Casting powder special for high-aluminum steel and application of casting powder

Abstract

The invention relates to the technical field of steel smelting, in particular to casting powder special for high-aluminum steel and application of the casting powder, and the casting powder contains BaO, Li2O, B2O3, CaO, SiO2, Al2O3, MgO, R2O and C; wherein the mass fraction of the BaO is 0.4%; the mass fraction of the Li2O is 2.5%; the mass fraction of the B2O3 is 0.6%; the mass fraction of the CaO is 20%; the mass fraction of the SiO2 is 38%; the mass fraction of Al2O3 is 3%; the mass fraction of MgO is 2%; the mass fraction of the R2O is 10%; the R2O is Na2O and / or K2O. According to the casting powder, by optimizing the chemical components of the casting powder and adjusting the physical properties of the casting powder, the casting powder has the low alkalinity of 0.5-0.6, the high F <-> content of 7%-8% in mass fraction of F <->, the low melting temperature, the melting point of 900-950 DEG C and the high viscosity, the viscosity of the casting powder is 0.30-0.40 Pa.s at the temperature of 1300 DEG C, and the casting powder can be used for casting powder casting. Through improvement of the performance, a series of problems caused by high aluminum content in the production process of the high-aluminum steel are solved, so that the casting powder can better meet the continuous casting requirement of the high-aluminum steel, and powerful technical support is provided for large-scale and high-quality production of the high-aluminum steel.

Description

Technical Field

[0001] The invention relates to the technical field of steel smelting, and in particular to a protective slag special for high-aluminum steel and application thereof. Background Art

[0002] High-aluminum steel (such as the typical 38CrMoAl) has broad application prospects in high-end equipment manufacturing, aerospace and automobile manufacturing due to its excellent mechanical properties and corrosion resistance. However, the high content of aluminum (Al) in the production process of this type of steel brings unique challenges. Specifically, the extremely high aluminum content in molten steel not only aggravates the secondary oxidation tendency of molten steel and significantly deteriorates the cleanliness of molten steel, but also easily leads to nozzle blockage during continuous casting, thereby interrupting the casting process and seriously affecting production efficiency and product quality.

[0003] In addition, the chemical reaction between aluminum in steel and silicon dioxide (SiO) in continuous casting mold slag is a problem that cannot be ignored. This reaction will not only increase the silicon content of molten steel, change the chemical composition of molten steel, and thus affect the final performance of steel; it will also change the physical and chemical properties of the mold slag, such as melting point, viscosity, basicity, etc. These changes will directly interfere with the stability of the continuous casting process, increase the risk of steel leakage, and may have an adverse effect on the surface quality of the ingot, such as cracks, slag inclusions and other defects. The existing mold slag formula is difficult to effectively solve these problems. Therefore, it is particularly important to develop a special mold slag suitable for high-aluminum steel. Summary of the invention

[0004] The purpose of the present invention is to solve a series of problems caused by high aluminum content in the production process of high aluminum steel, thereby providing a protective slag dedicated to high aluminum steel and its application.

[0005] In order to achieve the above-mentioned object, in the first aspect, the present invention provides a protective slag specially used for high aluminum steel, wherein the protective slag contains BaO, Li2O, B2O3, CaO, SiO2, Al2O3, MgO, R2O and C;

[0006] in,

[0007] The mass fraction of BaO is 0.4%;

[0008] The mass fraction of Li2O is 2.5%;

[0009] The mass fraction of B2O3 is 0.6%;

[0010] The mass fraction of CaO is 20%;

[0011] The mass fraction of SiO2 is 38%;

[0012] The mass fraction of Al2O3 is 3%;

[0013] The mass fraction of MgO is 2%;

[0014] The mass fraction of R2O is 10%;

[0015] The R2O is Na2O and / or K2O.

[0016] Preferably, the binary basicity of the protective slag is 0.5-0.6, wherein the binary basicity R2=ω(CaO) / ω(SiO2).

[0017] Preferably, the melting temperature of the mold slag is 900-950°C.

[0018] Preferably, at a temperature of 1300° C., the viscosity of the protective slag is 0.30-0.40 Pa·s.

[0019] Preferably, the melting rate of the protective slag is 35s.

[0020] In a second aspect, the present invention provides a use of the protective slag described in the first aspect in the production of high aluminum steel.

[0021] According to the above technical scheme, based on thermodynamic analysis, in order to ensure that the performance of the continuous casting protection slag remains relatively stable after the steel slag reacts and absorbs Al2O3 inclusions, the continuous casting protection slag adopts high-alkalinity and high-vitrification continuous casting protection slag. The present invention adopts the slag matching principle of "multiple components, equivalent content of each component", and promotes the formation of low-alkalinity and high-vitrification slag from the high-alkalinity and high-vitrification protection slag melt through the multi-component mixing effect, the reverse glass effect and the conversion of amphoteric oxides into network formers. The structure of these low-alkalinity and high-vitrification slags is in the category of ring-shaped, group-shaped and island-shaped silicates, which can absorb a large amount of inclusions. Al2O3 and TiO2 inclusions enter the slag and play a "chain-making" role, participating in the formation of the slag network. The slag structure is transformed into chain-shaped, layered and framework-shaped silicates, and the glassiness is improved. Specifically, by optimizing the chemical composition of the protection slag and adjusting its physical properties, the protection slag of the present invention has a lower alkalinity, with an alkalinity of 0.5-0.6 and a higher F - Content, F - The mass fraction of aluminum is 7%-8%, the melting point is 900-950℃ and the viscosity is high. At 1300℃, the viscosity of the protective slag is 0.30-0.40Pa·s. The improvement of these properties solves a series of problems caused by high aluminum content in the production process of high aluminum steel, so that the protective slag can better adapt to the continuous casting needs of high aluminum steel, and provide strong technical support for the large-scale and high-quality production of high aluminum steel.

[0022] At the same time, the use of the protective slag of the present invention in the continuous casting process of high-aluminum steel can significantly reduce the secondary oxidation of molten steel, improve the cleanliness of molten steel, prevent nozzle blockage, and improve the surface quality of continuous casting ingots. At the same time, the melting speed of the protective slag is accelerated, the thermal resistance is reduced, and the efficiency and stability of the continuous casting process are further improved.

[0023] Other features and advantages of the present invention will be described in detail in the following detailed description. DETAILED DESCRIPTION

[0024] The following is a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0025] In a first aspect, the present invention provides a protective slag specially used for high aluminum steel, wherein the protective slag contains BaO, Li2O, B2O3, CaO, SiO2, Al2O3, MgO, R2O and C; wherein:

[0026] The mass fraction of BaO is 0.4%;

[0027] The mass fraction of Li2O is 2.5%;

[0028] The mass fraction of B2O3 is 0.6%;

[0029] The mass fraction of CaO is 20%;

[0030] In order to inhibit the aluminum-silicon reaction, a protective slag with low SiO content or a special reaction inhibition mechanism is designed to reduce or avoid the reaction between aluminum in the steel and SiO in the slag, and prevent silicon increase in molten steel. The mass fraction of SiO2 is 38%;

[0031] The mass fraction of Al2O3 is 3%;

[0032] The mass fraction of MgO is 2%;

[0033] The mass fraction of R2O is 10%;

[0034] The R2O is Na2O and / or K2O.

[0035] Based on thermodynamic analysis, in order to ensure that the performance of continuous casting protection slag remains relatively stable after the steel slag reacts and absorbs Al2O3 inclusions, the continuous casting protection slag adopts low-alkalinity high-vitrification continuous casting protection slag. The present invention adopts the slag matching principle of "multiple components, equivalent content of each component", and promotes the formation of low-alkalinity high-vitrification slag from high-alkalinity high-vitrification protection slag melt through multi-component mixing effect, reverse glass effect and conversion of amphoteric oxides into network formers. The structure of these low-alkalinity high-vitrification slags is in the category of ring-shaped, group-shaped and island-shaped silicates, which can absorb a large amount of inclusions. Al2O3 and TiO2 inclusions enter the slag and play a "chain-making" role, participating in the formation of the slag network. The slag structure is transformed into chain-shaped, layered and framework-shaped silicates, and the glass properties are improved. Specifically, by optimizing the chemical composition of the protection slag and adjusting its physical properties, the protection slag of the present invention has a lower alkalinity, with an alkalinity of 0.5-0.6 and a higher F - Content, F - The mass fraction of aluminum is 7%-8%, the melting point is 900-950℃ and the viscosity is high. At 1300℃, the viscosity of the protective slag is 0.30-0.40Pa·s. The improvement of these properties solves a series of problems caused by high aluminum content in the production process of high aluminum steel, so that the protective slag can better adapt to the continuous casting needs of high aluminum steel, and provide strong technical support for the large-scale and high-quality production of high aluminum steel.

[0036] In a preferred embodiment of the present invention, the binary basicity of the protective slag is 0.5-0.6, wherein the binary basicity R2=ω(CaO) / ω(SiO2).

[0037] In a preferred embodiment of the present invention, the melting temperature of the mold slag is 900-950°C.

[0038] In a preferred embodiment of the present invention, at a temperature of 1300° C., the viscosity of the mold slag is 0.30-0.40 Pa·s.

[0039] In a preferred embodiment of the present invention, the melting rate of the mold slag is 35s.

[0040] In a second aspect, the present invention provides a use of the protective slag described in the first aspect in the production of high aluminum steel.

[0041] By implementing the above technical solution, the protective slag of the present invention is applied to the continuous casting process of high-aluminum steel, which can significantly reduce the secondary oxidation of molten steel, improve the cleanliness of molten steel, prevent nozzle blockage, and improve the surface quality of continuous casting ingots. At the same time, the melting speed of the protective slag is accelerated, the thermal resistance is reduced, and the efficiency and stability of the continuous casting process are further improved.

[0042] In addition to the above-mentioned key technical points which must be implemented as required, the present invention requires that other production processes be implemented in a conventional manner.

[0043] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0044] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0045] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A protective slag specially used for high aluminum steel, characterized in that: The protective slag contains BaO, Li2O, B2O3, CaO, SiO2, Al2O3, MgO, R2O and C; wherein, The mass fraction of BaO is 0.4%; The mass fraction of Li2O is 2.5%; The mass fraction of B2O3 is 0.6%; The mass fraction of CaO is 20%; The mass fraction of SiO2 is 38%; The mass fraction of Al2O3 is 3%; The mass fraction of MgO is 2%; The mass fraction of R2O is 10%; The R2O is Na2O and / or K2O.

2. The protective slag according to claim 1, characterized in that: The binary basicity of the protective slag is 0.5-0.6, wherein the binary basicity R2=ω(CaO) / ω(SiO2).

3. The protective slag according to claim 1 or 2, characterized in that: The melting temperature of the protective slag is 900-950°C.

4. The mold slag according to any one of claims 1 to 3, characterized in that: Under the condition of a temperature of 1300° C., the viscosity of the protective slag is 0.30-0.40 Pa·s.

5. The mold slag according to any one of claims 1 to 4, characterized in that: The melting speed of the protective slag is 35s.

6. Use of the protective slag as described in any one of claims 1 to 5 in the production of high aluminum steel.