A smelting method for producing steel for cord using pure scrap steel in an electric furnace

Abstract

The invention discloses a smelting method for producing steel for cord using pure scrap steel in an electric furnace, comprising scrap steel sorting, electric furnace primary smelting, deoxidation alloying, LF refining, argon blowing and continuous casting. Compared with the traditional blast furnace → converter (or electric furnace) → LF refining → continuous casting process, the smelting method for producing steel for cord using pure scrap steel in an electric furnace adopts an aluminum-free deoxidation process and a low-basicity slag desulfurization process, combined with a specific deoxidizer, etc., to effectively control residual elements, non-metallic inclusions and center segregation on the material in the steel, and is economical to realize mass production and meet the use requirements of downstream industries.

Description

Technical Field

[0001] The invention relates to the technical field of metallurgy, in particular to a smelting method for producing steel for cords from pure scrap steel in an electric furnace. Background Art

[0002] Cord steel is a fine product of high-quality hard wire steel and is the highest strength steel among commercial steels. Due to its working conditions and safety performance requirements, steel cord has extremely strict requirements on chemical composition, non-metallic inclusion content and its morphology, metallographic structure, etc. For steel wire with a wire diameter of 0.15-0.38mm, 1 ton of wire rod can pull 2000km of steel wire, and the number of wire breakages is not allowed to exceed 1. Therefore, there are very strict standards for cord steel. Cord steel requires uniform chemical composition, small fluctuations in C, Si, and Mn, and strict restrictions on P, S and other residual elements. It is also required that non-metallic inclusions have plasticity, and brittle inclusions such as Al2O3 and calcium aluminate are strictly restricted. In addition, the surface of the steel ingot for cord is not allowed to have pores, scars, inclusions, and cracks with a depth greater than 0.30mm, and shrinkage cavities above level 1.0 and cracks with a length of more than 10mm are not allowed inside.

[0003] Dating back to the 20th century, domestic steel for cord was basically dependent on imports. At that time, it was known as the "crown jewel" of the steel industry. However, with the rapid development of domestic smelting technology, by the beginning of this century, Baosteel, Qinggang and others had successfully developed and gradually realized localization, and the technology became increasingly mature. At present, the main domestic companies producing steel for cord are Baowu, Qinggang, Xingcheng Special Steel, Zhongtian and Shagang, and the smelting process they adopt is: blast furnace → converter (or electric furnace) → LF refining → continuous casting.

[0004] The biggest problem with the production of steel for cord from pure scrap steel in the short process of electric furnace is that the raw materials have complex origins and it is difficult to control residual elements such as Cr, Ni, Cu, As and Sn. Secondly, the process of blast furnace → converter (or electric furnace) → LF refining → continuous casting is adopted, and the nitrogen content in steel is usually 20-30ppm. However, when pure scrap steel is produced in electric furnace, the arc absorbs nitrogen, and the nitrogen content in steel is high, which will seriously affect the drawing and stranding performance, and even cause breakage. Summary of the invention

[0005] The purpose of this section is to summarize some aspects of the embodiments of the present invention and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the specification abstract and the invention title of this application to avoid blurring the purpose of this section, the specification abstract and the invention title, and such simplifications or omissions cannot be used to limit the scope of the present invention.

[0006] In view of the above and / or existing problems in producing steel for cord from pure scrap steel, the present invention is proposed.

[0007] Therefore, the purpose of the present invention is to provide a smelting method for producing steel for cord using pure scrap steel in an electric furnace, which adopts an aluminum-free deoxidation process and a low-basicity slag desulfurization process, combined with a specific deoxidizer, etc., to effectively control residual elements, non-metallic inclusions and central segregation on the steel, and is economical to achieve mass production and meet the use requirements of downstream industries.

[0008] To solve the above technical problems, according to one aspect of the present invention, the present invention provides the following technical solutions:

[0009] A smelting method for producing steel for cord using pure scrap steel in an electric furnace, the specific steps are as follows:

[0010] S1. Scrap steel sorting

[0011] After sorting, scrap steel is divided into high-quality scrap steel and ordinary scrap steel, and they are piled separately;

[0012] S2, electric furnace primary smelting

[0013] Calculated by mass percentage, 60-70% of high-quality scrap steel, 15-25% of ordinary scrap steel and 10-20% of blast furnace pig iron sorted in step S1 are smelted in an electric arc furnace at 1550° C. to 1650° C. for 44-48 minutes, and 35-40 kg / t of active lime is added at the same time. A bottom argon blowing process is adopted, and the bottom argon blowing flow rate is controlled at 10-50 NL / min. After the initial smelting, the steel is discharged;

[0014] S3, deoxidation alloying

[0015] When putting steel, add 0.20-0.25kg / t of 85% SiC into the ladle; add 2-3kg / t of active lime, 5kg / t of ferrosilicon and 1kg / t of low-aluminum ferrosilicon; add 5kg / t of low-nitrogen carburizer, and blow argon into the ladle while putting steel;

[0016] S4, LF refining

[0017] The primary molten steel obtained in step S3 is transported to the LF refining furnace, and 4-5 kg / t of active lime and 0.5-0.8 kg / t of refining slag are added; 0.8-1.0 kg / t of 85% SiC and 0.2-0.8 kg / t of low nitrogen recarburizer are added; 1.3-1.6 kg / t of ferrosilicon manganese and 0.8-1.0 kg / t of low aluminum ferrosilicon are added, and the LF refining time is 40-50 min. The Ar gas flow rate is larger in the early stage of smelting and is reduced in the middle and late stages;

[0018] S5, argon blowing

[0019] The refined molten steel obtained in step S4 is hoisted to the argon blowing station, and the soft blowing flow rate is controlled to be 25-40 Nl / min, and the soft blowing time is 15-20 min;

[0020] S6, continuous casting

[0021] The molten steel treated in step S5 is calmed and then poured at a pouring temperature of 1490° C. to 1510° C. to obtain a cast billet.

[0022] As a preferred embodiment of the smelting method for producing steel for cord from pure scrap steel in an electric furnace described in the present invention, in step S1, the content of Cr, Ni and Cu in the high-quality scrap steel is less than or equal to 0.04%, and the content of As and Sn is less than or equal to 0.004%.

[0023] As a preferred embodiment of the smelting method for producing steel for cord from pure scrap steel in an electric furnace described in the present invention, in step S2, the content of Cr, Ni and Cu in the blast furnace pig iron is less than or equal to 0.02%, and the content of As and Sn is less than or equal to 0.002%.

[0024] As a preferred embodiment of the smelting method for producing steel for cord from pure scrap steel in an electric furnace described in the present invention, the ferrosilicon manganese is FeMn62Si17, and its contents are: 62% manganese, 17% silicon, less than 5% of other impurities and the remainder is iron.

[0025] As a preferred embodiment of the smelting method for producing steel for cord from pure scrap steel in an electric furnace described in the present invention, the low-aluminum ferrosilicon is FeSi75, and its content is: 75% silicon, less than 0.5% aluminum, less than 5% other impurities and the remainder is iron.

[0026] As a preferred embodiment of the smelting method for producing steel for cord from pure scrap steel in an electric furnace described in the present invention, in the step S6, the molten steel obtained is hoisted onto the continuous casting turntable for calming, and the calming time is 8-12 minutes, wherein the calming time is the time period from LF refining to the start of pouring.

[0027] As a preferred embodiment of the smelting method for producing steel for cord from pure scrap steel in an electric furnace described in the present invention, in the step S6, the normal pulling speed of the ingot with a cross-section of 150×150 mm is 2.3-2.5 m / min.

[0028] As a preferred embodiment of the smelting method for producing steel for cord from pure scrap steel in an electric furnace described in the present invention, in the step S6, the pouring is protected throughout the pouring process, the long water nozzle of the ladle is sealed with argon, and the crystallizer and the end are electromagnetically stirred.

[0029] As a preferred embodiment of the smelting method for producing steel for cord from pure scrap steel in an electric furnace described in the present invention, in step S4, the Ar gas flow rate is 450-550 L / min in the early stage of smelting and 150-200 L / min in the middle and late stages.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] 1. Through scrap steel sorting, reasonable configuration of scrap steel ratio and argon blowing at the bottom of the electric furnace and other technical means, the residual elements Cr, Ni, Cu, As, Sn and N content in the steel are controlled; at the same time, the aluminum-free deoxidation process and the desulfurization process of low-basicity slag are adopted, combined with specific deoxidizers, etc., to strictly control the size, quantity and distribution of inclusions in the steel, so that the inclusions are distributed in a small and dispersed state, which is beneficial to the drawing and twisting of customers in subsequent processing; the type of lime for the electric furnace is reasonably selected, the slag basicity is controlled, and the steel and slag retention operation process is used to overcome the disadvantage of easy slag during converter smelting and steel tapping. The P content in the steel can be controlled below 0.010%, which can fully meet the quality requirements of the downstream steel cord manufacturing industry.

[0032] 2. Reasonable selection of lime types for electric furnaces, control of slag basicity, and use of steel-retaining and slag-retaining operation processes to avoid slagging during the steel-tapping process, thus overcoming the disadvantage of easy slagging during converter smelting and steel-tapping. The P content in the steel can be controlled below 0.010%, thereby improving the plasticity and toughness of the wire rod for cord, thereby better meeting the customer's process requirements.

[0033] 3. The aluminum-free deoxidation process is adopted to control the Al and Ti contents in the steel, reduce the sources of refractory and difficult-to-float inclusions such as Al2O3 in the molten steel, obtain low-melting-point plastic inclusions, avoid the formation of brittle and harmful inclusions in the wire rod for the cord, and strictly control the size, quantity and distribution of inclusions in the steel, so that the inclusions are small and dispersed, and the inclusion morphology is conducive to the drawing and twisting in the subsequent processing of customers; at the same time, the size of the inclusions can be basically controlled below 5μm, which can greatly improve the wire drawing performance of the cord steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the present invention will be described in detail below in combination with the accompanying drawings and detailed embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor. Among them:

[0035] Figure 1 The present invention is a flow chart of a smelting method for producing steel for cord using pure scrap steel in an electric furnace. DETAILED DESCRIPTION

[0036] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0037] Secondly, the present invention is described in detail with reference to schematic diagrams. When describing the embodiments of the present invention in detail, for the sake of convenience, the cross-sectional diagrams showing the device structure will not be partially enlarged according to the general scale, and the schematic diagrams are only examples, which should not limit the scope of protection of the present invention. In addition, in actual production, the three-dimensional dimensions of length, width and depth should be included.

[0038] To make the objectives, technical solutions and advantages of the present invention more clear, the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] The present invention provides a smelting method for producing steel for cord using pure scrap steel in an electric furnace. The method adopts an aluminum-free deoxidation process and a low-basicity slag desulfurization process, combined with a specific deoxidizer, etc., to effectively control residual elements, non-metallic inclusions and center segregation on the steel. The method is economical and can realize mass production, and can meet the use requirements of downstream industries.

[0040] Figure 1 The flowchart of the present invention is a smelting method for producing steel for cord from pure scrap steel in an electric furnace. Figure 1 A detailed introduction is given to the smelting method of producing steel for cord using pure scrap steel in the above-mentioned electric furnace.

[0041] Example 1

[0042] S1. Scrap steel sorting

[0043] Scrap steel is sorted when it enters the factory. If necessary, its composition is analyzed and divided into high-quality scrap steel and ordinary scrap steel, and stacked separately. Among them, the Cr, Ni, and Cu content in high-quality scrap steel is less than or equal to 0.04%, and the As and Sn content is less than or equal to 0.004%.

[0044] S2, electric furnace primary smelting

[0045] In terms of mass percentage, 65% of high-quality scrap steel, 25% of ordinary scrap steel and 10% of blast furnace pig iron sorted in step S1, totaling 85t, are smelted in an electric arc furnace at 1550°C to 1650°C for 45min, and 39kg / t of active lime is added at the same time. A bottom blowing argon process is adopted, and the bottom blowing argon gas flow rate is controlled at 10-50NL / min. After the initial smelting, the steel is discharged at a temperature of 1602°C, and the final carbon content is 0.12%, P0.003%, wherein the Cr, Ni and Cu contents in the blast furnace pig iron are less than or equal to 0.02%, and the As and Sn contents are less than or equal to 0.002%;

[0046] S3, deoxidation alloying

[0047] When putting steel, add 0.20kg / t of 85% SiC into the ladle; add 3kg / t of active lime, add 5kg / t of ferrosilicon manganese (FeMn62Si17, containing 62% manganese, 17% silicon, less than 5% of other impurities and the balance is iron); add 1kg / t of low-aluminum ferrosilicon (FeSi75, containing 75% silicon, less than 0.5% aluminum, less than 5% of other impurities and the balance is iron); add 5kg / t of low-nitrogen carburizer, and obtain 79t of primary molten steel, and blow argon into the ladle while putting steel;

[0048] S4, LF refining

[0049] The primary molten steel obtained in step S3 is transported to the LF refining furnace, and 4kg / t of active lime is added, and 0.6kg / t of refining slag is added; 0.9kg / t of 85% SiC is added, and 0.8Kg / t of low nitrogen recarburizer is added; 1.6Kg / t of ferrosilicon manganese (FeMn62Si17, including 62% manganese, 17% silicon, less than 5% of other impurities and the balance is iron) and 1.0Kg / t of low aluminum ferrosilicon (FeSi75, including 75% silicon, less than 0.5% aluminum, less than 5% of other impurities and the balance is iron) are added, and the LF refining time is 42min, and the Ar gas flow rate is 450 / min in the early stage of smelting, and 150L / min in the middle and late stages;

[0050] S5, argon blowing

[0051] The refined molten steel obtained in step S4 is hoisted to the argon blowing station, the soft blowing flow rate is controlled to be 40Nl / min, the soft blowing time is 18min, and the argon blowing end temperature is 1541°C;

[0052] S6, continuous casting

[0053] The molten steel obtained in step S5 is hoisted onto the continuous casting turntable for calming. The calming time (the time from LF refining to the start of pouring) is 10 minutes. The pouring is carried out at a pouring temperature of 1495°C. The cross-section of the continuous casting billet is 150×150mm, the fixed length is 12m, and the billet drawing speed is 2.4m / min to obtain the cast billet. The pouring is fully protected during the pouring process. The long water inlet of the ladle is sealed with argon, and the crystallizer and the end are electromagnetically stirred.

[0054] Example 2

[0055] S1. Scrap steel sorting

[0056] Scrap steel is sorted when it enters the factory. If necessary, its composition is analyzed and divided into high-quality scrap steel and ordinary scrap steel, and stacked separately. Among them, the Cr, Ni, and Cu content in high-quality scrap steel is less than or equal to 0.04%, and the As and Sn content is less than or equal to 0.004%.

[0057] S2, electric furnace primary smelting

[0058] According to the percentage by mass, 64% of high-quality scrap steel, 24% of ordinary scrap steel and 12% of blast furnace pig iron sorted in step S1, totaling 83t, are smelted in an electric arc furnace at a temperature of 1550°C to 1650°C for 44min, and 37kg / t of active lime is added at the same time. A bottom blowing argon process is adopted, and the bottom blowing argon gas flow rate is controlled at 10-50NL / min. After the initial smelting, the steel is discharged at a temperature of 1611°C, and the final carbon content is 0.15%, P0.006%, wherein the Cr, Ni and Cu contents in the blast furnace pig iron are less than or equal to 0.02%, and the As and Sn contents are less than or equal to 0.002%;

[0059] S3, deoxidation alloying

[0060] When putting steel, add 0.3kg / t of 85% SiC into the ladle; add 3kg / t of active lime, add 5kg / t of ferrosilicon manganese (FeMn62Si17, containing 62% manganese, 17% silicon, less than 5% of other impurities and the balance is iron); add 1kg / t of low-aluminum ferrosilicon (FeSi75, containing 75% silicon, less than 0.5% aluminum, less than 5% of other impurities and the balance is iron); add 5kg / t of low-nitrogen carburizer, and obtain 78t of primary molten steel, and blow argon into the ladle while putting steel;

[0061] S4, LF refining

[0062] The primary molten steel obtained in step S3 is transported to the LF refining furnace, and 4.5kg / t of active lime is added, and 0.7kg / t of refining slag is added; 0.9kg / t of 85% SiC is added, and 0.5kg / t of low nitrogen recarburizer is added; 1.5kg / t of ferrosilicon manganese (FeMn62Si17, including 62% manganese, 17% silicon, less than 5% of other impurities and the balance is iron) and 0.8kg / t of low aluminum ferrosilicon (FeSi75, including 75% silicon, less than 0.5% aluminum, less than 5% of other impurities and the balance is iron) are added, and the LF refining time is 45min, and the Ar gas flow rate is 500 / min in the early stage of smelting, and 180L / min in the middle and late stages;

[0063] S5, argon blowing

[0064] The refined molten steel obtained in step S4 is hoisted to the argon blowing station, the soft blowing flow rate is controlled to 35Nl / min, the soft blowing time is 17min, and the argon blowing end temperature is 1540°C;

[0065] S6, continuous casting

[0066] The molten steel obtained in step S5 is hoisted onto the continuous casting turntable for calming. The calming time (the time from LF refining to the start of pouring) is 8 minutes. The pouring is carried out at a pouring temperature of 1493°C. The cross-section of the continuous casting billet is 150×150mm, the fixed length is 12m, and the billet drawing speed is 2.4m / min to obtain the cast billet. The pouring is fully protected during the pouring process. The long water inlet of the ladle is sealed with argon, and the crystallizer and the end are electromagnetically stirred.

[0067] Example 3

[0068] S1. Scrap steel sorting

[0069] Scrap steel is sorted when it enters the factory. If necessary, its composition is analyzed and divided into high-quality scrap steel and ordinary scrap steel, and stacked separately. Among them, the Cr, Ni, and Cu content in high-quality scrap steel is less than or equal to 0.04%, and the As and Sn content is less than or equal to 0.004%.

[0070] S2, electric furnace primary smelting

[0071] In terms of mass percentage, 64% of high-quality scrap steel, 26% of ordinary scrap steel and 10% of blast furnace pig iron sorted in step S1, totaling 82t, are smelted in an electric arc furnace at 1550°C to 1650°C for 48min, and 35kg / t of active lime is added at the same time. A bottom blowing argon process is adopted, and the bottom blowing argon gas flow rate is controlled at 10-50NL / min. After the initial smelting, the steel is discharged at a temperature of 1622°C, the end carbon is 0.19%, and the P is 0.005%, wherein the Cr, Ni, and Cu contents in the blast furnace pig iron are less than or equal to 0.02%, and the As and Sn contents are less than or equal to 0.002%;

[0072] S3, deoxidation alloying

[0073] When putting steel, add 0.2kg / t of 85% SiC into the ladle; add 3kg / t of active lime, add 5kg / t of ferrosilicon manganese (FeMn62Si17, containing 62% manganese, 17% silicon, less than 5% of other impurities and the balance is iron); add 1kg / t of low-aluminum ferrosilicon (FeSi75, containing 75% silicon, less than 0.5% aluminum, less than 5% of other impurities and the balance is iron); add 5kg / t of low-nitrogen carburizer, and obtain 76t of primary molten steel, and blow argon into the ladle while putting steel;

[0074] S4, LF refining

[0075] The primary molten steel obtained in step S3 is transported to the LF refining furnace, and 4kg / t of active lime is added, and 0.6kg / t of refining slag is added; 0.8kg / t of 85% SiC is added, and 0.2kg / t of low nitrogen recarburizer is added; 1.3kg / t of ferrosilicon manganese (FeMn62Si17, including 62% manganese, 17% silicon, less than 5% of other impurities and the balance is iron) and 0.9kg / t of low aluminum ferrosilicon (FeSi75, including 75% silicon, less than 0.5% aluminum, less than 5% of other impurities and the balance is iron) are added, and the LF refining time is 43min, and the Ar gas flow rate is 550L / min in the early stage of smelting, and 200L / min in the middle and late stages;

[0076] S5, argon blowing

[0077] The refined molten steel obtained in step S4 is hoisted to the argon blowing station, the soft blowing flow rate is controlled to 25Nl / min, the soft blowing time is 20min, and the argon blowing end temperature is 1543°C;

[0078] S6, continuous casting

[0079] The molten steel obtained in step S5 is hoisted onto the continuous casting turntable for calming. The calming time (the time from LF refining to the start of pouring) is 8 minutes. The pouring is carried out at a pouring temperature of 1493°C. The cross-section of the continuous casting billet is 150×150mm, the fixed length is 12m, and the billet drawing speed is 2.4m / min to obtain the cast billet. The pouring is fully protected during the pouring process. The long water inlet of the ladle is sealed with argon, and the crystallizer and the end are electromagnetically stirred.

[0080] The ingots of Example 1, Example 2 and Example 3 were rolled into φ5.5 mm wire rods by a Morgan high-speed twist-free controlled cold wire mill. The content of each element was detected by a direct reading spectrometer and an oxygen, nitrogen and hydrogen combined instrument. The results are shown in Table 1.

[0081] Table 1

[0082]

[0083] The mechanical properties of the wire rod were tested using a universal testing machine, including the tensile strength Rm and the cross-sectional shrinkage Z value as shown in Table 2.

[0084] Table 2

[0085]

[0086] A metallographic microscope was used to grade non-metallic inclusions and central segregation and to measure the maximum size of longitudinal, transverse and titanium nitride non-metallic inclusions. The results are shown in Tables 3 and 4.

[0087] Table 3

[0088]

[0089] Table 4

[0090]

[0091] The results show that the chemical composition, mechanical properties, non-metallic inclusions and center segregation of the wire rods produced in Examples 1, 2 and 3 have met the technical requirements for steel cords.

[0092] After testing, the wire rods produced in Examples 1, 2 and 3 were used by cord manufacturers, and the physical and chemical properties, process properties, fatigue properties, adhesion and wire breakage rate of the finished cords met the requirements of industry standards. Some indicators were better than the level of similar products produced by blast furnace → converter (or electric furnace) → LF refining → continuous casting process.

[0093] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced by equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed in the present invention may be used in combination with each other in any manner, and the fact that these combinations are not exhaustively described in this specification is only for the sake of omitting space and saving resources. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A smelting method for producing steel for cord from pure scrap steel in an electric furnace, characterized in that: The specific steps are as follows: S1. Scrap steel sorting After sorting, scrap steel is divided into high-quality scrap steel and ordinary scrap steel, and they are piled separately; S2, electric furnace primary smelting Calculated by mass percentage, 60-70% of high-quality scrap steel, 15-25% of ordinary scrap steel and 10-20% of blast furnace pig iron sorted in step S1 are smelted in an electric arc furnace at 1550° C. to 1650° C. for 44-48 minutes, and 35-40 kg / t of active lime is added at the same time. A bottom argon blowing process is adopted, and the bottom argon blowing flow rate is controlled at 10-50 NL / min. After the initial smelting, the steel is discharged; S3, deoxidation alloying When putting steel, add 0.20-0.25kg / t of 85% SiC into the ladle; add 2-3kg / t of active lime, 5kg / t of ferrosilicon and 1kg / t of low-aluminum ferrosilicon; add 5kg / t of low-nitrogen carburizer, and blow argon into the ladle while putting steel; S4, LF refining The primary molten steel obtained in step S3 is transported to the LF refining furnace, and 4-5 kg / t of active lime and 0.5-0.8 kg / t of refining slag are added; 0.8-1.0 kg / t of 85% SiC and 0.2-0.8 kg / t of low nitrogen recarburizer are added; 1.3-1.6 kg / t of ferrosilicon manganese and 0.8-1.0 kg / t of low aluminum ferrosilicon are added, and the LF refining time is 40-50 min. The Ar gas flow rate is larger in the early stage of smelting and is reduced in the middle and late stages; S5, argon blowing The refined molten steel obtained in step S4 is hoisted to the argon blowing station, and the soft blowing flow rate is controlled to be 25-40 NL / min, and the soft blowing time is 15-20 min; S6, continuous casting The molten steel treated in step S5 is calmed and then poured at a pouring temperature of 1490° C. to 1510° C. to obtain a cast billet.

2. The smelting method for producing steel for cord from pure scrap steel in an electric furnace according to claim 1, characterized in that: In the step S1, the content of Cr, Ni and Cu in the high-quality scrap steel is less than or equal to 0.04%, and the content of As and Sn is less than or equal to 0.004%.

3. The smelting method for producing steel for cord from pure scrap steel in an electric furnace according to claim 1, characterized in that: In the step S2, the content of Cr, Ni and Cu in the blast furnace pig iron is less than or equal to 0.02%, and the content of As and Sn is less than or equal to 0.002%.

4. The smelting method for producing steel for cord from pure scrap steel in an electric furnace according to claim 1, characterized in that: The ferrosilicomanganese is FeMn62Si17, and its contents are: 62% manganese, 17% silicon, less than 5% other impurities and the balance is iron.

5. The smelting method for producing steel for cord from pure scrap steel in an electric furnace according to claim 1, characterized in that: The low aluminum ferrosilicon is FeSi75, and its content is: 75% silicon, less than 0.5% aluminum, less than 5% other impurities and the balance is iron.

6. The smelting method for producing steel for cord from pure scrap steel in an electric furnace according to claim 1, characterized in that: In the step S6, the obtained molten steel is hoisted onto the continuous casting turntable for cooling, and the cooling time is 8-12 minutes, wherein the cooling time is the time period from LF refining to the start of pouring.

7. The smelting method for producing steel for cord from pure scrap steel in an electric furnace according to claim 1, characterized in that: In step S6, the normal pulling speed of the ingot with a cross section of 150×150 mm is 2.3-2.5 m / min.

8. The smelting method for producing steel for cord from pure scrap steel in an electric furnace according to claim 1, characterized in that: In step S6, the pouring is protected throughout the pouring process, the long water inlet of the ladle is sealed with argon, and the crystallizer and the end are electromagnetically stirred.

9. The smelting method for producing steel for cord from pure scrap steel in an electric furnace according to claim 1, characterized in that: In step S4, the Ar gas flow rate is 450-550 L / min in the early stage of smelting, and 150-200 L / min in the middle and late stages.

Images