Smelting method of low-oxygen low-inclusion high-carbon GCr15 steel

Abstract

The invention relates to a smelting method of low-oxygen low-inclusion high-carbon GCr15 steel, and belongs to the technical field of material metallurgy. The process route of the smelting method comprises ECOARC ecological electric furnace smelting, LF refining, RH refining and continuous casting. By changing the alkalinity and the calcium-aluminum ratio of the refining slag, optimizing the thermodynamic and dynamic conditions of the refining slag and removing impurities and oxidizing inclusions generated in the tapping process of the electric furnace through the slagging-off means, the oxygen content and the inclusion content are reduced, and particularly the content of B-type inclusions is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of material metallurgy, and particularly to a method for smelting high-carbon GCr15 steel with low oxygen and low inclusions. Background Art

[0002] Due to their excellent strength, hardness, and wear resistance, high-carbon steels are widely used in fields such as mechanical manufacturing, the automotive industry, and tool manufacturing. However, during the traditional smelting process of high-carbon steels, problems such as high oxygen content and many inclusions exist, seriously affecting the purity and performance of the steel.

[0003] Currently, there are mainly two methods for smelting ultra-low oxygen steel or even very low oxygen medium-high carbon steel internationally. The first method is to add a large amount of aluminum-based deoxidizer during the tapping process of the converter, then make two high-alkalinity refining slags in the ladle furnace, followed by vacuum treatment, and then carry out calcium treatment and implement long-term soft blowing. The second method is to add a large amount of aluminum-based deoxidizer during the tapping process of the converter, adopt a two-stage vacuum treatment process, and insert a ladle furnace treatment process between the two vacuum treatments.

[0004] However, both of these methods have significant technical defects. First, during the deoxidation process, the use of a large amount of aluminum-based deoxidizer will inevitably generate aluminate-based inclusions, which are difficult to remove and seriously affect the purity and performance of the steel. Second, during the ladle slag skimming operation, secondary oxidation of the molten steel is extremely likely to occur, which not only causes metal loss but also results in a temperature drop, further affecting the smelting efficiency and product quality. In addition, the process of making two high-alkalinity refining slags in the ladle furnace significantly increases the consumption of slag materials and the production cost. At the same time, the entire refining treatment cycle is relatively long, resulting in complex production organization and difficulty in meeting the needs of high-efficiency production.

[0005] In summary, when producing ultra-low oxygen steel with the existing technology, there are not only technical problems such as difficult control of inclusions and high risk of secondary oxidation, but also economic problems such as large slag material consumption, long production cycle, and high cost. There is an urgent need for a more efficient, economical smelting method that can significantly improve the purity of molten steel. Summary of the Invention

[0006] The purpose of the present invention is to provide a method for smelting high-carbon GCr15 steel with low oxygen and low inclusions, by changing the alkalinity and calcium-aluminum ratio of the refining slag, optimizing the thermodynamic and kinetic conditions of the refining slag, changing the feeding method and timing, and through the means of adding aluminum during the tapping process and skimming the slag after adding carbon powder, reducing the addition amount of quicklime and synthetic slag during the tapping process, and adding them when remaking the slag after skimming the slag, greatly reducing the oxygen content of inclusions, especially reducing the content of type B inclusions in the steel grade.

[0007] To achieve the above purpose, the technical solution of the present invention is as follows:

[0008] The present invention provides a smelting method for high-carbon GCr15 steel with low oxygen and low inclusions. The process route of the smelting method is: ECOARC ecological electric furnace smelting → LF refining → RH refining → continuous casting; wherein:

[0009] In the LF furnace refining, before refining, the temperature is first raised to 1520 - 1560 °C and then slag is removed. 6.36 - 12.72 kg / t of active lime, 5.45 - 7.27 kg / t of synthetic slag, 1.36 - 2 kg / t of silicon carbide, 3.27 - 3.63 kg / t of coke particles, and 1.09 - 2.63 kg / t of low-titanium high-chromium are added. Argon is blown at the bottom of the ladle for stirring, the argon pressure is 0.2 - 0.4 MPa, the static argon blowing time is greater than 15 min, and the off-station temperature of the intermediate heat in the LF furnace is 1561 - 1571 °C.

[0010] In the LF furnace refining, before refining, the temperature is first raised and then slag is removed. When removing slag, slag retention treatment should be carried out to avoid secondary oxidation of the molten steel. The slag removal amount is 80% - 90% of the total slag amount. When smelting bearing steel in the electric furnace, the temperature drop to the LF furnace is large. Direct slag removal is likely to make the ladle airtight, and the slag layer is likely to form a shell. After heating up, the slag materials such as the active lime and pre-deoxidizer added during tapping are removed. Feeding silicon-calcium wire is strictly prohibited during the refining process to prevent the generation of large inclusions, and the white slag time is ≥ 20 min. By mass percentage, the composition of the LF furnace refining slag is: CaO: 43% - 49%, Al2O3: 28% - 30%, SiO2: 6% - 8%, MgO: ≤ 8%, FeO: ≤ 0.5%, and the balance is impurities. The CaO / Al2O3 ratio is between 1.43 and 1.75. Figure 1 ▼ The area is the composition range and corresponding melting point area of each slag system of the LF furnace refining slag, from Figure 1 It can be seen that after the slag in the LF furnace is modified, the melting point of the LF furnace refining slag is lower than 1450 °C, and the thermodynamic and kinetic conditions are at a good level.

[0011] In the above technical solution, further, in the ECOARC ecological electric furnace smelting, the tapping conditions are: by mass percentage, P ≤ 0.010%, the tapping temperature is 1610 - 1630 °C, the tapping time is 3 - 5 min, 1.54 - 2 kg / t of aluminum wire section is added during pre-deoxidation, and during the alloying process, the carburizer, alloy materials, and slag materials are added in sequence when 1 / 4 of the steel is tapped.

[0012] In the above technical solution, further, in the ECOARC ecological electric furnace smelting, the addition amount of the slag materials is: 3.63 - 5.45 kg / t of synthetic slag, 3.63 - 5.45 kg / t of active lime; the addition amount of the alloy materials is: 2.2 - 2.4 kg / t of silicomanganese alloy, 4.81 - 4.83 kg / t of high-carbon ferrochrome; the addition amount of the carburizer is: 5.43 - 5.45 kg / t.

[0013] In the above technical solution, further, by mass percentage, the composition and proportion of the synthetic slag are as follows: CaO 55% - 60%, Al2O3 40% - 45%.

[0014] In the above technical solution, further, in the ECOARC ecological electric furnace smelting, scrap steel and hot metal are used as furnace charges. By mass percentage, 60% ≤ scrap steel < 100%. Oxygen is blown into the furnace, and the oxygen flow rate is 2000 - 2500 m 3 / h. When the furnace temperature ≥ 1450 °C, the oxygen flow rate is increased to 4500 - 5500 m 3 / h. At the same time, active lime and lightly burned magnesia balls are added to make foamed slag, where the active lime is 31.81 - 33.63 kg / t and the lightly burned magnesia balls are 9.09 - 11.36 kg / t.

[0015] In the above technical solution, further, in the RH refining, the temperature entering RH is 1556 - 1566 °C. After vacuum, the hydrogen content is determined, and the determined hydrogen content does not exceed 1.2 ppm. The vacuum degree is maintained below 67 Pa for 25 - 30 min. Soft argon blowing and stirring (open the argon gas, first low and then high, gradually adjusted to make the slag surface slightly move), the stirring time is 30 - 35 min, the argon gas flow rate is controlled at 10 - 60 L / min, and the ladle hanging temperature is 1511 - 1521 °C.

[0016] In the above technical solution, further, in the continuous casting, the tundish temperature is 1471 - 1481 °C, the casting speed is 0.4 - 0.43 m / min, the water flow rate in the mold is 134 - 143 m 3 / h, the electromagnetic stirring current in the mold is 300 - 500 A, the frequency is 1.5 - 3.5 Hz, the electromagnetic stirring current at the end is 520 - 800 A, the frequency is 7 Hz, and the stirring method is: alternating (20 s - 5 s - 20 s).

[0017] In the above technical solution, further, in the continuous casting, the remaining steel in the ladle: ≥ 3.5 t, the remaining steel in the tundish: at the end of the furnace ≥ 10 t.

[0018] In the above technical solution, further, in the continuous casting, the whole process is protected by casting. The mold powder used is high-carbon steel mold powder, the superheat of the molten steel is controlled at 20 - 30 °C, and the argon gas flow rate for protecting the casting with the long nozzle at the ladle is 20 - 40 L / min.

[0019] The beneficial effects of the present invention are:

[0020] 1) The present invention optimizes the thermodynamic and kinetic conditions of the refining slag by changing the basicity and calcium-aluminum ratio of the refining slag, reduces the oxygen content and inclusion content, especially the content of type B inclusions. By adjusting the slag system, the Al content after sufficient refining is < 0.03%, thereby reducing the oxygen content. The present invention optimizes the composition of the synthetic slag and reduces its melting point, which is beneficial to slag melting.

[0021] 2) The present invention removes impurities and oxidizing inclusions generated during the tapping process of the electric furnace by slag skimming, reduces oxide inclusions such as alumina in the tapping of the electric furnace, and solves the technical problem of the high content of type B inclusions in the existing production process. Since strict requirements are imposed on the titanium element in bearing steel, the slag skimming process helps to reduce the titanium introduced by the slag, thereby maintaining the stability of the titanium content in the alloy, and remelting the slag is more conducive to adsorbing inclusions and purifying the molten steel.

[0022] 3) The ECOARC ecological electric furnace of the present invention reduces the amount of active lime used in the electric furnace (the active lime is reduced from the traditional usage of 36.36 - 40.90 kg / t to 31.81 - 33.63 kg / t) by slag skimming, thereby reducing the slag volume; after slag skimming, remelting the slag, because the new slag has good fluidity and air permeability, can accelerate the chemical reaction rate, thereby improving the refining efficiency, and the new slag can reduce the erosion of the LF furnace lining;

[0023] 4) The ECOARC ecological electric furnace of the present invention replaces dolomite with lightly burned magnesia balls to reduce the smelting cost. Description of the Drawings

[0024] Figure 1 It is a ternary phase diagram of the CaO - Al2O3 - SiO2 content of the LF furnace refining slag. Detailed Embodiments

[0025] The following embodiments can enable those of ordinary skill in the art to understand the present invention more comprehensively, but do not limit the present invention in any way.

[0026] Example 1

[0027] The smelting method of bearing steel of grade GCr15 includes the following steps:

[0028] (1) ECOARC ecological electric furnace smelting: Using scrap steel and hot metal as furnace charges, by mass percentage, 60% scrap steel and 40% hot metal, using three-phase electrodes to raise the temperature, blowing oxygen into the furnace, first with a low oxygen flow rate of 2000 m 3 / h. When the furnace temperature reaches 1450 °C, the oxygen flow rate is increased to 5000 m 3At a rate of / h, 31.81 kg / t of active lime and 9.09 kg / t of lightly burned magnesia balls are added simultaneously to form a foamy slag. Tapping conditions: P ≤ 0.010% (by mass percentage), tapping temperature 1610 °C, tapping time 3 min. During pre-deoxidation, 2 kg / t of aluminum wire segment is added. During alloying, when 1 / 4 of the steel is tapped, a carburizer, alloy materials, and slag materials are added in sequence. Among them: the addition amount of slag materials is: 3.63 kg / t of active lime, 3.63 kg / t of synthetic slag (its composition by mass percentage is CaO 57%, Al2O3 43%); the addition amount of alloy materials is: 2.2 kg / t of silicomanganese alloy, 4.81 kg / t of high-carbon ferrochrome; the addition amount of carburizer is: 5.43 kg / t;

[0029] (2) LF furnace refining: Before refining, the temperature is raised to 1540 °C first and then the slag is skimmed. The skimming amount is 80% of the total slag amount. When smelting bearing steel in an electric furnace, the temperature drop to the LF is large. Direct slag skimming is likely to make the ladle airtight. After heating up, the slag materials such as active lime and pre-deoxidizer added during tapping are skimmed off. After slag skimming, new slag is formed, adding 12.72 kg / t of active lime, 7.27 kg / t of synthetic slag, 1.36 kg / t of silicon carbide, 3.63 kg / t of coke particles, and 2.63 kg / t of low-titanium high-chromium. During the refining process, feeding silicon-calcium wire is strictly prohibited to prevent the generation of large inclusions, making the white slag time ≥ 20 min. The ladle is bottom-blown with argon for stirring, the argon pressure is 0.2 MPa, and the static argon blowing time is more than 15 min. The off-station temperature of the LF intermediate heat is 1561 °C; At this time, the composition of the LF furnace refining slag is: CaO: 49%, Al2O3: 29%, SiO2: 6.02%, MgO: 7.3%, FeO: 0.38%, and the balance is impurities. In the Figure 1 ▼ area, at this time, the CaO / Al2O3 ratio is between 1.43 - 1.75. ;

[0030] (3) RH refining: The temperature entering the RH is 1556 °C. After vacuum, the hydrogen is determined. The determined hydrogen content does not exceed 1.2 ppm. The vacuum degree is maintained below 67 Pa for 27 min. Soft argon blowing is carried out. The argon is turned on, and it is adjusted from low to high first, gradually adjusted until the slag surface vibrates slightly, and the stirring time is 30 min. For soft blowing, the slag surface vibrates slightly and the molten steel is not exposed, to prevent secondary oxidation. The argon flow rate is controlled at 20 L / min, and the ladle temperature is 1511 °C. No alloy and carburizer are added during the RH process. Feeding calcium wire is strictly prohibited during the RH process;

[0031] (4) Continuous casting: Measure the temperature of the ladle platform at 1506 °C, the tundish temperature at 1471 °C, the casting speed at 0.41 m / min, and the water flow rate of the mold at 140 m 3 / h, the electromagnetic stirring current of the mold is 500 A, the frequency is 2 Hz, the electromagnetic stirring current at the end is 650 A, the frequency is 7 Hz, stirring mode: alternating (20 s - 5 s - 20 s); strictly implement the whole-process protected casting, use high-carbon steel mold powder for the mold, control the superheat of the molten steel at 20 °C, the argon flow rate for protecting the casting with the long nozzle of the ladle is 40 L / min, with the liquid level in the tundish slightly moving and the steel liquid surface not being exposed, the remaining steel in the ladle: 3.5 t, the remaining steel in the tundish: 10 t for the last heat.

[0032] Example 2

[0033] The smelting method of bearing steel of grade GCr15 includes the following steps:

[0034] (1) ECOARC ecological electric furnace smelting: Use scrap steel plus hot metal as the furnace charge. By mass percentage, scrap steel is 60%, hot metal is 40%. Use three-phase electrodes to raise the temperature, blow oxygen into the furnace. First, use low oxygen of 2000 m 3 / h. When the furnace temperature reaches 1450 °C, the oxygen flow rate is increased to 5000 m 3 / h. At the same time, add 33.63 kg / t of active lime and 11 kg / t of lightly burned magnesia balls to make foamed slag. Tapping conditions: P ≤ 0.010% (by mass percentage), tapping temperature 1610 °C, tapping time 3 min. When pre-deoxidizing, add 2 kg / t of aluminum wire segment. During the alloying process, when 1 / 4 of the steel is tapped, add carburizer, alloy materials and slag materials in sequence. Among them: the addition amount of slag materials is: 4.5 kg / t of active lime, 4.2 kg / t of synthetic slag (its composition by mass percentage is CaO 57%, Al2O3 43%), the addition amount of alloy materials is: 2.3 kg / t of silico-manganese alloy, 4.82 kg / t of high-carbon ferrochrome, and the addition amount of carburizer is: 5.44 kg / t;

[0035] (2) LF furnace refining: First, raise the temperature to 1540 °C before refining and then skim the slag. The skimming amount is 80% of the total slag amount. The temperature drop of the bearing steel smelted in the electric furnace to the LF is large. Directly skimming the slag is likely to make the ladle airtight. After heating up, skim the slag materials such as the active lime and pre-deoxidizer added during tapping. After skimming the slag, re-make the slag, add 12 kg / t of active lime, 7 kg / t of synthetic slag, 1.45 kg / t of silicon carbide, 3.6 kg / t of coke particles, 2.6 kg / t of low-titanium high-chromium. During the refining process, it is strictly prohibited to feed silicon-calcium wire to prevent the generation of large particles of inclusions, so that the white slag time ≥ 20 min. Stir the ladle with bottom blowing argon, the argon pressure is 0.2 MPa, and the static blowing argon time is greater than 15 min. The off-station temperature of the intermediate heat in the LF furnace is 1561 °C; At this time, the composition of the refining slag in the LF furnace is: CaO: 49%, Al2O3: 29%, SiO2: 6.08%, MgO: 7.22%, FeO: 0.41%, and the balance is impurities. In Figure 1 ▼ area, at this time, the CaO / Al2O3 ratio is between 1.43 - 1.75;

[0036] (3)RH refining: The temperature of molten steel entering RH is 1556 °C. After vacuum treatment, the hydrogen content is determined, and the determined hydrogen content does not exceed 1.2 ppm. The vacuum degree is maintained below 67 Pa for 27 min. Soft argon blowing is carried out. Argon gas is turned on, and the flow rate is adjusted from low to high gradually until the slag surface starts to move slightly. The stirring time is 30 min. Soft argon blowing is carried out with the slag surface moving slightly and the molten steel not being exposed to prevent secondary oxidation. The argon gas flow rate is controlled at 20 L / min. The ladle temperature is 1512 °C. No alloy and carburizer are added during the RH process. Feeding calcium wire is strictly prohibited during the RH process;

[0037] (4)Continuous casting: The temperature of the ladle platform is measured as 1507 °C, the tundish temperature is 1472 °C, the casting speed is 0.41 m / min, the water flow rate of the mold is 140 m 3 / h, the current of the mold electromagnetic stirrer is 500 A, the frequency is 2 Hz, the current of the final electromagnetic stirrer is 650 A, the frequency is 7 Hz, and the stirring mode is: alternating (20 s - 5 s - 20 s); The whole process of protective casting is strictly implemented. The mold powder used is high-carbon steel mold powder. The superheat of the molten steel is controlled at 20 °C. The argon gas flow rate for protecting the ladle long nozzle during casting is 40 L / min, with the tundish liquid surface moving slightly and the steel liquid surface not being exposed as the standard. The remaining steel amount in the ladle is 3.5 t, and the remaining steel amount in the tundish is 10 t for the last furnace.

[0038] Comparative Example 1

[0039] The smelting method of bearing steel of grade GCr15 includes the following steps:

[0040] (1)ECOARC ecological electric furnace smelting: Scrap steel and hot metal are used as furnace charges. By mass percentage, scrap steel is 60%, and hot metal is 40%. Three-phase electrodes are used for heating, and oxygen is blown into the furnace. First, the low-oxygen flow rate is 2000 m 3 / h until the furnace temperature reaches 1450 °C, then the oxygen flow rate is increased to 5000 m 3 / h. At the same time, 36.36 kg / t of active lime and 18.18 kg / t of dolomite are added to make foamed slag. The tapping conditions are: P ≤ 0.010%, the tapping temperature is 1608 °C, the tapping time is 3 min. During pre-deoxidation, 1.02 kg / t of aluminum wire segment is added. During the alloying process, when 1 / 4 of the steel is tapped, a carburizer, alloy materials, and slag materials are added in sequence. Among them: the addition amount of the slag material is: 5.45 kg / t of ladle ash, 8.18 kg / t of synthetic slag (by mass percentage, CaO 57%, Al2O3 43%); the addition amount of the alloy materials is: 1.44 kg / t of medium-carbon ferromanganese, 1.47 kg / t of low-carbon ferrosilicon, 18.31 kg / t of low-titanium high-chromium; the addition amount of the carburizer is: 4.91 kg / t

[0041] (2) LF furnace refining: Add 4.93 kg / t of active lime, 1.95 kg / t of medium-carbon ferromanganese, 1.5 kg / t of ferrosilicon aluminum, 1.39 kg / t of alumina balls, 0.45 kg / t of aluminum wire, and 3.56 kg / t of low-titanium high-chromium. During the refining process, feeding calcium-silicon wire is strictly prohibited to prevent the generation of large inclusions, ensuring that the white slag time is ≥20 min. Argon is blown at the bottom of the ladle for stirring, with an argon pressure of 0.2 MPa and a static argon blowing time of more than 15 min. The off-station temperature of the intermediate heat in the LF furnace is 1561°C. At this time, the composition of the refining slag in the LF furnace is as follows: CaO: 50.55%, Al2O3: 26.92%, SiO2: 7.34%, MgO: 7.5%, FeO: 0.46%, and the remainder is impurities. At this time, the basicity of the refining slag: CaO / SiO2 = 6.89, and the ratio of calcium oxide to aluminum oxide CaO / Al2O3 = 1.87, which is not within the specified range;

[0042] (3) RH refining: The temperature entering the RH is 1556°C. After vacuum, the hydrogen is determined, and the hydrogen content does not exceed 1.2 ppm. The vacuum degree is maintained below 67 Pa for 25 min. Soft argon blowing is carried out. The argon is turned on, and it is adjusted from low to high first, gradually adjusted until the slag surface is slightly moving. The stirring time is 30 min. For soft blowing, it is appropriate that the slag surface is slightly moving and the molten steel is not exposed to prevent secondary oxidation. The argon flow rate is controlled at 20 L / min, and the ladle lifting temperature is 1512°C. No alloy and carburizer are added during the RH process, and feeding calcium wire is strictly prohibited during the RH process;

[0043] (4) Continuous casting: Measure the temperature of the tundish platform at 1507°C, the temperature of the intermediate tundish at 1472°C, the casting speed at 0.41 m / min, the water flow rate of the mold at 140 m 3 / h, the current of the mold electromagnetic stirrer at 500 A, the frequency at 2 Hz, the current of the final electromagnetic stirrer at 650 A, and the frequency at 7 Hz. Stirring method: Alternate (20 s - 5 s - 20 s); Strictly implement full-process protected casting. The mold powder used is high-carbon steel mold powder. The superheat of the molten steel is controlled at 21°C. The argon flow rate for protecting the casting with the long nozzle of the tundish is 40 L / min, based on the slight movement of the intermediate tundish liquid level and no exposure of the molten steel surface. The remaining molten steel in the tundish: 3.5 tons, and the remaining molten steel in the intermediate tundish: 10 tons for the last furnace.

[0044] The inclusion rating results of the continuous casting billets obtained in Example 1, Example 2, and Comparative Example 1 are shown in Table 1.

[0045] Table 1

[0046]

[0047]

[0048] The continuous casting billets obtained in Examples 1 - 2 and Comparative Example 1 are heated and rolled to obtain finished steel. The oxygen content and titanium content of the finished steel composition are shown in Table 2.

[0049] Table 2

[0050] Number Oxygen content Titanium content Example 1 5ppm 11ppm Example 2 6ppm 13ppm Comparative Example 1 9ppm 16ppm

[0051] The above embodiments are only the preferred embodiments of the present invention and not the limitations on the implementation manners. The protection scope of the present invention shall be subject to the scope defined by the claims. Based on the above description, other different forms of changes or alterations can be made. The obvious changes or alterations derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for smelting high-carbon GCr15 steel with low oxygen and low inclusions, characterized in that: The process route of the smelting method is: ECOARC ecological electric furnace smelting → LF refining → RH refining → continuous casting; wherein: In the LF furnace refining, the temperature is first raised to 1520-1560° C. before refining, and then the slag is skimmed, 6.36-12.72 kg / t of active lime, 5.45-7.27 kg / t of synthetic slag, 1.36-2 kg / t of silicon carbide, 3.27-3.63 kg / t of coke particles, and 1.09-2.63 kg / t of low-titanium high-chromium are added, argon is blown from the bottom of the ladle for stirring, the argon pressure is 0.2-0.4 MPa, the static argon blowing time is greater than 15 minutes, and the LF intermediate furnace leaving the station temperature is 1561-1571° C.

2. The method for smelting high-carbon GCr15 steel with low oxygen and low inclusions according to claim 1, characterized in that: In the ECOARC ecological electric furnace smelting, the steel tapping conditions are as follows: in terms of mass percentage, P≤0.010%, the steel tapping temperature is 1610-1630° C., the steel tapping time is 3-5 min, 1.54-2 kg / t of aluminum wire segments are added during pre-deoxidation, and during the alloying process, a carburizer, alloy material and slag are added in sequence when 1 / 4 of the steel is tapped.

3. The method for smelting high-carbon GCr15 steel with low oxygen and low inclusions according to claim 2 is characterized in that: In the ECOARC ecological electric furnace smelting, the amount of the slag added is: 3.63-5.45 kg / t of synthetic slag, 3.63-5.45 kg / t of active lime; the amount of the alloy material added is: 2.2-2.4 kg / t of silicon manganese alloy, 4.81-4.83 kg / t of high carbon ferrochrome; the amount of the recarburizer added is: 5.43-5.45 kg / t.

4. The method for smelting high-carbon GCr15 steel with low oxygen and low inclusions according to claim 1 or 3, characterized in that: Calculated by mass percentage, the composition and proportion of the synthetic slag are: CaO 55%-60%, Al2O3 40%-45%.

5. The method for smelting high-carbon GCr15 steel with low oxygen and low inclusions according to claim 1, characterized in that: In the ECOARC ecological electric furnace smelting, scrap steel and molten iron are used as furnace charge, and in terms of mass percentage, 60% ≤ scrap steel < 100%, oxygen is blown into the furnace, and the oxygen flow rate is 2000-2500m 3 / h, when the furnace temperature is ≥1450℃, the oxygen flow rate is increased to 4500~5500m 3 / h, and active lime and light-burned magnesium balls are added to make foamed slag, including 31.81-33.63 kg / t of active lime and 9.09-11.36 kg / t of light-burned magnesium balls.

6. The method for smelting high-carbon GCr15 steel with low oxygen and low inclusions according to claim 1, characterized in that: In the RH refining, the RH inlet temperature is 1556-1566°C, hydrogen is determined after vacuum, the determined hydrogen content is ≤1.2ppm, the vacuum degree is maintained below 67Pa for 25-30min, the soft argon blowing stirring time is 30-35min, the argon flow rate is controlled at 10-60L / min, and the bag temperature is 1511-1521°C.

7. The method for smelting high-carbon GCr15 steel with low oxygen and low inclusions according to claim 1, characterized in that: In the RH refining, the amount of slag skimming is 80% to 90% of the total slag amount.

8. The method for smelting high-carbon GCr15 steel with low oxygen and low inclusions according to claim 1, characterized in that: During the continuous casting, the tundish temperature is 1471-1481°C, the casting speed is 0.4-0.43 m / min, and the crystallizer water flow rate is 134-143 m 3 / h, crystallizer electromagnetic stirring current 300 ~ 500A, frequency 1.5 ~ 3.5Hz, end electromagnetic stirring current 520 ~ 800A, frequency 7Hz, stirring mode: alternating (20s ~ 5s ~ 20s).

9. The method for smelting high-carbon GCr15 steel with low oxygen and low inclusions according to claim 1, characterized in that: In the continuous casting, the remaining steel amount in the ladle is ≥3.5t, and the remaining steel amount in the tundish is ≥10t in the tail furnace.

10. The method for smelting high-carbon GCr15 steel with low oxygen and low inclusions according to claim 1, characterized in that: In the continuous casting, the whole process is protected casting, the mold protection slag uses high carbon steel protection slag, the superheat of the molten steel is controlled at 20-30° C., and the argon flow rate of the large ladle long nozzle protection casting is 20-40 L / min.

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