JPS62163941A - Continuous temperature sensor for molten metal - Google Patents

Abstract

PURPOSE:To increase the mechanical strength of a protective tube along with a longer life, by forming and firing the protective tube at a specified composition ratio of zirconia and graphite to bake. CONSTITUTION:A protective tube 1 is made of especial 50-90pts.wt. of zirconia and 10-50pts.wt. of graphite as main component and formed and fired as one- piece-type structure. Zirconia below 50wt% will reduce the corrosion resistance while that above 90wt% will decrease strength because of a worsened spalling. Graphite above 50wt% enhancing oxidization, which requires additional graphite in the steel.

Description

DETAILED DESCRIPTION OF THE INVENTION Product No. 19 This invention relates to an improvement in a continuous thermometer for molten metal.

[L-row good proof] An example of a conventional molten metal continuous A11 thermometer will be explained with reference to FIG.

In FIG. 1, the protection tube 1 is made of alumina-graphite,
Porcelain tube 2 is made of alumina C.

A porcelain tube 2 is housed inside a protection tube 1.

Protection mark 1 and magnetism? ! The A tube 2 is manufactured by integral molding.

Not so, Ho! There is also a structure in which graphite-based mortar is filled between the tube 1 and the porcelain tube 2. In any case, ↑ shell 3 is mounted on top of these, J3, and beyond that, although it is not shown in the drawing, ]shi7゛τ, ■report quality, terminal Departments, etc. have been established. A thermocouple 4 is inserted into the porcelain tube 2. Generally, the thermocouple 4 is made of platinum-platinum rhodium, for example. The end of this thermocouple 4 is connected to the terminal section through the inside of the aforementioned connecting sedge hat.

Usually, using such a continuous molten metal thermometer, the tip of the protective tube 1 is immersed in the molten metal and the thermoelectromotive force is measured with a potentiometer or recorded with a recorder. The temperature of the molten metal is continuously measured.

Since the material of the conventional protection tube 1 was made of alumina and graphite, for example, 20 to 90 parts by weight of alumina and 10 parts by weight of graphite
Since it had a composition of ~80 parts by weight, if it was used continuously for more than 30 hours, it would be dissolved by oxidation and eventually become unusable.

Also,! (because the certain strength jq is weak and the porosity is 1 higher,
It was practically impossible to reduce the thickness of the tip of the protective tube to less than iQmm. As a result, the responsiveness of the thermometer was poor.

This invention eliminates the drawbacks of the prior art as described in 01'J and extends the lifespan, while increasing the (; It is an object of the present invention to provide a continuous thermometer that can be used to make the wall thickness relatively dirty.

In order to calculate uj I÷; 9 In this invention, protection! The material of the tube 1 is made of a special material. For example, 50 to 90 parts of zirconia and 10 to 50 parts of graphite are combined into one component to form an integral structure or a two-layer structure, and then molded and fired. Also, zirconia 5
The main components are 0-90 parts by weight and 10-50 parts by weight of graphite, and in addition, BN, B4 C, Si, ΔQ, or SiC is added alone to the composition ratio of 1 to 50 parts by weight. Alternatively, they may be included in combination, and the entire structure may be molded and fired to form an integrated structure or a two-layer structure.

The aforementioned composition will be explained. First, zirconia (50~
Regarding 90%), if the amount of zirconia is reduced, the corrosion resistance will decrease, and if the amount of zirconia is increased, the spalling property will deteriorate and the strength will also decrease.

Regarding graphite (10 to 50ir!ffi%), when the amount of graphite is increased, oxidation increases and graphitic substances are added to the steel.

Also, regarding the inclusion of BN, B4C, Si, △9, or SiC in an outer ratio of 1 to 5 times maximum, these are for suppressing abnormal expansion and contraction of zirconia, and if there is less, cracking may occur. If there is a large amount of slag, the corrosion resistance against slag will deteriorate.

``Dr. L'' -@2 As shown in the figure, a porcelain tube 2 is placed inside a protective tube 1, and a thermocouple 4 is inserted into the porcelain tube 2. A metal fitting 3 is attached to the upper part of the floor protection pipe 1 and the porcelain pipe 2. Ahead of this is a terminal section, just like before.
A thermocouple 4 is connected thereto.

In this invention, the above-mentioned protective tube 1 is made of a special material. Zunawara, partially stabilized zirconia 50~
The main components are 90 parts by weight and 10 to 50 parts by weight of black 'J4), a modified binder is added thereto, mixed, and integrally molded using a rubber press. In this case, in the first embodiment, as shown in FIG. 3, the protective tube 1 is constructed as an integral structure as a whole.

In Example 2, the molten metal temperature meter also has the structure shown in FIG. 2, but the protective tube 1 is of a two-layered structure. That is, the protective tube 1 is divided into a main body part 1a and a tip part 1b, the main body part 1a is made of alumina-graphite material similar to the conventional one, and only the tip part 1b is made of partially stabilized zirconia 5.
It is a mixture of 0 to 90 parts by weight, 10 to 50,000 parts of graphite, and 77 parts of organic binder.

In Example 3 as well, the molten metal continuous thermometer has the structure shown in FIG. 2, but the material of the protective tube 1 is as follows. That is, partially stabilized zirconia 50-901
I think it's part 1! 110 to 50fffffiflffi are the main components, an organic binder is mixed with these, and 1 to
5 Small hanging part BN, 84 C, Si, AQ, Si C
Mix alone or in combination. Such a mixture is formed into a monolithic structure by means of a rubber press. Then, a molten metal continuous thermometer as shown in Figure 3 is made.

11i A mixture similar to that of Example 3 above was prepared, and the mixture was used for the tip 1b of the protective tube 1 shown in FIG.
to form. At this time, a conventional alumina-graphite shank τ1 is used for the main body portion 1a of the protection tube 1.

1 Scold 1 According to this invention, compared to the conventional alumina-graphite RTT, when the wall thickness of both protective tubes is the same, the temperature measurement time can be doubled by a ladle. be able to. Furthermore, if necessary, the wall thickness of the protective tube can be made b thinner than the conventional one. For example, the wall thickness of the protection tube can be reduced to 5 mm.In particular, if the tip of the protection tube can be made so thin, it will be difficult to use it in actual use.
The response time of thermometers can be significantly reduced. For example, compared to conventional temperature measurement time, it can be reduced to about 2/3 (within 3 minutes).

In order to more specifically demonstrate the effects of this invention, Table 1 shows examples of actual continuous use of molten steel.

[Brief explanation of drawings]

Fig. 1 is a schematic vertical cross-sectional view showing a conventional molten metal continuous thermometer, Fig. 2 is a schematic longitudinal cross-sectional view of a thermocouple-type melting full-bending 4-continuous thermometer according to the present invention, and Fig. 3 is a schematic longitudinal cross-sectional view showing a conventional molten metal continuous thermometer. FIG. 4 is a schematic side view showing the appearance of a two-layer thermocouple type continuous molten metal thermometer according to the present invention. It is. 1, Protection tube 2, Porcelain tube 3, Fittings Fig. 1 Fig. 2 Fig. 3

Claims (2)

[Claims] (1) In a continuous molten metal thermometer in which a porcelain tube is arranged in a protection tube and a thermocouple is inserted into the porcelain tube, the material of the protection tube is 50 to 90 parts by weight of zirconia and 10 parts by weight of graphite.
1. A continuous thermometer for molten metal, characterized in that it is molded and fired into an integral structure or a two-layer structure containing ~50 parts by weight as a main component. (2) In a continuous molten metal thermometer in which a porcelain tube is inserted into a protection tube and a thermocouple is inserted into the porcelain tube, the material of the protection tube is 50 to 90 parts by weight of zirconia and 10 to 10 parts by weight of graphite. 50 parts by weight as a main component, and 1 to 5 parts by weight of BN, B_4C, Si, Al or SiC, singly or in combination, and molded and fired as an integral structure or a two-layer structure. A continuous thermometer for molten metals featuring: