Production method of high-speed train axle box ultrapure bearing steel

Abstract

The invention relates to a production method of high-speed train axle box ultrapure bearing steel, and belongs to the technical field of bearing steel in iron-based alloy. By adopting the steps of molten iron pretreatment, refining promotion, ladle refining furnace, vacuum circulating degassing and large-section continuous casting CCM, the defect that in the prior art, the performance difference after heat treatment is large due to the fact that steel is low in purity, uneven in structure and unstable in chemical component is overcome, and efficient, low-cost and large-scale production of the high-speed rail bearing is achieved; the continuous casting billet obtained through the method is used for producing a bearing product through a large compression ratio, the O content of carburizing steel for ferrules is smaller than or equal to 6 ppm, and the O content of high-carbon chromium steel for rollers is smaller than or equal to 4 ppm. Ca < = 1 ppm, Ti < = 5 ppm, As + Sn + Sb < = 0.0050%, the level of large-particle non-deformable inclusions < = 0.5 level, and the bearing life is long.

Description

Technical Field

[0001] The invention belongs to the technical field of bearing steel in iron-based alloys, and in particular relates to a method for manufacturing ultra-pure bearing steel for axle box bearings of high-speed train sets. Background Art

[0002] In order to meet the requirements of railway transportation, the operating speed of railways is constantly increasing, and EMUs with a speed of more than 250 kilometers per hour are becoming the main models for passenger railway transportation. The construction of high-speed railways has brought huge market demand for railway vehicles and related parts manufacturing industries, and at the same time, the performance and quality level of bearing steel for high-speed railways are required to be higher and more stringent. At present, part of the steel for high-speed railway bearings in my country still needs to be imported. Taking axle box bearings as an example, the specific matching situation is as follows: CRH 1 and CRI-15 use SKF bearings; CRH 2 uses NTN and NSK bearings; CRH 3 uses FAG bearings.

[0003] Some countries with developed bearing manufacturing have always adopted high-cleanliness and high-strength materials for high-speed train bearings. Sweden's SKF high-speed rail axle box bearings use GCr18Mo, GCr15 M, and GCr15 materials for rings, and GCr15SiMn or GCr15 for rollers according to different working conditions and vehicle models; Germany's SCHAEFFLER high-speed rail bearing rings and rollers all use GCr15 materials; Japan's NTN high-speed rail bearing rings use similar G20CrNi2Mo materials, and rollers use GCr15 materials.

[0004] The service conditions of domestic high-speed railways are mainly characterized by long continuous operation time and large temperature changes in the operating environment. The axle box bearings need to bear the weight and load of the entire vehicle body, as well as the forces in all directions generated by the swaying of the vehicle during operation. In other words, in addition to static and dynamic radial loads, they also bear non-constant axial loads. The rings produced from fine-grained carburized bearing steel with high cleanliness and good uniformity have good toughness, high surface hardness after carburizing, can withstand strong impact loads, and have good fatigue resistance. The rollers produced from high-purity high-carbon chromium bearing steel have uniform hardness, high compressive strength, high contact fatigue strength, high wear resistance, and resistance to permanent deformation.

[0005] Application No. 201110156409.9 and Application No. 201110156392.7 disclose a method for preparing carburized bearing steel for high-speed railway. The basic idea is to reduce Cr and increase Ni, add trace V and Nb to refine the grains, and use a process combining vacuum induction and vacuum consumable remelting to improve the purity of steel. However, the production process is complicated, the production efficiency is low, and the production cost is much higher than the market, making it difficult to form competitiveness. Application No. 201310293630.8 introduces a method for producing high-performance high-carbon chromium bearing steel, which adopts the method of electric furnace + LF + VD + CCM, but the test results show that it can only meet the national GB / T18254 standard and cannot meet the requirements of high-speed rail roller materials. Application No. 200510027394.0 introduces a method for producing extremely high-purity high-carbon chromium bearing steel, which adopts a vacuum induction furnace of more than 1 ton for smelting. High cleanliness and uniformity of organization are important properties to ensure the long-term and high-stability operation of high-speed rail bearings. There is no report on the method of mass-producing ultra-pure high-speed railway axle box bearing steel by continuous casting. Summary of the invention

[0006] The purpose of the present invention is to provide a process method for high-speed rail axle box bearing steel, which adopts a single furnace of more than 100 tons of molten iron pretreatment KR-top and bottom double blowing converter BOF (or high-power electric arc furnace EAF)-ladle refining furnace LF-vacuum circulation degassing furnace RH (or VD furnace)-large-section arc continuous casting CCM, to overcome the shortcomings of low steel purity, uneven structure, unstable chemical composition and large performance differences after heat treatment in the prior art, and realize efficient and low-cost large-scale production of high-speed rail bearings. Through the implementation of the method of the present invention, it can achieve carburized bearing steel O≤6ppm for rings and high carbon chromium bearing steel O≤4ppm for rollers.

[0007] The technical solution adopted by the present invention to solve the above-mentioned problem is: a method for producing ultra-pure bearing steel for axle boxes of high-speed EMUs, wherein the mass percentages of the components of carburized bearing steel (for rings) are: C: 0.19-0.23%, Si: 0.25-0.45%, Mn: 0.50-0.70%, Cr: 0.45-0.60%, P: ≤0.015%, S: ≤0.005%, Mo: 0.20-0.30%, Ni: 1.65-1.90%, Al: 0.02-0.05%, Cu: ≤0.15%, Ca: ≤0.0005%, Ti: ≤0.0015%, O: ≤0.0008%, As: ≤0.01%, Sn: ≤0.02%, Sb: ≤0.005%, Pb: ≤0.002%, H: ≤0.0001%, and the remainder is Fe and unavoidable impurities.

[0008] The mass percentage of each component of high carbon chromium bearing steel (for rollers) is: C: 0.90~1.10%, Si: 0.15~0.35%, Mn: 0.25~0.50%, Cr: 1.30~1.65%, P≤0.015%, S≤0.015%, Mo≤0.08%, Ni≤0.25%, Al≤0.05%, Cu≤0.3%, Ca≤0.001%, Ti≤0.0015%, O≤0.0005%, As≤0.01%, Sn≤0.02%, Sb≤0.005%, Pb≤0.002%, and the balance is Fe and unavoidable impurities.

[0009] The specific process steps of the present invention are: Step 1: Hot metal KR pretreatment In order to strictly control the composition of crude molten iron, molten iron pretreatment technology is adopted. By pre-adding desulfurization agent, it is ensured that the molten iron entering the furnace has the following contents: S≤0.002%, Si≤0.3%.

[0010] Step 2: Preliminary smelting of molten iron In a 100-ton top-bottom combined-blowing converter (or electric furnace), low-phosphorus and low-titanium are carried out on the crude steel liquid to reduce the residual phosphorus content and titanium content in the steel liquid to below 0.012% and 0.0005%, respectively, and low-titanium alloys, deoxidizers and refractory materials are preferably used; The initial refining endpoint of molten steel corresponding to high carbon chromium bearing steel is C≥0.15%, P≤0.012%. The initial refining endpoint of molten steel corresponding to carburized bearing steel is C≥0.08%, P≤0.010%, and the tapping temperature T≥1620℃. According to the endpoint C%, the amount of Al-Fe added during tapping is adjusted to control the Al content of the first sample in the refining furnace between 0.040 and 0.055%. The converter tapping adopts slag plugs to block slag, slag removal after the furnace and other control process technologies to solve the problem of high content of harmful elements Ti, Ca, As, Sn, Pb, Sb and other harmful elements in bearing steel. Before the ladle is filled with molten steel, clean the slag steel on the edge of the large ladle and in the ladle to ensure that it is a red ladle that has been filled with ordinary bearing steel at least 3 times. The large ladle slide, nozzle, and air permeable core must be replaced with new ones to ensure that the nozzle is self-opening and has good air permeability.

[0011] Step 3: Ladle Refining The refined slag adopts the CaO-Al2O3-SiO2 ternary slag system (CaO≥40%, SiO2<16%, Al2O3>22%, MgO:5-8%), and maintains a slightly positive pressure atmosphere in the furnace, with a small amount of furnace smoke coming out of the furnace as the benchmark. Before taking the first sample, a large amount of argon is used for stirring during the power supply process to make the slag as soon as possible, and the argon is controlled at about 200L / min afterwards; the accuracy of sampling must be guaranteed each time, and strive to adjust the composition to the internal control target in 2 samples. Al+SiC is used for joint deoxidation, and the usage is increased. (%FeO+%MnO) in the slag is <1, which ensures a good deoxidation effect of the slag, ensures that the free oxygen content of the process is low, and gives full play to the advantages of LF furnace smelting to remove inclusions. The aluminum content of carburized steel is basically maintained between 0.025% and 0.045% during ladle refining, and the aluminum content of high carbon chromium steel is basically maintained between 0.015% and 0.030% during ladle refining, which can basically prevent the large-scale generation of oxides in the subsequent process. The refining time is ≥40min, and the molten steel temperature of carburized bearing steel is 1570~1620℃ after the refining process, and the molten steel temperature of high carbon chromium bearing steel is 1525~1575℃.

[0012] Step 4: Vacuum degassing The highest vacuum degree is ≤2.33mbar, and the high vacuum time is ≥10min. The processing time can be appropriately extended and the gas stirring flow rate under vacuum can be increased to fully exert its role in removing inclusions while ensuring degassing. After the degassing is completed, the soft stirring and soft blowing time is ≥12min. The soft blowing argon flow rate is generally 40-60L / min, subject to the molten steel not being exposed to the air. The addition of calcium-containing alloys and wire deoxidation is not allowed during the entire process. In order to increase the N in the carburizing steel, 150m of MnN wire is first fed during refining. Nitrogen is used as the lifting gas during the vacuum degassing process to make the nitrogen reach the target 90ppm; high carbon steel is blown with argon stirring throughout the process.

[0013] Step 5: Protect the pouring process Continuous casting uses electromagnetic stirring, induction heating of the tundish and light pressure to reduce the superheat of molten steel and improve the segregation of the cast billet. The tundish is enlarged, with a working capacity of 35t and an average casting speed of 1.8t per minute, to ensure that the average residence time of molten steel in the tundish is nearly 20 minutes. The asbestos gasket of the long shroud of the CCM ladle is correctly installed, and the argon seal of the long shroud must be checked before use to ensure that there is no leakage and the flow rate is appropriate during use. Dry materials are used in the tundish, and the inside of the ladle must be kept clean before baking. The tundish plug rod uses an argon blowing plug rod, and the sealing of the plug rod head must be ensured to be good. Before pouring, the sealing of the argon blowing pipeline in the impact zone and the tundish pouring zone and the accuracy of the argon blowing instrument must be checked. Do a good job of argon blowing protection for the tundish before the large ladle is poured and the secondary oxidation prevention of the tundish during the pouring process. The superheat degree of the tundish is △T≤20℃; the amount of molten steel in the tundish is 30-35 tons, the casting temperature of carburized bearing steel is 1530-1570℃, the pouring speed is 0.55m / min, and the light pressure reduction is 10mm; the casting temperature of high carbon chromium bearing steel is 1480-1520℃, the pouring speed is 0.50min / m, and the light pressure reduction is 18.5mm. If the crystallizer liquid level fluctuates more than 6mm, the excess steel in the large ladle shall not be less than 2 tons; in case of abnormal conditions, the billet shall be downgraded and re-judged separately; the hot billet of carburized steel continuous casting shall be slowly cooled in the pit for not less than 48 hours, and the pit start temperature shall be ≤300℃.

[0014] Compared with the prior art, the present invention has the following beneficial effects: (1) From the perspective of chemical composition, iron is pretreated by molten iron, and the quality of scrap steel is strictly controlled. Low-titanium alloys, deoxidizers and refractory materials are preferred. The converter steelmaking process adopts slag blocking and post-furnace slag removal control technologies to solve the problem of high content of harmful elements Ti, Ca, As, Sn, Pb and Sb in the existing technology.

[0015] (2) The core deoxidation technology of the present invention and vacuum cycle degassing are used to reduce the O and H contents in the steel to extremely low levels, and the number and size of inclusions reach the world's leading level.

[0016] (3) Continuous casting uses induction heating of the tundish, light pressure reduction and electromagnetic stirring to effectively improve the segregation and material structure of the ingot; the large-section full-process protection continuous casting is used to make the compression ratio of the ring steel greater than 30 and the compression ratio of the roller steel greater than 32, which effectively ensures the density of the material.

[0017] (4) From the perspective of continuous casting billet manufacturing process, the production cycle is greatly shortened, production efficiency is improved, and manufacturing costs are effectively reduced. Large-scale production is conducive to improving material composition and quality stability; (5) The ultra-pure bearing steel provided by the present invention meets the following index requirements of the axle box bearings of high-speed EMUs: Carburizing steel for ferrules: Microscopic inclusions are tested according to GB / T 10561 A method, B fine ≤ 1.0, B coarse ≤ 0.5, DS ≤ 1.0; Macro defects are tested according to SEP 1927 method, and the length of a single inclusion does not exceed 1mm; Macrostructure requirements are tested according to GB / T 15711, and central looseness, general looseness, and segregation are all not more than 1.0; High carbon chromium bearing steel for rollers: Microscopic inclusions are tested according to GB / T 10561 A method, B fine ≤ 1.0, B coarse ≤ 0.5, DS ≤ 0.5; Macro defects are tested according to SEP 1927 method, and the length of a single inclusion does not exceed 1mm; Macrostructure requirements are tested according to GB / T 18254, and central porosity, general porosity, and segregation are all not more than 1.0; Carbide network and band requirements are tested according to GB / T 18254, and are not more than 2.0. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the core structure diagram of carburized steel for the ferrule in the embodiment of the present invention (metallographic magnification 100×); Figure 2 This is a network photo of high carbon chromium steel carbide for rollers in an embodiment of the present invention (metallographic magnification 500X); Figure 3 This is a photo of the steel carbide band for the roller of the present invention (metallographic magnification 500X); Figure 4 This is a macrostructure diagram of the steel used for the ferrule of the present invention (specification Φ28mm); Figure 5 This is a macroscopic structure diagram of the roller steel of the present invention (specification Φ90mm); Figure 6 The ASPEX analyzer is used to analyze the 50mm steel used for the roller of the present invention. 2 The number and size of inclusions in the range; Figure 7 The 50 mm steel used for the ferrule of the present invention is analyzed by ASPEX analyzer. 2 Range of inclusion numbers and sizes. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with examples. The examples are exemplary and intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0020] Example 1-3 of carburizing steel for ferrule: The smelting raw materials are prepared according to the chemical composition of the carburizing steel for the ring. After KR molten iron pretreatment, the sulfur content of the molten iron is reduced to below 0.002%, and the temperature is 1326℃-1363℃. The roughing furnace adopts the iron slag forming route to ensure good slag fluidity in the early stage of dephosphorization. In the later stage, carbon is blown and pulled to increase the temperature. The terminal temperature is 1620℃-1629℃, carbon is 0.11%-0.14%, P is 0.004%-0.007%, 350-400kg aluminum particles are added after the furnace for deoxidation, and slag is removed after the furnace; 500kg pre-melted slag is added before the ladle filled with molten steel is transported to the LF refining station, and high-power heating is adopted. Al+SiC is used for joint deoxidation in the process. The refining time is 45-50min, and the final temperature is 1611-1617℃ , the aluminum content is basically maintained between 0.025% and 0.045%. In order to increase the N in the steel, the MnN wire is first fed in the LF for 150m. The maximum vacuum degree of the vacuum degassing furnace is 0.54mbar, the vacuum treatment time is 45-47min, and nitrogen is used as the lifting gas in the vacuum degassing stage. After the end, the soft stirring and soft blowing time is 13-16min, and the soft blowing argon flow rate is generally 40-60L / min. Electromagnetic stirring, induction heating of the tundish and light pressure are used for continuous casting. The amount of molten steel in the tundish is 32.5-34.2 tons, and the pouring and pulling speed is 0.55m / min; there is no abnormal situation that the liquid level of the crystallizer fluctuates by more than 6mm, and the amount of residual steel in the large package is not less than 2 tons.

[0021] See Table 1 for specific process data: Table 1

[0022] Examples 4-6 of high carbon chromium bearing steel for rollers: The smelting raw materials are prepared according to the chemical composition of the high carbon chromium bearing steel for rollers. After KR molten iron pretreatment, the sulfur content of the molten iron is reduced to below 0.002%, and the temperature is 1328℃-1342℃. The roughing furnace adopts the iron slag forming route to ensure good slag fluidity in the early stage of dephosphorization. In the later stage, carbon is blown and pulled to increase the temperature. The terminal temperature is 1621℃-1635℃, C0.18%-0.26%, P0.005%-0.008%, 250-350kg aluminum particles are added after the furnace for deoxidation, and the slag is removed after the furnace; 800kg pre-melted slag is added before the ladle filled with molten steel is transported to the LF station, and high-power heating is adopted. Al+SiC is used for joint deoxidation in the process, and the refining time is more than 50 min, end temperature 1550-1559℃, aluminum content at the end of refining is between 0.015%-0.030%; the maximum vacuum degree of the vacuum degassing furnace is 0.61mbar, the vacuum treatment time is 35-37min, the soft stirring and soft blowing time after the end is 21-25min, the soft blowing argon flow rate is generally 40-60L / min, continuous casting adopts electromagnetic stirring, induction heating of the tundish and light pressure, the amount of molten steel in the tundish is 32.2-34.1 tons, and the pouring and pulling speed is 0.50m / min; there is no abnormal situation that the liquid level of the crystallizer fluctuates more than 6mm, and the amount of residual steel in the large ladle is not less than 2 tons.

[0023] See Table 2 for specific process data: Table 2

[0024] The metallurgical quality of the material finally produced by the present invention is compared with the imported bearing materials (numbered 1-7#) of different models of domestic high-speed railways, which are CRH1-380 / CRH3-380 / CRH2A / CRH1-250 / CRH1-200: Comparison of harmful elements in materials is shown in Table 3 and Table 4: The detection equipment includes photoelectric direct reading spectrometer (QSN750) and oxygen and nitrogen combined measuring instrument (TC-600).

[0025] Table 3 Comparison of harmful elements in ferrule steel

[0026] Table 4 Comparison of harmful elements in roller steel

[0027] Phosphorus and sulfur are inevitable impurity elements in steel, which are easy to form defects such as segregation and inclusions, which will have an adverse effect on the fatigue life and hot workability of the bearing. Aluminum, oxygen and titanium can form brittle inclusions. Controlling the content of these harmful elements is beneficial to improving the fatigue life of the bearing. It can be seen from Tables 3 and 4 that the control level of harmful elements in the high-speed rail bearing steel produced by the present invention is much higher than that of the 1-7# sample).

[0028] Comparison of microscopic inclusions, tested according to GB / T 10561 standard A method, see Table 5 and Table 6: Table 5 Comparison of steel inclusions in bearing rings

[0029] Table 6 Comparison of inclusions in bearing roller steel

[0030] The non-metallic inclusions in the high-speed rail bearings destroy the continuity and uniformity of the metal. When the bearings are running, under the action of alternating stress, fatigue crack sources are easily formed between the non-metallic inclusions on the working surface and near the surface and the matrix structure of the material. Under the action of stress, this crack source gradually expands over time and eventually forms fatigue spalling. The early failure of high-speed rail bearings is mostly related to brittle, non-deformable chain-like B-type inclusions and large-particle DS inclusions. The present invention effectively controls the number and size of these two types of inclusions in the material. The inclusion levels of the embodiment are shown in Tables 5 and 6.

[0031] The ultra-pure bearing steel for high-speed EMU bearings formed by the technical process of the present invention has extremely high purity and good structural uniformity. The rolling contact fatigue test is carried out according to the standard JB / T10510-2005 "Contact fatigue test method for rolling bearing parts", and the results are shown in Table 7.

[0032] Table 7

Claims

1. A method for producing ultra-pure carburized bearing steel for axle boxes of high-speed train sets, characterized in that: The process flow is hot metal pretreatment - primary refining - ladle refining - vacuum cycle degassing - continuous casting. KR hot metal pretreatment technology is used to ensure that the hot metal entering the furnace meets the following requirements: S≤0.002%, Si≤0.3%; The primary smelting process is to reduce the phosphorus content and titanium content of the molten iron to below 0.012% and 0.0005% respectively, the end point C ≥ 0.08%, P ≤ 0.010%, the tapping temperature ≥ 1620℃, according to the end point C%, Al-Fe is added during tapping to control the Al content of the first sample in the refining furnace between 0.040 and 0.055%, and the slag is removed after the furnace; The refining slag used in ladle refining is a ternary slag system of CaO-Al2O3-SiO2, wherein CaO≥40wt%, SiO2<16wt%, Al2O3>22wt%, MgO:5-8wt%, and the atmosphere in the furnace is maintained at a slightly positive pressure, with a small amount of furnace smoke emerging from the furnace as the benchmark. Argon gas is used for stirring during the power supply process before taking the first sample to make the slag as quickly as possible, and the argon gas is controlled at 200L / min afterwards; Al+SiC is used for joint deoxidation, %FeO+%MnO in the slag is <1, and the aluminum content is basically maintained between 0.025%-0.045%, the refining time is ≥40min, and the molten steel temperature is 1570~1620℃ at the end of the refining process; The maximum vacuum degree of vacuum degassing is ≤2.33mbar, the high vacuum holding time is ≥10min, and the soft stirring and soft blowing time is ≥12min after the degassing is completed. In order to increase the N in the steel, 150m of MnN wire is fed during refining for carburizing steel. Nitrogen is used as the lifting gas during the vacuum degassing process to make the nitrogen reach the target of 90ppm. After the vacuum degassing is completed, the soft blowing stirring time is ≥12min, and the soft blowing argon flow rate is 40-60L / min; Continuous casting adopts electromagnetic stirring, induction heating of the tundish and light pressure. A larger tundish is used, and the superheat degree of the tundish △T≤20℃; the amount of molten steel in the tundish is 30-35 tons, the casting temperature is 1530-1570℃, the pouring and drawing speed is 0.55±0.05m / min, and the light pressure reduction is 10±0.5mm; if the crystallizer liquid level fluctuation exceeds 6mm, the amount of residual steel in the large ladle shall not be less than 2 tons; in case of abnormal situation, the billets are downgraded separately; the continuous casting hot billets are slowly cooled in the pit for not less than 48 hours, and the pit starting temperature is ≤300℃.

2. The method according to claim 1, characterized in that: Carburizing bearing steel is based on iron and contains other chemical components in percentage by mass: C: 0.19-0.23%, Si: 0.25-0.45%, Mn: 0.50-0.70%, Cr: 0.45-0.60%, P: ≤0.015%, S: ≤0.005%, Mo: 0.20-0.30%, Ni: 1.65-1.90%, Al: 0.02-0.05%, Cu: ≤0.15%, Ca: ≤0.0005%, Ti: ≤0.0015%, O: ≤0.0008%, As: ≤0.01%, Sn: ≤0.02%, Sb: ≤0.005%, Pb: ≤0.002%, H: ≤0.0001%.

3. The method according to claim 1, characterized in that: The bearing ring produced by the carburized bearing steel continuous casting billet obtained by the method has a compression ratio greater than 30, O≤6ppm, Ca≤1ppm, Ti≤5ppm, As+Sn+Sb≤0.0050% in the ring, and microscopic inclusions are tested according to GB / T 10561 A method, B fine ≤1.0 level, B coarse ≤0.5 level, DS≤1.0 level; the macro defect requirement is tested according to the SEP 1927 method, and the length of a single inclusion does not exceed 1mm; the macrostructure requirement is tested according to GB / T 15711, and the central looseness, general looseness, and segregation are all not more than 1.0 level.

4. A method for producing ultra-pure high-carbon chromium bearing steel for axle boxes of high-speed EMUs, characterized in that: The process flow is hot metal pretreatment - primary refining - ladle refining - vacuum cycle degassing - continuous casting. KR hot metal pretreatment technology is used to ensure that the hot metal entering the furnace meets the following requirements: S≤0.002%, Si≤0.3%; The primary smelting process is to reduce the phosphorus content and titanium content of the molten iron to below 0.012% and 0.0005% respectively, the end point C ≥ 0.15%, P ≤ 0.012%, the tapping temperature ≥ 1620℃, according to the end point C%, Al-Fe is added during tapping to control the Al content of the first sample in the refining furnace between 0.040 and 0.055%, and the slag is removed after the furnace; The refining slag used in ladle refining is a ternary slag system of CaO-Al2O3-SiO2, wherein CaO≥40wt%, SiO2<16wt%, Al2O3>22wt%, MgO:5-8wt%, and the atmosphere in the furnace is kept at a slightly positive pressure, with a small amount of furnace smoke emerging from the furnace as the benchmark. Argon gas is used for stirring during the power supply process before taking the first sample to make the slag as quickly as possible, and the argon gas is controlled at 200L / min afterwards; Al+SiC is used for joint deoxidation, %FeO+%MnO in the slag is <1, and the aluminum content is basically maintained between 0.015%-0.030%, the refining time is ≥40min, and the molten steel temperature is 1525~1575℃ at the end of the refining process; The maximum vacuum degree of vacuum degassing is ≤2.33mbar, the high vacuum holding time is ≥10min, after degassing, argon blowing and stirring soft blowing time is ≥12min, and the soft blowing argon flow rate is 40-60L / min; Continuous casting adopts electromagnetic stirring, induction heating of the tundish and light pressure. A larger tundish is used, and the superheat degree of the tundish △T≤20℃; the amount of molten steel in the tundish is 30-35 tons, the casting temperature is 1480-1520℃, the pouring and drawing speed is 0.50±0.05m / min, and the light pressure reduction is 18.5±0.5mm; if the crystallizer liquid level fluctuates by more than 6mm, the amount of excess steel in the large ladle shall not be less than 2 tons; in case of abnormal circumstances, the billets are downgraded individually; the continuous casting hot billets are slowly cooled in the pit for not less than 48 hours, and the pit starting temperature is ≤300℃.

5. The method according to claim 4, characterized in that: High carbon chromium bearing steel is based on iron and contains other chemical components in percentage by mass: C: 0.90~1.10%, Si: 0.15~0.35%, Mn: 0.25~0.50%, Cr: 1.30~1.65%, P≤0.015%, S≤0.015%, Mo≤0.08%, Ni≤0.25%, Al≤0.05%, Cu≤0.3%, Ca≤0.001%, Ti≤0.0015%, O≤0.0005%, As≤0.01%, Sn≤0.02%, Sb≤0.005%, Pb≤0.002%.

6. The method according to claim 4, characterized in that: The bearing roller produced by the high carbon chromium bearing steel continuous casting billet obtained by the method has a compression ratio of more than 32, O≤4ppm, Ca≤1ppm, Ti≤5ppm, As+Sn+Sb≤0.0050% in the roller, and microscopic inclusions are tested according to GB / T 10561 A method, with B fine ≤1.0 level, B coarse ≤0.5 level, and DS≤0.5 level; the macroscopic defect requirement is tested according to the SEP 1927 method, and the length of a single inclusion does not exceed 1mm; the macroscopic structure requirement is tested according to GB / T 18254, and the central looseness, general looseness, and segregation are all not more than 1.0 level; the carbide network and band requirements are tested according to GB / T 18254, and are all not more than 2.0 level.

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