Refining slag for producing chromium-containing refined steel and production method of chromium-containing refined steel

Abstract

The invention relates to the technical field of metallurgy, in particular to refining slag for producing chromium-containing refined steel and a production method of the chromium-containing refined steel, and the refining slag comprises the following chemical components in percentage by mass: 35%-40% of calcium oxide, 17%-24% of silicon dioxide, 17%-23% of aluminum oxide, 5%-9% of magnesium oxide, 12%-20% of ferrous oxide and the balance of inevitable impurities. According to the method, by controlling the activity of ferrous oxide in the refining slag, impurity elements of aluminum and titanium are fully oxidized and enter the slag to be removed, and metal chromium enters the metal molten pool, so that it is guaranteed that the content of the aluminum element and the content of the titanium element in the chromium-containing refined steel are controlled to be 0.005% or below, and meanwhile the yield of the chromium element is 95% or above; and the refining slag meets the raw material requirements of smelting of chromium-containing high-alloy ultra-high-strength steel such as ferrium s53 and the like.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, and in particular to a refined slag used for producing chromium-containing fine steel and a production method of the chromium-containing fine steel. Background Art

[0002] As a leader in structural material strength, ultra-high strength steel not only has ultra-high strength, but also has certain plastic toughness, excellent fatigue strength, good corrosion resistance and welding performance. It is widely used in high-end mechanical equipment manufacturing industries such as aviation, aerospace, high-speed rail, wind power, and gas turbines. While pursuing ultra-high strength, ultra-high strength steel also pays special attention to the improvement of toughness, especially fracture toughness, which is of great significance to the research and application of ultra-high strength steel.

[0003] The fracture toughness of ultra-high strength steel is closely related to the cleanliness of the steel, and high-purity smelting technology is needed to control the cleanliness of the steel. my country mostly uses pure metal raw materials, and then melts ultra-high strength steel through a double vacuum process of vacuum induction melting and vacuum consumable remelting. However, during the vacuum induction melting alloying process, impurity elements will be introduced into the metal molten pool, resulting in excessive impurity elements in the finished steel, which is particularly reflected in the excessive content of impurity elements aluminum and titanium.

[0004] High alloy ultra-high strength steel ferrium s53 needs to meet the requirements of chromium content of 11.0% to 12.5%, and aluminum and titanium content of less than 0.01%. The aluminum content of chromium is greater than 2%, and the titanium content is greater than 1%. During the vacuum induction melting alloying process, the aluminum and titanium in the chromium are introduced into the molten steel. It is difficult to remove the aluminum and titanium in the later refining process, which eventually leads to excessive aluminum and titanium in the finished steel, which cannot meet the steel standard requirements.

[0005] In view of this, the present invention is proposed. Summary of the invention

[0006] The invention provides a refined slag for producing chromium-containing refined steel, which is used to solve the problem of how to reduce the contents of aluminum and titanium in the refined steel while ensuring that the content of metal chromium in the refined steel meets product requirements.

[0007] On the one hand, the present invention provides a refined slag for the production of chromium-containing fine steel, wherein the refined slag comprises the following chemical components in percentage by mass: calcium oxide: 35% to 40%, silicon dioxide: 17% to 24%, aluminum oxide: 17% to 23%, magnesium oxide: 5% to 9%, ferrous oxide: 12% to 20%, and the rest are unavoidable impurities.

[0008] In some of the embodiments, the mass percentage of ferrous oxide in the refined slag is 12% to 16%, and the binary basicity CaO / SiO2 of the refined slag is 1.5 to 1.8.

[0009] In some of the embodiments, the mass percentage of ferrous oxide in the refined slag is 16% to 20%, and the binary basicity CaO / SiO2 of the refined slag is 1.8 to 2.1.

[0010] In some embodiments, the mass percentage of calcium oxide in the refined slag is 35% to 38%.

[0011] In some embodiments, the mass percentage of silicon dioxide in the refined slag is 18% to 23%.

[0012] In some embodiments, the mass percentage of the aluminum oxide in the refined slag is 18% to 22%.

[0013] In some embodiments, the mass percentage of magnesium oxide in the refined slag is 6% to 8%.

[0014] In some embodiments, the mass percentage of ferrous oxide in the refined slag is 14% to 18%.

[0015] On the other hand, the present invention also provides a method for producing chromium-containing refined steel, comprising: smelting to obtain molten steel with a predetermined composition, then adding refined slag to the molten steel, and pouring the molten steel into a casting mold after refining to finally obtain the chromium-containing refined steel.

[0016] Wherein, the refined slag is any of the refined slags described above, and the ratio of the mass of the refined slag to the mass of the molten steel is 1:8 to 1:12.

[0017] In some of the embodiments, the ratio of the mass of the refined slag to the mass of the molten metal is 1:9 to 1:11.

[0018] After adopting the above technical scheme, the present invention has the following beneficial effects compared with the prior art.

[0019] 1. The refined slag used for the production of chromium-containing fine steel in the present invention controls the activity of ferrous oxide in the refined slag, so that the impurity elements aluminum and titanium are fully oxidized and enter the slag to be removed, and the metal chromium enters the metal molten pool, thereby ensuring that the content of aluminum and titanium in the chromium-containing fine steel is controlled below 0.005%, and the chromium recovery rate is above 95%, so that the refined slag meets the raw material requirements for the smelting of chromium-containing high-alloy ultra-high strength steel such as ferrium s53.

[0020] 2. The refined slag used for the production of chromium-containing fine steel in the present invention has physical properties such as melting point, viscosity and surface tension that can meet actual production requirements and can be used in the refining production process of low-aluminum and low-titanium chromium-containing fine steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is the yield of chromium element in Examples 1 to 4 and Comparative Examples 1 to 5 of the present invention;

[0022] Figure 2 It is the activity of ferrous oxide in the slag of Examples 1 to 4 and Comparative Examples 1 to 5 of the present invention. DETAILED DESCRIPTION

[0023] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0024] Example 1

[0025] The present embodiment provides a refined slag for the production of chromium-containing fine steel, wherein the refined slag comprises the following chemical components in percentage by mass: calcium oxide: 37.9%, silicon dioxide: 21.1%, aluminum oxide: 20%, magnesium oxide: 7%, ferrous oxide: 14%, and the rest are unavoidable impurities.

[0026] This embodiment provides a method for producing a chromium-containing fine steel material, comprising the following steps:

[0027] Step 1: according to the chemical composition ratio of chromium-containing fine steel, industrial pure iron, high-purity metallic chromium, aluminum particles, sponge titanium, and raw materials for refined slag, calcium oxide powder, silicon dioxide powder, aluminum oxide powder, magnesium oxide powder, and ferrous oxalate powder are prepared. Since ferrous oxide is unstable at low temperatures, ferrous oxalate powder needs to be used for preparation, and its decomposition reaction is: FeC2O4·2H2O→FeO+CO↑+CO2↑+2H2O, and the mass fraction of ferrous oxide in the refined slag used for the production of chromium-containing fine steel is converted into the required ferrous oxalate, and the ferrous oxalate is decomposed into ferrous oxide using the experimental temperature during the experiment;

[0028] Step 2: Place about 600g of industrial pure iron with a brightly turned surface in a high-purity magnesium oxide crucible (with an inner diameter of 60mm and an inner height of 75mm) protected by a graphite crucible, and then place it in the heating zone of a molybdenum disilicide resistance furnace;

[0029] Step 3: The temperature of the molybdenum disilicide resistance furnace was manually raised from room temperature to 600°C, and 5 L / min of high-purity argon gas was introduced for protection. Then, the resistance furnace was automatically heated from 600°C to 1600°C at a heating rate of 5°C / min, and kept at this temperature for 10 minutes;

[0030] Step 4: After the industrial pure iron is completely melted, about 82g of high-purity metal chromium is added for alloying, and the mixture is kept warm for 4 minutes to make it completely melted. Subsequently, 0.68g of aluminum particles wrapped with pure iron sheets and 0.68g of sponge titanium are added, and the mixture is kept warm for 4 minutes to make it completely melted, thereby obtaining molten steel of a predetermined composition;

[0031] Step 5: prepare refined slag according to calcium oxide: 37.9%, silicon dioxide: 21.1%, aluminum oxide: 20%, magnesium oxide: 7%, and ferrous oxide: 14%, and adjust the binary basicity CaO / SiO2 of the refined slag to 1.8, then add the refined slag to the molten steel through a slag adding pipe, the ratio of the mass of the refined slag to the mass of the molten steel is 1:10, after the refined slag is completely melted, keep warm for 15 minutes, and finally turn off the molybdenum disilicide resistance furnace, turn off the argon when the temperature drops to 600°C, and wait until the molybdenum disilicide resistance furnace is cooled to room temperature to obtain a chromium-containing refined steel sample.

[0032] Example 2

[0033] The present embodiment provides a refined slag for the production of chromium-containing fine steel. The difference between the present embodiment and Example 1 is that the refined slag includes the following chemical components in mass percentage: calcium oxide: 35.4%, silicon dioxide: 19.6%, aluminum oxide: 20%, magnesium oxide: 7%, ferrous oxide: 18%, and the rest are unavoidable impurities.

[0034] This embodiment provides a method for producing chromium-containing refined steel. The difference between this embodiment and embodiment 1 is that:

[0035] Step 5: prepare refined slag according to calcium oxide: 35.4%, silicon dioxide: 19.6%, aluminum oxide: 20%, magnesium oxide: 7%, and ferrous oxide: 18%, and adjust the binary basicity CaO / SiO2 of the refined slag to 1.8, and then add the refined slag to the molten steel through a slag adding pipe, the ratio of the mass of the refined slag to the mass of the molten steel is 1:10, after the refined slag is completely melted, keep warm for 15 minutes, and finally turn off the molybdenum disilicide resistance furnace, turn off the argon when the temperature drops to 600°C, and wait until the molybdenum disilicide resistance furnace is cooled to room temperature to obtain a chromium-containing refined steel sample.

[0036] Example 3

[0037] The present embodiment provides a refined slag for the production of chromium-containing fine steel. The difference between the present embodiment and embodiment 1 is that the refined slag includes the following chemical components in mass percentage: calcium oxide: 35.4%, silicon dioxide: 23.6%, aluminum oxide: 20%, magnesium oxide: 7%, ferrous oxide: 14%, and the rest are unavoidable impurities.

[0038] This embodiment provides a method for producing chromium-containing refined steel. The difference between this embodiment and embodiment 1 is that:

[0039] Step 5: prepare refined slag according to calcium oxide: 35.4%, silicon dioxide: 23.6%, aluminum oxide: 20%, magnesium oxide: 7%, and ferrous oxide: 14%, and adjust the binary basicity CaO / SiO2 of the refined slag to 1.5, and then add the refined slag to the molten steel through a slag adding pipe, the ratio of the mass of the refined slag to the mass of the molten steel is 1:10, after the refined slag is completely melted, keep warm for 15 minutes, and finally turn off the molybdenum disilicide resistance furnace, turn off the argon when the temperature drops to 600°C, and wait until the molybdenum disilicide resistance furnace is cooled to room temperature to obtain a chromium-containing refined steel sample.

[0040] Example 4

[0041] The present embodiment provides a refined slag for the production of chromium-containing fine steel. The difference between the present embodiment and embodiment 1 is that the refined slag includes the following chemical components in mass percentage: calcium oxide: 37.3%, silicon dioxide: 17.7%, aluminum oxide: 20%, magnesium oxide: 7%, ferrous oxide: 18%, and the rest are unavoidable impurities.

[0042] This embodiment provides a method for producing chromium-containing refined steel. The difference between this embodiment and embodiment 1 is that:

[0043] Step 5: prepare refined slag according to calcium oxide: 37.3%, silicon dioxide: 17.7%, aluminum oxide: 20%, magnesium oxide: 7%, and ferrous oxide: 18%, and adjust the binary basicity CaO / SiO2 of the refined slag to 2.1, and then add the refined slag to the molten steel through a slag adding pipe, the ratio of the mass of the refined slag to the mass of the molten steel is 1:10, after the refined slag is completely melted, keep warm for 15 minutes, and finally turn off the molybdenum disilicide resistance furnace, turn off the argon when the temperature drops to 600°C, and wait until the molybdenum disilicide resistance furnace is cooled to room temperature to obtain a chromium-containing refined steel sample.

[0044] Comparative Example 1

[0045] A refined slag for the production of chromium-containing fine steel. The difference between Comparative Example 1 and Example 1 is that the refined slag includes the following chemical components in percentage by mass: calcium oxide: 47%, silicon dioxide: 26%, aluminum oxide: 20%, magnesium oxide: 7%, and the rest are unavoidable impurities.

[0046] A method for producing chromium-containing refined steel, the difference between comparative example 1 and embodiment 1 is:

[0047] Step 5: prepare refined slag according to calcium oxide: 47%, silicon dioxide: 26%, aluminum oxide: 20%, and magnesium oxide: 7%, and adjust the binary basicity CaO / SiO2 of the refined slag to 1.8, and then add the refined slag to the molten steel through a slag adding pipe, the ratio of the mass of the refined slag to the mass of the molten steel is 1:10, after the refined slag is completely melted, keep warm for 15 minutes, and finally turn off the molybdenum disilicide resistance furnace, turn off the argon when the temperature drops to 600°C, and wait until the molybdenum disilicide resistance furnace is cooled to room temperature to obtain a chromium-containing refined steel sample.

[0048] Comparative Example 2

[0049] A refined slag for the production of chromium-containing fine steel. The difference between Comparative Example 2 and Example 1 is that the refined slag includes the following chemical components in mass percentage: calcium oxide: 40.5%, silicon dioxide: 22.5%, aluminum oxide: 20%, magnesium oxide: 7%, ferrous oxide: 10%, and the rest are unavoidable impurities.

[0050] A method for producing chromium-containing refined steel, the difference between comparative example 1 and embodiment 1 is:

[0051] Step 5: prepare refined slag according to calcium oxide: 40.5%, silicon dioxide: 22.5%, aluminum oxide: 20%, magnesium oxide: 7%, and ferrous oxide: 10%, and adjust the binary basicity CaO / SiO2 of the refined slag to 1.8, and then add the refined slag to the molten steel through a slag adding pipe, the ratio of the mass of the refined slag to the mass of the molten steel is 1:10, after the refined slag is completely melted, keep warm for 15 minutes, and finally turn off the molybdenum disilicide resistance furnace, turn off the argon when the temperature drops to 600°C, and wait until the molybdenum disilicide resistance furnace is cooled to room temperature to obtain a chromium-containing refined steel sample.

[0052] Comparative Example 3

[0053] A refined slag for the production of chromium-containing fine steel. The difference between Comparative Example 1 and Example 1 is that the refined slag includes the following chemical components in mass percentage: calcium oxide: 32.8%, silicon dioxide: 18.2%, aluminum oxide: 20%, magnesium oxide: 7%, ferrous oxide: 22%, and the rest are unavoidable impurities.

[0054] A method for producing chromium-containing refined steel, the difference between comparative example 1 and embodiment 1 is:

[0055] Step 5: prepare refined slag according to calcium oxide: 32.8%, silicon dioxide: 18.2%, aluminum oxide: 20%, magnesium oxide: 7%, and ferrous oxide: 22%, and adjust the binary basicity CaO / SiO2 of the refined slag to 1.8, then add the refined slag to the molten steel through a slag adding pipe, the ratio of the mass of the refined slag to the mass of the molten steel is 1:10, after the refined slag is completely melted, keep warm for 15 minutes, and finally turn off the molybdenum disilicide resistance furnace, turn off the argon when the temperature drops to 600°C, and wait until the molybdenum disilicide resistance furnace is cooled to room temperature to obtain a chromium-containing refined steel sample.

[0056] Comparative Example 4

[0057] A refined slag for the production of chromium-containing fine steel. The difference between Comparative Example 1 and Example 1 is that the refined slag includes the following chemical components in mass percentage: calcium oxide: 37.9%, silicon dioxide: 21.1%, aluminum oxide: 20%, magnesium oxide: 7%, ferrous oxide: 14%, and the rest are unavoidable impurities.

[0058] A method for producing chromium-containing refined steel, the difference between comparative example 4 and example 1 is:

[0059] Step 5: prepare refined slag according to calcium oxide: 37.9%, silicon dioxide: 21.1%, aluminum oxide: 20%, magnesium oxide: 7%, and ferrous oxide: 14%, and adjust the binary basicity CaO / SiO2 of the refined slag to 1.8, then add the refined slag to the molten steel through a slag adding pipe, the ratio of the mass of the refined slag to the mass of the molten steel is 1:7.5, after the refined slag is completely melted, keep warm for 15 minutes, and finally turn off the molybdenum disilicide resistance furnace, turn off the argon when the temperature drops to 600°C, and wait until the molybdenum disilicide resistance furnace is cooled to room temperature to obtain a chromium-containing refined steel sample.

[0060] Comparative Example 5

[0061] A refined slag for the production of chromium-containing fine steel. The difference between Comparative Example 5 and Example 1 is that the refined slag includes the following chemical components in mass percentage: calcium oxide: 35.4%, silicon dioxide: 19.6%, aluminum oxide: 20%, magnesium oxide: 7%, ferrous oxide: 18%, and the rest are unavoidable impurities.

[0062] A method for producing chromium-containing refined steel, the difference between comparative example 5 and example 1 is:

[0063] Step 5: prepare refined slag according to calcium oxide: 35.4%, silicon dioxide: 19.6%, aluminum oxide: 20%, magnesium oxide: 7%, and ferrous oxide: 18%, and adjust the binary basicity CaO / SiO2 of the refined slag to 1.8, and then add the refined slag to the molten steel through a slag adding pipe, the ratio of the mass of the refined slag to the mass of the molten steel is 1:7.5. After the refined slag is completely melted, keep it warm for 15 minutes, and finally turn off the molybdenum disilicide resistance furnace. When the temperature drops to 600°C, turn off the argon gas until the molybdenum disilicide resistance furnace is cooled to room temperature to obtain a chromium-containing refined steel sample.

[0064] Indicator testing

[0065] The refined slag was prepared according to the chemical composition ratio of the refined slag shown in Table 1.

[0066] The mass fractions of aluminum, titanium and chromium elements in the chromium-containing fine steel samples in Examples 1 to 4 and Comparative Examples 1 to 5 were detected, and the results are shown in Table 2.

[0067] According to the mass fraction of chromium in the chromium-containing refined steel samples in Examples 1 to 4 and Comparative Examples 1 to 5, the yield of chromium is calculated using formula (1), as follows: Figure 1 shown.

[0068]

[0069] In the molten steel in step 4, the mass fraction of aluminum is about 0.1%, the mass fraction of titanium is about 0.1%, and the mass fraction of chromium is about 12%.

[0070] The activity of ferrous oxide in the refined slag in Examples 1 to 4 and Comparative Examples 1 to 5 was calculated using Factsage thermodynamic software. The results are as follows: Figure 2 shown.

[0071] Table 1 Refined slag composition (mass fraction / %)

[0072]

[0073] Table 2 Contents of aluminum, titanium and chromium in chromium-containing refined steel (mass fraction / %)

[0074]

[0075] The characteristics of the EAF+LF+MC (electric arc furnace+ladle refining furnace+die casting) process are as follows: during EAF smelting, the focus is on removing easily oxidized elements such as aluminum, phosphorus, titanium, arsenic, antimony, bismuth, etc. in ordinary industrial pure iron; in the early stage of LF refining, oxidizing refining slag is produced and metallic chromium is added. At this time, the aluminum and titanium contents in the molten steel are about 0.1%. Then, by utilizing the different affinities of chromium, aluminum, titanium and oxygen, aluminum and titanium are fully oxidized and enter the slag, as shown in formulas (2) and (3); at the same time, the oxidation of chromium is reduced as much as possible as shown in formula (4), so that it enters the metal molten pool; then, the slag removal operation is carried out, and reducing slag is re-produced for deoxidation and desulfurization.

[0076] 2[Al] + 3(FeO) = (Al2O3) + 3[Fe] (2)

[0077] [Ti] + 2(FeO) = (TiO2) + 2[Fe] (3)

[0078] 2[Cr] + 3(FeO) = (Cr2O3) + 3[Fe] (4)

[0079] From Table 1 to Table 2 and Figure 1 to Figure 2 It can be seen that in Comparative Example 1, no ferrous oxide was added, and in Comparative Example 2, 10% ferrous oxide was added. Although the recovery rate of chromium element was high and could meet the requirements, due to the low activity of ferrous oxide in the refined slag, the impurity elements aluminum and titanium in the molten steel could not be fully oxidized into the slag, resulting in the final aluminum and titanium contents being higher than 0.01%. On the contrary, in Comparative Example 3, 22% ferrous oxide was added, the activity of ferrous oxide in the refined slag was high, and the impurity elements aluminum and titanium in the molten steel were fully oxidized, and the final contents were all lower than 0.005%. However, the degree of oxidation of chromium element also increased, and its recovery rate was 91.76%. In Example 1 and Example 2, 14% and 18% ferrous oxide were added respectively, and the final aluminum and titanium contents and the recovery rate of chromium element could meet the requirements of refined steel. Therefore, the content of ferrous oxide in the refined slag should be controlled at 12% to 20%, preferably 14% to 18%.

[0080] Comparative Example 1 and Example 3 show that, on the basis of adding 14% of ferrous oxide, the basicity is reduced from 1.8 to 1.5, the activity of ferrous oxide in the refined slag is increased, and the contents of aluminum, titanium and chromium elements can meet the requirements, but the recovery rate of chromium element is reduced. If the basicity is further reduced, it will be difficult to ensure the recovery rate of chromium element. Therefore, when the content of ferrous oxide in the refined slag is 12% to 16%, the basicity should be controlled at 1.5 to 1.8. Comparative Example 2 and Example 4 show that, on the basis of adding 18% of ferrous oxide, the basicity is increased from 1.8 to 2.1, the activity of ferrous oxide in the refined slag is reduced, the recovery rate of chromium element is increased, but the content of aluminum and titanium is also increased. If the basicity is further increased, the aluminum and titanium content will exceed the standard. Therefore, when the content of ferrous oxide in the refined slag is 16% to 20%, the basicity should be controlled at 1.8 to 2.1.

[0081] Compared with Example 1 and Example 2, the slag-to-metal ratio of Comparative Examples 4 and 5 is increased, more oxygen ions enter the molten steel, and the oxidation of impurity elements aluminum and titanium is promoted, so that their final content is less than 0.005%, but the chromium element is also over-oxidized. Therefore, the slag-to-metal ratio should be controlled at 1:8 to 1:12, preferably 1:9 to 1:11.

[0082] In the description of the present invention, it is to be understood that the terms “center”, “longitudinal”, “lateral”, “length”, “width”, “thickness”, “up”, “down”, “front”, “back”, “left”, “right”, “vertical”, “horizontal”, “top”, “bottom”, “inside”, “outside”, “clockwise”, “counterclockwise”, “axial”, “radial”, “circumferential”, etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0083] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0084] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0085] In the present invention, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0086] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A refined slag for the production of chromium-containing fine steel, characterized in that: The refined slag includes the following chemical components in mass percentage: calcium oxide: 35% to 40%, silicon dioxide: 17% to 24%, aluminum oxide: 17% to 23%, magnesium oxide: 5% to 9%, ferrous oxide: 12% to 20%, and the rest are inevitable impurities.

2. The refined slag for producing chromium-containing fine steel according to claim 1, characterized in that: The mass percentage of the ferrous oxide in the refined slag is 12% to 16%, and the binary basicity CaO / SiO2 of the refined slag is 1.5 to 1.

8.

3. The refined slag for producing chromium-containing fine steel according to claim 1, characterized in that: The mass percentage of the ferrous oxide in the refined slag is 16% to 20%, and the binary basicity CaO / SiO2 of the refined slag is 1.8 to 2.

1.

4. The refined slag for producing chromium-containing fine steel according to claim 1, characterized in that: The mass percentage of the calcium oxide in the refined slag is 35% to 38%.

5. The refined slag for producing chromium-containing fine steel according to claim 1, characterized in that: The mass percentage of silicon dioxide in the refined slag is 18% to 23%.

6. The refined slag for producing chromium-containing fine steel according to claim 1, characterized in that: The mass percentage of the aluminum oxide in the refined slag is 18% to 22%.

7. The refined slag for producing chromium-containing fine steel according to claim 1, characterized in that: The mass percentage of the magnesium oxide in the refined slag is 6% to 8%.

8. The refined slag for producing chromium-containing fine steel according to claim 1, characterized in that: The mass percentage of the ferrous oxide in the refined slag is 14% to 18%.

9. A method for producing chromium-containing refined steel, characterized in that: include: The molten steel with a predetermined composition is obtained by smelting, and then refined slag is added to the molten steel, and after refining, it is poured into a casting mold to finally obtain chromium-containing refined steel. Wherein, the refined slag is the refined slag according to any one of claims 1 to 8, and the ratio of the mass of the refined slag to the mass of the molten steel is 1:8 to 1:

12.

10. The method for producing chromium-containing fine steel according to claim 9, characterized in that: The ratio of the mass of the refined slag to the mass of the molten steel is 1:9 to 1:11.

Images