Method for improving performance of H370 grade heavy rail steel by Ce and Y rare earth elements

Abstract

The application discloses a method for improving the performance of H370 grade heavy rail steel by Ce and Y rare earth elements, and comprises the following steps: a smelting process; a casting billet rolling process; and the H370 grade heavy rail steel has the following chemical components in percentage by weight: C: 0.80%, Si: 0.65%, Mn: 0.98%, Cr: 0.30%, V: 0.08%, P: 0.013%, S: 0.004%, Ce: 0.010%, Y: 0.010%, and the rest is Fe and inevitable impurities. The application aims to realize the synergistic improvement of the cleanliness, strength and toughness, toughness and plasticity and low-temperature toughness of the heavy rail steel.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical materials technology for heavy-haul railway rails, and particularly relates to a method for improving the performance of H370 grade heavy rail steel using Ce and Y rare earth elements. Background Technology

[0002] H370 grade heavy rail steel is a key structural steel in my country's heavy-haul railway system. Due to its excellent basic strength and load-bearing capacity, it is widely used in heavy-haul railway trunk lines carrying bulk commodities such as coal and minerals. With the continuous increase in railway carrying capacity and operational density, heavy rail steel needs to maintain stable operation under high contact stress, alternating loads, and complex environments for extended periods, placing stringent requirements on cleanliness, strength, toughness, low-temperature toughness, and microstructure stability. Traditional H370 heavy rail steel smelting processes have significant shortcomings: B, C, and D type inclusions in the steel are large and unevenly distributed, easily inducing stress concentration and crack initiation; high sulfur and oxygen impurity content leads to poor low-temperature toughness and an imbalance between strength and toughness; large pearlite lamellar spacing and insufficient microstructure uniformity make it prone to failures such as peeling, spalling, and excessive wear during service, seriously restricting the safety and lifespan of heavy-haul lines. Currently, some industry solutions employ single rare earth element modification of heavy rail steel, optimizing steel performance to a certain extent through the deoxidation, desulfurization, and inclusion spheroidization modification effects of rare earth elements. However, existing technologies mostly use single cerium-based rare earth elements for microalloying, resulting in limited modification effects and drawbacks such as incomplete inclusion refinement, insufficient microstructure stability during high-temperature rolling, and poor synergistic improvement in toughness and wear resistance. Furthermore, the addition of single rare earth elements easily leads to component segregation and secondary defects caused by rare earth inclusions, resulting in poor modification stability and difficulty in meeting the stringent performance requirements of H370 heavy-duty rail steel. Existing technologies often use single Ce or La rare earth elements, which also suffer from limited modification effects, insufficient microstructure stability, limited improvement in low-temperature toughness, and secondary defects caused by rare earth inclusions, making it difficult to simultaneously achieve a synergistic improvement in cleanliness, strength, toughness, and low-temperature toughness. Therefore, developing Ce-Y composite rare earth modification technology to construct an efficient and stable rare earth compound system, further purifying the steel, optimizing the microstructure, and comprehensively improving the cleanliness and overall service performance of H370 heavy-duty rail steel has become an urgent need for the high-performance development of H370 heavy-duty rail steel.

[0003] Patent application number 202211254842.0 discloses "A Production Method of High-Strength, High-Hardness Online Heat-Treated Rare Earth Rail Material". This patent heats rare earth wires before the LF station is removed, with a rare earth wire feeding amount of 150m, resulting in a rare earth Ce content of 0.001%. The rare earth Ce content in this patent is 0.001%, and no specific explanation is given on the cleanliness level, mechanical properties and microstructure of the rail. Based on the rare earth element content, the added rare earth wires can only play a role in improving inclusions and cannot play a role in alloying. This method has no significant effect on the mechanical properties and microstructure of heavy rail steel.

[0004] Patent application number 202511637178.1 discloses "A Rare Earth-Containing Rail with Excellent Low-Temperature Toughness and Its Online Heat Treatment Method". The chemical composition of the rail in this patent is C: 0.50-0.70%, Si: 0.60-0.75%, Mn: 0.40-0.60%, Cr: 0.50-0.70%, V: 0.03-0.06%, RE: 0.003-0.005%. The tensile strength of this invention is between 1100-1150MPa, and the hardness is between 325-345HB. It is H320 grade heavy rail steel. This steel grade has low strength and hardness, and is not suitable for the service requirements of heavy-load lines. Moreover, it does not reflect the influence of rare earth elements on the cleanliness and microstructure of heavy rail steel.

[0005] Patent application number 202511637178.1 discloses a "Preparation Process for Improving the Strength, Toughness, and Wear Resistance of H370 Grade Heat-Treated Rare Earth Steel Rails." The patent's chemical composition includes C: 0.71-0.81%, Si: 0.50-0.80%, Mn: 0.80-1.10%, Cr: 0.25-1.0%, V: 0.04-0.08%, and rare earth content of 0.0006-0.0021%. It incorporates La / Ce mixed rare earth elements, with Ce ≥ 70%, and adds Ti+Nb composite microalloying followed by low-temperature tempering to enhance the rail's strength and toughness. However, this patent adds high-value Ti and Nb elements, which does not meet standard requirements. Furthermore, the added tempering heat treatment further increases energy consumption, production cycle, and production costs, hindering large-scale industrial production. Moreover, the patent does not demonstrate the impact of rare earth elements on the cleanliness and microstructure of heavy rail steel. Summary of the Invention

[0006] The purpose of this invention is to provide a beneficial effect of Ce and Y rare earth elements on the modification and alloying of inclusions in H370 grade heavy rail steel. Through multiple mechanisms such as purifying the steel, refining the grains, modifying inclusions, and strengthening grain boundaries, the strength, toughness, ductility and low-temperature toughness of the steel are optimized simultaneously, so as to achieve a synergistic improvement in the strength and toughness of H370 grade heavy rail steel.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0008] This invention discloses a method for improving the performance of H370 grade heavy rail steel using Ce and Y rare earth elements, comprising:

[0009] Smelting process:

[0010] 1) Smelting is carried out using a vacuum electric furnace;

[0011] 2) Smelting stage: Add 95-97 kg of heavy rail scrap to the vacuum electric furnace, and vacuum the furnace to a vacuum degree of ≥30 Pa. After the vacuum degree requirement is met, turn on the electric induction heating to melt the furnace charge. The furnace charge melting power is ≥100 kW, and the temperature is raised to 1530–1560℃. The furnace charge melting heating time is controlled at 20-30 min.

[0012] 3) Second stage of smelting: After the furnace charge reaches the target temperature and time requirements during the melting stage, the alloy is added according to the target composition ratio. After the alloy is added, the refining power is ≥70kW, ensuring that the molten steel temperature is between 1550-1570℃, and the alloy refining time is controlled between 5-10min.

[0013] 4) Three-stage smelting: After the molten steel reaches the target temperature and time requirements through alloying and refining, 20-30% cerium-iron alloy and 20-30% yttrium-iron alloy are added according to the target composition ratio. The oxygen content in the added rare earth alloy must not exceed 100 ppm. Rare earth alloy refining is carried out continuously using a power of ≥70kW. The molten steel temperature is maintained between 1550-1570℃, and the rare earth alloy refining time is controlled within 2-5 minutes.

[0014] 5) Fourth stage of smelting: After the rare earth alloying refining of molten steel reaches the target temperature and time requirements, vacuum casting is carried out. The casting vacuum degree is ≥20 Pa, and the cross-sectional area of ​​the cast round or square billet should not be less than 7100 mm². 3 The cast billet needs to be slowly cooled to room temperature in the ingot mold before being demolded;

[0015] Billet rolling:

[0016] 1) The heating temperature of the billet is 1200-1250℃, the heating time is >180min, the heating rate is ≤400℃ / h, the soaking temperature is 1200-1230℃, and the soaking time is >40min;

[0017] 2) The billet rolling adopts a reversible rolling mill, and high-pressure water or mechanical means are used to remove the oxide scale on the billet. The oxide scale removal rate is not less than 95%, the number of rolling passes is not less than 11, the rolling compression ratio is not less than 10:1, and the final rolling shape of the billet is based on the actual rail shape or inspection requirements.

[0018] 3) The initial rolling temperature of the billet is 1050-1110℃, the final rolling temperature is not higher than 930℃, and the temperature reduction between rolling passes is controlled below 20℃.

[0019] 4) After the billet is finally rolled, the rail is immediately subjected to slow cooling treatment, cooling the rail from 930℃ to 490℃. The cooling rate should not be higher than 6℃ / s and should not be lower than 3℃ / s.

[0020] 5) After the rails are controlled to cool, they are air-cooled to room temperature to ensure that the rail temperature does not exceed 530℃.

[0021] Furthermore, in the second smelting stage, 80% ferrosilicon, 97% metallic manganese, 70% ferrochrome, and 85% ferrovanadium are added to a vacuum smelting furnace.

[0022] Furthermore, during the alloy refining process, a bottom-blowing device is used to stir the molten steel.

[0023] Furthermore, the forward and backward tilting operation of the tilting furnace device is adopted to tilt the crucible forward or backward, so as to achieve the purpose of stirring the molten liquid.

[0024] Furthermore, the cooling medium is water mist or a combination of high-pressure air and water mist.

[0025] Furthermore, the weight percentage of the chemical composition of the H370 grade heavy rail steel is C: 0.80%, Si: 0.65%, Mn: 0.98%, Cr: 0.30%, V: 0.08%, P: 0.013%, S: 0.004%, Ce: 0.010%, Y: 0.010%, with the remainder being Fe and unavoidable impurities.

[0026] Furthermore, the obtained H370 grade heavy rail steel containing Ce and Y rare earth elements meets the following performance requirements: tensile strength ≥1350MPa, elongation after fracture ≥12%, tread hardness ≥380HBW, impact energy at -20℃ ≥10J, fracture toughness at -20℃ KIC ≥35MPa·m1 / 2, pearlite lamellar spacing ≤0.16μm, microstructure consisting of pearlite and a small amount of ferrite, and the proportion of B, C, and D type inclusions ≤1.0 grade ≥80%.

[0027] Compared with the prior art, the beneficial technical effects of the present invention are as follows:

[0028] This invention addresses the problems of poor cleanliness, excessive inclusions, poor strength and toughness, and poor low-temperature toughness in H370 grade heavy rails. It utilizes the beneficial effects of rare earth element modification and alloying to simultaneously optimize the strength, toughness, plasticity, and low-temperature toughness of steel through multiple mechanisms such as purifying the steel, refining the grains, modifying inclusions, and strengthening grain boundaries, thereby achieving a synergistic improvement in the strength and toughness of the steel.

[0029] This invention utilizes the beneficial effects of Ce and Y rare earth elements on the modification and alloying of inclusions in heavy rail steel to obtain H370 grade heavy rail steel containing Ce and Y rare earth elements. The resulting steel has a tensile strength ≥1350MPa, elongation after fracture ≥12%, tread hardness ≥380HBW, impact energy at -20℃ ≥10J, fracture toughness KIC at -20℃ ≥35MPa·m1 / 2, pearlite lamellar spacing ≤0.16μm, and a microstructure consisting of pearlite and a small amount of ferrite. The proportion of B, C, and D type inclusions ≤1.0 grade is ≥80%, achieving a synergistic improvement in the cleanliness, strength, toughness, plasticity, and low-temperature toughness of the heavy rail steel. Attached Figure Description

[0030] The present invention will be further described below with reference to the accompanying drawings.

[0031] Figure 1 Example 3: Microstructure and interlaminar spacing of rail. Detailed Implementation

[0032] The specific implementation process of a method for improving the cleanliness and performance of H370 grade heavy rail steel using Ce and Y rare earth elements is as follows:

[0033] 1) The H370 grade heavy rail steel of this invention is smelted in a vacuum electric furnace, and the raw materials for smelting are: heavy rail scrap steel, ferroalloys, rare earth alloys, etc.

[0034] 2) Add 95-97 kg of heavy rail scrap to the vacuum furnace, and evacuate the furnace to a vacuum degree of ≥30 Pa. After the vacuum degree requirement is met, turn on the induction heating to melt the furnace charge. The furnace charge melting power is ≥100 kW, and the temperature is raised to 1530–1560 ℃. The furnace charge melting and heating time is controlled at 20-30 min.

[0035] 3) After the furnace charge reaches the target temperature and time requirements during the melting stage, add ferroalloys or metals according to the specific content of C: 0.80%, Si: 0.65%, Mn: 0.98%, Cr: 0.30%, V: 0.08% in the chemical composition of H370 grade heavy rail steel, including ferrosilicon with a grade of 80%, metallic manganese with a grade of 97%, ferrochrome with a grade of 70%, and ferrovanadium with a grade of 85%.

[0036] 4) After the alloy is added, the refining power is ≥70kW, the molten steel temperature is kept between 1550-1570℃, and the alloy refining time is controlled between 5-10min.

[0037] 5) After the molten steel alloying refining reaches the target temperature and time requirements, add various rare earth alloys according to the specific content of Ce: 0.010% and Y: 0.010% in the chemical composition of H370 grade heavy rail steel. The grade of cerium iron is 20-30% and the grade of yttrium iron is 20-30%. The oxygen content in the added rare earth alloys shall not exceed 100ppm.

[0038] 6) Use a power of ≥70kW for continuous rare earth alloy refining. Ensure the molten steel temperature is between 1550-1570℃, and control the rare earth alloy refining time to 2-5 minutes. During the alloy refining process, a bottom blowing device can be used to stir the molten steel, and the forward and backward tilting operation of the furnace device can also be used to tilt the crucible forward or backward to achieve the purpose of stirring the molten liquid.

[0039] 7) After the rare earth alloying refining of molten steel reaches the target temperature and time requirements, vacuum casting is carried out. The casting vacuum degree is ≥20pa. The cross-sectional area of ​​the round or square billet to be cast should not be less than 7100mm3. The cast billet needs to be slowly cooled to room temperature in the ingot mold before demolding.

[0040] 8) The weight percentage of the chemical composition of the cast billet should be: C: 0.80%, Si: 0.65%, Mn: 0.98%, Cr: 0.30%, V: 0.08%, P: 0.013%, S: 0.004%, Ce: 0.010%, Y: 0.010%, with the remainder being Fe.

[0041] 9) The cast billet is heated, rolled and cooled in a controlled manner. The heating temperature of the billet is 1200-1250℃, the heating time is >180min, the heating rate is ≤400℃ / h, the heat treatment temperature is 1200-1230℃ and the heat treatment time is >40min.

[0042] 10) The billet rolling adopts a reversible rolling mill, and high-pressure water or mechanical means are used to remove the oxide scale on the billet. The oxide scale removal rate is not less than 95%, the number of rolling passes is not less than 11, the rolling compression ratio is not less than 10:1, and the final rolling shape of the billet is based on the actual rail shape or inspection requirements.

[0043] 11) The initial rolling temperature of the billet is 1050-1110℃, the final rolling temperature is not higher than 930℃, and the temperature reduction between rolling passes is controlled below 20℃.

[0044] 12) After the billet is finally rolled, the rail is immediately subjected to slow cooling treatment. The cooling medium can be water mist, high-pressure air, water mist + high-pressure air, etc., to cool the rail from 930℃ to 490℃. The cooling rate should not be higher than 6℃ / s and should not be lower than 3℃ / s.

[0045] 13) After the rails are controlled to cool, they are air-cooled to room temperature to ensure that the rail temperature does not exceed 530℃.

[0046] 4.2 Comparison during implementation

[0047] The key technologies in the smelting and rolling process of H370 grade heavy rail steel designed in this invention were compared during implementation. Examples and comparative examples are shown in Tables 1-2.

[0048] Table 1. Comparison of different components (mass fraction) during implementation / %

[0049]

[0050] As shown in Table 1, the contents of C, Si, Mn, Cr, and V in the chemical composition of the rails are the same in Comparative Example 1, Comparative Example 2, and Examples 1-3. Among them, Comparative Example 2 contains 0.0005% rare earth element Ce, Example 1 contains 0.005% rare earth element Ce, Example 2 contains 0.005% rare earth element Ce and 0.005% rare earth element Y, and Example 3 contains 0.010% rare earth element Ce and 0.010% rare earth element Y.

[0051] Comparative Examples 1 and 2 were produced using the same smelting, rolling, and heat treatment processes: 95-97 kg of heavy rail scrap was added to a vacuum furnace, which was then evacuated to a vacuum level of 30 Pa. After achieving the required vacuum level, induction heating was applied to melt the charge. The furnace charge melting power was 102 kW, and the temperature was raised to 1565 °C. The melting and heating time was controlled within 23 minutes. The chemical composition was controlled according to the target chemical composition of the examples, with ferroalloys and rare earth alloys added simultaneously. After addition, the refining power was 74 kW to ensure the steel temperature was maintained. The alloy refining time is controlled between 5-10 min and 1555℃; the casting vacuum degree is ≥20 Pa, and the cross-sectional area of ​​the cast round or square billet should not be less than 7100 mm3; the heating temperature of the billet is 1220℃, the heating time is >180 min, the heating rate is ≤400℃ / h, the soaking temperature is 1210℃, and the soaking time is >40 min; the rolling passes are 11; the initial rolling temperature is 1110℃, and the final rolling temperature is 930℃; after final rolling, the rail is cooled from 930℃ to 490℃ at a cooling rate of 3.8℃ / s.

[0052] Examples 1-3 employ the same smelting, rolling, and heat treatment processes: 95-97 kg of heavy rail scrap is added to a vacuum furnace. The furnace is then evacuated to a vacuum level of 30-33 Pa, with a furnace charge melting power of 100-105 kW. The temperature is raised to 1530-1560℃, and the melting time is controlled at 20-30 minutes. After the furnace charge reaches the target temperature and time requirements during melting, ferroalloys or metals are added according to the specific content of H370 grade heavy rail steel: C: 0.80%, Si: 0.65%, Mn: 0.98%, Cr: 0.30%, V: 0.08%. After alloying, the refining power is ≥70 kW, ensuring the steel temperature is between 1550-1570℃, and the alloy refining time is controlled at 5-10 minutes. After the alloying refining of the steel reaches the target temperature and time requirements, the steel is further refined according to the H370 grade heavy rail steel chemical composition... The specific content of Ce: 0.010%, Y: 0.010% is determined by adding various rare earth alloys, and the oxygen content in the added rare earth alloys must not exceed 100 ppm. After adding the rare earth alloys, the rare earth alloy refining is carried out continuously with a power of ≥70kW, ensuring that the molten steel temperature is between 1550-1570℃, and the rare earth alloy refining time is controlled within 2-5 minutes. The casting vacuum degree is ≥20pa, and the cross-sectional area of ​​the cast round or square billet should not be less than 7100m². m3; the heating temperature of the billet is 1200-1250℃, the heating time is >180min, the heating rate is ≤400℃ / h, the soaking temperature is 1200-1230℃, and the soaking time is >40min; the rolling passes are 11; the initial rolling temperature is 1050-1110℃, and the final rolling temperature is not higher than 930℃; after final rolling, the rail is cooled from 930℃ to 490℃ at a cooling rate of 3.8℃ / s, and the rail reheating temperature is not higher than 530℃.

[0053] Table 2. Ratio of inclusions ≤1.0 in different implementation processes

[0054]

[0055] As shown in Table 2, the proportion of B and C inclusions ≤1.0 level in Comparative Examples 1 and 2 is between 57% and 75%, with the lowest proportion of C fine inclusions ≤1.0 level being 57%. Examples 1 and 2 show a significant improvement in the proportion of B, C, and D inclusions ≤1.0 level compared to the Comparative Examples, with the proportion of B and C inclusions ≤1.0 level between 71% and 88%, and the lowest proportion of C fine inclusions ≤1.0 level being 71%. In Example 3 of this invention, the proportion of B, C, and D inclusions ≤1.0 level is ≥80%, indicating the highest rail cleanliness.

[0056] Table 3 Comparison of mechanical properties during different implementation processes

[0057]

[0058] Table 3 shows that Comparative Example 1 has a tensile strength of 1327 MPa, an elongation of 10%, a tread hardness of 373 HBW, an impact energy of 6.5 J at -20℃, a fracture toughness of 30.1 MPa·m1 / 2 at -20℃, and a pearlite lamellar spacing of 0.198 μm; Comparative Example 2 has a tensile strength of 1328 MPa, an elongation of 10.5%, a tread hardness of 375 HBW, an impact energy of 7.1 J at -20℃, a fracture toughness of 31.5 MPa·m1 / 2 at -20℃, and a pearlite lamellar spacing of 0.191 μm; Example 1 has a tensile strength of 1335 MPa, an elongation of 11%, a tread hardness of 379 ... and a fracture toughness of 30.1 MPa·m1 / 2 at -20℃. Example 1 has an impact energy of 8.5 J at -20℃, a fracture toughness of 32.4 MPa·m1 / 2 at -20℃, and a pearlite lamellar spacing of 0.182 μm; Example 2 has a tensile strength of 1340 MPa, an elongation of 11.5%, a tread hardness of 381 HBW, an impact energy of 9.7 J at -20℃, a fracture toughness of 3.9 MPa·m1 / 2 at -20℃, and a pearlite lamellar spacing of 0.176 μm; Example 3 has a tensile strength of 1357 MPa, an elongation of 12%, a tread hardness of 386 HBW, an impact energy of 10.4 J at -20℃, a fracture toughness of 35.2 MPa·m1 / 2 at -20℃, and a pearlite lamellar spacing of 0.160 μm.

[0059] Examples 1-3 show significantly improved strength and toughness compared to Comparative Examples 1 and 2, with Example 3 exhibiting the best overall performance, achieving a synergistic improvement in the cleanliness, strength, toughness, plasticity, and low-temperature toughness of heavy rail steel.

[0060] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for improving the performance of H370 grade heavy rail steel using Ce and Y rare earth elements, characterized in that: include: Smelting process: 1) Smelting is carried out using a vacuum electric furnace; 2) Smelting stage: Add 95-97 kg of heavy rail scrap to the vacuum electric furnace, and vacuum the furnace to a vacuum degree of ≥30 Pa. After the vacuum degree requirement is met, turn on the electric induction heating to melt the furnace charge. The furnace charge melting power is ≥100 kW, and the temperature is raised to 1530–1560℃. The furnace charge melting heating time is controlled at 20-30 min. 3) Second stage of smelting: After the furnace charge reaches the target temperature and time requirements during the melting stage, the alloy is added according to the target composition ratio. After the alloy is added, the refining power is ≥70kW, ensuring that the molten steel temperature is between 1550-1570℃, and the alloy refining time is controlled between 5-10min. 4) Three-stage smelting: After the molten steel reaches the target temperature and time requirements through alloying and refining, 20-30% cerium-iron alloy and 20-30% yttrium-iron alloy are added according to the target composition ratio. The oxygen content in the added rare earth alloy must not exceed 100 ppm. Rare earth alloy refining is carried out continuously using a power of ≥70kW. The molten steel temperature is maintained between 1550-1570℃, and the rare earth alloy refining time is controlled within 2-5 minutes. 5) Fourth stage of smelting: After the rare earth alloying refining of molten steel reaches the target temperature and time requirements, vacuum casting is carried out. The casting vacuum degree is ≥20 Pa, and the cross-sectional area of ​​the cast round or square billet should not be less than 7100 mm². 3 The cast billet needs to be slowly cooled to room temperature in the ingot mold before being demolded; Billet rolling: 1) The heating temperature of the billet is 1200-1250℃, the heating time is >180min, the heating rate is ≤400℃ / h, the soaking temperature is 1200-1230℃, and the soaking time is >40min; 2) The billet rolling adopts a reversible rolling mill, and high-pressure water or mechanical means are used to remove the oxide scale on the billet. The oxide scale removal rate is not less than 95%, the number of rolling passes is not less than 11, the rolling compression ratio is not less than 10:1, and the final rolling shape of the billet is based on the actual rail shape or inspection requirements. 3) The initial rolling temperature of the billet is 1050-1110℃, the final rolling temperature is not higher than 930℃, and the temperature reduction between rolling passes is controlled below 20℃. 4) After the billet is finally rolled, the rail is immediately subjected to slow cooling treatment, cooling the rail from 930℃ to 490℃. The cooling rate should not be higher than 6℃ / s and should not be lower than 3℃ / s. 5) After the rails are controlled to cool, they are air-cooled to room temperature to ensure that the rail temperature does not exceed 530℃.

2. The method for improving the performance of H370 grade heavy rail steel using Ce and Y rare earth elements according to claim 1, characterized in that: The second smelting stage involves adding 80% ferrosilicon, 97% metallic manganese, 70% ferrochrome, and 85% ferrovanadium to a vacuum smelting furnace.

3. The method for improving the performance of H370 grade heavy rail steel using Ce and Y rare earth elements according to claim 1, characterized in that: During the alloy refining process, a bottom-blowing device is used to stir the molten steel.

4. The method for improving the performance of H370 grade heavy rail steel using Ce and Y rare earth elements according to claim 1, characterized in that: The forward and backward tilting operation of the tilting furnace device is used to tilt the crucible forward or backward, thereby achieving the purpose of stirring the molten liquid.

5. The method for improving the performance of H370 grade heavy rail steel using Ce and Y rare earth elements according to claim 1, characterized in that: The cooling medium is either water mist or a combination of water mist and high-pressure air.

6. The method for improving the performance of H370 grade heavy rail steel using Ce and Y rare earth elements according to claim 1, characterized in that: The weight percentage of the chemical composition of the H370 grade heavy rail steel is C: 0.80%, Si: 0.65%, Mn: 0.98%, Cr: 0.30%, V: 0.08%, P: 0.013%, S: 0.004%, Ce: 0.010%, Y: 0.010%, with the remainder being Fe and unavoidable impurities.

7. The method for improving the performance of H370 grade heavy rail steel using Ce and Y rare earth elements according to claim 1 or 6, characterized in that: The obtained H370 grade heavy rail steel containing Ce and Y rare earth elements meets the following performance requirements: tensile strength ≥1350MPa, elongation after fracture ≥12%, tread hardness ≥380HBW, impact energy at -20℃ ≥10J, fracture toughness at -20℃ KIC ≥35MPa·m1 / 2, pearlite lamellar spacing ≤0.16μm, microstructure consisting of pearlite and a small amount of ferrite, and the proportion of B, C, and D grade inclusions ≤1.0 ≥80%.

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