SU819182A1 - Device for measuring temperature of metal in convertor - Google Patents

Description

one

The invention relates to metallurgy, in particular to the design of devices for measuring the temperature of a liquid metal, and can be used to control the temperature during the converter melting process.

A device is known that measures the temperature of the metal bath during its probing from above through the throat of the converter 1. Due to the fact that in the process of measuring the sensitive elements of these devices fall into the most high-temperature and chemically aggressive part of the metal bath, their service life is very limited, as a result only discrete, periodic temperature control, which does not provide sufficiently complete information on the smelting progress. In addition, these devices usually require the use of bulky, complex and expensive drives, the weight of which is often measured in tens of tons.

It is also known a device mounted in less aggressive zones of a metal bath, for example, in the converter lining below the melt level, and having a longer service life, which allows for continuous temperature control for several heats. Such a device contains a refractory sleeve installed in a brick lining, into which a replaceable tip with a thermocouple screwed into the socket of the sleeve 2 is screwed.

The disadvantages of the described device include low accuracy of measurement, due to the fact that the thermocouple does not contact directly with the metal bath, but to measure the temperature of the end

bushing walls, hanging heavily

from a slag layer of uncontrollable thickness,

adhering to the lining in the installation area

devices.

In addition, when the end wall of the sleeve is burned out, liquid slag and metal will inevitably enter the device cavity and the latter will fail to replace. These drawbacks are partially eliminated in a device for measuring the temperature of a liquid metal, which contains a refractory sleeve installed in the channel of a brick lining, having a cylindrical section of reduced diameter in the form of a groove filled with a thermal expansion mass, and placed in the sleeve a thermocouple whose protective cover ends the fire surface of the lining and is in direct contact with the metal 3.

When the device is installed into the channel of the brick of the lining, the thermally expanding mass increases in volume and tightly closes the gap between the sleeve and the brick. However, due to the fact that the area of reduced diameter, on which the compaction is applied, and the mass, is removed from the firing end of the sleeve, the end gap penetrates the metal into the remaining between the brick and the tailbone, and solidifies, firmly connecting the sleeve and the lining brick.

When a thermocouple is removed after several heats, it makes it very difficult to replace the device, which only with great difficulty can be dislodged into the converter. When a layer of slag of considerable thickness adheres to the lining, which plays the role of a heat insulator, the metal in the gap can completely harden and the dismantling of the device becomes impossible. In addition, it should be emphasized that the device should be replaced only in the interval between melts, when the metal from the converter is lowered and the lining with adhered slag is rapidly cooled.

All of the above often leads to the impossibility of replacing a failed device, which in turn prevents further monitoring of the progress of melts until the converter for lining repair is stopped, during which you can install a new brick with a channel for mounting the device.

The lack of continuous monitoring leads to a violation of the optimal mode of melting and adversely affects the converter performance and the quality of the produced metal.

The purpose of the invention is to increase the reliability of temperature control over the entire turnaround time of the converter operation by ensuring prompt multiple device replacements.

This goal is achieved by the fact that in a device for measuring the temperature of a metal in a converter containing a refractory sleeve installed in the converter lining channel, having a cylindrical section of reduced diameter, onto which a sealing thermal expansion mass is applied, a section of reduced diameter adjoins the end in contact with the metal sleeve and forms an annular ledge, the wall of which is oriented relative to the longitudinal axis of the sleeve at an angle of 70-110 °, preferably - 90 °.

Palichi specified annular protrusion contributes, when changing the device, knocking out the metal flowed in the resulting gap and sintering sealing mass, which greatly facilitates the replacement of the device, eliminates cases of its jamming in the lining channel and thus provides the possibility of maintaining constant temperature control during heats.

The drawing shows the proposed device.

The device comprises a sleeve 1 made of a refractory material, for example pressed and sintered powder. The sleeve 1 is placed in the channel of the brick of the lining 2. Through the sleeve 1 passes the cover of thermocouple 3, the working end of which stands for the fire surface of the lining by 25-30 mm.

The end of the sleeve 1 facing the metal

made in the form of a cylindrical section of reduced diameter, and the transition has the shape of an annular ledge.

The wall of the ledge is oriented, as already indicated, with respect to the longitudinal

the axis of the sleeve at an angle of 70-110 °, preferably 90 °. The angle of inclination of the wall is chosen within such limits that the formed ledge has, on the one hand, sufficient edge strength (decreased with decreasing angle) and, on the other hand, would not contribute, when moving forward, to wedge the sealing mass and the metal that has penetrated into the gap. Optimal from the point of view of the stated requirements is the implementation of the step at an angle of 90 °. The difference in diameters of the sleeve and the reduced section is 4-10 mm, preferably 6 mm. The length of the section of reduced diameter may be

from 30 to 50 mm, preferably 40 mm. A sealing refractory thermally expanding mass 4 based on boron nitrate (15-25%), an aluminophosphate binder (10-

20%) and electrocorundum powder (the rest).

On the surface of the thermally expanding mass there is a layer of non-sintered material, for example, graphite powder.

(not shown in the drawing).

The length of the section of reduced diameter and the difference in diameters are chosen on the one hand, to ensure that there is a seal mass in the gap

partial leaching of the latter in the process of melting, and on the other hand, to prevent the complete hardening of the metal that has fallen into the formed cavity, which hardens more quickly than the gap

between the sleeve and the brick lining.

When the device is installed, the bushing with the applied mass is inserted into the channel of the lining brick in such a way that its front end is installed in the plane of fire

brick surface. As it warms up, the sealing mass expands, sintering and forms a tight sealing ring, partially protruding above the lining plane. Thermocouple enclosed

in the sleeve, connect to the regulating

the device (not shown) and subsequently measure and control the temperature in a known manner.

If it is necessary to replace the device, which takes place when the thermocouple protective tip fails (burned), the latter is removed from the lining bricks channel, after which the sleeve together with the thermocouple tip that is out of operation is knocked inside the converter and replaced with a new one.

It should be emphasized that the sealing mass during the melting process can be, as already mentioned, partially eroded and metal can penetrate into the resulting gap. Nevertheless, knocking out the sleeve is not difficult, since when the sleeve is mixed, the annular step on its surface exerts pressure on the metal that has penetrated into the gap, squeezing it out like a piston, after which the rest of the sleeve easily passes into the vacated hole.

When the sleeve is knocked out in the device of the prototype, the smooth cylindrical wall of the sleeve is unable to push the metal into the gap, as a result of which the promotion of the sleeve requires overcoming the friction forces between the metal and the sleeve along the entire length of the latter. In this case, as already indicated, the sleeve advances slowly and with difficulty, the metal has time to completely harden and the promotion of the sleeve becomes impossible.

In the proposed device, the mixing of the sleeve by several millimeters, which occurs already at the first impact, leads to the ejection of the metal that did not manage to harden and the further unhindered exit of the sleeve.

A large (up to 3 mm) width of the gap also contributes to the penetration of a metal penetrated into the gap, due to which the metal hardens to a lesser extent and retains plasticity at the time of the sleeve being knocked out.

Thus, this form of the sleeve, the area of reduced diameter of which is adjacent to the end and forms a rectangular annular step, provides the possibility of quick and repeated replacement of the device throughout the entire turnaround time of the converter, which, in turn, ensures the maintenance of a constant, uninterrupted

temperature control over the entire specified period, thereby increasing the performance of the converter and contributing to improving the quality of the metal.

Claims (3)

1. USSR author's certificate number 352941, cl. From 21C 5/30, 1970. 2. US patent number 3473968, cl. 136-230,1972. 3. Materials of the republican seminar “Continuous temperature measurement in steelmaking units. Kiev, Ed. Ukrainian Research Institute of Scientific and Technical Information, 1966, p. 11 - 13 (prototype).