CN118421860A - Bearing steel and method for controlling oxygen and calcium content in bearing steel - Google Patents
Bearing steel and method for controlling oxygen and calcium content in bearing steel Download PDFInfo
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- 239000010959 steel Substances 0.000 title claims abstract description 115
- 238000000034 method Methods 0.000 title claims abstract description 66
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- 229910052760 oxygen Inorganic materials 0.000 title claims abstract description 63
- 239000001301 oxygen Substances 0.000 title claims abstract description 63
- 239000011575 calcium Substances 0.000 title claims abstract description 40
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 title claims abstract description 39
- 229910052791 calcium Inorganic materials 0.000 title claims abstract description 39
- 239000002893 slag Substances 0.000 claims abstract description 48
- 238000007670 refining Methods 0.000 claims abstract description 39
- 230000008569 process Effects 0.000 claims abstract description 31
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- 238000009749 continuous casting Methods 0.000 claims abstract description 16
- 239000002245 particle Substances 0.000 claims abstract description 15
- 239000000463 material Substances 0.000 claims abstract description 10
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- 229910045601 alloy Inorganic materials 0.000 claims description 8
- 239000000956 alloy Substances 0.000 claims description 8
- 229910052799 carbon Inorganic materials 0.000 claims description 8
- 229910004298 SiO 2 Inorganic materials 0.000 claims description 7
- 229910052786 argon Inorganic materials 0.000 claims description 7
- 239000012535 impurity Substances 0.000 claims description 7
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 6
- 229910000604 Ferrochrome Inorganic materials 0.000 claims description 2
- 229910000616 Ferromanganese Inorganic materials 0.000 claims description 2
- 229910000519 Ferrosilicon Inorganic materials 0.000 claims description 2
- DALUDRGQOYMVLD-UHFFFAOYSA-N iron manganese Chemical compound [Mn].[Fe] DALUDRGQOYMVLD-UHFFFAOYSA-N 0.000 claims description 2
- 238000009628 steelmaking Methods 0.000 claims 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 10
- 238000004519 manufacturing process Methods 0.000 description 8
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- 229910000677 High-carbon steel Inorganic materials 0.000 description 2
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
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- 229910052719 titanium Inorganic materials 0.000 description 2
- 238000009489 vacuum treatment Methods 0.000 description 2
- 229910000838 Al alloy Inorganic materials 0.000 description 1
- 229910018516 Al—O Inorganic materials 0.000 description 1
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- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical class O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 235000011941 Tilia x europaea Nutrition 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
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- ZMIGMASIKSOYAM-UHFFFAOYSA-N cerium Chemical compound [Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce][Ce] ZMIGMASIKSOYAM-UHFFFAOYSA-N 0.000 description 1
- GSVIBLVMWGSPRZ-UHFFFAOYSA-N cerium iron Chemical compound [Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Fe].[Ce].[Ce] GSVIBLVMWGSPRZ-UHFFFAOYSA-N 0.000 description 1
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- Treatment Of Steel In Its Molten State (AREA)
Abstract
The invention relates to bearing steel and a method for controlling the oxygen and calcium content in the bearing steel, which comprises the following steps of: (1) tapping: obtaining a ladle; (2) LF smelting: adding low-alkalinity reducing slag-making materials into the ladle in the step (1); (3) After LF smelting, adding SiC nano particles into the slag surface before the ladle enters a VD refining furnace, and then refining; (4) continuous casting: and obtaining the bearing steel. The low-alkalinity slag is manufactured for refining in the prior LF refining process, the VD refining process continues to refine the low-alkalinity slag, and nano SiC particles are added on the VD refining slag surface. The invention solves the problem of harm to the quality of bearing steel caused by high oxygen content, and realizes the scheme of controlling B-class and D-class inclusion under the condition of low oxygen of the bearing steel. The method solves the problem that the oxygen content and the calcium in the bearing steel bring harm to the bearing steel, and further reduces the generation and the harm of oxide inclusion to cracks in the service process of the bearing steel.
Description
Technical Field
The invention relates to the technical field of ferrous metallurgy, in particular to bearing steel and a method for controlling oxygen and calcium content in the bearing steel.
Background
Bearing steel, an important metal material, plays a significant role in the modern industry. Its excellent properties, such as good wear resistance, fatigue resistance and high elastic limit, make it widely used in many critical fields of automobiles, machinery, aerospace, etc. The performance of bearing steel is directly related to the operational stability and service life of the relevant equipment, and therefore, there are extremely high demands on the production and quality control of bearing steel.
During application and service of the bearing, the condition of the bearing surface is critical. If inclusions are present at or near the bearing surface, these inclusions may at any time lead to initiation of cracks in the bearing surface. Once the cracks are formed, the cracks gradually expand, so that the normal operation of the bearing is seriously affected, and the service life of the bearing is further reduced. Therefore, how to effectively reduce and control inclusions in bearing steel is a great challenge in the production process of bearing steel.
At present, in order to reduce the oxygen content in the bearing steel and improve the quality of the bearing steel, most of smelting processes adopt Al for deoxidation. Al is used as a deoxidizer and can be effectively combined with oxygen in steel to form compounds such as aluminum oxide, so that the total oxygen content in the steel is reduced. However, despite this deoxidization process, the total oxygen content in the steel is still difficult to control at very low levels. Currently, the oxygen content in most bearing steels can be controlled between 6-10ppm, a value that, although significantly reduced compared to the past, still leaves room for further improvement.
In addition to the oxygen content problem, the calcium content in the bearing steel is also an important factor affecting the formation of inclusions. Calcium in the steel reacts with the B-type oxides in the steel to produce D-type inclusions. Class D inclusions are generally of larger size and irregular shape, they are more prone to crack formation on or in the bearing surface, which can have a severe impact on the performance and service life of the bearing. Therefore, in the production process of bearing steel, it is important to control the oxygen and calcium contents.
To improve the quality and performance of bearing steels, various attempts have been made by those skilled in the art to control the oxygen content in bearing steels. For example: patent application number: CN202211040874, filing date: 2022.08.29, in the application of the patent name of 'a smelting method of aluminum-free deoxidized high-carbon chromium bearing steel', the smelting method comprises the working procedures of molten iron pre-desulfurization, converter smelting, LF refining, RH vacuum treatment and continuous casting; pre-desulfurizing molten iron, wherein the S content of the final molten iron is 0.002-0.005 wt%; converter process: the S content of the final molten steel is less than or equal to 0.015wt%; the alkalinity of the final slag after LF refining is 1.5-2.5, feO+MnO is less than 1.0wt percent, and Al 2O3 is less than or equal to 5wt percent; RH process: the vacuum degree is less than or equal to 100Pa, and the high vacuum time is 15-30 min; the soft blowing time is 10-20 min after the breaking; continuous casting process: the whole process of protection pouring is carried out, and the ladle long nozzle is protected by argon seal; an integral tundish is adopted. The patent adopts a method of deoxidizing without Al and refining high-alkalinity slag in LF low-alkalinity smelting, controls the oxygen content in bearing steel, and controls the oxygen content in the steel to be within 10 ppm.
For example, the patent application number is: CN202310367354, filing date: 2023.04.07, in the application of the patent name of 'a method for modifying and deoxidizing the refined slag of bearing steel by using rare earth alloy to reduce slag TFe', when bearing steel is produced, adding a proper amount of aluminum alloy into the steel for preliminary deoxidization in the tapping process, keeping the steel to contain a certain amount of [ Al ], maintaining the balance of Al-O, and simultaneously adding a proper amount of alloy and slag; after molten steel enters an LF furnace, adding a certain amount of deoxidizer into the steel in batches according to the deoxidizing degree of the molten steel, and performing diffusion deoxidization on the slag surface; in the refining process, in order to thoroughly remove LF slag oxygen, rare earth cerium-iron alloy is added into the refined slag, the oxygen in the slag is removed by utilizing the combination effect of rare earth and oxygen, the oxidizing property of the slag is controlled, lime and fluorite are added according to the slag condition, and meanwhile, the operation of white slag is maintained; in the refining process, molten steel is kept not exposed, and the aluminum content is strictly controlled to ensure the Alt content before VD. The invention solves the problem of high TFe content of the refining slag and effectively reduces the oxygen content of molten steel. The patent reduces the total oxygen content in the bearing steel by deoxidizing Al and adding rare earth cerium.
For example, the patent application number is: CN202310928546, filing date: 2023.07.26, in the application of the patent name of a smelting method for controlling the oxygen content of a stainless steel bearing, stainless steel molten iron from a blast furnace is treated in a desulfurization station to meet the requirement that the sulfur content of the stainless steel molten iron is less than 0.0035%, then high-carbon drawing is adopted to carry out converter smelting, then a double slag method is adopted to operate, ar is blown in a large tank after tapping in the whole course, when LF furnace refining adopts white slag operation, VD furnace operation molten steel is carried out for vacuum treatment time of less than 67Pa for more than 15 minutes, and then continuous casting operation is carried out to obtain the stainless steel bearing steel; the smelting method for controlling the oxygen content of the stainless steel bearing is characterized in that the dynamic condition of molten steel decarburization, namely the stirring of a molten pool is enhanced, slag steel is allowed to react, the reaction is promoted to approach carbon-oxygen balance, so that the oxygen content of the molten steel is reduced, the slag quantity under a converter is strictly reduced, and the slag quantity under the converter is controlled to be less than 5kg/t of steel. The alkalinity and the oxidability of the top slag should be properly controlled, the alkalinity of the top slag should be controlled to be about 2.0-2.5, and the content of (FeO) + (MnO) in the slag is less than 0.5%. This patent makes the oxygen content of the cast slab less than 15ppm by making low-alkalinity slag at LF.
For example, the patent application number is: CN202310634534, filing date: 2023.05.31, in the application of the patent name of 'a high-purity bearing steel electric furnace high-carbon steel tapping production process', adopting electric furnace smelting, external refining, continuous casting and rolling processes to produce bearing steel with the specification phi of 55mm, and meeting the GB/T18254 special grade bearing steel standard; the bearing steel has lower oxygen, titanium and calcium contents and the titanium content is within 10ppm by reasonable component design and production process, so that the bearing steel is ensured to have higher purity, and a series of requirements of high fatigue strength, elastic strength, yield strength, high toughness, wear resistance, high and uniform hardness, long service life and the like of the bearing steel are completely met, and the product quality is stable; the low-power structure and nonmetallic inclusion and metallography of the finished steel meet the requirements of high-end products; the high-carbon steel tapping has great significance for controlling inclusions in bearing steel produced by an electric furnace and improving the quality grade of bearing steel products, and realizes the breakthrough of mass production of high-quality bearing steel GCr15 bars in the continuous casting process of the electric furnace. The patent obtains the bearing steel with low oxygen content by optimizing the smelting process and controlling the raw material components.
However, in the above method, it is difficult to stably control the oxygen content to 5ppm or less, and there is no concern about the control of the calcium content.
Disclosure of Invention
Aiming at the technical defects, the invention aims to control the oxygen content in the bearing steel to be below 6ppm and the calcium content to be below 3ppm, solves the problem that the high oxygen and calcium content causes harm to the quality of the bearing steel, and realizes the scheme of controlling the B-class and D-class inclusion in the bearing steel under the condition of low oxygen.
In order to solve the technical problems, the invention adopts the following technical scheme:
the invention provides a method for controlling the oxygen and calcium content in bearing steel, which comprises the following steps of:
(1) Tapping: obtaining a ladle;
(2) LF smelting: adding low-alkalinity reducing slag-making materials into the ladle in the step (1);
(3) After LF smelting, adding SiC nano particles into the slag surface before the ladle enters a VD refining furnace, and then refining;
(4) Continuous casting: and obtaining the bearing steel.
As a further preferable mode of the invention, in the step (1), when the carbon mass fraction of the molten steel end point is more than or equal to 0.1%, tapping is carried out at 1600-1660 ℃.
In the step (1), a deoxidizer is added during tapping to deoxidize the alloy, thereby obtaining a ladle.
As a further preferred aspect of the present invention, the deoxidizer is one or more of Al ingot, ferromanganese, ferrochrome and ferrosilicon.
As a further preferred aspect of the invention, in step (2), argon is blown into the inner bottom of the ladle during LF smelting for 40-50 min.
As a further preferred aspect of the present invention, in the step (2), the low alkalinity reducing slag has a basicity (CaO/SiO 2) R of 1.5 to 2.0, wherein CaO is 30 to 50%, al 2O3 is 20 to 30%, mgO is 1 to 10%, siO 2 is 10 to 30%, and the balance is unavoidable impurities.
As a further preferred aspect of the present invention, in the step (3), vacuum refining is subsequently performed for 15 to 25 minutes.
As a further preferred aspect of the present invention, in the step (3), the nano SiC particles have a particle diameter of 20 to 60nm.
As a further preferred aspect of the present invention, the sample for measuring the oxygen content in step (4) is a bar.
The invention provides a bearing steel material, which is prepared by the method.
The invention provides a method for controlling the oxygen and calcium content in bearing steel, which comprises the following steps of:
(1) Tapping: tapping at 1600 ℃ when the carbon mass fraction of the molten steel end point is more than or equal to 0.1%, and adding a deoxidizer for alloy deoxidization in the tapping process to obtain a ladle;
(2) Adding low-alkalinity reducing slag-making material into the ladle in the step (1), and blowing argon into the inner bottom of the ladle in the refining process in LF smelting for 40-50 min; wherein, the low alkalinity reducing slag forming material is common in the field and mainly comprises CaO, mgO, siO 2 and Al 2O3.
The alkalinity (CaO/SiO 2) R of the low alkalinity reducing slag is 1.5-2.0, wherein CaO is 30-50%, al 2O3 is 20-30%, mgO is 1-10%, siO 2 is 10-30%, and the balance is unavoidable impurities.
(3) Before the ladle enters the VD refining furnace, siC nano particles are added on the slag surface. And then vacuum refining is carried out for 15-25min.
The particle diameter of the nano SiC particles is 20-60nm.
(4) And (3) the steel ladle enters a continuous casting machine to obtain continuous casting process operation, and bearing steel with oxygen content below 6ppm and calcium content below 3ppm is obtained.
Compared with the prior art, the invention has the following beneficial effects:
1. The invention does not change the existing production operation process, and the operation is carried out before the ladle reaches the LF operation procedure, so that the burden on production is avoided.
2. According to the method, low-alkalinity slag and nano SiC particles are added on the slag surface in the VD refining process, so that the control strategy is that the amount of CaO used by the low-alkalinity slag is reduced, and the Ca content is reduced. The oxygen content is reduced by further precipitation deoxidization of SiC; on one hand, the generation of B-class and D-class inclusions can be well controlled, and on the other hand, the total oxygen is further reduced through the slag surface deoxidation of SiC.
3. The SiC nano particles of the invention can not pollute molten steel.
Therefore, the invention provides a new method and thought for controlling the oxygen content and the calcium content in the bearing steel, greatly limits the influence of oxide inclusions on the service life of the bearing, and has great effect on improving the quality of the bearing steel.
Drawings
FIG. 1 is a process flow diagram of the present invention;
FIG. 2 is the oxygen content of a bearing steel bar;
fig. 3 shows the calcium content of the bearing steel.
Detailed Description
In order to make the technical scheme and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings and examples. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Example 1
The invention provides a method for controlling the oxygen and calcium content in bearing steel, which comprises the following steps:
(1) Tapping: tapping at 1600 ℃ when the carbon mass fraction of the molten steel end point is more than or equal to 0.1%, and adding a deoxidizer for alloy deoxidization in the tapping process to obtain a ladle;
(2) Adding low-alkalinity reducing slag-making material into the ladle in the step (1), and blowing argon into the inner bottom of the ladle in the refining process in LF smelting for 40 min;
The alkalinity (CaO/SiO 2) R of the low alkalinity reducing slag is 1.5, wherein CaO is 44%, al 2O3 is 20%, mgO is 5%, siO 2 is 30%, and the balance is unavoidable impurities.
(3) Before the ladle enters the VD refining furnace, siC nano particles are added on the slag surface. Vacuum refining is then carried out for 20min.
The particle diameter of the nano SiC particles is 40nm.
(4) And (3) the steel ladle enters a continuous casting machine to obtain continuous casting process operation, and bearing steel with oxygen content below 6ppm and calcium content below 3ppm is obtained.
Example 2
The invention provides a method for controlling the oxygen and calcium content in bearing steel, which comprises the following steps:
(1) Tapping: tapping at 1600 ℃ when the carbon mass fraction of the molten steel end point is more than or equal to 0.1%, and adding a deoxidizer for alloy deoxidization in the tapping process to obtain a ladle;
(2) Adding low-alkalinity reducing slag-making material into the ladle in the step (1), blowing argon into the inner bottom of the ladle in the LF smelting process for 45min, and carrying out slag-raking operation after the LF is finished;
The alkalinity (CaO/SiO 2) R of the low alkalinity reducing slag is 1.7, wherein CaO is 41%, al 2O3 is 28%, mgO is 5%, siO 2 is 24%, and the balance is unavoidable impurities.
(3) Before the ladle enters the VD refining furnace, siC nano particles are added on the slag surface. Vacuum refining is then carried out for 18min.
The particle diameter of the nano SiC particles is 40nm.
(4) And (3) the steel ladle enters a continuous casting machine to obtain continuous casting process operation, and bearing steel with oxygen content below 6ppm and calcium content below 3ppm is obtained.
Example 3
The invention provides a method for controlling the oxygen and calcium content in bearing steel, which comprises the following steps:
(1) Tapping: tapping at 1630 ℃ when the carbon mass fraction of the molten steel end point is more than or equal to 0.1%, and adding a deoxidizer for alloy deoxidization in the tapping process to obtain a ladle;
(2) Adding low-alkalinity reducing slag-making material into the ladle in the step (1), blowing argon into the inner bottom of the ladle in the LF smelting process for 48min, and carrying out slag-removing operation after the LF is finished;
The alkalinity (CaO/SiO 2) R of the low alkalinity reducing slag is 1.8, wherein CaO is 43%, al 2O3 is 27%, mgO is 5%, siO 2 is 24%, and the balance is unavoidable impurities.
(3) Before the ladle enters the VD refining furnace, siC nano particles are added on the slag surface. Vacuum refining is then carried out for 20min.
The particle diameter of the nano SiC particles is 40nm.
(4) And (3) the steel ladle enters a continuous casting machine to obtain continuous casting process operation, and bearing steel with oxygen content below 6ppm and calcium content below 3ppm is obtained.
Comparative example 1
The same procedure as in examples 1-3 is followed, except that in step (2) the LF process still uses high alkalinity slag for refining, directly into VD refining, and no other operations are performed.
The alkalinity (CaO/SiO 2) R of the high alkalinity reducing slag is 6.5, wherein CaO is 52%, al 2O3 is 31%, mgO is 8%, siO 2 is 8%, and the balance is unavoidable impurities.
Bearing steel materials having oxygen contents of 6ppm or less and calcium contents of 3ppm or less were obtained in examples 1 to 3 of the present invention, and the effects of examples 1 to 3 and comparative example 1 were compared. The final composition of this example 1-3 and comparative example 1 is shown in Table 1:
TABLE 1 Steel product composition (mass percent)
The components of the finished bearing steel product refined by the four furnaces meet the GB/T18254-2016 (metallurgical quality: high-quality steel) standard: GB/T18254-2016 criteria are determined as shown in Table 2:
Table 2 GB/T18254-2016 Steel composition (high-quality Steel)
From tables 1 and 2, it can be seen that the component contents of the four groups of experimental bearing steels meet the GB/T18254-2016 standard.
For the comparison of the oxygen and calcium contents in the examples and comparative examples, the oxygen and calcium contents of the test heats were measured, and the measurement results are shown in FIGS. 2 and 3. As can be seen from FIG. 2, the oxygen content in examples 1-3 was below 5ppm, and the oxygen content in the comparative example was 7.8ppm. In FIG. 3, the calcium content in examples 1 to 3 was about 2ppm, and in the comparative example, the calcium content was 6.4ppm. Therefore, the invention well reduces the oxygen and calcium content in the bearing steel, thereby reducing the generation of B-class and D-class inclusions and prolonging the service life of the bearing.
The invention specifically operates to make low-alkalinity slag for refining in the conventional LF refining process, and the VD refining process continues low-alkalinity slag refining, and nano SiC particles are added on the VD refining slag surface. The invention solves the problem that the oxygen content and the calcium in the bearing steel bring harm to the bearing steel, and further reduces and controls the generation and the harm of oxide inclusions to cracks in the service process of the bearing steel.
The method can be realized by the upper and lower limit values of the interval and the interval value of the process parameters (such as temperature, time and the like), and the examples are not necessarily listed here.
The invention may be practiced without these specific details, using any knowledge known in the art.
Finally, it should be noted that the above embodiments are only for illustrating the technical solution of the present invention and are not limiting. Although the present invention has been described in detail with reference to the embodiments, it should be understood by those skilled in the art that modifications and equivalents may be made thereto without departing from the spirit and scope of the present invention, which is intended to be covered by the appended claims.
Claims (10)
1. A method for controlling the oxygen and calcium content in bearing steel, converter or electric furnace steelmaking to obtain molten steel, comprises the following steps:
(1) Tapping: obtaining a ladle;
(2) LF smelting: adding low-alkalinity reducing slag-making materials into the ladle in the step (1);
(3) After LF smelting, adding SiC nano particles into the slag surface before the ladle enters a VD refining furnace, and then refining;
(4) Continuous casting: and obtaining the bearing steel.
2. The method for controlling the oxygen and calcium contents in bearing steel according to claim 1, wherein in the step (1), steel is tapped at 1600-1660 ℃ when the carbon mass fraction of the molten steel end point is not less than 0.1%.
3. The method for controlling the oxygen and calcium contents in bearing steel according to claim 1, wherein in the step (1), a deoxidizer is added during tapping to perform alloy deoxidization, thereby obtaining a ladle.
4. A method of controlling the oxygen and calcium content in bearing steel according to claim 3, wherein the deoxidizer is one or more of Al ingot, ferromanganese, ferrochrome and ferrosilicon.
5. The method for controlling the oxygen and calcium contents in bearing steel according to claim 1, wherein argon is blown into the inner bottom of the ladle during the refining process in the LF smelting for 40-50min in the step (2).
6. The method for controlling the oxygen and calcium contents in bearing steel according to claim 1, wherein in the step (2), the basicity (CaO/SiO 2) R of the low basicity reducing slag is 1.5-2.0, wherein CaO is 30-50%, al 2O3 is 20-30%, mgO is 1-10%, siO 2 is 10-30%, and the balance is unavoidable impurities.
7. The method for controlling the oxygen and calcium content in bearing steel according to claim 1, wherein in step (3), vacuum refining is performed subsequently for 15-25min.
8. The method for controlling the oxygen and calcium content of bearing steel according to claim 1, wherein in the step (3), the nano SiC particles have a particle diameter of 20 to 60nm.
9. The method for controlling the oxygen and calcium content of bearing steel according to claim 1, wherein the sample for measuring the oxygen content in the step (4) is a bar.
10. Bearing steel, characterized in that it is produced by the method according to any one of claims 1-9.
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