RU2016083C1 - Apparatus for measuring temperature of liquid steel and sampling it for determining carbon content by "liquidus" method - Google Patents

Abstract

FIELD: metallurgy. SUBSTANCE: apparatus has the water cooled rod 1, the sampler 2 and the thermocouple 6 with the protective jacket 7. The ceramic ring 4 is placed in the sampler 2; the refractory tube 8 is arranged in an upper part of the sampler 2, the tube 8 connects inner cavities of the sampler and the water cooled rod and at filling the sampler by liquid metal limits a level of the ceramic ring lifting. At such case the ceramic ring operates as locking valve, preventing liquid metal sample flowing out of the sampler, being raised from a furnace by any angle value. EFFECT: enhanced reliability and lowered error at determining carbon content. 1 cl, 2 dwg, 1 tbl

Description

 The invention relates to ferrous metallurgy, in particular to devices for monitoring the technological parameters of the smelting.

 A device for controlling metallurgical processes is known, consisting of a water-cooled rod, at the end of which a replaceable sampler is installed with an opening for passing liquid metal and a thermocouple integrated into it with a protective cover for measuring the bath temperature and crystallization temperature of the metal sample.

 In this device, the cold ends of the thermocouple integrated in the sampler are connected to the compensation wires using sliding contacts, which reduces the reliability and accuracy of measurement.

 In addition, a single-acting sampler during steelmaking requires multiple measurements with the accuracy that thermocouples made of noble metals can provide, so the consumption of expensive thermoelectrodes is inevitable, which increases the cost of measurement.

 The closest in technical essence and the achieved result is a device containing a water-cooled rod, a removable sampler with holes for passing liquid metal and a noble metal thermocouple with a protective cover. The thermocouple is autonomous with respect to the interchangeable sampler, which simplifies its manufacture by eliminating the contact connector. Removing the free ends of the thermocouple into the water-cooled zone and rigid connection with the measuring line eliminates the errors that occur during measurement.

A common drawback of all analog devices is that they can only work reliably when vertically removing a water-cooled rod from a steelmaking unit, which is rarely achieved in practice. Typically, water-cooled steel bar output from the unit at an angle ^of 40-60 to the vertical. With this tilt angle of the sampler, a significant amount of the sample metal will inevitably leak out through the side openings. This leads to a violation of the uniformity of the thermal conditions for cooling the sample metal and to an error in measuring the temperature of its crystallization.

 In addition, the operation of the prototype device in steelmaking units is impossible, since there is no protection of the probe from mechanical stress.

 The purpose of the invention is to increase the reliability of the device and reduce the error in determining the carbon content.

 This goal is achieved by the fact that in the device for measuring the temperature of liquid steel and sampling for determining the carbon content by the liquidus method, containing a water-cooled rod, a sampler with a hole and a thermocouple with a protective cover connected to a secondary device, according to the invention, the sampler is equipped with a movable ceramic ring with an emphasis restricting the movement of the ring when the latter blocks the hole for the flow of metal. The emphasis is made in the form of a refractory tube connecting the internal cavity of the sampler and the water-cooled rod.

 Comparative analysis with the prototype shows that the claimed device is characterized in that the movable ceramic ring and the refractory tube connecting the internal cavities of the sampler and the water-cooled rod placed in the sampler prevents the flow of the metal sample from the sampler when it is lifted from the furnace at any angle, which increases the reliability of the device and also provides stable thermal conditions for cooling the sample metal around the junction of the thermocouple, which reduces the error in determining the carbon content .

 In FIG. 1 shows a device for measuring the temperature of liquid steel and sampling to determine the carbon content by the liquidus method; figure 2 is a diagram that fixes the temperature of the metal sample.

 At the end of the water-cooled rod 1, a quartz sampler 2 is mounted in the form of a test tube with an opening 3 for the flow of metal. A movable ceramic ring 4 is located inside the sampler, which can move along the axis of the sampler. Below is an aluminum spiral 5 for deoxidation of metal. On the axis of the sampler there is a thermocouple 6 in a protective quartz case 7. To equalize the pressure, the internal cavities of the sampler and the water-cooled rod are connected by a refractory tube 8, which serves simultaneously as a limiter to lift the ceramic ring 4 when filling the sampler with liquid metal. The refractory tube 8 and the protective quartz case 7 are fixed with a refractory cement in a metal ring 9. On the outside, the sampler is enclosed in a steel casing 10. The sampler is mounted in a water-cooled rod using asbestos 11. The thermocouple is connected to the recording devices by compensation wires 12.

 The device operates as follows. After the device is inserted into the molten bath, the protective metal casing 10 is melted and the steel flows through the hole 3 into the sampler 2. In this case, the ceramic ring 4 rises to the stop with the refractory tube 8 and covers the hole 3. The thermocouple 6 measures the changing temperature of the sample metal, fixed on the diagram of FIG. .2.

 After the temperature of the sample metal is equalized to the temperature of the bath, a "a" appears on the curve, after which a command is issued to remove the water-cooled rod 1 from the metallurgical unit. At any angle of inclination of the rod 1, liquid metal does not flow out of the sampler, since the hole 3 is closed by a ceramic ring 4. After lifting the water-cooled rod 1, the sample metal begins to crystallize and a “b” area appears on the cooling curve. The crystallization temperature and the iron-carbon diagram determine the carbon content in the metal. The extracted sample can also be used for ongoing analysis for the content of other elements.

 The main advantage of the described device is the fact that when the sampler is removed from the bath, the volume of the sample metal remains unchanged, which ensures stable thermal conditions for cooling the sample metal around the junction of the thermocouple and its crystallization uniformity, i.e., the thermal center of the sample in this case coincides with the location thermocouple layer.

 A comparison of the reliability of the prototype and the proposed device and the error in determining the carbon content are presented in the table.

 Improving the reliability of the proposed device and reducing the error in determining the carbon content makes it possible to optimize the technological process of steel smelting in high-speed units, namely, to reduce the duration of smelting by 1.5%, as well as reduce the consumption of carbon-containing additives and energy resources.

Claims (1)

 DEVICE FOR MEASURING LIQUID STEEL TEMPERATURE AND SAMPLING FOR DETERMINING THE CARBON CONTENT BY THE LIQUIDUS METHOD, containing a water-cooled rod, a sampler with a hole and a thermocouple with a protective cover, and the thermocouple is connected to the secondary device, which is equipped with a ceramic ring sampler, and focusing to limit the movement of the ring.

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