Method for accurately measuring RH and VD vacuum degrees
By adding vacuum degree measurement points on the top of the RH vacuum tank and at the VD vacuum tank lid, the problem of inaccurate vacuum degree measurement in the prior art is solved, and accurate measurement of the vacuum degree in the RH and VD vacuum tanks and the pipe line is realized. The timely treatment of ash accumulation improves the accuracy of the degassing effect of the molten steel and the prediction of the fixed hydrogen value.
Patent Information
- Application Number
- CN202411364204.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-28
- Publication Date
- 2025-01-03
AI Technical Summary
The prior art cannot accurately measure the vacuum degree in the RH and VD vacuum furnace, which affects the degassing effect of the steel water. Due to the lack of monitoring of the vacuum degree in the vacuum tank and vacuum tank, the degassing effect is misjudged and delayed discovery.
Add a vacuum degree measurement point at the top of the RH vacuum tank and at the VD vacuum tank cover, use a vacuum meter to measure the vacuum degree, and judge the pipeline dust accumulation by comparing the vacuum degree behind the main valve, guide maintenance, and ensure that the vacuum degree is ≤67Pa to optimize Degassing effect.
Accurate measurement of the vacuum degree in RH and VD vacuum tanks and tanks is achieved, timely detection and treatment of pipeline blockages is detected and dealt with, the accuracy of the degassing effect of the steel water and the prediction of the hydrogen value are improved, and scientific and reasonable cleaning and maintenance standards are formulated.
Smart Images
Figure CN119242885A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of metallurgy and relates to a method for accurately measuring RH and VD vacuum degrees. Background Art
[0002] Vacuum degree (i.e. vacuum pressure) is a key process parameter for refining RH and VD, and is directly related to the vacuum degassing effect. According to the square root law, the content of gas elements such as nitrogen and hydrogen in molten steel is proportional to the square root of the vacuum degree. The lower the vacuum degree, the better the RH and VD vacuum degassing effect. Since nitrogen and hydrogen are harmful elements to most types of steel, high hydrogen content can easily lead to hydrogen-induced crack failure of steel, and high nitrogen content reduces the toughness and welding performance of steel. The control level of ultra-low nitrogen and hydrogen has become an important indicator to measure the process level of each steel plant.
[0003] In order to obtain ultra-low nitrogen and hydrogen content, it is first necessary to accurately grasp the vacuum value of the RH and VD furnaces closest to the molten steel surface. At present, the measurement points of the vacuum degree of the RH and VD systems are designed before and after the vacuum main valve. The vacuum degree before the main valve can reflect the exhaust capacity of the vacuum pump system, and the vacuum degree after the main valve can reflect the sealing condition of the pipeline equipment from the molten steel to the main valve section.
[0004] For RH, the vacuum degree measurement point after the main valve can generally reflect the level in the vacuum tank, but there are hot bends, gas coolers, dust collectors and connected vacuum pipes between the measurement point after the valve and the vacuum tank. During the operation of the RH furnace, dust and slag are easily accumulated, which causes a certain blockage in the passage from the measurement point after the valve to the vacuum tank. At this time, although the vacuum degree after the main valve is normal, the degassing effect of the molten steel is very poor, often significantly higher than the normal value. The main reason is that the vacuum degree in the vacuum tank is higher than the vacuum degree measured after the valve, that is, the vacuum degree after the valve cannot accurately reflect the vacuum degree inside the vacuum tank.
[0005] For VD furnace, there are also rotating elbows, gas coolers, dust collectors and connected vacuum pipes between the measuring point after the valve and the vacuum tank. VD furnace is also prone to dust accumulation during operation, which causes a certain blockage in the passage from the measuring point after the valve to the vacuum tank, and also causes the vacuum degree in the vacuum tank to be higher than the vacuum degree measured after the valve, affecting the degassing effect.
[0006] Since the vacuum degree in the RH vacuum tank and VD vacuum tank, which are closer to the molten steel, is not monitored, the vacuum degree behind the valve has been used instead. When the difference between the two is large, it will cause misjudgment of the degassing effect of the molten steel; on the other hand, hydrogen determination of molten steel is only a random inspection method, and it is basically impossible to monitor each furnace, which leads to a certain impact on the vacuum degassing effect and cannot be discovered in time. For example, the vacuum degree is displayed to be good, but the vacuum degree in the vacuum tank or vacuum tank is actually poor. Summary of the invention
[0007] In view of the difficulties existing in the above-mentioned prior art, the present invention aims to provide a method for accurately measuring the vacuum degree of RH and VD, which can directly and accurately measure the vacuum degree inside the RH vacuum tank and the VD vacuum tank.
[0008] The technical solution of the present invention: A method for accurately measuring RH and VD vacuum degrees comprises the following steps: S1: Add a vacuum degree measurement point on the top of the RH furnace vacuum tank, and use a vacuum gauge to measure the vacuum degree inside the RH furnace vacuum tank as the key parameter for RH vacuum degassing process control; in the RH deep degassing stage, the vacuum degree at the vacuum tank or vacuum tank is required to be ≤67Pa, and the dust accumulation of the RH vacuum pipeline is judged by comparing with the value of the vacuum degree measurement point after the RH vacuum main valve, and the RH vacuum system inspection and maintenance is guided; if the vacuum degree after the valve is ≤67Pa, and the vacuum degree at the vacuum tank or vacuum tank is >67Pa, the RH vacuum pipeline needs to be cleaned of dust and inspected; S2: Add a vacuum degree measurement point in the vacuum tank of the VD furnace, and use a vacuum gauge to measure the vacuum degree inside the VD vacuum tank, which is also used as a key parameter for VD vacuum degassing process control; in the VD deep degassing stage, the vacuum degree at the vacuum tank or vacuum tank is required to be ≤67Pa; and by comparing the value with the vacuum degree measurement point after the VD vacuum main valve, the dust accumulation condition of the VD vacuum pipeline is judged to guide the inspection and maintenance of the VD vacuum system; if the vacuum degree after the valve is ≤67Pa, and the vacuum degree at the vacuum tank or vacuum tank is >67Pa, the VD vacuum pipeline must be cleaned of dust and inspected.
[0009] Beneficial effects of the present invention: Aiming at the problem that the vacuum degree behind the RH and VD valves cannot accurately reflect the vacuum degree in the vacuum tank and vacuum tank, the present method adds a vacuum degree measurement point at the top of the RH vacuum tank and the cover of the VD vacuum tank, so that the vacuum degree inside the RH vacuum tank and the VD vacuum tank can be directly measured, which is closer to the surface of the molten steel and can better reflect the degassing effect of the molten steel, avoiding the influence of the blockage of the vacuum pipeline and other reasons on the degassing effect. By comparing with the vacuum degree behind the valve, the blockage of the vacuum pipeline can be discovered in time, and the problem can be dealt with in time to avoid the influence on the vacuum degassing of the molten steel. After using this method, the vacuum degree detection means of our factory are more scientific and reasonable. According to the vacuum degree, the degassing effect of the molten steel can be predicted more accurately, especially the hydrogen value of the molten steel, and the cleaning and maintenance standards for the vacuum pipeline according to the vacuum degree have been formulated, which have achieved good results. BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The illustrative embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation on the present application. In the drawings: Figure 1 Schematic diagram of the RH vacuum system.
[0011] Figure 2 Schematic diagram of VD vacuum system.
[0012] In the figure: P1-vacuum degree before valve; P2-vacuum degree after valve; P3-vacuum degree of vacuum tank or vacuum vessel. DETAILED DESCRIPTION
[0013] See also Figure 1 , Figure 2 A method for accurately measuring RH and VD vacuum degrees comprises the following steps: S1: Add a vacuum degree measurement point P3 on the top of the RH furnace vacuum tank, and use PM-4 Maxwell vacuum gauge to measure the vacuum degree P3 inside the RH furnace vacuum tank more accurately. As the key parameter for RH vacuum degassing process control, the RH deep degassing stage requires the vacuum degree P3 of the vacuum tank or vacuum tank to be ≤67Pa; and by comparing with the value of the vacuum degree measurement point after the RH vacuum main valve, the dust accumulation of the RH vacuum pipeline can be judged to guide the inspection and maintenance of the RH vacuum system. If the vacuum degree P2 after the valve is ≤67Pa, and the vacuum degree at the vacuum tank or vacuum tank P3 is greater than 67Pa, the RH vacuum pipeline should be cleaned and inspected.
[0014] S2: Add a vacuum degree measurement point to the vacuum tank of the VD furnace. The VD vacuum system can be measured with a PM-4 Maxwell vacuum gauge to more accurately measure the vacuum degree inside the VD vacuum tank. It is also a key parameter for VD vacuum degassing process control. In the VD deep degassing stage, the vacuum degree of the vacuum tank or vacuum tank at P3 is required to be ≤67Pa; and by comparing the value of the vacuum degree measurement point after the VD vacuum main valve, the dust accumulation of the VD vacuum pipeline can be judged to guide the inspection and maintenance of the VD vacuum system. If the vacuum degree after the valve is ≤67Pa, and the vacuum degree at P3 is greater than 67Pa, the VD vacuum pipeline must be cleaned and repaired.
[0015] Choose a measuring device suitable for low vacuum degree, you can use PM-4 Maxwell vacuum gauge and electronic vacuum instrument. The measuring point must be connected to the vacuum tank or vacuum tank to avoid blockage affecting the accuracy of the measurement results.
Claims
1. A method for accurately measuring RH and VD vacuum degree, characterized in that The steps include: S1: Add a vacuum degree measurement point on the top of the RH furnace vacuum tank, and use a vacuum gauge to measure the vacuum degree inside the RH furnace vacuum tank as the key parameter for RH vacuum degassing process control; in the RH deep degassing stage, the vacuum degree at P3 is required to be ≤67Pa, and the dust accumulation of the RH vacuum pipeline is judged by comparing the value with the vacuum degree measurement point after the RH vacuum main valve, and the RH vacuum system inspection and maintenance is guided; if the vacuum degree after the valve is ≤67Pa, and the vacuum degree at the vacuum tank or vacuum tank is >67Pa, the RH vacuum pipeline needs to be cleaned and inspected; S2: Add a vacuum measurement point in the vacuum tank of the VD furnace, and use a vacuum gauge to measure the vacuum inside the VD vacuum tank, which is also used as a key parameter for VD vacuum degassing process control; in the VD deep degassing stage, the vacuum degree at P3 is required to be ≤67Pa; and the dust accumulation of the VD vacuum pipeline is judged by comparing the value with the vacuum measurement point after the VD vacuum main valve, guiding the inspection and maintenance of the VD vacuum system; if the vacuum degree after the valve is ≤67Pa, and the vacuum degree at P3 of the vacuum tank or vacuum tank is greater than 67Pa, the VD vacuum pipeline must be cleaned of dust and inspected.