阅读说明：本技术 低成本耐磨钢的制备方法 (Preparation method of low-cost wear-resistant steel ) 是由 曾建华 张敏 谢鑫 李平凡 于 2020-05-29 设计创作，主要内容包括：本发明涉及低成本耐磨钢的制备方法,属于钢铁冶金技术领域。本发明所要解决的技术问题是现有高钛含量的钢一般采用模注形式生产,生产成本高。本发明提供低成本耐磨钢的制备方法,按照转炉-LF-VD-方坯连铸工艺流程生产,转炉终点控制,转炉出钢、LF、VD分步对钢水进行脱氧合金化,LF加入耐磨钢精炼渣造渣并控制钢包渣成分,浇注过程采用保护渣,以质量分数计钢中钛含量0.1-0.8％。本发明可实现高Ti含量耐磨钢的顺利浇注,成材率得到了大幅提升,由模注的65％提高到95％以上。(The invention relates to a preparation method of low-cost wear-resistant steel, belonging to the technical field of ferrous metallurgy, and aiming at solving the technical problems that the existing high-titanium-content steel is generally produced in a mold injection mode and has high production cost.)

1. The preparation method of the low-cost wear-resistant steel is characterized by comprising the following steps of producing according to the converter-L F-VD-square billet continuous casting process flow, controlling the end point of the converter, tapping in the converter, deoxidizing and alloying molten steel in L F, VD steps, and adding TiO-containing L F₂The slag of the wear-resistant steel refining slag is formed and the components of the ladle slag are controlled, and the whole process of the pouring process adopts high TiO₂The content of the covering slag is 0.1 to 0.8 percent of the titanium content in the steel by mass fraction.

2. The method of producing a low cost wear resistant steel as claimed in claim 1, characterized in that: the components of the wear-resistant steel refining slag comprise (CaO + BaO): 40-60% of SiO₂：0.1-8％，Al₂O₃：20-35％，F^-：1-5％，TiO₂: 5-30% and unavoidable impurities; melting point 1260-.

3. The method of producing a low-cost wear-resistant steel according to claim 1 or 2, characterized in that: the components of the covering slag comprise TiO in percentage by mass₂：5％～20％，(CaO+BaO)：30％～50％，SiO₂：9％～13％，Al₂O₃：20％-28％，(NaF+B₂O₃)：10％-20％，Li₂O: 3% -8%, C: 5 to 10 percent and inevitable impurities; viscosity at 1300 ℃ of 0.1-0.3 Pa.S and melting point at 900-1100 ℃.

4. The composition according to any one of claims 1 to 3, which is low-cost and durableThe preparation method of the mill steel is characterized by comprising the following steps: refining final slag (CaO + BaO)/(SiO)₂+Al₂O₃) The ratio is controlled to be 1.3-2.6, and the melting point is 1220-1350 ℃.

5. The method for preparing the low-cost wear-resistant steel according to any one of claims 1 to 4, wherein L F slagging is specifically to add 1 to 5kg of wear-resistant steel refining slag per ton of steel at the beginning of L F refining, heat the steel for 5 to 15min, add 1 to 5kg of wear-resistant steel refining slag per ton of steel again, and continue to heat the molten steel until the target temperature is reached.

6. The method for preparing the low-cost wear-resistant steel according to any one of claims 1 to 5, wherein during the period from casting to stable drawing speed of the continuous casting, the liquid level of a crystallizer needs to be protected by argon gas, the flow rate is 5-30L/min, and the whole casting process adopts covering slag.

7. The method for producing low-cost wear-resistant steel according to any one of claims 1 to 6, characterized by: the [ S ] entering the converter is less than or equal to 0.008 percent; the tapping temperature of the converter is 1670-1690 ℃, and the end point carbon is more than or equal to 0.05 percent; argon is blown on line in the tapping process, the tapping time is more than or equal to 4 minutes, the slag thickness control target is less than or equal to 80mm, and the clearance height of the ladle is controlled according to 300-500 mm.

8. The preparation method of the low-cost wear-resistant steel according to any one of claims 1 to 7, characterized in that deoxidation alloying is specifically characterized in that manganese-containing alloy and aluminum-containing alloy are added when converter tapping is carried out at 1/4-2/3 to control the manganese and aluminum elements in the steel to be lower limit of finished product components, L F is used for adjusting the carbon, manganese and aluminum in the steel to be the finished product components, VD treatment is carried out for 10-20 minutes, then titanium-containing alloy is added, and treatment is carried out for 3-10 minutes to control the titanium in the steel to be the finished product components.

9. The preparation method of the low-cost wear-resistant steel according to the claims 1-8, wherein an air curtain retaining wall is adopted in the tundish, the argon flow rate of the air curtain retaining wall is 3-9L/min, the argon flow rate of a long water gap and each stopper position is 10-20L/min, and positive pressure is maintained.

10. The preparation method of the low-cost wear-resistant steel according to the claims 1 to 9, characterized in that the superheat degree of the molten steel in the tundish in the continuous casting process is controlled to be 25-50 ℃, the secondary cooling adopts a strong cooling system of solidification end point region strong cooling, and the cooling strength is properly improved at the same time, the specific water amount is 0.65kg/t steel-0.80 kg/t steel, wherein the cooling strength of 7-8 sections of the solidification end point region is 50-60L/(min-m) m²)。

Technical Field

The invention belongs to the technical field of ferrous metallurgy, and particularly relates to a preparation method of low-cost wear-resistant steel.

Background

Titanium is a good deoxidizing and degassing agent in steel and an effective element for fixing nitrogen and carbon. The application of titanium in steel is mainly in a micro-alloying mode, and the addition of a certain amount of titanium (0.01-0.03%) in the steel can realize the effects of refining the steel structure, improving the strength of the steel, improving the plasticity and impact toughness of the steel and the like. Along with the improvement of the titanium content in the steel, the toughness, the processing performance and the wear resistance of the product are greatly improved, particularly when the Ti content in the steel is more than or equal to 0.15%, a large amount of micron-sized (1-5 mu m) TiC (more than or equal to 80%) and a small amount of TiN can be obtained, the wear resistance of the product is more than 10 times of that of titanium microalloyed steel, and the service life of the product is obviously prolonged.

Titanium is a very active metal element at the steelmaking and casting temperatures, and is easy to be oxidized and also easy to react with air and nitrogen in molten steel, TiN is very easy to form in the molten steel under high titanium content, and the defects of nozzle nodulation and blockage, steel leakage and serious blank material caused by cold steel formed by a crystallizer and fish are often caused. Therefore, the prior steel with high titanium content is generally produced by adopting an injection molding mode, thereby limiting the application field of the product and being difficult to realize scale and low-cost production.

Disclosure of Invention

The invention solves the technical problem that the existing steel with high titanium content is generally produced in a mode of injection molding, and the production cost is high.

The technical scheme for solving the problems is to provide a smelting and continuous casting method of high-cleanliness wear-resistant steel, which comprises the steps of production according to the converter-L F-VD-square billet continuous casting process flow, converter end point control, converter tapping, L F, VD step-by-step deoxidation alloying of molten steel, L F adding of titanium dioxide (TiO) -containing alloy₂The abrasion-resistant steel refining slag is slagging and the components of the ladle slag are controlled, and the high TiO is adopted in the pouring process₂The content of the covering slag is 0.1 to 0.8 percent of the titanium content in the steel by mass fraction.

Wherein the refining slag comprises (CaO + BaO) 40-60%, and SiO₂0.1-8％，Al₂O₃20-35％，F^-1-5％，TiO₂5 to 30 percent. Here, (CaO + BaO) indicates that at least one of CaO and BaO is contained.

Wherein the component of the covering slag is TiO₂：5％-20％，(CaO+BaO)：30％-50％，SiO₂：9％-13％，Al₂O₃：20％-28％，(NaF+B₂O₃)：10％-25％，Li₂O: 3% -8%, C: 5% -10%; the viscosity of the mold flux is 0.1-0.3 Pa.S at 1300 ℃ and the melting point is 900-1100 ℃. Here, (CaO + BaO) represents a compound containing at least one of CaO and BaO, and (NaF + B)₂O₃) Shows that contains NaF and B₂O₃At least one of (1).

Wherein, the refining final slag (CaO + BaO)/(SiO)₂+Al₂O₃) The ratio is controlled to be 1.3-2.6, and the melting point is 1220-1350 ℃.

Wherein, 1-5kg of wear-resistant steel refining slag per ton of steel is added at the beginning of L F refining, 1-5kg of the refining slag per ton of steel is added again after heating for 5-15min, and the molten steel is continuously heated until the target temperature is reached.

Wherein, during the continuous casting from the casting to the stable pulling speed, the liquid level of the crystallizer needs to adopt argon protection, the flow is 5-30L/min, and the whole casting process adopts covering slag.

Wherein the [ S ] entering the converter is less than or equal to 0.008 percent; the tapping temperature of the converter is 1670-1690 ℃, and the end point carbon is more than or equal to 0.05 percent; argon is blown on line in the tapping process, the tapping time is more than or equal to 4 minutes, the slag thickness control target is less than or equal to 80mm, and the clearance height of the ladle is controlled according to 300-500 mm.

Wherein, manganese-containing alloy and aluminum-containing alloy are added when steel is tapped from a converter at 1/4-2/3 to control manganese and aluminum elements in the steel to be in the lower limit of the range of finished product components, L F carbon, manganese and aluminum in the steel are adjusted to be in the finished product components, VD treatment is carried out for 10-20 minutes, then titanium-containing alloy is added, treatment is carried out for 3-10 minutes, and titanium in the steel is controlled to be in the finished product components.

Wherein, the titanium-containing alloy is one or more of 40TiFe, 70TiFe, 80TiFe or pure titanium.

Wherein, the tundish adopts an air curtain retaining wall, the argon flow of the air curtain retaining wall is 3-9L/min, the argon flow of the long water gap and each stopper position is 10-20L/min, and the positive pressure is kept.

Wherein, the superheat degree of the molten steel of the tundish in the continuous casting process is controlled at 25-50 ℃, the secondary cooling adopts a secondary cooling system of strong cooling in a solidification end point region, the cooling strength is properly improved, the specific water amount is 0.65kg/t steel-0.80 kg/t steel, and the cooling strength of 7-8 sections of the solidification end point region is 50-60L/(min m & lt/m & gt)²)。

The invention has the beneficial effects that:

the invention can realize the smooth casting of the wear-resistant steel with high Ti content, the number of continuous casting furnaces is more than or equal to 4 in a continuous casting mode, and the yield is greatly improved from 65 percent of die casting to more than 95 percent.

Detailed Description

The invention provides a preparation method of low-cost wear-resistant steel, which comprises the steps of production according to the converter-L F-VD-square billet continuous casting process flow, converter end point control, converter tapping, L F, VD step-by-step molten steel deoxidation alloying, L F adding wear-resistant steel refining slag for slagging and controlling ladle slag components, wherein the casting process adopts covering slag, and the titanium content in the steel is 0.1-0.8 percent by mass fraction.

Wherein the refining slag comprises the following components (CaO + BaO): 40-60% of SiO₂：0.1-8％，Al₂O₃：20-35％，F^-：1-5％，TiO₂：5-30％。

Wherein the component of the covering slag is TiO₂：5％-20％，(CaO+BaO)：30％-50％，SiO₂：9％-13％，Al₂O₃：20％-28％，(NaF+B₂O₃)：10％-25％，Li₂O: 3% -8%, C: 5% -10%; the viscosity of the mold flux is 0.1-0.3 Pa.S at 1300 ℃ and the melting point is 900-1100 ℃.

Wherein, the refining final slag (CaO + BaO)/(SiO)₂+Al₂O₃) The ratio is controlled to be 1.3-2.6, and the melting point is 1220-1350 ℃.

Wherein, 1-5kg of wear-resistant steel refining slag per ton of steel is added at the beginning of L F refining, 1-5kg of the refining slag per ton of steel is added again after heating for 5-15min, and the molten steel is continuously heated until the target temperature is reached.

Wherein, during the continuous casting from the casting to the stable pulling speed, the liquid level of the crystallizer needs to adopt argon protection, the flow is 5-30L/min, and the whole casting process adopts covering slag.

Wherein the [ S ] entering the converter is less than or equal to 0.008 percent; the tapping temperature of the converter is 1670-1690 ℃, and the end point carbon is more than or equal to 0.05 percent; argon is blown on line in the tapping process, the tapping time is more than or equal to 4 minutes, the slag thickness control target is less than or equal to 80mm, and the clearance height of the ladle is controlled according to 300-500 mm.

Wherein, manganese-containing alloy and aluminum-containing alloy are added when steel is tapped from a converter at 1/4-2/3 to control manganese and aluminum elements in the steel to be in the lower limit of the range of finished product components, L F carbon, manganese and aluminum in the steel are adjusted to be in the finished product components, VD treatment is carried out for 10-20 minutes, then titanium-containing alloy is added, treatment is carried out for 3-10 minutes, and titanium in the steel is controlled to be in the finished product components.

Wherein, the titanium alloy is one or more of 40TiFe, 70TiFe, 80TiFe or pure titanium.

Wherein the manganese-containing alloy is ferromanganese and/or metal manganese; the aluminum-containing alloy is one or more of aluminum iron, aluminum balls and aluminum wires.

Wherein, the tundish adopts an air curtain retaining wall, the argon flow of the air curtain retaining wall is 3-9L/min, the argon flow of the long water gap and each stopper position is 10-20L/min, and the positive pressure is kept.

Wherein, the superheat degree of the molten steel of the tundish in the continuous casting process is controlled at 25-50 ℃, the secondary cooling adopts a secondary cooling system of strong cooling in a solidification end point region, the cooling strength is properly improved, the specific water amount is 0.65kg/t steel-0.80 kg/t steel, and the cooling strength of 7-8 sections of the solidification end point region is 50-60L/(min m & lt/m & gt)²)。

The preparation method of the low-cost wear-resistant steel is particularly suitable for the titanium content in the steel of 0.1-0.8%.

The invention is further illustrated and described by the following examples and comparative examples.