阅读说明：本技术 一种低碳低硅焊丝钢的精炼脱氧方法 (Refining deoxidation method of low-carbon low-silicon welding wire steel ) 是由 刘志龙 万翔 曾令宇 刘志明 任世岗 胡现锋 余衍丰 余大华 赵科 邓长付 韦乾 于 2019-01-25 设计创作，主要内容包括：本发明涉及一种低碳低硅焊丝钢精炼脱氧方法,具体步骤为：1)转炉出钢对钢水进行脱氧合金化；2)LF精炼炉根据氩站Als含量,加入高铝精炼渣进行渣面脱氧,加入硅铁粉脱氧。通过优化精炼脱氧方法,解决连铸水口堵塞,减少连铸坯皮下气泡问题。(The invention relates to a refining and deoxidizing method of low-carbon low-silicon welding wire steel, which comprises the following specific steps: 1) carrying out deoxidation alloying on the molten steel by converter tapping; 2) and adding high-aluminum refining slag into the LF refining furnace for slag surface deoxidation according to the content of Als in the argon station, and adding ferrosilicon powder for deoxidation. By optimizing the refining deoxidation method, the problems of blocking of a continuous casting nozzle and reduction of bubbles under the skin of a continuous casting billet are solved.)

1. A refining deoxidation method for low-carbon low-silicon welding wire steel is characterized by comprising the following specific steps:

1) carrying out deoxidation alloying on the molten steel by tapping from the converter, adding 2.2-2.8kg/t of low-carbon ferromanganese, 2.5-3kg/t of aluminum iron and 0.9-1.1kg/t of silicon manganese, and sampling in an argon station after deoxidation alloying;

2) adding high-aluminum refining slag into an LF refining furnace for slag surface deoxidation according to the content of Als in an argon station, and adding 1.6-2kg/t of high-aluminum refining slag when the sample Als in the argon station is less than or equal to 0.005%; adding 1-1.6kg/t of high-aluminum refining slag when the Als of the argon station sample is between 0.005-0.015 percent; when the Als of the argon station sample is between 0.015 and 0.025 percent, 0.4 to 1kg/t of high-aluminum refining slag is added; when the Als of the argon station sample is more than or equal to 0.025 percent, no high aluminum refining slag is added; after the LF refining furnace samples 1, adding ferrosilicon powder for deoxidation according to the silicon content in steel, and when the silicon content of the sample 1 is less than or equal to 0.01 percent, adding 0.4-0.5kg/t of ferrosilicon powder; adding 0.15-0.25kg/t ferrosilicon powder when the silicon content of the sample 1 is 0.01-0.02%; when the silicon content of the sample 1 is more than or equal to 0.02 percent, no ferrosilicon powder is added, the LF refining furnace is treated according to the silicon content of the sample 1, then the sample 2 is sampled in the LF refining furnace, a silicon-barium line is fed according to the silicon content in the sample 2 for deoxidation and silicon increase, then calcium treatment is carried out to improve the fluidity of molten steel, and a pure calcium line is fed for the calcium treatment at a speed of 1.2-1.5 m/t; controlling the content of Als, silicon and free oxygen at the molten steel outlet, controlling the content of Als at the molten steel outlet to be 0.001-0.008%, controlling the content of silicon to be 0.01-0.03%, and controlling the content of free oxygen at the molten steel outlet to be 5-25 ppm.

2. The method for refining and deoxidizing a low carbon, low silicon wire steel as set forth in claim 1, wherein: when the silicon content of the sample 1 in the step 2) is less than or equal to 0.01 percent, adding 0.4-0.5kg/t of ferrosilicon powder; adding 0.15-0.25kg/t ferrosilicon powder when the silicon content of the sample 1 is 0.01-0.02%; and when the sample silicon content is more than or equal to 0.02 percent, the ferrosilicon powder is not added.

3. The method for refining and deoxidizing a low carbon, low silicon wire steel as set forth in claim 1, wherein: when the silicon content of the sample 2 in the step 2) is less than or equal to 0.01 percent, feeding a silicon-barium line at 1.4-1.6 m/t; sample 2, when the silicon content is between 0.01 and 0.02 percent, feeding a silicon-barium line for 0.6 to 0.8 m/t; and no silicon-barium wire is fed when the silicon content is more than or equal to 0.02 percent.

Technical Field

The invention belongs to the technical field of refining methods, and relates to a refining and deoxidizing method of low-carbon low-silicon welding wire steel.

Background

The deoxidation of molten steel is the key of refining control in smelting low-carbon low-silicon wire welding steel, and if the deoxidation is poor in the refining process, a water blocking opening is easy to occur in the continuous casting steel casting process, and meanwhile serious subcutaneous bubbles can be caused to occur in a casting blank.

The first is an LF refining deoxidation method for producing low-carbon welding wire steel with patent application number CN201710197468.8, wherein molten steel is smelted by a converter and enters an LF furnace for refining; in the LF furnace, a mixture of ferrosilicon powder and carbon powder is used as a foaming deoxidizer, the materials are vibrated by a storage bin to realize the small-batch and multi-batch whole-process addition on the slag surface for diffusion deoxidation, and the slag foaming and reducing atmosphere in the whole refining process is kept. The deoxidation and slagging method by using the mixture has better service performance than the traditional slagging and deoxidation process. However, in this way, carbon powder is added to deoxidize in the refining process, which is easy to cause recarburization of molten steel.

The second method is a smelting method of low-carbon low-silicon wire-welding steel with patent application number CN201510145835.0, which adopts the technological process of molten iron pretreatment desulphurization, converter, LF refining, continuous casting of 150mm x 150mm small square billets, the carbon content is stably controlled to be less than or equal to 0.08%, the silicon content is stably controlled to be less than or equal to 0.027%, the total oxygen content is not more than 0.0040%, so that the problem of nozzle nodulation is successfully solved, and the surface and internal quality of the casting billets are greatly improved. The mode uses calcium carbide for deoxidation, which is easy to cause recarburization of molten steel.

Disclosure of Invention

In order to overcome the defects in the prior art, the invention provides a refining and deoxidizing method for low-carbon low-silicon welding wire steel, which solves the problems of continuous casting nozzle blockage and continuous casting billet subsurface bubble reduction by optimizing the refining and deoxidizing method.

The technical scheme adopted by the invention for solving the technical problems is as follows: a refining deoxidation method for low-carbon low-silicon welding wire steel comprises the following specific steps:

1) carrying out deoxidation alloying on the molten steel by tapping from the converter, adding 2.2-2.8kg/t of low-carbon ferromanganese, 2.5-3kg/t of aluminum iron and 0.9-1.1kg/t of silicon manganese, and sampling in an argon station after deoxidation alloying;

2) adding high-aluminum refining slag into an LF refining furnace for slag surface deoxidation according to the content of Als in an argon station, and adding 1.6-2kg/t of high-aluminum refining slag when the sample Als in the argon station is less than or equal to 0.005%; adding 1-1.6kg/t of high-aluminum refining slag when the Als of the argon station sample is between 0.005-0.015 percent; when the Als of the argon station sample is between 0.015 and 0.025 percent, 0.4 to 1kg/t of high-aluminum refining slag is added; when the Als of the argon station sample is more than or equal to 0.025 percent, no high aluminum refining slag is added; after the LF refining furnace samples 1, adding ferrosilicon powder for deoxidation according to the silicon content in steel, and when the silicon content of the sample 1 is less than or equal to 0.01 percent, adding 0.4-0.5kg/t of ferrosilicon powder; adding 0.15-0.25kg/t ferrosilicon powder when the silicon content of the sample 1 is 0.01-0.02%; and when the silicon content of the sample 1 is more than or equal to 0.02 percent, no ferrosilicon powder is added, the LF refining furnace is treated according to the silicon content of the sample 1, then the sample 2 is sampled in the LF refining furnace, a silicon-barium line is fed according to the silicon content in the sample 2 for deoxidation and silicon increase, then calcium treatment is carried out to improve the fluidity of molten steel, and a pure calcium line is fed for the calcium treatment at a speed of 1.2-1.5 m/t. Controlling the content of Als, silicon and free oxygen at the molten steel outlet, controlling the content of Als at the molten steel outlet to be 0.001-0.008%, controlling the content of silicon to be 0.01-0.03%, and controlling the content of free oxygen at the molten steel outlet to be 5-25 ppm.

When the silicon content of the sample 1 in the step 2) is less than or equal to 0.01 percent, adding 0.4-0.5kg/t of ferrosilicon powder; adding 0.15-0.25kg/t ferrosilicon powder when the silicon content of the sample 1 is 0.01-0.02%; and when the sample silicon content is more than or equal to 0.02 percent, the ferrosilicon powder is not added.

When the silicon content of the sample 2 in the step 2) is less than or equal to 0.01 percent, feeding a silicon-barium line at 1.4-1.6 m/t; sample 2, when the silicon content is between 0.01 and 0.02 percent, feeding a silicon-barium line for 0.6 to 0.8 m/t; and no silicon-barium wire is fed when the silicon content is more than or equal to 0.02 percent.

The invention has the positive effects that:

(1) by optimizing the refining deoxidation method, the problems of blocking of a continuous casting nozzle and reduction of subcutaneous bubbles of a continuous casting billet are solved.

(2) And (3) performing slag surface deoxidation by using high-aluminum refining slag before the refining sampling 1 to realize rapid deoxidation, and reducing the Als content in LF refining end steel without using an aluminum-containing deoxidizer subsequently.

(3) And ferrosilicon powder is adopted for deoxidation between the sampling 1 and the sampling 2 of the LF refining furnace, the Als content in steel is reduced, and the production of aluminum-containing deoxidation products is reduced.

(4) And 2, deoxidizing and increasing silicon by using a silicon-barium wire after sampling, deoxidizing by using barium, further reducing the oxygen content in steel, and simultaneously directly feeding the silicon-barium wire into molten steel to ensure the stability and controllability of the silicon content.

(5) The continuous casting nozzle blockage can be reduced by controlling the content of Als in steel and carrying out calcium treatment, and the continuous casting billet subcutaneous bubbles can be reduced by controlling the content of silicon in the steel and the content of free oxygen in a refining outlet.

Detailed Description

The present invention will be further described with reference to the following examples.

The H08A steel is produced, and the control requirements of the components of the finished product are as follows: c: 0.03-0.08%, Si is less than or equal to 0.03%, Mn: 0.40-0.65%, P: less than or equal to 0.025%, S: less than or equal to 0.025 percent. Through refining and deoxidation, the free oxygen content in steel is reduced, the problem of continuous casting nozzle blockage is solved, and casting blank subcutaneous bubbles are reduced.

[ example 1 ]

The method comprises the following specific steps: 2.5kg/t of low-carbon ferromanganese, 2.6kg/t of aluminum iron, 1kg/t of silicon and manganese and 0.004 percent of Als content in an argon station are added in the converter tapping process. According to the condition that the Als content of an argon station sample is 0.004 percent to 0.005 percent, 1.6 to 2kg/t of high-aluminum refining slag is added in the station during refining, and 1.7kg/t of high-aluminum refining slag is actually added. The actual silicon content of the subsequent refined sample 1 is 0.017 percent, the ferrosilicon powder is added at 0.15-0.25kg/t when the silicon content of the sample 1 is between 0.01-0.02 percent, and the ferrosilicon powder is actually added at 0.2 kg/t. The actual silicon content of the refined sample 2 is 0.011 percent, the silicon of the sample 2 is 0.01 to 0.02 percent, the silicon-barium wire is fed for 0.6 to 0.8m/t, and the silicon-barium wire is actually fed for 0.8 m/t. The calcium treatment is fed into a pure calcium line 1.2-1.5m/t, and the actual calcium treatment is fed into a pure calcium line 1.3 m/t. The content of Als in the molten steel discharged from the station is 0.003 percent, the content of silicon is 0.022 percent, the content of free oxygen is 19ppm, the component requirements of the discharged station are met, the liquid level curve in the continuous casting pouring process is stable, the phenomenon of water gap blockage does not exist, and the casting blank does not have obvious subcutaneous bubbles.

[ example 2 ]

The method comprises the following specific steps: 2.5kg/t of low-carbon ferromanganese, 2.7kg/t of aluminum iron, 1kg/t of silicon and manganese and 0.013% of Als content in an argon station are added in the converter tapping process. According to the condition that the content of Als is 0.013-0.015% in an argon station sample, 1-1.6kg/t of high-aluminum refining slag is added in the station after refining, and 1.2kg/t of high-aluminum refining slag is actually added. And when the actual silicon content of the sample 1 in the subsequent refining is 0.022 percent and the silicon content of the sample 1 is more than or equal to 0.02 percent, the ferrosilicon powder is not added. The actual silicon content of the refined sample 2 is 0.015 percent, the silicon-barium line is fed for 0.6-0.8m/t when the silicon content of the sample 2 is between 0.01-0.02 percent, and the silicon-barium line is actually fed for 0.6 m/t. The calcium treatment is fed into a pure calcium line 1.2-1.5m/t, and the actual calcium treatment is fed into a pure calcium line 1.3 m/t. The content of Als in the molten steel discharged from the station is 0.005%, the content of silicon is 0.022%, the content of free oxygen is 13ppm, the component requirements of the discharged station are met, the liquid level curve in the continuous casting pouring process is stable, the phenomenon of water gap blockage does not exist, and the casting blank does not have obvious subcutaneous bubbles.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent replacements, improvements, etc. within the principle of the present invention should be included in the protection scope of the present invention.