JPH019006Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of a sampling device for hydrogen analysis in molten metals such as steel or non-ferrous metals.

As shown in FIG. 1, a conventionally known vacuum type molten metal gas collecting device has a cap-shaped body 4 made of an easily meltable material 5 fitted into a quartz tube 1 whose upper end is sealed and whose lower end is opened. (Japanese Patent Publication No. 39-8648), and as shown in Figure 2, one end is made of easily meltable material 9.
A vacuum-sealed tube with an insertion tube 8 provided inside a tube 7 made of a thin steel plate (Japanese Patent Publication No. 1983-45157)
However, in the former case, the diameter of the quartz tube 1 is usually larger than 6 mm, so in addition to quantifying the hydrogen trapped in the vacuum section, it is necessary to quantify the hydrogen remaining in the solidified metal. Therefore, in order to determine the total amount of hydrogen, the amount of hydrogen collected in the sampling device must be determined, then the sample must be cut and polished, heated and melted, and the amount of hydrogen extracted must be determined separately, which is a complicated operation and requires a separate method such as in front of a furnace. On the other hand, the latter method introduces molten metal into the insertion tube 8 and is designed to collect most of the hydrogen in gaseous form in the vacuum section during solidification. Hydrogen gradually released not only from the molten steel sucked up into the insertion pipe section but also from the molten steel sucked up into the pool inside the easily meltable material 9 gives an error to the quantitative value.

As mentioned above, the present invention is proposed to improve the drawbacks of conventionally known devices of this type. A hollow space in a tubular body having a molten metal suction port that opens when melted and is evacuated, and that communicates with the suction port so that the molten metal sucked up solidifies into a predetermined shape. It has a built-in conduit made of hydrogen permeable material to form a
and a sample collection device for quantifying the amount of hydrogen in the molten metal, which is provided with a space for accommodating hydrogen released during solidification and cooling of the molten metal.

Hereinafter, specific examples of the present invention will be explained with reference to the drawings. FIG. 3 shows an example of the device of the present invention. When the thin-walled suction port 12 of an inorganic refractory sampling pipe 11 with a vacuum inside is immersed in molten metal, this part melts and is damaged. The molten metal is sucked and fills the pre-dehydrogenated thin steel plate conduit 13, reaches the pre-dehydrogenated chiller 14, and enters the vent hole 1.
5 is occluded and coagulated. 16 is for fixing the conduit 13 at a fixed position within the collection tube 11.
Hydrogen released during solidification and cooling is collected in the residual space 17 either directly as a gas or by diffusing in the thickness direction of the conduit 13 .

Further, according to FIG. 4 showing another embodiment of the device of the present invention, the molten metal fills the middle part of a double cylinder formed by an inorganic refractory sampling pipe 11 and a thin steel plate conduit 13, The released hydrogen is collected in the residual space 17. According to the sampling device shown in FIG. 3, the residual space is the outer periphery of the solidified metal, and according to the sampling device shown in FIG. 4, the inside of the solidified metal is the residual space. Place in a collection container as shown in the figure and use for quantitative analysis.

In FIG. 5, the collection tube 11 is inserted into the collection container 18, the lid 19 is sealed, and the inside of the container is replaced with carrier gas or evacuated, and then the bellows 20 welded to the container is attached to the external screw 21. A blade 22 is driven by the bellows 20 and is provided inside the bellows 20.
is pressed against the collection tube 11 supported by the support 23 to break it and open the residual space 17 to release the hydrogen inside, and the hydrogen in the container is quantified with an analyzer such as a gas chromatograph or mass spectrometer. do. In FIG. 6, the wall of the residual space 17 formed in the collection tube 11 is broken by the blade 22 by the same operation, and the hydrogen in the space is released into the collection container 18 and quantified by the gas analyzer. . In order to quantitatively capture most of the hydrogen (95% or more) in the suction-collected molten metal in the residual space, it is necessary to keep the following points in mind. First, the radius in the solidified metal, that is, the hydrogen diffusion distance, must be kept below a certain value. This constant value is determined by the temperature of the molten metal, the cooling rate, the temperature dependence of the hydrogen diffusion coefficient, etc. It is recommended that the thickness be 2.5 mm or less for aluminum and other materials. If this value is exceeded, the proportion of residual hydrogen in the metal cannot be ignored. Secondly, it is important to reduce as much as possible the amount of metal that solidifies in the molten pool inside the easily meltable material, as shown in 9 in Figure 2. It is important to use a collection tube that is free of When a large-diameter pool is formed, the influence of errors due to the amount of hydrogen remaining in this portion becomes significant.

In FIG. 3 or 4, the collection tube 11 is made of an inorganic refractory material such as quartz or ceramics, and while the suction port 12 is easily melted away by the heat of the molten metal, other parts are damaged during collection. It is also required that the material and shape do not allow the trapped hydrogen to escape to the outside. Further, although the conduit 13 is made of a thin steel plate, it may be made of metal such as Al or Cu, or a refractory material with high air permeability such as porous ceramics or rock wool. In any case, it is necessary to have good hydrogen permeability without melting at high temperatures, and when using a steel plate, the thickness
A thickness of 0.1 to 0.5 mm is suitable.

The contents of the present invention have been explained above with reference to examples, but in short, according to the present invention, most of the hydrogen (more than 95%) in the collected metal can be absorbed by simply quantifying the hydrogen collected in the vacuum space. ) can be determined with high accuracy, the amount of hydrogen in the molten metal can be determined quickly and accurately, and various defects caused by hydrogen in metal can be prevented, which is extremely useful industrially.

[Brief explanation of the drawing]

1 and 2 are conventionally known vacuum type molten metal gas collection devices, FIGS. 3 and 4 are sectional views showing embodiments of the present invention, and FIGS. 5 and 6 are respectively FIG. 5 is a cross-sectional view of a collection container for releasing hydrogen collected by the apparatus shown in FIGS. and FIG. 4 and guiding it to an analyzer. 1: Tubular body, 2: Opening, 3: Sealing part, 4: Cap-shaped body, 5: Thin wall part, 6: Bonding material, 7: Pipe, 8: Insertion tube, 9: Easily soluble material, 10: Residual space, 11 : Collection pipe, 12: Suction port, 13: Conduit, 14: Cold metal,
15: ventilation hole, 16: fixing material, 17: residual space,
18: Collection container, 19: Lid, 20: Bellows,
21: Screw, 22: Blade, 23: Support.

Claims (1)

[Scope of utility model registration request] In a tubular body whose wall is made of an inorganic refractory, which has a molten metal suction port at one end that is opened by melting when immersed in the molten metal of the sample, and whose interior is evacuated, the above-mentioned A conduit made of a hydrogen-permeable material is built in so as to communicate with the suction port and form a cavity in which the molten metal sucked up solidifies into a predetermined shape, and is discharged when the molten metal is solidified and cooled. A sample collection device for hydrogen analysis in molten metal, which is equipped with a space for accommodating hydrogen.