JPS5925453B2 - Hydrogen gas measuring device in molten metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for measuring the amount of hydrogen gas contained in molten metal such as aluminum or aluminum alloy.

For example, in the process of casting aluminum, if a large amount of hydrogen gas is contained in the molten metal, various internal defects will occur during casting and the quality of the product will deteriorate significantly.

For this reason, the amount of hydrogen gas in the molten metal is measured and the amount of hydrogen is strictly controlled in order to obtain high-quality products. Conventional methods for measuring the amount of hydrogen gas in molten metal include, for example, the initial bubble test method (IBT). This initial, bubble, test method takes an appropriate amount of molten metal to be used as an analysis sample, holds it in a molten state, and then reduces the gas phase pressure around the molten metal at a uniform rate, so that hydrogen initially appears on the surface of the molten metal. Determine the pressure of the gas phase and the temperature of the molten metal at the instant when the bubbles are generated, and then, based on these pressure values and measured temperature values, place a ruler a on a comparison table, such as the one shown in Figure 1, and use a scale to indicate the amount of hydrogen. The amount of hydrogen (the figure shows 0.2PmlH2/100g) is read at the point where it intersects. However, in the conventional method described above, it is necessary to read the pressure of the gas phase and the temperature of the molten metal at the moment when hydrogen bubbles are first generated on the surface of the molten metal. The work of monitoring the occurrence of bubbles, the work of reading the pressure of the gas phase with a vacuum gauge when bubbles are generated, and the work of reading the temperature must be carried out separately, and even if the pressure and temperature values are measured, the above-mentioned Since the amount of hydrogen gas could not be measured without using the comparison table shown in Figure 1, there was a drawback that the amount of hydrogen gas could not be measured quickly.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to measure hydrogen gas in molten metal by quickly measuring the amount of hydrogen gas in molten metal without requiring any troublesome effort during measurement. It must be something that provides equipment. That is, the present invention includes a pressure adjustment mechanism that changes the gas phase pressure of a container containing molten metal, and a detector that measures changes in the temperature of the molten metal and changes in the gas phase force, and detects the air around the molten metal when bubbles are generated in the molten metal. A hydrogen gas measuring device that detects the amount of hydrogen gas in the molten metal based on the phase pressure and the temperature of the molten metal, a first indicator connected to the molten metal temperature detector; a drive mechanism;
A second indicator drive mechanism connected to the gas phase pressure detector and a scale displaying a hydrogen amount scale are installed in parallel, and a rod-shaped indicator intersecting the scale is installed between both drive mechanisms, and the molten metal is In the molten metal, the indicator needle is moved by a drive mechanism that operates based on a temperature detection signal and a gas phase pressure detection signal, and the amount of hydrogen gas is detected from the scale display where the indicator needle intersects. This is a hydrogen gas measuring device.

The present invention will be explained in detail below based on the drawings. FIG. 2 is a schematic diagram showing an embodiment of the device of the present invention, which includes a pressure adjustment mechanism 3 that changes the gas phase pressure in a decompression chamber 2 containing molten metal 1, and a detector that measures temperature changes of the molten metal 1. 4 and a detector 5 for measuring changes in gas phase pressure, and both detectors 4 and 5 are connected to pointer drive mechanisms 6 and 7, respectively. The decompression chamber 2 is constituted by a fixed container 8 that is airtightly covered with a lid 9, and houses a heat insulating furnace 10 for keeping the molten metal 1 warm. Further, the pressure adjustment mechanism 3 provided with a vacuum pump is connected to the fixed container 8 via a suction pipe 11, and the pressure inside the decompression chamber 2 is successively reduced by the adjustment mechanism 3. Further, a pressure detector 5 such as a pluton tube pressure gauge or a bellows pressure gauge is attached to the suction pipe 11, and a pressure transducer 13 is attached to the pressure detector 5.
is connected. This pressure transducer 13 is the pressure sensor 5
The pressure transducer 13 is connected to a servo mechanism 14, and the servo mechanism 14 operates the first indicator and drive mechanism 6 equipped with a servo motor. I'm starting to do that. On the other hand, a thermocouple constituting the temperature sensor 4 is inserted through the upper part of the lid 9, and the tip of the thermocouple is inserted into the molten metal 1.

A servo mechanism 15 is connected to the detector 4, and the servo mechanism 15 transfers the input signal from the detector 4 to the servo motor 1.
The electric signal for driving is converted to operate a second pointer drive mechanism 7 provided with a servo motor.
In the figure, 16 is a switch that opens and closes the connection between the pressure transducer 13 and the pressure sensor 5, and 17 is a switch that opens and closes the connection between the temperature sensor 4 and the servo mechanism 15. Furthermore, both of the above drive mechanisms 6 and 7 are connected to a hydrogen amount indicator 18 shown in FIG.
The rod-shaped indicator needle 19 is driven once.

In the first indicator drive mechanism 6, an endless wire 21 is stretched between the drive wheel 6a and the idle wheel 20, and a fixture 21a is provided on the endless wire 21 to which one end of the indicator needle 19 is attached. There is. In addition, the second indicator drive mechanism 7 has an endless wire 23 stretched between the first drive wheel 7a and the idle wheel 22, and a fitting 23a is provided on this stress wire 23 so that the above-mentioned indicator The other end of the needle 19 is attached.Furthermore, a scale 24 displaying a hydrogen amount scale is provided between the two drive mechanisms 6 and 7, and the indicator needle 19 crosses over this scale 24. In this case, the fixture 21a corresponds to the pressure display section shown in FIG. 1, and the fixture 23a corresponds to the temperature display section, and the indicator needle 19
The graduations on the scale 24 that intersect with the molten metal indicate the temperature of the molten metal and the amount of hydrogen at the gas phase pressure around the molten metal. In order to measure the amount of hydrogen contained in the molten metal 1 with the hydrogen measuring device configured as described above, the molten metal 1 is placed in the heat retention furnace 1 in the decompression chamber 2.
0 and maintained at a constant temperature, and in this state, the pressure adjustment mechanism 3 is operated to lower the pressure inside the decompression chamber 2. In this case, the gas phase pressure around the molten metal is detected by the pressure detector 5, and based on this detection signal, the drive wheel 6a of the first indicator drive mechanism 6 rotates, and the end of the indicator needle 19 is connected to the endless wire 21. It moves together with the attached fixture 21a. This fixture 21a is designed to move downward by -L as the pressure changes, as shown by the pressure display scale in the comparison table of FIG. In addition, the temperature of the molten metal 1 is detected by a temperature 1 degree detector 4,
This detection signal (second indicator needle 1 drive mechanism 7
The drive wheel 7a rotates, and the other end of the indicator needle 19 moves together with the fixture 23a to which the endless wire 231 is attached. This fixture 23a is designed to move up and down as the temperature changes, approximately as shown by the temperature display scale in the comparison table of FIG. In this manner, the indicator needle 19 moves while intersecting with the scale 24 as the temperature and pressure change.
In this way, the pressure inside the decompression chamber 2 is lowered, and when this pressure becomes lower than the partial pressure of hydrogen contained in the molten metal 1, hydrogen bubbles are generated on the surface of the molten metal.

When hydrogen bubbles are generated, when the switches 16 and 17 are turned off, the driving mechanisms 6 and 7 are stopped and the indicator needle 19 is turned off.
stops at the same time. Therefore, this indicator 19 is the scale 2.
The scale at the intersection with 4 indicates the amount of hydrogen contained in the molten metal 1, and by reading this scale, the amount of hydrogen can be immediately measured. In the above embodiment, the amount of hydrogen in the molten metal was measured by measuring the temperature and pressure at the time hydrogen bubbles were generated while lowering the pressure in the decompression chamber 2. The temperature and pressure may be measured. Further, in the above embodiment, the scale 24 is provided between the two driving mechanisms 6 and 7, but the scale 24 is provided outside the driving mechanism 6 or 7, and the indicator needle 19 can intersect with the scale 24. You can do it like this.

As explained above, according to the present invention, the drive mechanisms are actuated based on changes in the temperature of the molten metal and changes in the gas phase pressure around the molten metal, and the indicator needle indicates the amount of hydrogen based on the changes in these drive mechanisms. Since it moves on the scale, once hydrogen generation in the molten metal is confirmed, the drive mechanism can be stopped and the scale display can be read, allowing a single measurer to quickly measure the amount of hydrogen. This is extremely useful for molten metal management.

[Brief explanation of drawings]

Fig. 1 is a front view showing a comparison table for conventional hydrogen gas measurement, Fig. 2 is a schematic explanatory diagram of a hydrogen gas measuring device showing an embodiment of the present invention, and Fig. 3 is a summary of Fig. 2. FIG. 1... Molten metal, 2... Decompression chamber, 3...
...Pressure adjustment mechanism, 4...Temperature detector, 5.
...pressure detector, 6,7...indicator drive mechanism, 16,17...switch, 20,22...
...Idle wheel, 21, 23...
Endless wire, 24... scale.

Claims (1)

[Claims] 1. A pressure adjustment mechanism that changes the gas phase pressure in a container containing molten metal, and a detector that measures changes in the temperature of the molten metal and changes in gas phase pressure, respectively, are installed, and the gas phase pressure around the molten metal is measured when hydrogen bubbles are generated in the molten metal. In the hydrogen gas measuring device that detects the amount of hydrogen gas in the molten metal from the molten metal temperature and the molten metal temperature, the hydrogen gas measuring device includes a first indicator drive mechanism connected to the molten metal detector, and a second indicator connected to the gas phase pressure detector. A drive mechanism and a scale displaying a hydrogen amount scale are installed in parallel, and a rod-shaped indicator needle that intersects with the scale is installed between both drive mechanisms, and a molten metal temperature detection signal and a gas phase pressure detection signal are A measuring device for measuring hydrogen gas in molten metal, wherein the indicator needle is moved by both drive mechanisms operated by the two drive mechanisms, and the amount of hydrogen gas is detected from the scale display on the scale where the indicator needles intersect.