JPS58223742A - Measuring apparatus of oxygen concentration in molten copper - Google Patents

Abstract

PURPOSE:To perform repeatedly many times measurement of oxygen concentration in molten copper (copper alloy) preventing the contamination or damage of an oxygen probe, by providing a ceramic protective pipe notched the one side or cut aslant on the outside of the oxygen probe. CONSTITUTION:A protective pipe 10 made of ceramics such as SiC etc. is cut aslant on the outside of a detecting part (an oxygen probe) 1 of a containing oxygen measuring apparatus in a molten material 8 to a flowing direction (shown by the arrow mark toward the left) 14 of the material 8 of pure copper or copper alloy and is immersed so that the length side 13 is placed on the upper stream. Hereby, it is prevented that slag or a copper oxide is stuck to an exposed bottom surface 12 of a solid electrolyte 2 at the time of immersing the oxygen probe in the molten copper and the accurate measurement is performed. Further, sudden heat conduction to the probe 1 is relieved by the pipe 10 and crack generation or damage of the probe is prevented.

Description

[Detailed description of the invention] Kibatsu E! Pure copper or copper alloy (hereinafter abbreviated as copper)
O Oxygen in steel, especially in tough pitch copper used as a conductive material, influences its properties and EL properties. Therefore, it is important to control this to an appropriate concentration, and it has been proposed to measure the oxygen concentration in molten copper continuously or intermittently during casting.
It is being put into practical use.

As an apparatus for measuring this oxygen concentration, a measuring apparatus based on an electrochemical principle forming an oxygen concentration cell as shown in FIG. 1 is used. In the figure, 1 is a detection part (hereinafter referred to as an oxygen probe) of an oxygen concentration measuring device, in which a lead wire 3 made of platinum or the like is fixed at a contact part 4 to the inner bottom of a loop-shaped solid electrolyte with one end closed. ing. The inside of the solid electrolyte 2 is filled with metal and metal oxide 5 as a standard electrode. As the metal or metal oxide 5, Fe-FexO
.

Ni-NiO, Mo-MoO2, Cr-Cr2O5
etc. are used. Air is also sometimes used as the standard electrode. In this case, the lead wire 3 is in fixed contact with the inner bottom of the solid electrolyte 2.

The solid electrolyte 2 is fixed with cement 6 in an outer shell 7 made of l1iJ hot steel or the like.

As the solid electrolyte 2, for example, magnesia (MgO),
Zirco=7 (ZrO2) stabilized with ittria (Y, os), calcia (CaO), etc., HfO,
A material made of TbO2, CeO2, etc. is used.

Metal and metal oxide standards are formed inside the crucible-shaped solid electrolyte 2 . This oxygen concentration (activity) is used as a standard electrode with a known constant value, and when the solid electrolyte 2 through which oxygen ions passes is passed, the heat of the oxygen concentration battery is generated between the molten copper 8 of the object to be measured and the standard electrode. By measuring the electromotive force value with a 5 millivolt meter 9, the oxygen concentration in the molten copper 8 can be measured.

The one shown in FIG. 1 is one in which a metal or metal oxide standard is formed as a solid electrolyte, or another one in which an air standard electrode is formed is also used.

However, when such an oxygen probe is inserted into or taken out from molten steel for measurement, the solid electrolyte 2 made of ZrO2 or the like is likely to crack or break due to thermal shock. It is necessary to take measures to use an electric furnace to heat the product to 7 T' to achieve 6 class 0 thermal shock, which makes the operation complicated and troublesome.

Further, at this time, slag floating on the surface of the molten steel tends to adhere to the solid electrolyte 2, making it impossible to accurately measure the oxygen concentration in the molten steel.

This invention has been made to solve the problems described in 1d and J- of the present invention.By attaching a special protective tube to the outside of the oxygen globe, the oxygen probe is suspended on the surface of the molten steel while it is immersed in the molten copper. It is possible to accurately measure the electromotive force for a long time by preventing M-scale adhesion to slag or copper oxide solid molds, and it also alleviates thermal shock when inserting or taking out the oxygen probe into molten steel, especially when taking it out. It is an object of the present invention to provide an oxygen concentration measuring device which has a remarkable relaxation effect and can prevent damage due to cracking.

In a device that uses a finished Ht solid electrolyte to form an oxygen concentration cell and measures the oxygen concentration in molten steel based on its electromotive force value, the outside of the oxygen probe is cut at 97 mm on one side or diagonally. This is a device for measuring oxygen concentration in molten steel, which is equipped with a ceramic pipe as a protective tube.

The oxygen globe in the final BA is not limited to the metal or metal oxide standard shown in FIG. 2, but may be one that uses the air standard electrode as the standard.

Hereinafter, the final completion rJ1 will be explained in two examples using the drawings. FIG. 2 is a longitudinal sectional view showing the embodiment of the end 1.

In the figure, the same reference numerals as in FIG. 1 indicate the same parts. In the figure, 1 is an oxygen globe similar to that shown in FIG. 1, and a crucible-shaped solid electrolyte 2. Platinum Riet wire 3. It consists of metal, metal oxide 5° cement 6 and outer shell 7.

In the present invention, a ceramic pipe 10 is further attached to the outside of the outer shell 7 of the oxygen probe 1 as a protection tube.

The ceramic pipe 10 is a pipe-shaped piece with the lower part cut at an angle Vζ as shown in the figure, or with a notch on one side, and when installing it, the long end face 11 is cut or notched.
is fixed to the outer shell 7 so as to protrude from the bottom surface 12 of the solid electrolyte 2. SiC, A/?, has heat resistance as a ceramic and does not react with molten steel. 20s, graphite, etc. are used.

In addition, the ceramic pipe 10 has even one layer as shown in the figure.
Further, two or more layers may be provided.

In order to immerse the oxygen globe of the finished F3A constructed in this way into the molten copper 8, the ceramic pipe IO is inserted so that the long side 13 is on the first flow side in the flow direction 14 of the molten steel. In this way, the long side 13 of the pipe 10 enters the molten steel 8 first and dams up the slug and copper oxide floating on the molten steel surface 2', thereby preventing these from adhering to the solid electrolyte 2 and reducing the electromotive force. The value can be precisely measured with a millivoltmeter 9. Furthermore, the ceramic pipe 10 alleviates rapid heat conduction to the oxygen probe 1, prevents cracks from occurring due to thermal shock, and prevents breakage.

This effect is particularly remarkable when the oxygen probe is extracted from molten steel, and this has made it easy to use the oxygen probe repeatedly on an industrial scale.

Embodiment Fig. 1 (conventional example) and Fig. 2 (final example 8I'1)
) was inserted into the molten steel in a transport trough or tundish, the oxygen concentration was measured, and the procedure of taking it out was repeated. Table 1 shows the number of probe breakages due to slag, copper oxide adhesion, and thermal shock during insertion and removal.

Table 1 According to Table 1, it can be seen that in comparison with the conventional example, slag and copper oxide adhesion are significantly reduced, and damage to the prog due to thermal shock is also significantly reduced in the case of FG4.

In particular, the breakage rate when taking out the Pronige from molten steel has been significantly reduced, and has almost completely disappeared.

The end-of-life equipment constructed as described above has the following effects.

(a) Cut out one side on the outside of the oxygen probe, or
A diagonally cut ceramic pipe is installed as a protection tube, so when inserting it into molten copper, the long downward side of the ceramic pipe should be on the first flow side in the flow direction of molten steel. Since the side enters first and dams up the slag and copper oxide floating on the surface of the molten copper, slag and copper oxide will not adhere to the solid electrolyte during insertion into, immersion in, and extraction of the molten copper. Electromotive force values can be measured with time accuracy.

(b) The long side of the ceramic pipe of the protective tube is immersed in the molten copper first, and the heat from that part is transferred to the outer shell of the oxygen probe and the solid electrolyte by conduction and is preheated, so there is no thermal shock when inserting it into the molten steel. prevents cracks and damage.

eC) Ceramic pipes have a larger heat capacity than metals, so when they are removed from molten copper, they slowly return to room temperature, creating a thermal gradient similar to furnace cooling, which reduces thermal shock and prevents cracks in the oxygen probe. , damage is prevented, and in addition to the effect of item (b), the oxygen probe can be easily used repeatedly.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an example of a conventional oxygen concentration measuring device. FIG. 2 is a longitudinal sectional view showing an embodiment of the present invention. 1...Detection section (oxygen probe) of the oxygen concentration measuring device. 2... Solid electrolyte, 3... Platinum lead wire, 4...
contact part. 5''...metal, metal oxide'', 6...cement, 7...
··shell. 8... Molten copper, 9... Millivolt meter, 10...
・Ceramic pipe, 11...end surface, 12...bottom surface, 13 years old 2 Figure

Claims (1)

[Claims] +1+ In a device that uses a solid electrolyte to form an oxygen concentration cell and measures the oxygen concentration in molten copper based on the electromotive force value, one side is placed outside the oxygen blow 7. An apparatus for measuring oxygen concentration in molten copper, which is equipped with a notched or diagonally cut ceramic pipe as a protective tube. (2) The oxygen concentration measuring device in molten steel according to claim 1, which is made of a ceramic pipe or SiC.