JPH063196A - Lance for temperature measurement and molten metal treatment - Google Patents

Abstract

PURPOSE:To reduce a cost for temperature measurement and improve temperature measurement task to obtain desired temperature of molten metal by burying a temperature measuring body with a thermocouple line built in into a molten metal soaking portion of a lance and having its tip exposed from an outer peripheral surface of the lance. CONSTITUTION:A temperature measuring body 25 with a thermocouple line 5 built in is buried into a refractory material 3 at a portion soaked by molten metal in a lower part of a thick part A of a lance 1. The tip of the temperature measuring body 25 is provided to be exposed from an outer peripheral surface of the lance 1, preferably protruding by 5 to 10mm from the outer peripheral surface of the lance 1 in order to improve response. The temperature measuring body 25 with the thermocouple line 5 set is fixed to a core metal 2. An extension leadwire 15 connected to a terminal 17 of the thermocouple line is led through the refractory material 3 to outside from the upper end of the lance 1. A terminal 16 of the leadwire 15 and the terminal 17 is joined by pressure welding by a connection sleeve tube. The lance 1 is soaked into molten metal 22 inside a ladle 21. Normally, since temperature of the molten metal 22 is high, gas is jetted from a discharge hole 4 by a tube 23, temperature is successively measured by the temperature measuring body 25 to realize set temperature, then gas supply is halted and the lance 1 is pulled up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molten metal processing lance for blowing gas or powder into molten metal for processing, and more particularly to a lance having a molten metal processing function and a temperature measuring function.

[0002]

2. Description of the Related Art Molten metal discharged from a melting furnace or a refining furnace is contained in a molten metal container such as a mixing pig car or a ladle. The contained molten metal is mixed with a gas such as argon gas or nitrogen gas from the lance soaked in the molten metal or the above gas and powder such as calcium powder for the purpose of component adjustment, reduction of inclusions or temperature adjustment. Work for blowing the mixture (blowing work) is performed. In the above work, adjustment of the composition of the molten metal and reduction of inclusions can be performed almost as intended by injecting a gas and powder in a preset amount according to the analysis value of the molten metal and the amount of the molten metal. However, at this time, the temperature of the molten metal is usually higher than the target temperature. For this reason, normally, only gas is blown after the above treatment to adjust the temperature of the molten metal. However, the temperature of the molten metal varies depending on the amount of gas or powder blown in, the preheating temperature of the molten metal container before containing the molten metal, and the like, so that the temperature of the molten metal must be measured frequently or continuously. Further, a process of blowing only gas is performed only for adjusting the temperature of the molten metal, but in this case as well, it is necessary to measure the temperature of the molten metal frequently or continuously as in the above case.

[0003]

However, in the conventional temperature measuring method, since the temperature measuring probe (temperature measuring instrument) made of, for example, a paper pipe is immersed in molten metal to measure the temperature, the temperature measuring probe is used for a short time. It will burn out and will not function. For this reason, the temperature measuring probe is frequently replaced with a new one and immersed in the molten metal. As a result, the temperature probe is discarded because it is discarded after one measurement, and the temperature probe is frequently immersed in the molten metal, which complicates the work and continuously measures the molten metal. There was a problem that the desired temperature could not be obtained because it could not be heated.

As a technique for solving the above-mentioned problems, Japanese Patent Laid-Open No. Sho 6
According to Japanese Patent Laid-Open No. 1-91529, there is known a molten metal temperature measuring device in which a temperature measuring tube of an optical fiber type is embedded in a refractory lining a side wall of a molten metal container. However, in the above temperature measuring device, in order to protect the optical fiber line, the inert gas must be constantly jetted from the periphery of the optical fiber line while the molten metal is being accommodated. The molten metal around the embedded portion of the optical fiber line is agitated by the inert gas ejected from around the optical fiber line, and this agitation causes severe damage to the refractory. Further, since the through hole for inserting the temperature measuring tube is provided in the refractory lining the side wall of the molten metal container, the risk of leakage of the molten metal to the outside of the container increases.

Further, when the temperature of the contained molten metal is measured during transportation and movement, a gas tank which can be moved together with the molten metal container is required. However, in the case of a ladle, it is often moved by an overhead crane, and it is difficult to install a movable gas tank. The present invention solves such problems in the work of blowing gas or powder into the molten metal to reduce the temperature measurement cost, improve the temperature measurement work, and further improve the temperature of the molten metal as intended. The challenge is to obtain.

[0006]

In order to solve the above problems, the present invention provides a lance for dipping gas or powder in a molten metal by immersing a thermocouple wire in the molten metal-immersed portion of the lance. (EN) A lance for combined use of temperature measurement and molten metal treatment, characterized in that a built-in temperature measurement body is buried, and a tip of the temperature measurement body is exposed from an outer peripheral surface of the lance.

[0007]

[Function] By embedding the temperature measuring element in the molten metal immersion portion of the molten metal processing lance, the processing of the molten metal and the temperature measurement of the molten metal can be performed in parallel, so consumable tools such as temperature measuring probes are not required. Therefore, the cost required for temperature measurement can be reduced, and since temperature measurement can be continuously and automatically performed, complicated temperature measurement work can be released, and the desired temperature of the molten metal can be obtained.

[0008]

Embodiments of the present invention will be described in detail below with reference to the drawings. FIG. 1 shows a cross-sectional view of a temperature measuring / melting metal processing combined lance of the present invention in which a temperature measuring element is embedded. In FIG.
The lance 1 which is immersed in molten metal and blows gas or powder is provided with a refractory 3 on the peripheral surface of a cored bar 2 (iron pipe), and the tip of the lance 1 is gas or powder. A discharge hole 4 for discharging the body is provided. A is a thick-walled portion located in the slag layer when the lance 1 is immersed in molten metal, and the refractory 3 is constructed so that the wall thickness T is thicker than the wall thickness t of other parts. Erosion has been addressed.

A temperature measuring body 25 having a thermocouple wire 5 built therein is embedded in the refractory 3 at a portion below the thick portion A of the lance, which is immersed in the molten metal, and the tip of the temperature measuring body 25 is embedded. Is exposed from the outer peripheral surface of the lance 1. It is preferable that the temperature measuring element 25 preferably protrude from the outer peripheral surface of the lance 1 by about 5 to 10 mm in order to improve the response of the thermocouple. As shown in the enlarged view of FIG. 2, the temperature sensing element 25 has a protective tube 6 whose tip is closed, and a contact point 5 a which is inserted into the protective tube 6 and has a contact point 5 a.
The thermocouple wire 5 is in contact with the tip of the lance and has its end guided to the outside of the lance, and a refractory 10 filled in the space between the thermocouple wire 5 and the protective tube 6. It is preferable that the material of the protective tube 6 has a melting point of 1800 ° C. or higher. For example, a refractory material such as alumina-carbonaceous material, zirconia-carbonaceous material, zirconium boride, or boronite, or a composite of a metal such as molybdenum-zirconia and an oxide. It is preferable to use a material such as a body which has excellent heat resistance and melting loss resistance against molten metal and has high thermal conductivity.

The inner diameter φ1 of the protective tube is preferably about 10 to 20 mm so that the thermocouple wire 5 can be set therein.
Although the wall thickness t ₁ of the protective tube varies depending on the material used for the protective tube 6, for example, when the above refractory material is used, the material strength is insufficient, so that it is preferably about 20 to 30 mm.
When using a material composed of a complex of the above metal and oxide, the material itself has a strength of 5 to 15
mm is enough. Distal portion 6a of the protective tube wall thickness t ₂ to the hemispherical shape same as the thickness t ₁ of the protective tube, or it is better to slightly thicker. An outlet 7 for the thermocouple wire 5 is provided at the rear end 6b of the protective tube. By providing the spiral groove 8 on the outer peripheral surface of the protection tube 6, the contact area with the refractory 3 is increased to allow the insertion of the metal into the joint 9 (FIG. 3) between the protection tube 6 and the refractory 3. It is structured to prevent.

As the thermocouple wire 5, for example, a PR (platinum-platinum-rhodium) element wire thermocouple wire or a sheath thermocouple wire is used. When using the strand thermocouple wire, the setting method is to pass the strand thermocouple wire 5 through an insulating tube (not shown) in advance, and the contact point 5a of the thermocouple wire is on the inner surface of the tip portion 6a of the protection tube. Set to join. In this case, in order to set easily and accurately, a concave groove is provided on the inner surface of the tip 6a of the protective tube with which the contact 5a of the thermocouple wire abuts. Also,
The sheath thermocouple wire is also set by the same method as the above-mentioned strand thermocouple wire setting method, but in this case, the insulating tube need not be used. A refractory material 10 such as castable made of refractory powder particles is filled inside the protective tube 6 in which the thermocouple wire 5 is set. If the refractory 10 is not filled inside the protective tube 6, the inside of the protective tube 6 becomes a closed air reservoir, so that when the lance is immersed in the molten metal, the heat of the molten metal causes the air to flow. Expands and protect tube 6
May be damaged. Therefore, when the refractory material 10 is not filled, it is preferable to provide a gas vent passage. The end portion of the thermocouple wire 5 is guided to the outside of the protective tube 6 through the outlet 7 of the protective tube 6.

The temperature measuring element 25 having the thermocouple wire 5 set in this manner is fixed to the core metal 2. The fixed state diagram is shown in FIG. In FIG. 3, an iron sleeve tube 11 for fixing the temperature measuring body 25 to the cored bar 2 is welded, and a nut 12 is welded to the sleeve tube 11. Nut 12
A hole having the same diameter as the hole diameter of the nut 12 is bored in the sleeve tube 11 at a portion located in the hole, and a bolt 13 is screwed into the nut 12. A temperature measuring element 25 is inserted into the sleeve tube 11 and fixed by a bolt 13. FIG. 4 shows another example of the fixing structure of the temperature sensing element 25 to the core metal 2,
Sleeve tube 11 provided with spiral screw 14 on the inner surface
Is welded to the core metal 2 as described above, and the sleeve tube 1
The temperature measuring element 25 is screwed into the device 1. In this case, the fixing can be made stronger by applying an adhesive material such as refractory mortar to the spiral screw 14.

As shown in FIG. 1, the compensating conductor 15 connected to the end 17 of the thermocouple wire passes through the refractory 3 and the lance 1
Is led to the outside from the upper end of. As the compensating lead wire 15, for example, a compensating lead wire dedicated to the PR thermocouple, a PR thermocouple element wire, or a sheath wire is used. The end 16 of the compensating lead wire and the end 17 of the thermocouple wire are joined by crimping with a connecting sleeve tube (not shown), and the joint portion is provided with insulation measures by CF paper, a mike tube or the like. A connection connector 18 is attached to the upper end of the compensation lead wire 15. A refractory material 3 is installed around the lance core bar 2 to which the temperature sensing element 25 and the compensating lead wire 15 are attached. The thermocouple wire 5 may be extended to the outside of the lance 1 and connected to the connector 18 without using the compensation lead wire 15.

FIG. 5 shows a state diagram in which the lance for temperature measurement and molten metal treatment of the present invention is immersed in the molten metal in the ladle to perform the treatment of the molten metal and the temperature measurement in parallel. . Pipe 23 to which gas or powder is supplied and upper end 2 of core metal
a and the connector 18 and the connector 20 connected to the temperature display / recorder 19 are connected. Next, as in a normal operation, the lance 1 is immersed in the molten metal 22 in the ladle 21 so that the thick portion A is located in the slag layer 24 floating on the upper surface of the molten metal 22, and the gas is blown into the molten metal 22 to blow the molten metal. 22 processing is performed.

Of course, the gas must be ejected before the lance 1 is immersed in the molten metal 22. The gas used for blowing is mainly an inert gas such as nitrogen or argon. A few minutes after the start of blowing the gas, the powder is supplied into the gas, and the mixture of the gas and the powder is blown. The powder to be blown is, for example, CaO-Si.
_{O 2, CaO, Ni-CaO} , Ca, CaF 2, alone or in a mixture thereof such as Al may be used. The amount of powder to be blown is set in advance, and the supply of powder is stopped when the blowing of the set amount of powder is completed, whereby the component adjustment and inclusion reduction processing ends. At this time, since the temperature of the molten metal is usually higher than the target value, only gas is subsequently blown. The temperature of the molten metal is measured by the temperature measuring body 25 from the initial stage of gas blowing, and is continuously displayed on the temperature instruction and the recorder 19. As soon as the temperature of the molten metal reaches a preset temperature, the lance 1 is pulled up from the molten metal, and after a while, the ejection of gas from the discharge holes 4 is stopped and the blow operation is completed.

[0016]

As described above, the temperature measurement according to the present invention
Since the temperature measuring element is embedded in the molten metal dipping part in the molten metal processing combined lance, an extra consumable temperature measuring instrument (temperature measuring probe), which was conventionally required, is not required, and the cost required for temperature measurement is reduced to about 1/2. Was reduced. In addition, since the temperature of the molten metal can be automatically and in parallel simultaneously with the processing of the molten metal, labor saving is achieved, and continuous temperature measurement can be performed, so that the temperature of the molten metal can be surely obtained. I can do it now.

[Brief description of drawings]

FIG. 1 is a view showing a cross-sectional view of a lance for temperature measurement and molten metal treatment of the present invention,

FIG. 2 is a partially enlarged view of FIG. 1, showing a cross-sectional view of a temperature sensing element having a thermocouple incorporated therein;

FIG. 3 is a cross-sectional view showing a structure for fixing the lance of the temperature sensing element to the core bar;

FIG. 4 is a sectional view showing another embodiment of a structure for fixing the lance of the temperature sensing element to the core bar;

FIG. 5 is a cross-sectional view showing a state diagram in which the temperature measurement / molten metal treatment combined lance of the present invention is used.

[Explanation of symbols]

 1 Lance for temperature measurement / molten metal treatment of the present invention 2 Core metal (iron pipe) 3 Refractory 4 Discharge hole 5 Thermocouple wire 5a Contact point 6 Protective tube 6a Protective tube tip 6b Protective tube rear end 7 Notch 8 Spiral groove 9 Joint 10 Refractory 11 Iron sleeve tube 12 Nut 13 Bolt 14 Spiral screw 15 Compensation lead wire 16 Compensation lead wire end 17 Thermocouple wire end 18 Connector 19 Temperature indicator / recorder 20 Connector 21 Ladle 22 Molten metal 23 Piping 24 Slag layer 25 Thermometer

Continued Front Page (72) Inventor Takashi Matsunaga 1 No. 7 Tsukiji, Kisarazu City, Chiba Prefecture Kurosaki Kiln Co., Ltd. Kisarazu Plant

Claims (1)

[Claims] 1. In a lance which is immersed in a molten metal and blows gas or powder, a temperature measuring element having a built-in thermocouple wire is embedded in the molten metal immersion part of the lance, and the temperature measuring element A lance for both temperature measurement and molten metal treatment, characterized in that the tip is exposed from the outer peripheral surface of the lance.