JPS585974Y2 - Sample collector for measuring hydrogen content in molten metal - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a sample collector for quickly and accurately measuring the hydrogen content in a molten tank layer.

Hydrogen deposited in a gold layer in a metal material has a great influence on the properties of the metal.

For example, when the hydrogen content in a steel material increases, it not only causes embrittlement, but also causes serious defects such as whitening and clutching.

Therefore, it is extremely important to accurately understand the behavior of hydrogen in, for example, molten iron or molten steel during the melting process of these metal materials, and to control the hydrogen content within an appropriate range.

As a premise, it is necessary to establish a technology to accurately measure the amount of hydrogen in molten metal, but in order to do so, it is necessary to obtain representativeness without causing hydrogen dissipation or mixing from the molten metal bath to be measured. It becomes an absolute prerequisite to collect a certain sample quickly.

From this point of view, various sample collectors have been developed up to now, but it is difficult to say that they are perfect.

By the way, known sampling techniques for molten metal, particularly molten steel, can be roughly divided into the following two types.

(1) A method of cooling the collected sample as quickly as possible and freezing the hydrogen in the molten steel.

Specifically, there are ■ pumping mold casting method, ■ dropper suction method, ■ suction method using a reduced pressure quartz pipe, etc. These methods are widely put into practical use because they are superior in terms of workability, but cooling If the operation is not performed carefully, hydrogen will dissipate and it will be difficult to recover the hydrogen completely, so the measured value will be much lower than the true value, depending on the hydrogen level and the type of alloy.

(2) A method in which a space is provided inside the sampler to store the hydrogen released during cooling and solidification of the sample.

Specifically, there are vacuum sampling methods, metal absolute vacuum molding methods, etc., and theoretically, true hydrogen values should be obtained.

However, with this method, gaseous hydrogen and residual hydrogen in the solidified sample Φ must be measured separately, which not only results in poor workability but also increases measurement errors.

In addition, the structure of the collector is complicated and the success rate of the collection operation is low, so it seems that it is not put into practical use very often.

In contrast to these methods, the immersion mold method (Imn
A method called the J.G. Mold method) or the G.G. Ba5sett method has been proposed.

This method uses an instrument as shown in FIG. 1, in which a copper mold 2 is inserted into a quartz tube 1.

Note that 3 is a sealing device, 5 is a thin wall portion, and the inside of the mold 4 is reduced in pressure if necessary.

When this device is used, molten metal penetrates through the thin walled portion 5 and flows into the mold interior 4.

Therefore, since there is no need to perform a pumping operation using a spoon, the amount of hydrogen released during sample collection is reduced.

Also, since the mold 2 is made of copper, it has a high cooling effect on the molten metal.
After cooling and solidifying the metal, the amount of hydrogen is measured on a sample piece removed from the mold.

Therefore, although hydrogen loss during collection is small, the hydrogen released during the cooling and solidification process is not included in the measurement target, and the disadvantage is that only a lower value than the true hydrogen value can be obtained.

In this manner, when taking a sample from molten metal for measurement, supersaturated hydrogen is released due to a decrease in the solubility of hydrogen accompanying a rapid drop in sample temperature.

That is, hydrogen release during sample collection is unavoidable, and the actual situation is that the above-mentioned known methods have no choice but to ignore this released hydrogen.

The present invention was developed in view of these circumstances, and its purpose is to prevent hydrogen release during sample collection.

In addition, it is a device that can also measure the hydrogen released during the measurement of the salt after it has been collected, and can measure residual hydrogen in the solidified metal and released hydrogen at the same level, making it possible to accurately measure hydrogen. The aim is to provide a sample collector that can give a large amount of water.

The collector of the present invention that has achieved the above purpose is lined with water, a metal that is difficult to diffuse, or a metal that is soluble in hydrogen so that it can be peeled off, the inside is μ-chained under reduced pressure, and there are some thin-walled parts. The gist lies in that the heat-resistant container formed with is housed and held in a container made of a protective material, except for the thin wall portion.

Therefore, when this collector is inserted into molten metal, the thin wall portion is ruptured by the impact force when inserted into the molten metal, the external pressure of the molten metal, etc., and the molten metal is sucked into the container.

The sample is then pulled out of the molten metal and cooled and solidified. During this process, the molten metal and the lining metal are fused or adhered to each other to prevent the diffusion of hydrogen or to absorb the released hydrogen into the lining material. Therefore, by measuring the sample metal and the lining material together, almost the entire amount of hydrogen in the original molten metal can be detected.

The configuration and effects of the present invention will be explained below based on drawings showing embodiments, but the following is not intended to limit the present invention, and it is within the scope of the present invention to make changes in accordance with the spirit of the preceding and following. It does not go beyond the technical scope.

FIG. 2 shows an embodiment of the present invention, in which a quartz tube 1 serving as a heat-resistant container is inserted into a protective material 6 made of paper (for example, a paper sleeve). A thin-walled metal tube T having a slightly smaller outer diameter is lined inside.

Therefore, a slight gap will be formed between the quartz tube 1 and the thin-walled tube T, but this gap will improve the peelability from the thin-walled tube 7 when the quartz tube 1 is cooled and crushed after sample collection and solidification. do.

Although quartz was used as the material for the heat-resistant container, other heat-resistant materials may be used instead.

In addition, as the material of the thin-walled tube 7, as mentioned above, a material in which hydrogen is relatively difficult to diffuse or has a high hydrogen solubility is used.
Typically, high chromium alloy steel, T I % Z r %
Examples include Nb% Ta, and measurement accuracy can be improved by setting the amount of hydrogen contained in these metals to about 2 ppm or less in advance.

The reason for this is that in the sampler of the present invention, even thin-walled pipes are subject to hydrogen content measurement.

The size of the thin-walled tube 1 also affects the measurement accuracy, and when using a tube like the one shown in the figure, it should satisfy the equation for the relationship between the outer diameter (R1) and the inner diameter (R2). It is preferable.

Although the total length of this thin-walled tube differs slightly depending on the object to which the present collector is applied, it is generally formed to have a diameter of 100 to 200 m, preferably 60 to 1201 m1.

Further, although the illustrated thin-walled tube 7 is open on both sides, it is of course possible to close the side opposite to the suction portion (the upper side in the figure) to form a test tube shape.

The degree of vacuum or pressure inside the quartz tube 1 is not particularly limited to the present invention, but in order to smoothly perform suction and filling of molten metal, it is recommended to keep it at about 0.3 atmospheres or less.

In addition, in Fig. 2, a slight gap is left between the paper sleeve 6 whose surface is coated with mortar 11 and the quartz tube 10, making it easy to take out the quartz tube 1 after sample collection. In order to prevent separation during sampling, asbestos 8 is filled, and a cement head 9 for fixation is formed at the tip of the paper sleeve 6, and a head 9 made of cement is formed to protect the thin wall part 5 when not in use. An Al cap 10 is attached.

In addition, when inserting the scrap 1 with an Al cap into molten steel, it not only prevents the thin wall portion 5 from being contaminated by slag on the surface of the molten steel, but also prevents the thin wall portion 5 from being exposed due to melting after insertion. Since the time until breakage can be slightly delayed, it is advantageous in collecting samples at any location in molten steel.

The sampler shown in Figure 1 is vertically shaped to conveniently collect molten steel from a blast furnace, ladle, or mold. In this case, the tip of the quartz tube 1 may be bent as shown in FIG. 3, and the sample may be collected by inserting it horizontally into the injection flow.

When using the collector shown in FIG. 2, it can be immersed deeply in molten steel, so the thin walled portion 5 is easily damaged by the pressure of the molten metal.

However, since the collector shown in Figure 3 does not penetrate deeply,
It is recommended that the thin wall portion 5 in the case shown in the figure be made larger than in the case shown in FIG. 2 so that it is easily damaged by external pressure.

Once the collection of the molten metal is completed, the following steps can be taken according to the conventional method: For example, the collector is rapidly cooled to room temperature with water, etc., and then cooled with liquid nitrogen or dry ice.
Let stand by while cooling in Alconyl until measurement.

Naturally, the quartz 1 is crushed in water during water cooling, and the thin-walled tube 7 containing the sample (-next sample) is exposed and cooled, which makes the vehicle heavier.

For measurements, the sample and thin-walled tube 7 may be returned to room temperature, and an appropriate amount is cut to serve as a secondary sample.

When measuring the hydrogen content in molten steel, the weight of the thin-walled tube is calculated from the cutting length of the secondary sample, the outer diameter of the thin-walled tube 7, its wall thickness, density, etc., and is used as a correction factor. It goes without saying that the amount of water in the thin-walled tube 7 when it is not in use should be determined in advance.

As mentioned above, the amount of hydrogen in the hard food should be kept as small as possible in the thin-walled tube 7, and it is recommended that sufficient dehydrogenation treatment be carried out in advance.

Next, the results of measuring the amount of hydrogen in the steel bath and injection stream of 0.5% C molten steel using the device of the present invention will be shown.

The equipment shown in Figure 2 was used to measure the amount of hydrogen in the steel bath.

However, the outer diameter of the quartz tube 1 is 9 mm, the inner diameter is 7 mm, the outer diameter of the thin wall tube 7 (stainless steel tube) is 6.5 mm, the inner diameter is 6.0 mm, and the length is 10 mm.
The length from the tip of the paper sleeve 6 to the tip 1 of the quartz tube 1 was 30 mm.

The equipment shown in Figure 3 was used to measure the amount of hydrogen in the injected stream.

However, the specifications of the quartz tube 1 etc. are the same as in Figure 2, and t in the figure
The lengths were 15 mm and 20 mm, respectively.

The results are shown in Figure 4, and compared to the conventional method (low-pressure quartz pipe suction method), using the inventive sampler always yields higher hydrogen values, which are close to the true values. considered to be a thing.

Figure 5 is an example of a hydrogen segregation graph in the primary sample that can be placed in this sampler, and shows extremely stable values in the center of the J thin-walled tube.

Also, looking at an example of the distribution of hydrogen in the thin-walled pipe 7 and the solidified metal in the collected sample, the former is 5.16 p pin < the latter is 3.89 ppm, and the hydrogen concentration in the molten steel can be calculated from these volumes. The result was 5.74 ppm.

When the amount of hydrogen in the molten steel was measured using a conventional method, a value of 8.91 ppm was obtained, which is close to the above-mentioned 3.89 ppm.

Therefore, by measuring the amount of hydrogen diffused into the thin-walled tube 7, it was possible to approach the exact amount of hydrogen for the first time.

Since the present invention is constructed as described above, the following effects can be obtained.

■ Hydrogen in molten steel is difficult to dissipate during the sampling, cooling and solidification process, making it possible to obtain more accurate hydrogen content.

■ There is little variation in measured values due to the skill and skill of the measurer.

(2) Since the thin-walled tube and the solidified metal can be measured in one piece, there is no need to repeat the process twice as in the vacuum sampling method described above, and the measurement accuracy is also high.

■ As seen in Figure 4, the higher the hydrogen level, the more useful this collector is.

Therefore, its utility value is particularly high in metal areas with high hydrogen levels, which require high hydrogen content adjustment.

[Brief explanation of drawings]

Figure 1 is a sectional view showing a known collector, Figures 2 and 3 are sectional views of the collector of the present invention, and Figures 4 and 5 are graphs showing the effects of using the collector of the present invention. be. 1...Quartz tube, 5...Thin wall part, 7...
...Thin-walled tube.

Claims (1)

[Scope of utility model registration request] A heat-resistant container is releasably lined with a hydrogen-hardly-diffusible or hydrogen-soluble metal, and the inside is sealed while reducing tails, and a thin-walled portion is formed in two parts, excluding the thin-walled portion. A sample collector for measuring hydrogen content in molten metal, characterized in that the sample collector is housed and held in a container made of a protective material.