Monitoring device for protecting atmosphere oxygen concentration in tundish through continuous casting argon blowing

Abstract

The utility model relates to a monitoring device for atmosphere oxygen concentration in a continuous casting argon blowing protection tundish, which comprises an oxygen analyzer (1), a sampling and purging device (2), a sampling probe pipe (3) and an auxiliary gas holder (4), and is characterized in that the oxygen analyzer (1) is connected with the sampling and purging device (2) through a sample conveying pipeline (6); the auxiliary gas holder (4) is connected with the sampling and purging device (2) and is used for providing auxiliary gas, the sampling and purging device (2) is connected with the sampling probe pipe (3) through a sampling pipeline (5), a steel overflow groove (7) is formed in the top of a tundish (8), and the sampling probe pipe (3) can stretch into the steel overflow groove (7) to sample the atmosphere in the tundish. The method can effectively measure the oxygen concentration percentage of the gas atmosphere in the tundish, and is used for evaluating the argon blowing effect of the tundish.

Description

Technical Field

[0001] The utility model relates to a monitoring device for atmospheric oxygen concentration, in particular to a monitoring device for atmospheric oxygen concentration in a tundish. Background Art

[0002] Nowadays, steel mills generally adopt the multi-machine multi-stream continuous casting process to produce ingots. Especially when producing high-grade special steel, the requirements for molten steel cleanliness are getting higher and higher. Full protection pouring is one of the main process technologies to prevent molten steel from secondary oxidation during the pouring process of the continuous casting machine. If there is no good protection pouring measure, the molten steel will inevitably come into contact with the air, causing secondary oxidation, reducing the content of dissolved aluminum in the steel, increasing the content of nitrogen and oxygen, deteriorating the purity of the molten steel, and failing to meet the requirements of high-quality steel. At the same time, it also has a certain impact on the stable and smooth production. Especially when producing bearing steel and high-sulfur and high-Al automobile steel, improper protection pouring is very likely to cause nozzle nodules, which has a great impact on the quality of steel. In severe cases, it causes product degradation or even scrapping. For this reason, many steel mills have systematically studied the full protection pouring of the continuous casting process while ensuring the normal production of the converter refining process: from the outflow of molten steel from the large ladle - the molten steel flows into the tundish - the crystallizer, a systematic analysis and research is conducted on the exposure of molten steel and secondary oxidation caused by each joint, and the equipment is upgraded and transformed to fully upgrade the full protection pouring process.

[0003] However, in the full protection pouring process of the continuous casting process, after the molten steel flows from the ladle into the tundish, the molten steel stays in the tundish for the longest time and has the greatest chance of being re-oxidized. This link should be paid the most attention to, and for this reason, many steel mills have adopted the tundish argon blowing protection technology. Although the tundish argon blowing protection technology has been widely used and has achieved the purpose of improving the secondary oxidation of molten steel to a certain extent, in actual production, how to verify the effect of argon blowing protection cannot be obtained from the current technology.

[0004] The patent application with Chinese patent publication number CN204770624A (the announcement date is November 18, 2015, and the name is "An Argon Blowing Sealed Tundish" which discloses an Argon Blowing Sealed Tundish). An argon blowing conduit is buried in the upper part of the permanent layer, and an argon blowing branch pipe is passed through the working layer to be connected to the argon blowing conduit, so that the argon blowing branch pipe is located above the steel liquid surface, thereby isolating the air and preventing the secondary oxidation of the molten steel.

[0005] The patent application with Chinese patent publication number CN205393522A (the announcement date is July 27, 2016, and the name is Tundish Argon Blowing Device, which discloses Tundish Argon Blowing Device), can blow argon into the tundish, and the argon blowing effect is good.

[0006] By reviewing the above patent documents, no mention was made of the oxygen determination technology for the tundish with argon blowing protection. Even if the tundish was protected with argon blowing, it was not specifically verified whether the effect was reliable, and there were deficiencies in the control of steel product quality. Utility Model Content

[0007] The technical problem to be solved by the utility model is to provide a monitoring device for the oxygen concentration in the continuous casting argon blowing protection tundish in view of the above-mentioned prior art, which can effectively measure the oxygen concentration percentage of the gas atmosphere in the tundish, increase the quantitative index of the argon blowing protection effect of the tundish, and truly measure the effect of the tundish protection casting with specific parameters.

[0008] The technical solution adopted by the utility model to solve the above-mentioned problem is: a monitoring device for oxygen concentration in a continuous casting argon-blown protection ladle, characterized in that it includes an oxygen analyzer, a sampling and purging device, a sampling probe tube and an auxiliary gas cabinet, the oxygen analyzer is connected to the sampling and purging device through a sample delivery pipeline, the auxiliary gas cabinet is connected to the sampling and purging device for providing auxiliary gas (inert gas, such as nitrogen), the sampling and purging device is connected to the sampling probe tube through a sampling pipeline, an overflow trough is arranged on the top of the ladle, and the sampling probe tube can be extended into the overflow trough to sample the atmosphere in the ladle.

[0009] As one of the preferred embodiments of the present application, the sample delivery pipeline is a metal hard pipe, which has the functions of high temperature resistance and ensuring the stability of the sample delivery airflow.

[0010] As one of the preferred embodiments of the present application, the sampling pipeline is a metal hose, which is resistant to high temperatures and convenient for sampling operations with a sampling probe tube.

[0011] As one of the preferred embodiments of the present application, the probe tube is arranged vertically during sampling, which is more conducive to atmosphere sampling.

[0012] As one of the preferred embodiments of the present application, the sampling probe tube is a ceramic tube.

[0013] As one of the preferred embodiments of the present application, the auxiliary gas cabinet is connected to the sample delivery pipeline through a pipeline, and the purge gas provided by the auxiliary gas cabinet fills the sample delivery pipeline to ensure the cleanliness of the sample delivery pipeline and facilitate reverse purge of the sampling pipeline before sampling.

[0014] A method for monitoring oxygen concentration in a tundish based on the above device is as follows:

[0015] Process (1): Preparation work: Before continuous casting begins, the connection parts must be sealed with raw tape and tested for leaks. Parts that are in direct contact with high temperatures must be wrapped and protected (with fiber cloth).

[0016] Process (2): The argon replacement is turned on. After the nozzle of the tundish roaster is turned off, the opening on the tundish is sealed and the argon replacement is performed during the movement of the tundish car.

[0017] Process (3): Collect gas samples. After the tundish is opened to the pouring position and enters steady-state pouring, the selection switch of the oxygen analyzer is turned from the "off" position to the "on" position. At this time, backblowing begins through the auxiliary gas in the sampling and purging device 2 to purge the original atmosphere and debris in the sampling pipeline. After more than 5 minutes, the operator places the sampling probe tube 3 into the position of the tundish overflow tank 7 to collect the measured gas.

[0018] Process (4): Detect gas samples. The collected measuring gas passes through the sampling and purging device 2 and the metal hard pipe 6 into the oxygen analyzer 1. The measured oxygen concentration is fed back to the HMI screen through the PLC. Under normal circumstances, the oxygen concentration of the normal pouring in the impact zone of the tundish is 0-3.0%, which is more suitable.

[0019] Process (5): Process monitoring. During the pouring process, pay special attention to the reverse purge function within a 30-40 minute period to ensure that the pipeline for collecting and measuring gas is unobstructed. Under normal pouring conditions, an oxygen content concentration of ≥0.5% is abnormal and needs to be checked.

[0020] Compared with the prior art, the advantages of the utility model are:

[0021] The oxygen analyzer in the utility model analyzes the oxygen concentration percentage by collecting the measuring gas, the sampling and purging device collects the sample gas through the sampling probe tube placed in the overflow steel tank of the tundish, the sampling and purging device is connected to the sampling probe tube through a metal hose, the measuring gas enters the oxygen analyzer through a metal hard pipe, and the auxiliary gas cabinet blows auxiliary gas into the oxygen analyzer and the sampling and purging device through the metal hard pipe. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 It is a schematic diagram of the working state of the monitoring device for oxygen concentration in the continuous casting argon blowing protection tundish in the embodiment of the utility model;

[0023] In the figure: 1- oxygen analyzer; 2- sampling and purging device; 3- sampling probe tube; 4- auxiliary gas cabinet; 5- metal hose; 6- metal hard pipe; 7- steel overflow port; 8- tundish. DETAILED DESCRIPTION

[0024] The present invention is further described in detail below in conjunction with the accompanying drawings. The embodiments are exemplary and intended to be used to explain the present invention, but should not be understood as limiting the present invention. The text description in this embodiment corresponds to the accompanying drawings, and the description of the orientation is also based on the description of the accompanying drawings, and should not be understood as limiting the scope of protection of the present invention.

[0025] The present embodiment relates to a method and device for monitoring oxygen concentration in a continuous casting tundish with argon blowing protection, and the process of the method is as follows: process (1): preparation work, before continuous casting starts, the connection parts must be sealed with raw tape and checked for leaks, and those in direct contact with high temperature must be wrapped with fiber cloth for protection; process (2): argon replacement is turned on, after the drying nozzle of the tundish 8 is turned off, the opening on the tundish 8 is sealed, and argon replacement is performed during the movement of the tundish car 8; process (3): gas sampling, after the tundish is opened to the pouring position and enters the steady-state pouring, the operator turns the selection switch of the oxygen analyzer 1 from the "off" position to the "on" position, and the auxiliary gas in the sampling and purge device 2 is started Back-blowing, purge the debris in the sampling pipeline, after 5 minutes, the operator puts the sampling probe tube 3 into the position of the overflow tank 7 of the tundish to collect the measurement gas; process (4): detect the gas sample, the collected measurement gas passes through the sampling and purging device, and enters the oxygen analyzer 1 through the metal hard tube 6. The measured oxygen concentration is fed back to the HMI screen through the PLC. Under normal circumstances, the normal pouring oxygen concentration in the impact zone of the tundish is 0-3.0%, which is more suitable; process (5): process monitoring, during the pouring process, pay special attention to the reverse purge function within a period of 30-40 minutes to ensure that the pipeline for collecting the measurement gas is unobstructed. The oxygen content concentration in the normal pouring state ≥0.5% is abnormal and needs to be checked. The present invention is further explained below in conjunction with an implementation example:

[0026] Example 1

[0027] Before continuous casting, after the tundish roaster nozzle is turned off, the opening on the tundish 8 is sealed. The connection parts must be sealed with raw tape and tested for leakage. Argon replacement is performed during the movement of the tundish car. After the tundish 8 is opened to the pouring position and enters the steady-state pouring, the operator turns the selection switch of the oxygen analyzer 1 from the "off" position to the "on" position. At this time, the auxiliary gas in the sampling and purging device 2 starts to backflush and purge the debris in the sampling pipeline. After 5 minutes, the operator puts the sampling probe tube 3 into the position of the tundish overflow tank 7 to collect the measurement gas. The collected measurement gas passes through the sampling and purging device 2, passes through the metal hard pipe 6, and enters the oxygen analyzer 1. The measured oxygen concentration is fed back to the operation screen. When producing alloy structural steel, the oxygen concentration in the impact zone of the tundish is usually between 0-0.5% during normal pouring, and the oxygen concentration is 0.5-3.0% when changing to a large ladle, which is more suitable. At the same time, during the pouring process, special attention should be paid to the reverse purge function within a period of 30-40 minutes to ensure that the pipeline for collecting and measuring gas is unobstructed.

[0028] Example 2

[0029] Before continuous casting, after the tundish roaster nozzle is turned off, the opening on the tundish 8 is sealed. The connection parts must be sealed with raw tape and tested for leaks. Argon replacement is performed during the movement of the tundish car. After the tundish 8 is opened to the pouring position and enters the steady-state pouring, the operator turns the selection switch of the oxygen analyzer 1 from the "off" position to the "on" position. At this time, the auxiliary gas in the sampling and purging device 2 is used to start backwashing to purge the debris in the sampling pipeline. After 5 minutes, the operator puts the sampling probe tube 3 into the position of the tundish overflow tank 7 to collect the measurement gas. The collected measurement gas passes through the sampling and purging device 2, passes through the metal hard pipe 6, and enters the oxygen analyzer 1. The measured oxygen concentration is fed back to the operation screen. When producing bearing steel, the oxygen concentration in the impact zone of the tundish is usually between 0-0.5% during normal pouring, and the oxygen concentration is 0.5-2.0% when changing to a large bag, which is more suitable. At the same time, during the pouring process, special attention should be paid to the reverse purge function within a period of 30-40 minutes to ensure that the pipeline for collecting and measuring gas is unobstructed.

Claims

1. A monitoring device for oxygen concentration in the atmosphere of a continuous casting argon-blowing protection tundish, characterized in that: The invention comprises an oxygen analyzer (1), a sampling and purging device (2), a sampling probe tube (3) and an auxiliary gas cabinet (4); the oxygen analyzer (1) is connected to the sampling and purging device (2) via a sample delivery pipeline (6); the auxiliary gas cabinet (4) is connected to the sampling and purging device (2) for providing auxiliary gas; the sampling and purging device (2) is connected to the sampling probe tube (3) via a sampling pipeline (5); a steel overflow groove (7) is arranged on the top of the tundish (8); the sampling probe tube (3) can extend into the steel overflow groove (7) to sample the atmosphere in the tundish.

2. The monitoring device for oxygen concentration in the atmosphere of the continuous casting argon blowing protection tundish according to claim 1, characterized in that: The sample delivery pipeline (6) is a metal hard pipe.

3. The monitoring device for oxygen concentration in the atmosphere of the continuous casting argon blowing protection tundish according to claim 1, characterized in that: The sampling pipeline (5) is a metal hose.

4. The monitoring device for oxygen concentration in the atmosphere of the continuous casting argon blowing protection tundish according to claim 1, characterized in that: The sampling probe tube (3) is arranged vertically during sampling.

5. The monitoring device for oxygen concentration in the atmosphere of the continuous casting argon blowing protection tundish according to claim 1, characterized in that: The sampling probe tube (3) is a ceramic tube.

6. The monitoring device for oxygen concentration in the atmosphere of the continuous casting argon blowing protection tundish according to claim 1, characterized in that: The auxiliary gas cabinet (4) is connected to the sample delivery pipeline (6) via a pipeline, and the purge gas provided by the auxiliary gas cabinet fills the sample delivery pipeline.

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