JPS62228423A - Method for collecting information on refining - Google Patents

Abstract

PURPOSE:To accurately collect information to represent the entire part of a steel by temporarily injecting an inert gas from a top blowing lance for injecting a refining gas which has a photodetecting part of a fiber scope connecting to a measuring instrument at the top end and collecting the prescribed information. CONSTITUTION:The photodetecting part 8 of the fiber scope connecting via a fiber cable 9 to a two-color pyrometer 4 and a television camera 5 is attached to the top end of the top blowing lance 1. After the inside of a converter 2 is thoroughly preheated, the molten iron is charged therein and gaseous N2 is supplied from bottom blowing tuyeres 6 into the converter. Gaseous O2 is supplied from the top blowing lance 1 to execute blowing. The inert gas is temporarily introduced in the converter in place of the refining gas from the top blowing lance 1 and the temp. on the bath surface is measured by the two- color pyrometer 4, then the temp. in the bath is measured by a sub-lance at the time of collecting the information on the refining at the bath surface in the stage of blowing. The various kinds of the average data on the in-furnace conditions are thereby collected and the accuracy of blowing is improved.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to a method for collecting refining information such as the composition and temperature of molten iron and molten steel by observing the bath surface. This is a proposal for a method for obtaining various metallurgical information using a top-blowing lance for injecting refining gas equipped with a fiberscope suspended in a position facing the molten metal bath surface in a converter.

(Conventional technology) Conventionally, the best way to accurately grasp the situation inside the converter, especially the situation on the surface of the molten steel bath, and to collect refining information in order to analyze that information and use it for operation and blowing control is by using a sublance method. Common.

On the other hand, recently, a technology using a top-blown lance equipped with a fiber scope, disclosed in Japanese Utility Model Application Publication No. 60-9957, has been proposed as an improvement over the above-mentioned sub-lance. This known technology extracts the temperature and composition of molten steel at the hot point during blowing as optical signals through the light receiving part of a fiber scope installed in the nozzle part at the tip of the lance, converts them into electrical signals, and performs the specified refining process. This is a method of obtaining information.

Although this technique has various advantages as described in Japanese Utility Model Application Publication No. 60-9957, it still has the following problems.

(Problems to be Solved by the Invention) The problem to be solved by the present invention in the prior art is that the bath surface during the blowing of the refining 02 gas is the object of observation. This shows that this is the location where the 0□ gas flow collides with the bath surface, and the information optically obtained by the fiberscope there is nothing more than the temperature and composition of the molten steel at the "flaming point." ing. In short, the optical information obtained in this way cannot be average data representative of the entire molten steel in the furnace. Therefore, such information G impairs the identification of suitable furnace operating conditions and its application to blowing control, and results in making end point control difficult.

An object of the present invention is to overcome the problems of the prior art by establishing a sampling technique that can obtain information representative of the entire steel bath in a timely manner even when using a fiberscope.

(Means for solving the problem) The purpose of the upper part can be surely achieved by adopting a structure based on the following points. That is, the present invention provides a method for collecting refining information at the bath surface using a top-blower lance used for injecting refining gas, which has a light-receiving part at the tip of a fiberscope connected to a measuring device through a fiber cable. Collection of refining information characterized by temporarily introducing an inert gas instead of the refining gas into the blowing lance and blowing it onto the bath surface, and obtaining predetermined information using the fiber scope in an inert gas atmosphere. The method is.

(Function) The idea of the present invention is that when a fiberscope is used, the average value representing the entire molten steel in the furnace becomes C+1/20z -'-' co, Fe+1 by 0□ injection.
/20z-FeO, which cannot be obtained by collecting from a place where the reaction peculiar to the flash point is occurring; ■The state of the static bath surface seen when gas injection is stopped, or the bath surface is covered with slag. This problem was solved by focusing on the fact that it is not possible to capture the state in the process of refining if the material is harvested in a still state.

In other words, when the temperature and composition of the steel bath are required, 0□
They decided to realize the above idea by injecting an inert gas such as Ar from a lance for a while after blowing. By measuring at such timing, even when observing using a fiberscope, data from the unique situation of the fire point can be excluded, and the true average value of the entire steel bath can be known, allowing accurate measurement. You can collect refinement information. If blowing is performed based on such refining and dissolution, the accuracy of various operational controls will be improved.

(Example) This example is an example of steel refining using a 5-ton top-bottom blowing converter and a top-blowing lance equipped with a fiber scope. Fig. 1 is a schematic diagram of the applicable equipment, where 1 is a top-blowing lance that can switch between 02 and N2, and the tip of the lance has a fiber attached at a position facing the center of the gas injection hole 10, as shown in Fig. 2. A scope light receiving section 8 is provided.

Optical signals such as the temperature of the molten steel and its composition detected by the light receiving section 8 can be transmitted to the two-color pyrometer 4 and the television camera 5 via the fiber cable 9 inside the lance 1. Note that inert gas (Ar, Nz) can be blown into the converter 2 through four tuyeres 6 at the bottom of the furnace.

Further, numeral 3 in the figure is a sub-lance, and a consumable probe 7 is attached to a holder at the tip of the lance, making it possible to measure the temperature of molten steel, solidification temperature, and dissolved oxygen, and to collect samples.

In operation, after sufficiently preheating the inside of the converter with coke oven gas, C: 4.3 tχ, Si: O, 15 wt
Mn: 0.2wtχ, P: 0.15wtχ, S: 0.0
25wtχ? Pig (1320°C) was charged. N2 gas is supplied at 0.5Nm3/mi from the bottom tuyere 6 of the vertical furnace.
It was supplied at a rate of n. At the same time, lower the top blowing lance 1 with the fiberscope inside from the furnace mouth and pour 02 gas into the tank.
5Nm'/min was supplied. The lance stopped at a position where the distance between its tip and the bath surface was 0.7 m. Blowing was performed in this state for about 20 minutes.

Next, at four points in time when the elapsed time of the blowing is 5, 10, 15, and 20 minutes, the 02 gas supply from the top blowing lance 1 is instantly switched to N2 gas (15 Nm'/m1n), and the two-color high temperature The temperature of the bath surface was measured with a meter. In addition, at the same time, the temperature in the bath was measured using a sublance.

Figure 3 shows the measurement results of the fiberscope and sublance. As you can see from this figure, the results of analyzing the optical signal obtained through the fiberscope and the Sublance 3
The measurement results are almost the same as those obtained by the method, and the accuracy is within the range of about ±2.5°C, so it can be fully utilized as refining information. In addition, the time required for temperature measurement is approximately 1 second to switch from oxygen (02) to nitrogen (N2) gas, and 2 to 5 seconds to measure.
It took about 1 second to switch from N2 gas to 02 gas, and the temperature could be measured in 4 to 7 seconds in total. As a secondary effect, the bubbling of the slag that occurred in the early stage of blowing could be confirmed on the monitor TV without changing from 0□ to N2 gas, and the lance height was lowered to 0.4 m when bubbling was confirmed. However, bubbling was suppressed and it was possible to avoid blowing out or slopping of molten iron and molten slag.

As mentioned above, when measuring temperature, the gas supplied from the top blowing lance inside the fiberscope is changed from 0□ to inert gas (A
r or NZ) and measured the steel bath temperature with a two-color pyrometer connected to a fiberscope, it was possible to measure with high accuracy and quickly.

(Comparative Example) Blowing was performed using the same equipment as in the above example and under the same operating conditions. Furthermore, at exactly the same timing as in the example, temperature measurement of molten iron was carried out using top-blowing lance 1 and sub-lance 3 equipped with fiberscopes.

At this time, only 0□ gas was supplied from the top blowing lance l even during temperature measurement. The measurement results are shown in FIG.

From this figure, the temperature of the two-color pyrometer of the fiber scope shows a value of +800 to too0°C with respect to the temperature of the sublance 1, and the transition as the blowing progresses is also different from the temperature of the sublance 3. For this reason, not only could the temperature of the two-color pyrometer not be used as blowing information, but it was predicted that the target molten iron temperature and composition would not be obtained if this value was used, so subsequent blowing Ren used what he learned from Sublance 3.

(Effects of the Invention) As explained above, according to the present invention, even when a fiberscope is used, there is no factor that hinders the collection of true data such as observation of the fire spot, so various average data of the inside situation of the reactor can be obtained. can be collected and improve the accuracy of blowing.

[Brief explanation of drawings]

Figures 1 and 2 are cross-sectional views of the converter and top blowing lance used in the present invention, and Figures 3 and 4 are blowing times and diagrams for the examples of the present invention and the comparative example (Figure 4). It is a graph showing the relationship with hot metal temperature. 1...Top-blowing lance 2...Converter 3...Sub-lance 4...Two-color pyrometer 5...TV camera
6...Bottom blowout 7...Probe 8...Light receiving part of fiber scope 9...Fiber cable 10...Nozzle injection hole Figure 1 Figure 3 Mouth gap East time (mt'n)

Claims (1)

[Claims] 1. In collecting refining information at the bath surface with a top-blowing lance used to inject refining gas, the tip of which is a light-receiving part of a fiber scope connected to a measuring device through a fiber cable, Refining information characterized in that an inert gas is temporarily introduced into the top blowing lance instead of the refining gas and blown onto the bath surface, and predetermined information is obtained by the fiber scope under an inert gas atmosphere. collection method.