阅读说明：本技术 一种Ti微合金化钢Ti含量窄范围控制方法 (Narrow range control method for Ti content of Ti microalloyed steel ) 是由 胡楚江 于 2019-10-31 设计创作，主要内容包括：本发明公开了钢铁冶金领域的一种Ti微合金化钢Ti含量窄范围控制方法,包括以下具体步骤：S1：在电炉出钢时,进行钢包预脱氧及合金化,根据电炉终点碳含量控制钢包预脱氧时吨钢水铝锭加入量,保证到LF钢液中[Al]s≥0.030％、到LF钢液中溶解氧含量≤0.0005％、钢包顶渣中的SiO2含量≤10％、且二元碱度≥5、钢包顶渣中FeO+MnO≤1％；S2：在钢包顶渣中FeO+MnO≤1％条件下精炼时间≥20分钟,且精炼全程钢液中[Al]s≥0.020％；S3：精炼结束喂入硅钙线进行深脱氧钙处理,喂硅钙线结束后将氩气流量调整至10NL/min,然后再加入钛铁；S4：加入一定量钛铁后,在10NL/min的氩气流量条件下软吹≥10min；S5：检测成品钢液Ti含量,根据检测结果按与目标值±0.002％的范围完成Ti微合金化。(The invention discloses a narrow range control method of Ti content in Ti microalloyed steel in the field of ferrous metallurgy, which comprises the following steps: s1: during electric furnace tapping, ladle pre-deoxidation and alloying are carried out, the adding amount of molten steel aluminum ingots per ton during ladle pre-deoxidation is controlled according to the end point carbon content of the electric furnace, and the conditions that [ Al ] s in LF molten steel is more than or equal to 0.030%, dissolved oxygen content in the LF molten steel is less than or equal to 0.0005%, SiO2 content in ladle top slag is less than or equal to 10%, binary alkalinity is more than or equal to 5, and FeO + MnO in the ladle top slag is less than or equal to 1% are ensured; s2: the refining time is more than or equal to 20 minutes under the condition that FeO and MnO in the steel ladle top slag are less than or equal to 1 percent, and [ Al ] s in the molten steel in the whole refining process is more than or equal to 0.020 percent; s3: after refining, feeding a calcium silicate wire for deep calcium deoxidation treatment, adjusting the argon flow to 10NL/min after the calcium silicate wire is fed, and then adding ferrotitanium; s4: after a certain amount of ferrotitanium is added, soft blowing is carried out for more than or equal to 10min under the condition of argon flow of 10 NL/min; s5: and detecting the Ti content of the finished molten steel, and completing Ti microalloying according to the detection result and the target value within the range of +/-0.002%.)

1. A narrow range control method for Ti content of Ti microalloyed steel is characterized by comprising the following steps: the method comprises the following specific steps:

s1: during electric furnace tapping, ladle pre-deoxidation and alloying are carried out, the adding amount of molten steel aluminum ingots per ton during ladle pre-deoxidation is controlled according to the end point carbon content of the electric furnace, and the conditions that [ Al ] s in LF molten steel is more than or equal to 0.030%, dissolved oxygen content in the LF molten steel is less than or equal to 0.0005%, SiO2 content in ladle top slag is less than or equal to 10%, binary alkalinity is more than or equal to 5, and FeO + MnO in the ladle top slag is less than or equal to 1% are ensured;

s2: the refining time is more than or equal to 20 minutes under the condition that FeO and MnO in the steel ladle top slag are less than or equal to 1 percent, and [ Al ] s in the molten steel in the whole refining process is more than or equal to 0.020 percent;

s3: after refining, feeding a calcium silicate wire for deep calcium deoxidation treatment, adjusting the argon flow to 10NL/min after the calcium silicate wire is fed, and then adding ferrotitanium;

s4: after a certain amount of ferrotitanium is added, soft blowing is carried out for more than or equal to 10min under the condition of argon flow of 10 NL/min;

s5: and detecting the Ti content of the finished molten steel, and finishing Ti microalloying according to the detection result within the range of +/-0.002 percent of the difference from the target value.

2. The narrow control method for Ti content of Ti microalloyed steel according to claim 1, characterized in that: the ferrotitanium is selected from FeTi 30-A.

3. The narrow control method for Ti content of Ti microalloyed steel according to claim 2, characterized in that: the addition amount of the FeTi30-A is determined by calculating 90 percent according to the analyzed residual Ti content in the molten steel, the analyzed Ti content in the FeTi30-A and the analyzed Ti yield under the conditions.

4. The narrow control method for Ti content of Ti microalloyed steel according to claim 2, characterized in that: the addition amount of the FeTi30-A is calculated according to the following formula:

1000W·(Ti_m-Ti₀)/C_Ti/90％，

wherein W is the total amount of molten steel in the furnace, and the unit is ton, Ti_mThe target control value of Ti content in the finished molten steel is Ti₀The residual Ti content of the molten steel before Ti microalloying, C_TiThe actual Ti content in FeTi30-A used.

5. The narrow control method for Ti content of Ti microalloyed steel according to claim 1, characterized in that: and the detection result of the Ti content of the finished molten steel is the result of the spectral sample analysis of the tundish molten steel when the furnace molten steel is poured by half.

Technical Field

The invention relates to the technical field of ferrous metallurgy, in particular to a narrow range control method for Ti content of Ti microalloyed steel.

Background

Ti is an active metal element which is easy to oxidize, Ti is easy to oxidize and lose under the refining condition, and the recovery rate of Ti is unstable under the conditions of poor molten steel deoxidation effect and improper titanium microalloying occasion, so that the fluctuation range of the Ti content is large, and the stability of the steel performance is influenced.

FeTi is added when the deoxidation effect of molten steel is poor, or oxidation loss of Ti is caused when a molten pool is boiled seriously after the FeTi is added, meanwhile, TiO2 generated by Ti oxidation is a high-melting-point brittle inclusion, is not easy to float upwards and is discharged and is more in steel, and the cleanliness of the steel and the performance of steel are influenced.

The method improves and stabilizes the recovery rate of Ti during Ti microalloying, controls the content of Ti in steel within a narrow range, eliminates the influence of TiO2 inclusion in the Ti microalloyed steel on the performance of steel, and is the key point of common attention of various steel enterprises.

Based on the method, the invention designs a narrow-range control method of Ti content in Ti microalloyed steel so as to solve the problems.

Disclosure of Invention

The invention aims to provide a narrow-range control method for Ti content of Ti microalloyed steel, which aims to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following technical scheme: a narrow range control method for Ti content of Ti microalloyed steel comprises the following steps:

s1: during electric furnace tapping, ladle pre-deoxidation and alloying are carried out, the adding amount of molten steel aluminum ingots per ton during ladle pre-deoxidation is controlled according to the end point carbon content of the electric furnace, and the conditions that [ Al ] s in LF molten steel is more than or equal to 0.030%, dissolved oxygen content in the LF molten steel is less than or equal to 0.0005%, SiO2 content in ladle top slag is less than or equal to 10%, binary alkalinity is more than or equal to 5, and FeO + MnO in the ladle top slag is less than or equal to 1% are ensured;

s2: the refining time is more than or equal to 20 minutes under the condition that FeO and MnO in the steel ladle top slag are less than or equal to 1 percent, and [ Al ] s in the molten steel in the whole refining process is more than or equal to 0.020 percent;

s3: after refining, feeding a calcium silicate wire for deep calcium deoxidation treatment, adjusting the argon flow to 10NL/min after the calcium silicate wire is fed, and then adding FeTi;

s4: after a certain amount of ferrotitanium is added, soft blowing is carried out for more than or equal to 10min under the condition of argon flow of 10 NL/min;

s5: and detecting the Ti content of the finished molten steel, and finishing Ti microalloying according to the detection result within the range of +/-0.002 percent of the difference from the target value.

Preferably, the ferrotitanium is selected from FeTi 30-A.

Preferably, the addition amount of the FeTi30-A is determined according to the analyzed residual Ti content in the molten steel, the analyzed Ti content in the FeTi30-A and the analyzed Ti yield under the conditions according to 90 percent.

Preferably, the addition amount of the FeTi30-A is calculated according to the following formula:

1000W·(Ti_m-Ti₀)/C_Ti/90％，

wherein W is the total amount of molten steel in the furnace, and the unit is ton, Ti_mThe target control value of Ti content in the finished molten steel is Ti₀The residual Ti content of the molten steel before Ti microalloying, C_TiThe actual Ti content in FeTi30-A used.

Preferably, the detection of the Ti content of the finished molten steel is the result of the spectral sample analysis of the tundish molten steel when the furnace molten steel is poured by half.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the invention, when Ti microalloying is ensured, the content of [ O ] in molten steel is low and controlled within a narrow range, so that the recovery rate of Ti is high and stable when Ti microalloying is carried out, and narrow-range control of Ti is realized by strictly controlling the refining time to be more than or equal to 20min under the conditions that the content of Als in refined full-program controlled steel is more than or equal to 0.020%, the content of FeO + MnO in ladle top slag is less than or equal to 1%, and the content of FeO + MnO in ladle top slag is less than or equal to 1%.

2. When the refining is finished, Ti is microalloyed, the content of dissolved [ O ] in the molten steel is low, and the yield of Ti is high; the Ti microalloying time is controlled to be carried out in a soft blowing state after the calcium silicon wire feeding is finished, so that the gas suction of molten steel is less, and the oxidation loss of Ti is less; and keeping the temperature for more than 10min in a soft blowing state to ensure that the obtained Ti content with uniform and stable components is obtained.

3. According to the invention, the SiO2 in the ladle top slag is controlled within the range of less than or equal to 10%, and the alkalinity of the ladle top slag is controlled within the range of more than or equal to 5, so that the reaction loss of Ti and SiO2 in the ladle top slag is reduced.

4. The invention selects ferrotitanium with the mark of FeTi30-A to carry out Ti micro-alloying, thereby improving and stabilizing the yield of Ti.

5. The invention specifically selects ferrotitanium with the trade name of FeTi30-A and the addition amount thereof, and stably controls the Ti content in a narrow range.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.