Control method for RH deep decarburization process of non-oriented silicon steel

Abstract

The invention discloses a non-oriented silicon steel RH (Ruhrstahl Heraeus) deep decarburization process control method which comprises the following steps: smelting in a converter: desulfurizing molten iron, and smelting in a top-bottom combined blown converter; after smelting is finished, molten steel is fed into an RH vacuum refining device; rH refining: temperature control; gas ring flow control; vacuum degree control: keeping the vacuum degree in the RH refining device stable so as to promote the decarburization reaction; casting by a casting machine: after the RH refining is finished, casting the molten steel; in the continuous casting process, the recarburization amount in the pouring process is controlled by adopting a carbon-free covering agent and casting powder special for silicon steel, and the quality and performance of a casting blank are ensured. According to the control method for the RH deep decarburization process of the non-oriented silicon steel, the temperature, the gas flow and other parameters in the RH refining process are accurately controlled, the carbon content in the non-oriented silicon steel is deeply reduced, and the magnetic performance and the mechanical performance of a product are improved.

Description

Technical Field

[0001] The invention belongs to the field of sports equipment, and in particular relates to a method for controlling a non-oriented silicon steel RH deep decarburization process. Background Art

[0002] Non-oriented silicon steel is an important electrical steel material, widely used in power equipment such as motors and transformers. Its magnetic and mechanical properties directly affect the efficiency and reliability of the equipment. In the production process of non-oriented silicon steel, the control of carbon content is one of the keys. Traditional decarburization methods have problems such as insufficient decarburization depth and unstable temperature control, which affect the performance of non-oriented silicon steel. Summary of the invention

[0003] The purpose of the present invention is to provide a RH deep decarburization process control method for non-oriented silicon steel, which achieves a deep reduction in the carbon content in non-oriented silicon steel and improves the magnetic properties and mechanical properties of the product by accurately controlling parameters such as temperature and gas flow rate during the RH refining process.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] The present invention provides a non-oriented silicon steel RH deep decarburization process control method, comprising:

[0006] Converter smelting: After desulfurization, the molten iron enters the top and bottom double-blown converter for smelting; after smelting, the molten steel is sent to the RH vacuum refining device;

[0007] RH Refining:

[0008] Temperature control: During the RH refining process, the progress of the decarburization reaction and the temperature change trend in the furnace are used to determine whether the molten steel temperature meets the production requirements. When the molten steel temperature is too high, it will cause overheating and oxidation, which will affect subsequent pouring. At this time, the furnace temperature will be lowered by gradually adding cold materials. When the molten steel temperature is too low, the decarburization rate will decrease, affecting production efficiency. At this time, oxygen is blown into the furnace to react with the molten steel to release a large amount of heat, thereby increasing the furnace temperature.

[0009] Gas circulation flow control: During the RH refining process, the circulation speed and decarburization speed of molten steel are controlled by adjusting the flow of inert gases such as argon. When the decarburization speed needs to be accelerated, the gas flow is increased; when the decarburization speed needs to be stabilized, the gas flow is reduced.

[0010] Vacuum control: Maintain a stable vacuum in the RH refining unit to promote the decarburization reaction;

[0011] Casting machine pouring: After RH refining, the molten steel is poured; during the continuous casting process, the carbon addition amount of the pouring process is controlled by using carbon-free covering agent and silicon steel special protective slag to ensure the quality and performance of the ingot.

[0012] Furthermore, the cold material at least includes small scrap steel.

[0013] Furthermore, the vacuum degree is ensured to be within a set range by adjusting the suction speed of the vacuum pump.

[0014] Further, including:

[0015] Converter smelting: the desulfurized molten iron is added to the converter, and slag-forming materials such as active lime, light-burned dolomite, and iron balls are added during the converter smelting process. The blowing process adopts the top and bottom combined blowing mode. When the end point is controlled, the carbon is 360ppm, the oxygen is 873ppm, and the temperature is 1682℃. The sliding plate slag blocking process is adopted in the steel tapping process; then, the molten steel is sent to the RH vacuum refining device;

[0016] RH Refining:

[0017] Temperature control: During the RH refining process, the progress of the decarburization reaction and the temperature change trend in the furnace are used to determine whether the molten steel temperature meets the production requirements; the molten steel in-situ temperature is 1645°C, the oxygen content is 559ppm, and the carbon content is 300ppm. The molten steel temperature, oxygen content, and carbon content all meet the production requirements and do not require temperature rise and fall operations;

[0018] Gas circulation flow control: During the RH refining process, the circulation speed and decarburization speed of molten steel are controlled by adjusting the flow of inert gases such as argon. Since the carbon-oxygen reaction is too intense in the early stage, the circulation flow is controlled at 1000 l / min. After 5 minutes, the circulation flow is adjusted to 1500 l / min. After 12 minutes, the carbon-oxygen reaction is basically completed and the circulation flow is adjusted to 2000 l / min.

[0019] Vacuum control: Keep the vacuum in the RH refining unit stable to promote the decarburization reaction; in the early stage of decarburization, the concentrations of carbon and oxygen are high and the reaction speed is fast, so the vacuum should be appropriately reduced and controlled at 21mba, adjusted to 2.5mba after 5 minutes, and adjusted to below 1.0mba in the late stage of decarburization;

[0020] Casting machine pouring: After RH refining, the molten steel is poured; during the continuous casting process, the carbon increase in the pouring process is controlled by using carbon-free covering agent and silicon steel special protective slag. The carbon increase in the steel tundish of this furnace is 2ppm;

[0021] Through the above control, the final composition of non-oriented silicon steel is: C: 0.0015%, Si: 0.80%, Mn: 0.31%, P: 0.063%, S: 0.0022%, Als: 0.432%, N: 0.0015%, Ti: 0.0011%; iron loss: 3.73W / Kg; magnetic induction: 1.73T; yield strength: 235Mpa, which meets customer requirements.

[0022] Further, including:

[0023] Converter smelting: the desulfurized molten iron is added to the converter, and slag-forming materials such as active lime, light-burned dolomite, and iron balls are added during the converter smelting process. The blowing process adopts the top and bottom combined blowing mode. When the end point is controlled, the carbon is 410ppm, the oxygen is 737ppm, and the temperature is 1672℃. The sliding plate slag blocking process is adopted in the steel tapping process; then, the molten steel is sent to the RH vacuum refining device;

[0024] RH Refining:

[0025] Temperature control: During the RH refining process, the progress of the decarburization reaction and the temperature change trend in the furnace are used to determine whether the molten steel temperature meets the production requirements. The molten steel temperature is 1635°C, the oxygen is 456ppm, and the carbon is 313ppm. The molten steel temperature is low and the decarburization speed is slow. It is necessary to blow 80m 3 Oxygen, for heating operation;

[0026] Gas circulation flow control: During the RH refining process, the circulation speed and decarburization speed of the molten steel are controlled by adjusting the flow of inert gases such as argon. Due to the low temperature, oxygen blowing is required to increase the temperature to avoid excessive carbon-oxygen reaction in the early stage. The circulation flow is controlled at 1000l / min. After the oxygen blowing is completed, the circulation flow is 1500l / min. After the carbon-oxygen reaction is completed, the circulation flow is adjusted to 2000l / min.

[0027] Vacuum control: Keep the vacuum in the RH refining unit stable to promote the decarburization reaction; in the early stage of decarburization, the concentrations of carbon and oxygen are high and the reaction speed is fast, so the vacuum should be appropriately reduced and controlled at 20mba. After 5 minutes, adjust to 2.6mba, and adjust to below 1.0mba in the later stage of decarburization;

[0028] Casting machine pouring: After RH refining, the molten steel is poured; during the continuous casting process, the carbon increase in the pouring process is controlled by using carbon-free covering agent and silicon steel special protective slag. The carbon increase in the steel tundish of this furnace is 3ppm;

[0029] Through the above control, the final composition of non-oriented silicon steel is: C: 0.0020%, Si: 0.81%, Mn: 0.32%, P: 0.060%, S: 0.0030%, Als: 0.423%, N: 0.0012%, Ti: 0.0009%; iron loss: 3.82W / Kg; magnetic induction: 1.72T; yield strength: 232Mpa, which meets customer requirements.

[0030] Further, including:

[0031] Converter smelting: the desulfurized molten iron is added to the converter, and slag-forming materials such as active lime, light-burned dolomite, and iron balls are added during the converter smelting process. The blowing process adopts the top and bottom combined blowing mode. When the end point is controlled, the carbon is 370ppm, the oxygen is 835ppm, and the temperature is 1692℃. The sliding plate slag blocking process is adopted in the steelmaking process; then, the molten steel is sent to the RH vacuum refining device;

[0032] RH Refining:

[0033] Temperature control: During the RH refining process, the progress of the decarburization reaction and the temperature change trend in the furnace are used to determine whether the molten steel temperature meets the production requirements; the molten steel temperature is 1655°C, the oxygen is 657ppm, and the carbon is 290ppm. The molten steel temperature is high, so 2.0t of small scrap steel is added at the beginning of the treatment to cool it down;

[0034] Gas circulation flow control: During the RH refining process, the circulation speed and decarburization speed of molten steel are controlled by adjusting the flow of inert gases such as argon. Due to the high temperature, small scrap steel needs to be added for cooling. The initial circulation flow is controlled at 1500l / min. After the carbon-oxygen reaction is completed, the circulation flow is adjusted to 2000l / min.

[0035] Vacuum control: Keep the vacuum in the RH refining unit stable to promote the decarburization reaction; in the early stage of decarburization, the concentrations of carbon and oxygen are high and the reaction speed is fast, so the vacuum should be appropriately reduced and controlled at 15mba. After 5 minutes, adjust to 2.6mba, and adjust to below 1.0mba in the later stage of decarburization;

[0036] Casting machine pouring: After RH refining, the molten steel is poured; during the continuous casting process, the carbon increase in the pouring process is controlled by using carbon-free covering agent and silicon steel special protective slag. The carbon increase in the steel tundish of this furnace is 2ppm;

[0037] Through the above control, the final composition of non-oriented silicon steel is: C: 0.0018%, Si: 0.80%, Mn: 0.30%, P: 0.058%, S: 0.0025%, Als: 0.433%, N: 0.0014%, Ti: 0.0010%; iron loss: 3.78W / Kg; magnetic induction: 1.72T; yield strength: 243Mpa, which meets customer requirements.

[0038] Compared with the prior art, the beneficial technical effects of the present invention are:

[0039] The present invention achieves a deep reduction in carbon content in non-oriented silicon steel by precisely controlling parameters such as temperature and gas flow rate during the RH refining process, thereby improving the magnetic properties and mechanical properties of the product. DETAILED DESCRIPTION

[0040] The present invention is further described below by way of examples.

[0041] Embodiment 1

[0042] Converter smelting: Desulfurized molten iron is added to the converter, and slag-making materials such as active lime, light-burned dolomite, and iron balls are added during the converter smelting process. The blowing process adopts the top and bottom combined blowing mode. When the end point is controlled, the carbon is 360ppm, the oxygen is 873ppm, and the temperature is 1682℃. The sliding plate slag blocking process is used in the steel tapping process. After that, the molten steel is sent to the RH vacuum refining device.

[0043] RH Refining:

[0044] Temperature control: During the RH refining process, the progress of the decarburization reaction and the temperature change trend in the furnace are used to determine whether the molten steel temperature meets the production requirements. The molten steel temperature is 1645°C, the oxygen content is 559ppm, and the carbon content is 300ppm. The molten steel temperature, oxygen content, and carbon content all meet the production requirements and do not require temperature rise and fall operations.

[0045] Gas circulation flow control: During the RH refining process, the circulation speed and decarburization speed of molten steel are controlled by adjusting the flow of inert gases such as argon. Since the carbon-oxygen reaction is too intense in the early stage, the circulation flow is controlled at 1000l / min; after 5 minutes, the circulation flow is adjusted to 1500l / min, and after 12 minutes, the carbon-oxygen reaction is basically completed, and the circulation flow is adjusted to 2000l / min.

[0046] Vacuum control: Keep the vacuum in the RH refining unit stable to promote the decarburization reaction. In the early stage of decarburization, the concentrations of carbon and oxygen are high and the reaction speed is fast. The vacuum should be appropriately reduced and controlled at 21mba. After 5 minutes, adjust it to 2.5mba, and adjust it to below 1.0mba in the later stage of decarburization.

[0047] Casting machine pouring: After RH refining, the molten steel is poured. In the continuous casting process, the carbon increase in the pouring process is controlled by using carbon-free covering agent and silicon steel special protective slag. The carbon increase in the steel package of this furnace is 2ppm.

[0048] Through the above control, the final composition of non-oriented silicon steel is: C: 0.0015%, Si: 0.80%, Mn: 0.31%, P: 0.063%, S: 0.0022%, Als: 0.432%, N: 0.0015%, Ti: 0.0011%; iron loss: 3.73W / Kg; magnetic induction: 1.73T; yield strength: 235Mpa, which meets customer requirements.

[0049] Embodiment 2

[0050] Converter smelting: Desulfurized molten iron is added to the converter, and slag-making materials such as active lime, light-burned dolomite, and iron balls are added during the converter smelting process. The blowing process adopts the top and bottom combined blowing mode. When the end point is controlled, the carbon is 410ppm, the oxygen is 737ppm, and the temperature is 1672℃. The sliding plate slag blocking process is used in the steel tapping process. After that, the molten steel is sent to the RH vacuum refining device.

[0051] RH Refining:

[0052] Temperature control: During the RH refining process, the progress of the decarburization reaction and the temperature change trend in the furnace are used to determine whether the molten steel temperature meets the production requirements. The molten steel temperature is 1635°C, the oxygen is 456ppm, and the carbon is 313ppm. The molten steel temperature is low and the decarburization speed is slow. It is necessary to blow 80m 3 Oxygen, heating operation.

[0053] Gas circulation flow control: During the RH refining process, the circulation speed and decarburization speed of molten steel are controlled by adjusting the flow of inert gases such as argon. Due to the low temperature, oxygen blowing is required to increase the temperature to avoid excessive carbon-oxygen reaction in the early stage. The circulation flow is controlled at 1000l / min; after the oxygen blowing is completed, the circulation flow is 1500l / min, and after the carbon-oxygen reaction is completed, the circulation flow is adjusted to 2000l / min.

[0054] Vacuum control: Keep the vacuum in the RH refining unit stable to promote the decarburization reaction. In the early stage of decarburization, the concentrations of carbon and oxygen are high and the reaction speed is fast. The vacuum should be appropriately reduced and controlled at 20mba. After 5 minutes, adjust it to 2.6mba, and adjust it to below 1.0mba in the later stage of decarburization.

[0055] Casting machine pouring: After RH refining, the molten steel is poured. In the continuous casting process, the carbon increase in the pouring process is controlled by using carbon-free covering agent and silicon steel special protective slag. The carbon increase in the steel package of this furnace is 3ppm.

[0056] Through the above control, the final composition of non-oriented silicon steel is: C: 0.0020%, Si: 0.81%, Mn: 0.32%, P: 0.060%, S: 0.0030%, Als: 0.423%, N: 0.0012%, Ti: 0.0009%; iron loss: 3.82W / Kg; magnetic induction: 1.72T; yield strength: 232Mpa, which meets customer requirements.

[0057] Embodiment 3

[0058] Converter smelting: Desulfurized molten iron is added to the converter, and slag-making materials such as active lime, light-burned dolomite, and iron balls are added during the converter smelting process. The blowing process adopts the top and bottom combined blowing mode. When the end point is controlled, the carbon is 370ppm, the oxygen is 835ppm, and the temperature is 1692℃. The sliding plate slag blocking process is used in the steel tapping process. After that, the molten steel is sent to the RH vacuum refining device.

[0059] RH refining.

Claims

1. A non-oriented silicon steel RH deep decarburization process control method, characterized in that: include: Converter smelting: After desulfurization, the molten iron enters the top and bottom double-blown converter for smelting; after smelting, the molten steel is sent to the RH vacuum refining device; RH Refining: Temperature control: During the RH refining process, the progress of the decarburization reaction and the temperature change trend in the furnace are used to determine whether the molten steel temperature meets the production requirements. When the molten steel temperature is too high, it will cause overheating and oxidation, which will affect subsequent pouring. At this time, the furnace temperature will be lowered by gradually adding cold materials. When the molten steel temperature is too low, the decarburization rate will decrease, affecting production efficiency. At this time, oxygen is blown into the furnace to react with the molten steel to release a large amount of heat, thereby increasing the furnace temperature. Gas circulation flow control: During the RH refining process, the circulation speed and decarburization speed of molten steel are controlled by adjusting the flow of inert gases such as argon. When the decarburization speed needs to be accelerated, the gas flow is increased; when the decarburization speed needs to be stabilized, the gas flow is reduced. Vacuum control: Maintain a stable vacuum in the RH refining unit to promote the decarburization reaction; Casting machine pouring: After RH refining, the molten steel is poured; during the continuous casting process, the carbon addition amount of the pouring process is controlled by using carbon-free covering agent and silicon steel special protective slag to ensure the quality and performance of the ingot.

2. The method for controlling RH deep decarburization process of non-oriented silicon steel according to claim 1, characterized in that: The cold material at least includes small scrap steel.

3. The method for controlling RH deep decarburization process of non-oriented silicon steel according to claim 1, characterized in that: By adjusting the vacuum pump's exhaust speed, ensure that the vacuum degree is within the set range.

4. The method for controlling RH deep decarburization process of non-oriented silicon steel according to claim 1, characterized in that: include: Converter smelting: the desulfurized molten iron is added to the converter, and slag-forming materials such as active lime, light-burned dolomite, and iron balls are added during the converter smelting process. The blowing process adopts the top and bottom combined blowing mode. When the end point is controlled, the carbon is 360ppm, the oxygen is 873ppm, and the temperature is 1682℃. The sliding plate slag blocking process is adopted in the steel tapping process; then, the molten steel is sent to the RH vacuum refining device; RH Refining: Temperature control: During the RH refining process, the progress of the decarburization reaction and the temperature change trend in the furnace are used to determine whether the molten steel temperature meets the production requirements; the molten steel in-situ temperature is 1645°C, the oxygen content is 559ppm, and the carbon content is 300ppm. The molten steel temperature, oxygen content, and carbon content all meet the production requirements and do not require temperature rise and fall operations; Gas circulation flow control: During the RH refining process, the circulation speed and decarburization speed of molten steel are controlled by adjusting the flow of inert gases such as argon. Since the carbon-oxygen reaction is too intense in the early stage, the circulation flow is controlled at 1000 l / min. After 5 minutes, the circulation flow is adjusted to 1500 l / min. After 12 minutes, the carbon-oxygen reaction is basically completed and the circulation flow is adjusted to 2000 l / min. Vacuum control: Keep the vacuum in the RH refining unit stable to promote the decarburization reaction; in the early stage of decarburization, the concentrations of carbon and oxygen are high and the reaction speed is fast, so the vacuum should be appropriately reduced and controlled at 21mba, adjusted to 2.5mba after 5 minutes, and adjusted to below 1.0mba in the late stage of decarburization; Casting machine pouring: After RH refining, the molten steel is poured; during the continuous casting process, the carbon increase in the pouring process is controlled by using carbon-free covering agent and silicon steel special protective slag. The carbon increase in the steel tundish of this furnace is 2ppm; Through the above control, the endpoint composition of non-oriented silicon steel is: C: 0.0015%, Si: 0.80%, Mn: 0.31%, P: 0.063%, S: 0.0022%, Als: 0.432%, N: 0.0015%, Ti: 0.0011%; Iron loss: 3.73W / Kg; magnetic induction: 1.73T; yield strength: 235Mpa, meeting customer requirements.

5. The method for controlling RH deep decarburization process of non-oriented silicon steel according to claim 1, characterized in that: include: Converter smelting: the desulfurized molten iron is added to the converter, and slag-forming materials such as active lime, light-burned dolomite, and iron balls are added during the converter smelting process. The blowing process adopts the top and bottom combined blowing mode. When the end point is controlled, the carbon is 410ppm, the oxygen is 737ppm, and the temperature is 1672℃. The sliding plate slag blocking process is adopted in the steel tapping process; then, the molten steel is sent to the RH vacuum refining device; RH Refining: Temperature control: During the RH refining process, the progress of the decarburization reaction and the temperature change trend in the furnace are used to determine whether the molten steel temperature meets the production requirements. The molten steel temperature is 1635°C, the oxygen is 456ppm, and the carbon is 313ppm. The molten steel temperature is low and the decarburization speed is slow. It is necessary to blow 80m 3 Oxygen, for heating operation; Gas circulation flow control: During the RH refining process, the circulation speed and decarburization speed of the molten steel are controlled by adjusting the flow of inert gases such as argon. Due to the low temperature, oxygen blowing is required to increase the temperature to avoid excessive carbon-oxygen reaction in the early stage. The circulation flow is controlled at 1000l / min. After the oxygen blowing is completed, the circulation flow is 1500l / min. After the carbon-oxygen reaction is completed, the circulation flow is adjusted to 2000l / min. Vacuum control: Keep the vacuum in the RH refining unit stable to promote the decarburization reaction; in the early stage of decarburization, the concentrations of carbon and oxygen are high and the reaction speed is fast, so the vacuum should be appropriately reduced and controlled at 20mba. After 5 minutes, adjust to 2.6mba, and adjust to below 1.0mba in the later stage of decarburization; Casting machine pouring: After RH refining, the molten steel is poured; during the continuous casting process, the carbon increase in the pouring process is controlled by using carbon-free covering agent and silicon steel special protective slag. The carbon increase in the steel tundish of this furnace is 3ppm; Through the above control, the final composition of non-oriented silicon steel is: C: 0.0020%, Si: 0.81%, Mn: 0.32%, P: 0.060%, S: 0.0030%, Als: 0.423%, N: 0.0012%, Ti: 0.0009%; iron loss: 3.82W / Kg; magnetic induction: 1.72T; yield strength: 232Mpa, which meets customer requirements.

6. The method for controlling RH deep decarburization process of non-oriented silicon steel according to claim 1, characterized in that: include: Converter smelting: the desulfurized molten iron is added to the converter, and slag-forming materials such as active lime, light-burned dolomite, and iron balls are added during the converter smelting process. The blowing process adopts the top and bottom combined blowing mode. When the end point is controlled, the carbon is 370ppm, the oxygen is 835ppm, and the temperature is 1692℃. The sliding plate slag blocking process is adopted in the steelmaking process; then, the molten steel is sent to the RH vacuum refining device; RH Refining: Temperature control: During the RH refining process, the progress of the decarburization reaction and the temperature change trend in the furnace are used to determine whether the molten steel temperature meets the production requirements; the molten steel temperature is 1655°C, the oxygen is 657ppm, and the carbon is 290ppm. The molten steel temperature is high, so 2.0t of small scrap steel is added at the beginning of the treatment to cool it down; Gas circulation flow control: During the RH refining process, the circulation speed and decarburization speed of molten steel are controlled by adjusting the flow of inert gases such as argon. Due to the high temperature, small scrap steel needs to be added for cooling. The initial circulation flow is controlled at 1500l / min. After the carbon-oxygen reaction is completed, the circulation flow rate is adjusted to 2000 l / min; Vacuum control: Keep the vacuum in the RH refining unit stable to promote the decarburization reaction; in the early stage of decarburization, the concentrations of carbon and oxygen are high and the reaction speed is fast, so the vacuum should be appropriately reduced and controlled at 15mba. After 5 minutes, adjust to 2.6mba, and adjust to below 1.0mba in the later stage of decarburization; Casting machine pouring: After RH refining, the molten steel is poured; during the continuous casting process, the carbon increase in the pouring process is controlled by using carbon-free covering agent and silicon steel special protective slag. The carbon increase in the steel tundish of this furnace is 2ppm; Through the above control, the final composition of non-oriented silicon steel is: C: 0.0018%, Si: 0.80%, Mn: 0.30%, P: 0.058%, S: 0.0025%, Als: 0.433%, N: 0.0014%, Ti: 0.0010%; iron loss: 3.78W / Kg; magnetic induction: 1.72T; yield strength: 243Mpa, which meets customer requirements.