Intelligent determination method and system for temperature and oxygen measurement timing during RH refining of non-oriented silicon steel

Abstract

The present invention discloses a method for intelligently determining the timing of temperature measurement and oxygen determination during RH refining of non-oriented silicon steel, comprising the following steps: if the non-oriented silicon steel is low-grade non-oriented silicon steel, then during the RH treatment of the molten steel, the temperature measurement and oxygen determination times of the molten steel are sequentially determined at the time of entering the station, during the decarburization process, before the end of decarburization, after oxygen supplementation before the end of decarburization, after the end of deoxidation, and before RH air breaking, until the temperature measurement and oxygen determination time is reached; if the oriented silicon steel is medium- or high-grade non-oriented silicon steel, then during the RH treatment of the molten steel, the temperature measurement and oxygen determination times of the molten steel are sequentially determined at the time of entering the station, during the decarburization process, before the end of decarburization, after oxygen supplementation before the end of decarburization, after the end of desulfurization, and before RH air breaking, and after the temperature measurement and oxygen determination time is reached. The method can quantitatively determine the timing of temperature measurement and oxygen determination during the RH smelting of non-oriented silicon steel, improve the level of on-site standardized operation, and enhance the accuracy of molten steel temperature and composition control.

Description

Technical Field

[0001] The present invention belongs to the technical field of iron and steel metallurgy, and more specifically, relates to a method and system for intelligently determining the timing of temperature measurement and oxygen determination during RH refining of non-oriented silicon steel. Background Art

[0002] Non-oriented silicon steel is a binary ferrosilicon alloy with an extremely low carbon content, typically between 0.2% and 4.0%. Its iron loss and magnetic induction intensity are low, making it primarily used in medium and large motors and generators with large capacities. It is an irreplaceable soft magnetic alloy material for the electronics, power, and military industries. Depending on the Si or (Al+Si) content, it is divided into low-grade silicon steel ((Al+Si) <1.5%) and medium- and high-grade silicon steel ((Al+Si): 1.5-4.5%). The smelting process for non-oriented silicon steel is "desulfurization station → top and bottom combined blown converter → RH vacuum furnace → continuous casting." The main metallurgical functions of the RH vacuum furnace include decarburization, adjusting the molten steel temperature, deoxidation, desulfurization, alloying, and removing inclusions.

[0003] When smelting non-oriented silicon steel in an RH refining furnace, molten steel temperature and oxygen content are crucial technical parameters. The molten steel temperature must meet the requirements for smooth continuous casting. Excessively high temperatures can easily lead to production quality issues such as breakouts and bulging of the ingots, while excessively low temperatures can cause ingot stagnation. Furthermore, chemical heating operations must not be performed after the addition of ferrosilicon. The molten steel's oxygen content must meet the requirements for decarburization of the non-oriented silicon steel. If the temperature is insufficient, a compensation temperature must be reserved for the exothermic reaction between oxygen and aluminum. Therefore, during the RH treatment process, molten steel temperature and oxygen content play a crucial role in the quality of non-oriented silicon steel.

[0004] In the RH smelting process of non-oriented silicon steel, the temperature and oxygen content of the molten steel need to be measured multiple times to adjust subsequent operations. The scientific paper "The Influence of RH Refining Process on the Quality of Non-Oriented Electrical Steel" (Electrical Steel, Issue 2, 2021, P22) mentions that after the ladle containing qualified molten steel in the previous process is transported to the processing station by the ladle car, the first temperature and oxygen measurement and sampling are carried out to determine the incoming steel conditions. It also mentions that the final sampling, temperature measurement and oxygen measurement are carried out before the vacuum chamber is re-pressurized after the RH treatment is completed. The timing of temperature measurement and oxygen determination during the entire RH treatment cycle is not disclosed. Summary of the Invention

[0005] The present invention provides a method for intelligently determining the timing of temperature measurement and oxygen determination in the RH refining process of non-oriented silicon steel, aiming to improve the above-mentioned problem.

[0006] The present invention is achieved by providing a method for intelligently determining the timing of temperature and oxygen measurement during RH refining of non-oriented silicon steel, the method specifically comprising the following steps:

[0007] If the non-oriented silicon steel is a low-grade non-oriented silicon steel, then during the RH treatment of the molten steel, the temperature and oxygen measurement time of the molten steel shall be determined in sequence at the time of entering the station, during the decarburization process, before the end of decarburization, after oxygenation before the end of decarburization, after the end of deoxidation, and before RH breaking.

[0008] If the oriented silicon steel is medium or high grade non-oriented silicon steel, then during the RH treatment of the molten steel, the temperature and oxygen measurement times of the molten steel shall be determined in sequence: when the molten steel enters the station, during the decarburization process, before the end of decarburization, after oxygen supplementation before the end of decarburization, after the end of desulfurization, and before RH breaking;

[0009] After the temperature and oxygen measurement time is reached, a temperature and oxygen measurement prompt will be issued.

[0010] Furthermore, the timing of temperature and oxygen measurement during the decarburization process is as follows:

[0011] If, based on the results of temperature measurement and oxygen determination when the molten steel enters the station, no deoxidation carbon powder is added, no oxygen is blown, and no cold material is added, then temperature measurement and oxygen determination are performed after the set time I from the moment when RH starts vacuuming; if, based on the results of temperature measurement and oxygen determination when the molten steel enters the station, at least one of the operations of adding deoxidation carbon powder, blowing oxygen, and adding cold material is required, then temperature measurement and oxygen determination are performed after the following conditions are met:

[0012] Condition (1): Set duration II after the last operation is completed;

[0013] Condition (2): set time length I from the moment when RH starts to evacuate;

[0014] The set time I is the time required for the temperature drop of the ladle and the vacuum tank to stabilize and oxygen evolution to be sufficient, and the set time II is the time required for the chemical reaction and mixing of the added substances with the molten steel.

[0015] Furthermore, the timing of temperature and oxygen measurement before the end of decarburization is as follows:

[0016] If, based on the results of temperature and oxygen determination during the decarburization process, any of the following operations, such as adding deoxidized carbon powder, blowing oxygen, or adding cold material, is required, the temperature and oxygen determination should be performed after the following conditions are met:

[0017] Condition (1): Set duration II after the last operation is completed;

[0018] Condition (2): High vacuum cumulative time ≥ A minutes, where A is set based on the vacuum pump's exhaust capacity, the amount of molten steel, and the target carbon content at the end of RH treatment;

[0019] If, based on the results of temperature and oxygen determination during the decarburization process, there is no need to add deoxidized carbon powder, blow oxygen, or add cold material, then temperature and oxygen determination should be carried out after the high vacuum cumulative time is ≥A minutes.

[0020] Furthermore, the timing of temperature measurement and oxygen determination after oxygen supplementation before the end of decarburization is as follows:

[0021] Based on the results of temperature and oxygen measurement before the end of decarburization, it is judged whether oxygen supplementation is needed. If oxygen supplementation is needed, temperature and oxygen measurement will be performed after the set time II after the end of oxygen blowing.

[0022] Furthermore, if the non-oriented silicon steel is a low-grade non-oriented silicon steel, the method for detecting whether oxygen supplementation is required before the end of decarburization is as follows:

[0023] If the oxygen content obtained by temperature measurement and oxygen determination before the end of decarburization is less than the target oxygen content at the end of decarburization, oxygen supplementation is required before the end of decarburization;

[0024] Calculate whether oxygen blowing compensation temperature is required before decarburization is completed based on the temperature measurement and oxygen determination results before decarburization is completed. For low-grade non-oriented silicon steel: if the molten steel temperature at the time of temperature measurement and oxygen determination before decarburization is completed + the molten steel oxygen content at the time of temperature measurement and oxygen determination before decarburization is completed / 25 - the natural temperature drop of the molten steel from the time of temperature measurement and oxygen determination before decarburization to the time of RH breaking - the temperature drop of alloying alloy - the temperature drop of desulfurizer is less than the target temperature of RH breaking, then oxygen supplementation is required before decarburization is completed;

[0025] If the oriented silicon steel is medium or high grade non-oriented silicon steel, the method for detecting whether oxygen supplementation is required before the end of decarburization is as follows:

[0026] If the oxygen content obtained by temperature measurement and oxygen determination before the end of decarburization is less than the target oxygen content at the end of decarburization, oxygen supplementation is required before the end of decarburization;

[0027] Calculate whether it is necessary to blow oxygen to compensate the temperature before the end of decarburization based on the temperature measurement and oxygen determination results before the end of decarburization. If the molten steel temperature during the temperature measurement and oxygen determination before the end of decarburization + the molten steel oxygen content during the temperature measurement and oxygen determination before the end of decarburization / 25 is less than the RH deoxidation end target temperature, oxygen supplementation is required before the end of decarburization.

[0028] Furthermore, the timing of temperature measurement and oxygen determination after deoxygenation is as follows:

[0029] The temperature and oxygen are measured and determined for a set time III after the aluminum-containing material is added, wherein the set time III is the reaction and homogenization time of the aluminum-containing material.

[0030] Furthermore, the timing of temperature and oxygen measurement after desulfurization is as follows:

[0031] If desulfurization is performed by adding a desulfurizer, temperature and oxygen determination are performed at a set time IV after the addition of the desulfurizer; if desulfurization is performed without adding a desulfurizer, temperature and oxygen determination are performed at a set time VI after the first alloying alloy is added, where the set time VI is the time taken for analyzing the steel sample taken after the first alloying.

[0032] Furthermore, the timing of temperature and oxygen measurement before RH breaks through is as follows:

[0033] If the non-oriented silicon steel is a low-grade non-oriented silicon steel, if a desulfurizer is added for desulfurization, the temperature and oxygen are measured for a set time IV after the desulfurizer is added, wherein the set time IV is the reaction and homogenization time of adding the desulfurizer; if no desulfurizer is added for desulfurization, the temperature and oxygen are measured for a set time V after the alloyed alloy is added, wherein the set time V is the reaction and homogenization time of adding the alloy.

[0034] If the oriented silicon steel is medium or high grade non-oriented silicon steel, a second alloying and / or scrap cooling operation is performed, and temperature and oxygen are measured for a set time VII after the last operation is completed.

[0035] The present invention is achieved by providing an intelligent determination system for temperature measurement and oxygen determination during RH refining of non-oriented silicon steel, the system comprising:

[0036] A temperature and oxygen measuring instrument for measuring temperature and determining oxygen, wherein the output end is connected to the input end of the control unit, the output end of the control unit is connected to the input end of the prompt unit, and the prompt unit is arranged in the control room;

[0037] After the addition of carbon powder, oxygen, cold material and alloyed aluminum-containing material is completed, the control unit reads the relevant signals and calculates the temperature and oxygen measurement time of low-grade non-oriented silicon steel liquid at the time of entering the station, during decarburization, before the end of decarburization, after oxygen supplementation before the end of decarburization, after the end of deoxidation and before RH breaking based on the above-mentioned method for determining the timing of temperature and oxygen measurement for non-oriented silicon steel in the RH refining process, or calculates the temperature and oxygen measurement time of medium and high-grade non-oriented silicon steel liquid at the time of entering the station, during decarburization, before the end of decarburization, after oxygen supplementation before the end of decarburization, after the end of desulfurization and before RH breaking based on the above-mentioned method for determining the timing of temperature and oxygen measurement for non-oriented silicon steel in the RH refining process; after the smelting time reaches the temperature and oxygen measurement time, the control prompt unit issues a temperature and oxygen measurement prompt, and temperature and oxygen measurement are performed based on the temperature and oxygen measurement prompt, and the temperature and oxygen measurement instrument uploads the temperature and oxygen measurement results to the control unit.

[0038] Furthermore, the system further comprises:

[0039] a display unit, wherein an input end is connected to an output end of the control unit, and an input end of the control unit is connected to an output end of the input unit;

[0040] After the temperature measuring and oxygen determination instrument uploads the temperature measuring and oxygen determination results to the control unit, the control unit displays them through the display unit; if it is found that the current temperature measuring and oxygen determination results are abnormal, the temperature measuring and oxygen determination instructions are input through the input unit. After the input unit receives the input temperature measuring and oxygen determination instructions, the control unit controls the prompt unit again to issue a temperature measuring and oxygen determination prompt, so that the operator can perform the temperature measuring and oxygen determination operation again.

[0041] The intelligent method for determining the temperature and oxygen measurement time during smelting non-oriented silicon steel in an RH refining furnace provided by the present invention can quantitatively determine the timing of temperature and oxygen measurement during the RH smelting process of non-oriented silicon steel, improve the level of on-site standardized operations, and enhance the accuracy of molten steel temperature and composition control. By adopting the temperature and oxygen measurement method provided by the present invention, the RH air-break temperature compliance rate reaches 99.1%, and the internal control qualified rate of molten steel carbon content reaches 99.6%. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 A schematic diagram of temperature and oxygen measurement for low-grade non-oriented silicon steel provided in an embodiment of the present invention;

[0043] Figure 2 Schematic diagram of temperature and oxygen measurement for medium and high grade non-oriented silicon steel provided in an embodiment of the present invention;

[0044] Figure 3 A schematic structural diagram of a system for determining the timing of temperature and oxygen measurement during RH refining of non-oriented silicon steel provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The specific implementation methods of the present invention will be further explained in detail below by describing the embodiments with reference to the accompanying drawings, so as to help those skilled in the art to have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention.

[0046] When RH vacuum furnace smelts non-oriented silicon steel, it is divided into decarburization period, deoxidation period, alloying period, desulfurization period and molten steel net circulation period according to the time process; among them, the main purpose of the decarburization period is to decarburize and control the oxygen content and temperature of the molten steel before the end of decarburization. The control means are adding carbon powder, cooling cold materials, blowing oxygen and other operations. This period is the main time window for controlling the oxygen content and temperature of the molten steel before the end of decarburization; the deoxidation period is to add aluminum-containing materials to the molten steel to remove excess oxygen in the molten steel, and simultaneously release heat to compensate for the temperature; the main purpose of the alloying period is to adjust the chemical composition of the molten steel; the desulfurization period is mainly to add desulfurizer for desulfurization according to the incoming S content; the purpose of the molten steel net circulation period is to make the temperature and composition of the molten steel uniform and remove inclusions.

[0047] When RH is used to smelt different grades of non-oriented silicon steel, the temperature and composition control strategies are different. In terms of temperature control: in the smelting of low-grade silicon steel, due to the small amount of alloy addition, the temperature drop of the molten steel is stable after the alloy is added. Therefore, when controlling the temperature during the decarburization period, the goal is to hit the RH air-breaking target temperature; while in the medium and high-grade silicon steel, due to the large amount of alloy addition, the alloy causes the temperature drop of the molten steel to be unstable. Therefore, the deoxidation end target temperature is designed: according to the normal molten steel temperature drop rate, if the molten steel temperature reaches the deoxidation end target temperature at the end of deoxidation, the molten steel temperature is higher than the RH air-breaking target temperature at the end of RH treatment, that is, there is a certain amount of surplus; in terms of composition control: in the smelting of low-grade silicon steel, due to the low content of Si and AL elements, the alloy addition is small, and the alloy yield is relatively stable, so the target can be hit in one go. However, in the smelting of medium and high-grade silicon steel, due to the large amount of Si and AL alloy addition, the yield is unstable, and the weight of the molten steel increases after the alloy is added, it is difficult to accurately hit the target in one adjustment. Therefore, a two-step adjustment process is designed.

[0048] The following describes the method for determining the timing of temperature and oxygen measurement for low-grade non-oriented silicon steel and medium- and high-grade non-oriented silicon steel. Figure 1 This is a schematic diagram of temperature and oxygen measurement for low-grade non-oriented silicon steel provided in an embodiment of the present invention. The chemical composition of the low-grade non-oriented silicon steel is shown in Table 1, with the remainder being iron and impurities.

[0049] Table 1 Chemical composition of low grade non-oriented silicon steel

[0050] Element Name C％ Si% Mn% P％ S％ Als% RH outbound range % ≤0.0030 0.10～0.50 0.20-0.80 ≤0.090 ≤0.005 0.15-1.20

[0051] In order to control the carbon content of molten steel to meet the requirements, the target oxygen content at the end of decarburization is 200-600ppm. The method for determining the timing of temperature and oxygen determination for low-grade non-oriented silicon steel is as follows:

[0052] During the RH treatment of molten steel, the temperature and oxygen measurement times are determined in sequence when the molten steel enters the station, during decarburization, before the end of decarburization, after oxygenation before the end of decarburization, after the end of deoxidation, and before RH breaking. When the temperature and oxygen measurement times are reached, a temperature and oxygen measurement prompt is issued.

[0053] (11) Timing of temperature measurement and oxygen determination when entering the station: After the molten steel enters the RH treatment station, it starts to be lifted. When the lifting height of the ladle trolley meets the on-site temperature measurement height, the lifting of the ladle trolley is stopped and the temperature and oxygen are measured.

[0054] (12) Timing of temperature measurement and oxygen determination during decarburization: If, based on the results of temperature measurement and oxygen determination when the molten steel enters the station, no deoxidizing carbon powder is added, no oxygen is blown, and no cold material is added, then temperature measurement and oxygen determination are performed after the set time I from the moment when the RH starts to evacuate; if, based on the results of temperature measurement and oxygen determination when the molten steel enters the station, at least one of the operations of adding deoxidizing carbon powder, blowing oxygen, and adding cold material is required, then temperature measurement and oxygen determination are performed after the following conditions (1) and (2) are met. Conditions (1) and (2) are as follows:

[0055] Condition (1): Set duration II after the last operation is completed;

[0056] Condition (2): set time length I from the moment when RH starts to evacuate;

[0057] The set time I is the time required for the temperature drop of the ladle and the vacuum tank to stabilize and oxygen evolution to be sufficient, and the set time II is the time required for the chemical reaction and mixing of the added substances with the molten steel.

[0058] (13) Timing of temperature and oxygen measurement before the end of decarburization: If, based on the results of temperature and oxygen measurement during the decarburization process, any of the following operations, such as adding deoxidized carbon powder, blowing oxygen, or adding cold material, is required, the temperature and oxygen measurement should be performed after the following conditions are met:

[0059] Condition (1): Set duration II after the last operation is completed;

[0060] Condition (2): High vacuum cumulative time ≥ A minutes, where A is set based on the vacuum pump's exhaust capacity, the amount of molten steel, and the target carbon content at the end of RH treatment;

[0061] If, based on the results of temperature and oxygen determination during the decarburization process, there is no need to add deoxidized carbon powder, blow oxygen, or add cold material, then temperature and oxygen determination should be carried out after the high vacuum cumulative time is ≥A minutes.

[0062] (14) Timing of temperature measurement and oxygen determination after oxygen supplementation before the end of decarburization: Based on the results of temperature measurement and oxygen determination before the end of decarburization, it is determined whether oxygen supplementation is required. If oxygen supplementation is required, temperature measurement and oxygen determination are performed after the set time II after the end of oxygen blowing. The specific method for detecting whether oxygen supplementation is required before the end of decarburization is as follows:

[0063] (1) If the oxygen content obtained by temperature measurement and oxygen determination before the end of decarburization is less than the target oxygen content at the end of decarburization, oxygen supplementation is required before the end of decarburization;

[0064] (2) Calculate whether it is necessary to blow oxygen to compensate for the temperature before the end of decarburization based on the temperature measurement and oxygen determination results before the end of decarburization. For low-grade non-oriented silicon steel: if the molten steel temperature at the time of temperature measurement and oxygen determination before the end of decarburization + the oxygen content of the molten steel at the time of temperature measurement and oxygen determination before the end of decarburization / 25-the natural temperature drop of the molten steel from the time of temperature measurement and oxygen determination before the end of decarburization to the time of RH breaking-the temperature drop of the alloying alloy-the temperature drop of the desulfurizer is less than the target temperature of RH breaking, then oxygen supplementation is required before the end of decarburization, where 25 is the deoxidation temperature rise constant, that is, the oxygen content (ppm) required for each 1°C increase in the temperature of the molten steel.

[0065] (15) Timing of temperature measurement and oxygen determination after deoxidation: Temperature measurement and oxygen determination are performed at a set time III after the addition of the aluminum-containing material, wherein the set time III is the reaction and homogenization time of the aluminum-containing material.

[0066] (16) Timing of temperature measurement and oxygen determination before RH breaks through the air: If desulfurization agent is required, the desulfurizer is added after the alloying alloy is added. Therefore, if desulfurization agent is added for desulfurization, temperature measurement and oxygen determination are performed at the set time IV after the desulfurizer is added, wherein the set time IV is the reaction and homogenization time of adding the desulfurizer; if desulfurization agent is not added for desulfurization, temperature measurement and oxygen determination are performed at the set time V after the alloying alloy is added, wherein the set time V is the reaction and homogenization time of adding the alloy, wherein the set time IV and the set time V are slightly longer than the length of the net circulation period.

[0067] Figure 2 This is a schematic diagram of temperature and oxygen measurement for medium and high grade non-oriented silicon steel provided in an embodiment of the present invention. The chemical composition of the medium and high grade non-oriented silicon steel is shown in Table 2, and the rest is iron and impurities.

[0068] Table 2 Chemical composition of medium and high grade non-oriented silicon steel

[0069] Element Name C％ Si% Mn% P％ S％ Als% RH outbound range % ≤0.0030 1.25～4.0 0.20-0.80 ≤0.090 ≤0.005 0.15-1.20

[0070] In order to control the carbon content of molten steel to meet the requirements, the target oxygen content at the end of decarburization is 200-600ppm. The method for determining the timing of temperature measurement and oxygen determination for medium and high grade non-oriented silicon steel is as follows:

[0071] During the RH treatment of molten steel, the temperature and oxygen measurement times are determined in sequence: when the molten steel enters the station, during decarburization, before the end of decarburization, after oxygen replenishment before the end of decarburization, after the end of desulfurization, and before RH breaking; after the temperature and oxygen measurement time is reached, a temperature and oxygen measurement prompt is issued.

[0072] (21) Timing of temperature measurement and oxygen determination when entering the station: After the molten steel enters the RH treatment station, it starts to be lifted. When the lifting height of the ladle trolley meets the on-site temperature measurement height, the lifting of the ladle trolley is stopped and the temperature and oxygen are measured.

[0073] (22) Timing of temperature measurement and oxygen determination during decarburization: If no deoxidation carbon powder, oxygen blowing, or cold material is added based on the temperature measurement and oxygen determination results when the molten steel enters the station, the temperature measurement and oxygen determination shall be carried out after the set time I from the moment when the RH starts vacuuming;

[0074] If at least one of the following operations, namely, adding deoxidized carbon powder, blowing oxygen, or adding cold material, is required based on the results of temperature and oxygen measurement when the molten steel enters the station, the temperature and oxygen measurement shall be performed after the following conditions are met:

[0075] Condition (1): Set duration II after the last operation is completed;

[0076] Condition (2): set time length I from the moment when RH starts to evacuate;

[0077] The set time I is the time required for the temperature drop of the ladle and the vacuum tank to stabilize and oxygen evolution to be sufficient, and the set time II is the time required for the chemical reaction and mixing of the added substances with the molten steel.

[0078] (23) Timing of temperature and oxygen measurement before the end of decarburization: If, based on the results of temperature and oxygen measurement during the decarburization process, any of the following operations, such as adding deoxidized carbon powder, blowing oxygen, or adding cold material, is required, the temperature and oxygen measurement should be performed after the following conditions are met:

[0079] Condition (1): Set duration II after the last operation is completed;

[0080] Condition (2): High vacuum cumulative time ≥ A minutes, where A is set based on the vacuum pump's exhaust capacity, the amount of molten steel, and the target carbon content at the end of RH treatment;

[0081] If, based on the results of temperature and oxygen determination during the decarburization process, there is no need to add deoxidized carbon powder, blow oxygen, or add cold material, then temperature and oxygen determination should be carried out after the high vacuum cumulative time is ≥A minutes.

[0082] (24) Timing of temperature measurement and oxygen determination after oxygen supplementation before the end of decarburization: Based on the results of temperature measurement and oxygen determination before the end of decarburization, it is determined whether oxygen supplementation is required. If oxygen supplementation is required, temperature measurement and oxygen determination are performed after the set time II after the end of oxygen blowing. The specific method for detecting whether oxygen supplementation is required before the end of decarburization is as follows:

[0083] (1) If the oxygen content obtained by temperature measurement and oxygen determination before the end of decarburization is less than the target oxygen content at the end of decarburization, oxygen supplementation is required before the end of decarburization;

[0084] (2) Calculate whether it is necessary to blow oxygen to compensate for the temperature before the end of decarburization based on the temperature measurement and oxygen determination results before the end of decarburization. If the molten steel temperature at the time of temperature measurement and oxygen determination before the end of decarburization + the oxygen content of the molten steel at the time of temperature measurement and oxygen determination before the end of decarburization / 25 is less than the RH deoxidation target temperature, then oxygen supplementation is required before the end of decarburization, where 25 is the deoxidation temperature constant, that is, the oxygen content (ppm) required for each 1°C increase in the temperature of the molten steel. The RH deoxidation target temperature is related to the type of steel.

[0085] (25) Timing of temperature and oxygen measurement after desulfurization: If desulfurization is performed with a desulfurizer, temperature and oxygen measurement shall be performed at a set time IV after the addition of the desulfurizer; if desulfurization is performed without a desulfurizer, temperature and oxygen measurement shall be performed at a set time VI after the addition of the alloy for the first alloying, wherein the set time VI is the time taken for analysis of the steel sample taken after the first alloying.

[0086] (26) Timing of temperature and oxygen measurement before RH breaks through: Perform the second alloying and / or cooling operation of scrap steel, and perform temperature and oxygen measurement for a set time VII after the last operation is completed. The set time VII is slightly longer than the length of the net circulation period.

[0087] The net circulation period before breaking the air refers to the time required to promote the removal of inclusions in molten steel and ensure uniform composition and temperature. It is generally required that the time be ≥ 7 minutes after alloy, scrap steel and desulfurizer are added to the molten steel.

[0088] Figure 3 A schematic diagram of the structure of a system for determining the timing of temperature and oxygen measurement during RH refining of non-oriented silicon steel provided in an embodiment of the present invention. For ease of explanation, only the portion related to the embodiment of the present invention is shown. The system includes:

[0089] A temperature and oxygen measuring instrument for measuring temperature and determining oxygen, wherein the output end is connected to the input end of the control unit, the output end of the control unit is connected to the input end of the prompt unit, and the prompt unit is arranged in the control room;

[0090] After the addition of carbon powder, oxygen, cold material and alloyed aluminum-containing material is completed, the control unit reads the relevant signals and calculates the temperature and oxygen measurement time of low-grade non-oriented silicon steel liquid at the time of entering the station, during decarburization, before the end of decarburization, after oxygen supplementation before the end of decarburization, after the end of deoxidation and before RH breaking based on the above-mentioned method for determining the timing of temperature and oxygen measurement for non-oriented silicon steel in the RH refining process, or calculates the temperature and oxygen measurement time of medium and high-grade non-oriented silicon steel liquid at the time of entering the station, during decarburization, before the end of decarburization, after oxygen supplementation before the end of decarburization, after the end of desulfurization and before RH breaking based on the above-mentioned method for determining the timing of temperature and oxygen measurement for non-oriented silicon steel in the RH refining process; after the smelting time reaches the temperature and oxygen measurement time, the control prompt unit issues a temperature and oxygen measurement prompt, the operator or the temperature measurement and oxygen measurement robot performs temperature and oxygen measurement based on the temperature and oxygen measurement prompt, and the temperature and oxygen measurement instrument uploads the temperature and oxygen measurement results to the control unit.

[0091] In an embodiment of the present invention, the system further includes:

[0092] a display unit, wherein an input end is connected to an output end of the control unit, and an input end of the control unit is connected to an output end of the input unit;

[0093] After the temperature measuring and oxygen determination instrument uploads the temperature measuring and oxygen determination results to the control unit, the control unit displays them through the display unit; if the current temperature measuring and oxygen determination results are found to be abnormal, a temperature measuring and oxygen determination instruction can be input through the input unit. After the input unit receives the manually input temperature measuring and oxygen determination instruction, the control unit controls the prompt unit to issue a temperature measuring and oxygen determination prompt again, so that the operator can perform the temperature measuring and oxygen determination operation again.

[0094] The present invention will be further described below by taking the smelting of non-oriented silicon steel in a 300TRH refining furnace as an example.

[0095] Example 1: Low-grade non-oriented silicon steel, grade: A, the chemical composition of the non-oriented silicon steel is shown in the following table, and the rest is iron and impurities.

[0096]

[0097]

[0098] The target oxygen content for this steel grade at the end of decarburization is 350ppm, and the target air breaking temperature is 1585℃. The S content of the incoming molten steel in this furnace is 0.0022%, and no desulfurizer is required for desulfurization. The primary molten steel after converter smelting enters the RH furnace treatment position, and the carbon content of the molten steel at the RH station is 215ppm.

[0099] Temperature and oxygen measurement timing at the station: After the molten steel enters the RH treatment station, it begins to be lifted. When the ladle trolley's lifting height meets the on-site temperature measurement height conditions, the lifting of the ladle trolley is stopped and temperature and oxygen measurement are performed at the station. The measured molten steel temperature T1: 1638℃, [O]1: 655ppm. According to general metallurgical knowledge, 65kg of carbon powder and 900kg of cooling material need to be added during the decarburization process, and oxygen blowing is not required. After the RH is vacuumed, 65kg of carbon powder and 900kg of cooling material are added in sequence. The cooling material addition ends 5 minutes after the start of the treatment.

[0100] Timing of temperature measurement and oxygen determination during the decarburization process: Since the addition of carbon powder and cooling cold material was carried out according to the temperature measurement and oxygen determination results at the time of entering the station, and the last cooling cold material addition operation ended 5 minutes after the start of the treatment, the time of completion of this operation + 2 minutes. That is, the temperature measurement and oxygen determination during the decarburization process was carried out 7 minutes after the start of the treatment. The measured molten steel temperature T2: 1617℃, [O]2: 374ppm. According to general knowledge of metallurgy, it is known that 500kg of cooling cold material needs to be added. After the temperature measurement and oxygen determination during the decarburization process, 500kg of cooling cold material is added, and the addition of cooling cold material ends 9 minutes after the start of the treatment;

[0101] The timing of temperature and oxygen measurement before the end of decarburization needs to meet conditions 1 to 4. The specific conditions 1 to 4 are as follows:

[0102] Condition 1: According to the temperature and oxygen measurement results during the decarburization process, it is calculated that there is no need to add deoxidized carbon powder, so this condition is considered to be met;

[0103] Condition 2: According to the temperature and oxygen measurement results during the decarburization process, the time when 500 kg of cold material is added is calculated to be 9 minutes from the start of extraction. Therefore, condition 2 is met when the time from the start of extraction is 11 minutes;

[0104] Condition 3: According to the temperature measurement and oxygen determination results during the decarburization process, it is calculated that oxygen blowing is not required, so this condition is considered to be met;

[0105] Condition 4: For this steel grade, the carbon content meets the RH requirement if the cumulative high vacuum (vacuum degree ≤ 200 Pa) time is ≥ 9 minutes. During production, the cumulative high vacuum (vacuum degree ≤ 200 Pa) time reaches 9 minutes 14 minutes after the start of the pumping operation. Therefore, this condition is considered to be met 14 minutes after the start of the pumping operation.

[0106] In summary, 14 minutes from the start of extraction, the timing for temperature and oxygen measurement before the end of decarburization was met, and the temperature and oxygen measurement operation was performed. The measured molten steel temperature was T3: 1584°C, [O]3: 355ppm.

[0107] According to the results of temperature measurement and oxygen determination before the end of decarburization, since [O]3 measured by temperature measurement and oxygen determination before the end of decarburization is 355ppm> the target oxygen content at the end of decarburization (350ppm), no oxygen blowing operation (oxygen supplementation) is performed; since "the molten steel temperature measured during temperature measurement and oxygen determination before the end of decarburization + the molten steel oxygen content during temperature measurement and oxygen determination before the end of decarburization / 25-the natural temperature drop of the molten steel from the time of temperature measurement and oxygen determination before the end of decarburization to the time of RH breaking through air - the temperature drop of the alloying alloy - the temperature drop of the desulfurizer = 1584+355 / 25-15+1.5-0=1584.7°C, which is greater than the target RH breaking through air temperature (1580°C)", no oxygen blowing operation (oxygen supplementation) is required, and therefore there is no need to perform temperature measurement and oxygen determination after oxygen supplementation before the end of decarburization.

[0108] Temperature and oxygen measurement after deoxidation: The amount of aluminum-containing material to be added for deoxidation alloying is calculated based on the oxygen content obtained from temperature and oxygen measurement before decarburization and the target Als. 1677 g of aluminum-containing material is required. The addition of 1677 kg of aluminum-containing material is completed 19 minutes after the start of pumping. Four minutes after this addition, or 23 minutes after the start of pumping, temperature and oxygen measurement are performed after deoxidation. The measured molten steel temperature T4 is 1589°C, and [O]4 is 1.12 ppm. After the temperature is measured by temperature and oxygen measurement after deoxidation, ferrosilicon, ferromanganese, and ferrophosphorus alloy are added. This addition is completed 23 minutes after the start of pumping.

[0109] Temperature measurement and oxygen determination before RH breaks the air: Since no desulfurizer is needed for desulfurization, the temperature measurement and oxygen determination will be prompted 5 minutes after the addition of ferrosilicon, ferromanganese and ferrophosphorus alloy. The temperature measurement and oxygen determination time before RH breaks the air is 28 (23 + 5) minutes from the start of extraction.

[0110] Example 2: High-grade non-oriented silicon steel, grade: B. The chemical composition of the non-oriented silicon steel is shown in the following table, with the remainder being iron and impurities.

[0111] Element Name C％ Si% Mn% P％ S％ Als% RH outbound range % ≤0.0015 3.20-3.60 0.30-0.60 ≤0.020 ≤0.0015 0.70-0.90％

[0112] The target oxygen content for this steel grade at the end of decarburization is 400ppm, the target temperature for deoxidation is 1575°C, and the target temperature for air break is 1570°C. The incoming S content of this furnace's molten steel is 0.0024%, requiring the addition of 500kg of desulfurizer. The primary molten steel, smelted in the converter, enters the RH furnace for treatment. The carbon content of the molten steel at the incoming RH furnace is 198ppm.

[0113] Temperature and oxygen measurement timing when entering the station: After the molten steel enters the RH treatment station, it starts to be lifted. When the lifting height of the ladle trolley meets the on-site temperature measurement height condition, the lifting of the ladle trolley is stopped and the temperature and oxygen are measured. The measured molten steel temperature T1: 1583℃, [O]1: 532ppm. According to general metallurgical knowledge, it is known that 26Nm of oxygen blowing is required during the decarburization process. 3 , add 1200kg of cooling material, no need to add carbon powder. After RH vacuum, blow oxygen 26Nm 3 , add 1200kg of cooling material, and the time for adding cooling material is 6.5 minutes after the start of treatment;

[0114] Timing of temperature measurement and oxygen determination during the decarburization process: Since oxygen blowing and the addition of cooling material were performed based on the temperature measurement and oxygen determination results upon entry, and the final cooling material addition operation ended 6.5 minutes after the start of the process, the temperature measurement and oxygen determination during the decarburization process was performed 2 minutes after the completion time of this operation. That is, the temperature measurement and oxygen determination during the decarburization process was performed 8.5 minutes after the start of the process. The measured molten steel temperature T2: 1564°C, [O]2: 436ppm. According to general metallurgical knowledge, it is not necessary to add deoxidizing carbon powder, blow oxygen, or add cooling material.

[0115] The timing of temperature and oxygen measurement before the end of decarburization needs to meet the following conditions 1 to 4. The details of conditions 1 to 4 are as follows:

[0116] Condition 1: According to the temperature and oxygen measurement results during the decarburization process, it is calculated that there is no need to add deoxidized carbon powder, so this condition is considered to be met;

[0117] Condition 2: According to the temperature and oxygen measurement results during the decarburization process, it is calculated that no cold material is needed, so this condition is considered to be met;

[0118] Condition 3: According to the temperature measurement and oxygen determination results during the decarburization process, it is calculated that oxygen blowing is not required, so this condition is considered to be met;

[0119] Condition 4: For this steel grade, the carbon content meets the RH requirement if the cumulative high vacuum (vacuum degree ≤ 200 Pa) time is ≥ 12 minutes. During production, the cumulative high vacuum (vacuum degree ≤ 200 Pa) time reaches 12 minutes 16 minutes after the start of the pumping operation. Therefore, this condition is considered to be met 16 minutes after the start of the pumping operation.

[0120] Based on the above, 16 minutes from the start of extraction is the time to measure temperature and determine oxygen before the end of decarburization, which prompts temperature and oxygen measurement. The measurement time is 16.8 minutes from the start of extraction. The measured molten steel temperature T3: 1556℃, [O]3: 403ppm.

[0121] According to the results of temperature measurement and oxygen determination before the end of decarburization, since the third measured [O]3 is 403ppm> the target oxygen content at the end of decarburization (400ppm), no oxygen blowing operation (oxygen supplementation) is performed; since "the temperature of the molten steel at the time of temperature measurement and oxygen determination before the end of decarburization + the oxygen content of the molten steel at the time of temperature measurement and oxygen determination before the end of decarburization / 25=1556+403 / 25=1572℃, which is less than the target temperature at the end of RH deoxidation (1575℃)", oxygen blowing operation (oxygen supplementation) is required. Oxygen blowing 50Nm 3 The time between oxygen blowing and oxygen pumping is 18.4 minutes, so the temperature measurement and oxygen determination prompt is given at the time of oxygen blowing completion + 2 minutes, that is, 20.4 minutes after the start of treatment. This is the temperature measurement and oxygen determination prompt after oxygen supplementation before the end of decarburization. 3补测 :1554℃,[O] 3补测 :495ppm.

[0122] Timing of temperature and oxygen measurement after desulfurization: Based on the oxygen content obtained from temperature and oxygen measurement after oxygen addition before decarburization and the target Als, the amount of aluminum-containing material to be added for deoxidation alloying is calculated. 2650g of aluminum-containing material is required. After the aluminum-containing material is added, ferrosilicon and ferromanganese are added for alloying. After the alloy is added, 500kg of desulfurizer is added for desulfurization. The desulfurizer is added to the molten steel 35 minutes after the start of pumping. Therefore, the temperature and oxygen measurement after desulfurization is performed 3 minutes after the desulfurizer addition is completed, that is, 38 minutes after the start of treatment. The measured molten steel temperature T4 is 1578°C, and [O]4 is 1.05ppm.

[0123] Timing of temperature measurement and oxygen determination before RH breaking: After the temperature measurement and oxygen determination are completed after desulfurization, ferrosilicon, ferromanganese and aluminum-containing materials are added respectively to fine-tune the composition to the target value, and 500kg of cold material is added to adjust the temperature of the molten steel. The time when the cold material is added to the molten steel is 43 minutes after the start of pumping, so the temperature measurement and oxygen determination before RH breaking is prompted at the time of completion of the cold material addition operation + 2 minutes, that is, 45 minutes after the start of treatment.

[0124] The present invention has been described exemplarily. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. A method for intelligently determining the timing of temperature and oxygen measurement during RH refining of non-oriented silicon steel, characterized in that: The method specifically comprises the following steps: If the non-oriented silicon steel is a low-grade non-oriented silicon steel, then during the RH treatment of the molten steel, the temperature and oxygen measurement times of the molten steel shall be determined in sequence: when the molten steel enters the station, during the decarburization process, before the end of decarburization, after oxygenation before the end of decarburization, after the end of deoxidation, and before RH breaking; If the non-oriented silicon steel is a medium or high grade non-oriented silicon steel, then during the RH treatment of the molten steel, the temperature and oxygen measurement times of the molten steel shall be determined in sequence at the time of entering the station, during the decarburization process, before the end of decarburization, after oxygen supplementation before the end of decarburization, after the end of desulfurization, and before RH breaking; After the temperature and oxygen measurement time is reached, a temperature and oxygen measurement prompt will be issued; Among them, the timing of temperature and oxygen measurement during the decarbonization process is as follows: If, based on the results of temperature measurement and oxygen determination when the molten steel enters the station, no deoxidation carbon powder is added, no oxygen is blown, and no cold material is added, then temperature measurement and oxygen determination are performed after the set time I from the moment when RH starts vacuuming; if, based on the results of temperature measurement and oxygen determination when the molten steel enters the station, at least one of the operations of adding deoxidation carbon powder, blowing oxygen, and adding cold material is required, then temperature measurement and oxygen determination are performed after the following conditions are met: Condition (1): Set duration II after the last operation is completed; Condition (2): set time length I from the moment when RH starts to evacuate; Set time Ⅰ as the time required for the temperature drop of the ladle and vacuum tank to stabilize and oxygen evolution to be sufficient, and set time Ⅱ as the time required for the chemical reaction and mixing of the added substances with the molten steel; Among them, the timing of temperature and oxygen measurement before the end of decarburization is as follows: If, based on the results of temperature and oxygen determination during the decarburization process, any of the following operations, such as adding deoxidized carbon powder, blowing oxygen, or adding cold material, is required, the temperature and oxygen determination should be performed after the following conditions are met: Condition (1): Set duration II after the last operation is completed; Condition (2): High vacuum cumulative time ≥ A minutes, where A is set based on the vacuum pump's exhaust capacity, the amount of molten steel, and the target carbon content at the end of RH treatment; If, based on the results of temperature and oxygen determination during the decarburization process, it is not necessary to add deoxidized carbon powder, blow oxygen, or add cold material, then temperature and oxygen determination should be performed after the high vacuum cumulative time is ≥ A minutes; Among them, the timing of temperature measurement and oxygen determination after oxygen supplementation before the end of decarburization is as follows: Based on the results of temperature and oxygen measurement before the end of decarburization, it is judged whether oxygen supplementation is needed. If oxygen supplementation is needed, temperature and oxygen measurement will be performed after the set time II after the end of oxygen blowing.

2. The method for intelligently determining the timing of temperature measurement and oxygen determination during RH refining of non-oriented silicon steel according to claim 1, characterized in that: If the non-oriented silicon steel is low-grade non-oriented silicon steel, the method for detecting whether oxygen supplementation is required before the end of decarburization is as follows: If the oxygen content obtained by temperature measurement and oxygen determination before the end of decarburization is less than the target oxygen content at the end of decarburization, oxygen supplementation is required before the end of decarburization; Calculate whether oxygen blowing compensation temperature is required before decarburization is completed based on the temperature measurement and oxygen determination results before decarburization is completed. For low-grade non-oriented silicon steel: if the molten steel temperature at the time of temperature measurement and oxygen determination before decarburization is completed + the molten steel oxygen content at the time of temperature measurement and oxygen determination before decarburization is completed / 25 - the natural temperature drop of the molten steel from the time of temperature measurement and oxygen determination before decarburization to the time of RH breaking - the temperature drop of alloying alloy - the temperature drop of desulfurizer is less than the target temperature of RH breaking, then oxygen supplementation is required before decarburization is completed; If the non-oriented silicon steel is medium or high grade, the method for detecting whether oxygen supplementation is required before the end of decarburization is as follows: If the oxygen content obtained by temperature measurement and oxygen determination before the end of decarburization is less than the target oxygen content at the end of decarburization, oxygen supplementation is required before the end of decarburization; Calculate whether it is necessary to blow oxygen to compensate the temperature before the end of decarburization based on the temperature measurement and oxygen determination results before the end of decarburization. If the molten steel temperature at the time of temperature measurement and oxygen determination before the end of decarburization + the molten steel oxygen content at the time of temperature measurement and oxygen determination before the end of decarburization / 25 is less than the RH deoxidation end target temperature, oxygen supplementation is required before the end of decarburization. The unit of temperature is °C, and the unit of oxygen content obtained by temperature measurement and oxygen determination before the end of decarburization is ppm.

3. The method for intelligently determining the timing of temperature measurement and oxygen determination during RH refining of non-oriented silicon steel according to claim 2, characterized in that: The timing of temperature measurement and oxygen determination after deoxygenation is as follows: The temperature and oxygen are measured and determined for a set time III after the aluminum-containing material is added, wherein the set time III is the reaction and homogenization time of the aluminum-containing material.

4. The method for intelligently determining the timing of temperature measurement and oxygen determination during RH refining of non-oriented silicon steel according to claim 2, characterized in that: The timing of temperature and oxygen measurement after desulfurization is as follows: If desulfurization is performed by adding a desulfurizer, temperature and oxygen determination are performed at a set time IV after the addition of the desulfurizer; if desulfurization is performed without adding a desulfurizer, temperature and oxygen determination are performed at a set time VI after the first alloying alloy is added, where the set time VI is the time taken for analyzing the steel sample taken after the first alloying.

5. The method for intelligently determining the timing of temperature measurement and oxygen determination during RH refining of non-oriented silicon steel according to claim 3 or 4, characterized in that: The timing of temperature and oxygen measurement before RH breaks through is as follows: If the non-oriented silicon steel is a low-grade non-oriented silicon steel, if a desulfurizer is added for desulfurization, the temperature and oxygen are measured for a set time IV after the desulfurizer is added, wherein the set time IV is the reaction and homogenization time of the addition of the desulfurizer; if no desulfurizer is added for desulfurization, the temperature and oxygen are measured for a set time V after the alloying alloy is added, wherein the set time V is the reaction and homogenization time of the addition of the alloy; If the non-oriented silicon steel is a medium or high grade non-oriented silicon steel, a second alloying and / or scrap cooling operation is performed, and temperature and oxygen are measured for a set time VII after the last operation is completed. The set time VII is slightly longer than the length of the net circulation period.

6. An intelligent system for determining the timing of temperature and oxygen measurement during RH refining of non-oriented silicon steel, characterized in that: The system comprises: A temperature and oxygen measuring instrument for measuring temperature and determining oxygen, wherein the output end of the temperature and oxygen measuring instrument is connected to the input end of the control unit, the output end of the control unit is connected to the input end of the prompt unit, and the prompt unit is arranged in the control room; For low-grade non-oriented silicon steel liquid, after the addition of carbon powder, oxygen, cold material, and aluminum-containing material, the control unit reads relevant signals and calculates the temperature and oxygen measurement time of the low-grade non-oriented silicon steel liquid at the time of entering the station, during decarburization, before the end of decarburization, after oxygen supplementation before the end of decarburization, after the end of deoxidation, and before RH breaking based on the method for determining the timing of temperature measurement and oxygen measurement of non-oriented silicon steel in the RH refining process as described in claim 5. After the smelting time reaches the temperature and oxygen measurement time, the control prompt unit issues a temperature and oxygen measurement prompt, and temperature and oxygen measurement are performed based on the temperature and oxygen measurement prompt. The temperature and oxygen measurement instrument uploads the temperature and oxygen measurement results to the control unit; For medium and high grade non-oriented silicon steel liquid, after the carbon powder, oxygen and cold material are added, the control unit reads the relevant signals and calculates the temperature and oxygen determination time of the medium and high grade non-oriented silicon steel liquid when entering the station, during decarburization, before the end of decarburization, after oxygen replenishment before the end of decarburization, after the end of desulfurization, and before RH breaking based on the temperature and oxygen determination timing determination method for non-oriented silicon steel in the RH refining process as described in claim 5. After the smelting time reaches the temperature and oxygen determination time, the control prompt unit issues a temperature and oxygen determination prompt, and temperature and oxygen determination are performed based on the temperature and oxygen measurement prompt. The temperature and oxygen measurement instrument uploads the temperature and oxygen measurement results to the control unit.

7. The intelligent determination system for temperature and oxygen measurement timing during RH refining of non-oriented silicon steel according to claim 6, characterized in that: The system further comprises: a display unit, wherein an input end of the display unit is connected to an output end of the control unit, and an input end of the control unit is connected to an output end of the input unit; After the temperature measuring and oxygen determination instrument uploads the temperature measuring and oxygen determination results to the control unit, the control unit displays them through the display unit; if it is found that the current temperature measuring and oxygen determination results are abnormal, the temperature measuring and oxygen determination instructions are input through the input unit. After the input unit receives the input temperature measuring and oxygen determination instructions, the control unit controls the prompt unit again to issue a temperature measuring and oxygen determination prompt, so that the operator can perform the temperature measuring and oxygen determination operation again.

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