temperature, and a compression load is applied to the test piece TP as it is. Therefore, the control device 40 detects the compression load accompanying the thermal expansion of the test piece TP based on the signal from the load cell 17, and controls the motor 15 so that this load always becomes 0 (zero load holding). Adjust the position of the crosshead 14.

The power applied to the coil 25 is a thermocouple 3
Controlled by an output signal from 0, as shown in FIG.
When the output signal from the thermocouple 30 reaches a predetermined temperature, the test piece T
Until a part of P is melted, the temperature is controlled to be a constant heating rate, and when a part of the test piece TP (indicated by M in FIG. 6A) is melted, the power is kept constant. . While the power is kept constant, the output signal from the thermocouple 30 is not used for control. The predetermined temperature as a criterion for maintaining the power constant is obtained in advance from an output signal from the thermocouple 30 when the test piece TP is melted under the same conditions, and is input into the control device 40. . The test piece TP
When a part of is melted, the compressive load caused by the thermal expansion is not applied, so the control device 40 stops the zero load holding control immediately before the output signal from the thermocouple 30 becomes a signal corresponding to the above-mentioned predetermined temperature. .

At this time, since the number of turns of the coil 25 is one, the portion M to be melted by the coil 25 is limited to a minute area, and is, for example, about 5 mm long. When the test piece TP is melted only in such a small area M, the melted portion M is prevented from flowing down due to surface tension, and furthermore, the melted portion M is formed by the magnetic field formed by the coil 25.
Is further prevented from flowing down by convection.

At the stage where the power applied to the coil 25 is kept constant, the control device 40 controls the driving of the motor 23 to raise the tip 25a of the coil 25 at a constant speed. The ascending speed is the test piece T in the range R to be melted and solidified.
P is uniformly melted and solidified, and a portion M that is melted at a time is determined so as to be contained in a minute region, and has a very slow speed as a whole (for example, 1 mm / mm).
Minutes). The test piece TP in the portion C that has deviated from the distal end portion 25a of the coil 25 is naturally cooled and solidified as shown in FIG.

After the coil 25 is raised by a predetermined length to melt the entire range R of the test piece TP to be melted and solidified, as shown in FIG. 7, the thermocouple is heated at a constant temperature decreasing rate. The control unit 40 controls the power output to the coil 25 based on the output signal of the control unit 30.

After all the melted portions have solidified, the controller 40 controls the motor 15 to raise the crosshead 14 and apply a tensile load to the test piece TP in the same manner as in a normal tensile test.

Therefore, according to the present embodiment, the coil 2
5 is made one turn, and the portion M to be melted at one time is a minute region, so that the surface tension of the melted portion M and the coil 2
It is possible to prevent the molten portion M from flowing down due to the magnetic field 5 or the like. Then, the coil 25 is connected to the load shaft AX.
Is melted and solidified in the desired range R of the test piece, so that the desired range of the test piece TP can be melted and solidified to evaluate the characteristics in the process.

The details of the material testing machine of the present invention are not limited to the above-described embodiment, and various modifications are possible. As an example, in one embodiment, the present invention is applied to a material testing machine for performing a tensile test, but can be applied to a known material testing machine such as a compression testing machine and a creep testing machine. Further, in one embodiment, the coil is formed in one turn. However, if a portion to be melted by the coil does not flow down in a minute area, a coil having a plurality of turns may be used.

[0027]

As described above in detail, according to the present invention, the heating means for heating and melting a predetermined area of the test piece is moved along the test piece to thereby add the test piece .
Heat, melting, and solidification are performed in order from one end to the other end of the predetermined range , so that heating, melting , and solidifying are performed over a desired range of the test piece while limiting the melting range at a time to a predetermined region. be able to. This makes it possible to perform the property evaluation by melting and solidifying the test piece over a desired range while preventing the molten portion of the test piece from flowing down.

[Brief description of the drawings]

FIG. 1 is a schematic view showing a material testing machine according to one embodiment of the present invention.

FIG. 2 is a partially cutaway front view of a tester main body.

FIG. 3 is a partially cutaway right side view of the tester main body.

FIG. 4 is a partially cutaway front view showing a coil.

FIG. 5 is a cross-sectional view showing a state where the coil is attached to a vacuum furnace.

FIG. 6 is a diagram showing melting and solidification of a test piece by a coil.

FIG. 7 is a diagram showing temperature control by a control device.

[Explanation of symbols]

 AX Load shaft LF Load frame M Fused portion TP Test piece 10 Test machine main body 12a, 12b, 22 Screw rod 14 Cross head 15, 23 Motor 25 Coil 30 Thermocouple 40 Control device

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 3/18 JICST file (JOIS)

Claims (1)

(57) [Claims] A load unit configured to load a test piece; a heating unit configured to heat and melt a predetermined area of the test piece; and a heating unit configured to move the heating unit along the test piece so that the test piece is moved.
Heating, melting and solidification in order from one end of the predetermined range to the other end
A material testing machine comprising: a control unit for performing the test.