RH refining desulphurization process of non-oriented electrical steel

Abstract

The invention discloses an RH refining desulphurization process of non-oriented electrical steel, belonging to the technical field of steel making. The process comprises the following steps: setting the lift gas flowrate to 1200 NL / min after the entering of the RH, and enhancing the lift gas flowrate to 1600 NL / min 3 minutes later; blowing oxygen to perform the forced decarburization when the vacuum degree is reduced to 2.0 mba, and when the oxygen blowing is finished and the vacuum degree is lower than 2.0 mba, performing the natural decarburization for 20 minutes; adding the aluminum for deoxidation when the vacuum decarburization is finished; and performing the silicon alloying by using the low carbon ferrosilicon, and adding the desulfurizing agent into the vacuum chamber in two timesthrough the RH alloy bin. The circulation time of the test furnace batch is from 10 minutes to 15 minutes. The process provided by the invention has the advantages that the RH device needs no reconstruction, and the operation is simple. The average RH desulphurization degree is 36.7%, and the desulphurization effect is better. The contents of the FeO and the MnO of the ladle slag have significantinfluence on the desulphurization effect, and the enhancing of the alkalinity of the ladle slag can increase the RH desulphurization efficiency as well as reduce the corrosion of the RH device.

Description

technical field

[0001] The invention belongs to the technical field of steelmaking, and in particular relates to a RH refining desulfurization process for non-oriented electrical steel, which is the preferred process method for desulfurization of non-oriented electrical steel. Background technique

[0002] With the gradual improvement of users' requirements for steel quality, the smelting technology of high-grade ultra-low carbon and ultra-low sulfur steel such as non-oriented electrical steel is in urgent need of development. The traditional non-oriented electrical steel production process only relies on deep desulfurization of molten iron and reduction of converter sulfur return to control sulfur content. However, the production of non-oriented electrical steel with lower sulfur content only through the pretreatment of molten iron and the control of sulfur return in the converter will not only cause a huge smelting pressure in the converter, but also cannot meet the sulfur...

Examples

Embodiment 1

[0024] The process of the present invention is as follows: after the RH enters the station, the lifting gas flow rate is set to 1200NL / min, and the lifting gas flow rate is increased to 1600NL / min after 3 minutes. After the vacuum degree is reduced to 2.0mba, oxygen is blown to carry out forced decarburization. After the oxygen blowing is completed, the vacuum degree is controlled below 2.0mba, and natural decarburization is started, and the natural decarburization time is guaranteed to be 20 minutes. After vacuum decarburization, aluminum is added for deoxidation. Firstly, low-carbon ferrosilicon is used for silicon alloying, and then the desulfurizer is put into the vacuum chamber through the RH alloy silo, and the desulfurizer is added in two batches. The test furnace cycle time is 10min to 15min.

[0025] It is carried out on the RH refining furnace of the slab production line of an iron and steel enterprise, and the test steel is non-oriented electrical steel. The produ...

comparative example 1

[0027] It was carried out on the RH refining furnace of the slab production line of the same steel plant and steel company, and the test steel was non-oriented electrical steel. Hot metal pretreatment desulfurization → LD → slag blocking tapping → LF → RH decarburization → continuous casting production process. After the RH enters the station, set the lifting gas flow rate to 1200NL / min, and increase the lifting gas flow rate to 1600NL / min after 3 minutes. After the vacuum degree is reduced to 2.0mba, oxygen is blown to carry out forced decarburization. After the oxygen blowing is completed, the vacuum degree is controlled below 2.0mba, and natural decarburization is started, and the natural decarburization time is guaranteed to be 20 minutes. No desulfurization treatment is carried out, and the ladle top slag out of the ladle RH is not modified. The sulfur content of the finished product is above 65ppm, and the RH process has no desulfurization ability. RH insert tube life ...

comparative example 2

[0029] It was carried out on the RH refining furnace of the slab production line of the same steel plant and steel company, and the test steel was non-oriented electrical steel. Adopt hot metal pretreatment desulfurization → LD → slag retaining and tapping → LF → RH decarburization, desulfurization → continuous casting production process. After the RH enters the station, set the lifting gas flow rate to 1200NL / min, and increase the lifting gas flow rate to 1600NL / min after 3 minutes. After the vacuum decarburization is completed, aluminum is added for deoxidation, and FeO+MnO in the top slag is not controlled. The pre-melted traditional desulfurizer is used, and the addition method is the direct addition method of the alloy silo. The particle size of the desulfurizer is controlled at 3-5mm, and the addition amount is 3-5Kg / t. While using low-carbon ferrosilicon for silicon alloying, the desulfurizer is added at one time. After adding the desulfurizer, the vacuum cycle time t...

technical field

[0001] The invention belongs to the technical field of steelmaking, and in particular relates to a RH refining desulfurization process for non-oriented electrical steel, which is the preferred process method for desulfurization of non-oriented electrical steel. Background technique

[0002] With the gradual improvement of users' requirements for steel quality, the smelting technology of high-grade ultra-low carbon and ultra-low sulfur steel such as non-oriented electrical steel is in urgent need of development. The traditional non-oriented electrical steel production process only relies on deep desulfurization of molten iron and reduction of converter sulfur return to control sulfur content. However, the production of non-oriented electrical steel with lower sulfur content only through the pretreatment of molten iron and the control of sulfur return in the converter will not only cause a huge smelting pressure in the converter, but also cannot meet the sulfur...

Examples

Embodiment 1

[0024] The process of the present invention is as follows: after the RH enters the station, the lifting gas flow rate is set to 1200NL / min, and the lifting gas flow rate is increased to 1600NL / min after 3 minutes. After the vacuum degree is reduced to 2.0mba, oxygen is blown to carry out forced decarburization. After the oxygen blowing is completed, the vacuum degree is controlled below 2.0mba, and natural decarburization is started, and the natural decarburization time is guaranteed to be 20 minutes. After vacuum decarburization, aluminum is added for deoxidation. Firstly, low-carbon ferrosilicon is used for silicon alloying, and then the desulfurizer is put into the vacuum chamber through the RH alloy silo, and the desulfurizer is added in two batches. The test furnace cycle time is 10min to 15min.

[0025] It is carried out on the RH refining furnace of the slab production line of an iron and steel enterprise, and the test steel is non-oriented electrical steel. The produ...

comparative example 1

[0027] It was carried out on the RH refining furnace of the slab production line of the same steel plant and steel company, and the test steel was non-oriented electrical steel. Hot metal pretreatment desulfurization → LD → slag blocking tapping → LF → RH decarburization → continuous casting production process. After the RH enters the station, set the lifting gas flow rate to 1200NL / min, and increase the lifting gas flow rate to 1600NL / min after 3 minutes. After the vacuum degree is reduced to 2.0mba, oxygen is blown to carry out forced decarburization. After the oxygen blowing is completed, the vacuum degree is controlled below 2.0mba, and natural decarburization is started, and the natural decarburization time is guaranteed to be 20 minutes. No desulfurization treatment is carried out, and the ladle top slag out of the ladle RH is not modified. The sulfur content of the finished product is above 65ppm, and the RH process has no desulfurization ability. RH insert tube life ...

comparative example 2

[0029] It was carried out on the RH refining furnace of the slab production line of the same steel plant and steel company, and the test steel was non-oriented electrical steel. Adopt hot metal pretreatment desulfurization → LD → slag retaining and tapping → LF → RH decarburization, desulfurization → continuous casting production process. After the RH enters the station, set the lifting gas flow rate to 1200NL / min, and increase the lifting gas flow rate to 1600NL / min after 3 minutes. After the vacuum decarburization is completed, aluminum is added for deoxidation, and FeO+MnO in the top slag is not controlled. The pre-melted traditional desulfurizer is used, and the addition method is the direct addition method of the alloy silo. The particle size of the desulfurizer is controlled at 3-5mm, and the addition amount is 3-5Kg / t. While using low-carbon ferrosilicon for silicon alloying, the desulfurizer is added at one time. After adding the desulfurizer, the vacuum cycle time t...

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