High-quality guide rail steel and preparation method thereof

Abstract

The present invention belongs to the technical field of alloy steel, specifically relating to a high-quality guide rail steel and its preparation method. The corrosion-resistant element Cu is added to the steel composition, and the aluminum-nitrogen ratio in the steel is controlled. The process includes KR desulfurization, electric furnace smelting, an argon station, LF refining, RH vacuum treatment, billet continuous casting, and rolling. By optimizing the process route, rationally selecting raw and auxiliary materials, and controlling process parameters during steelmaking and rolling, the generation of low-melting-point inclusions is reduced, the corrosion-resistant element Cu is increased, and the aluminum-nitrogen ratio in the steel is controlled. Continuous casting uses appropriate pouring and stirring parameters, and the rolling process utilizes a high-temperature diffusion process, making the low-magnification structure more uniform and more conducive to improving hardenability. The resulting steel has ultra-low oxygen and ultra-low calcium, is purer, has a more uniform structure, and has a shallower decarburization layer, making it more convenient for customers to use.

Description

Technical Field

[0001] The present invention belongs to the technical field of alloy steel, and in particular relates to high-quality guide rail steel and a preparation method thereof. Background Art

[0002] Guide rails are widely used parts in machinery. The accuracy, load-bearing capacity and service life of guide rails directly affect the working quality of the machinery. In recent years, with the continuous expansion of China's power industry, data communication industry, urban rail transportation industry, shipbuilding industry, automobile industry and other industries, the application areas of guide rails have become increasingly wider and wider. They are widely used in high-precision machine tools, laser welding machines, medical equipment and semiconductor industries. Inclusions are an important indicator for evaluating the purity of steel and directly affect the various performance indicators of guide rails. Inclusions in steel will destroy the continuity of the steel matrix and generate fatigue crack sources under the action of alternating stress, which directly affects the service life of the guide rails. The degree of homogenization of the steel directly affects the hardenability. As the guide rail application industry becomes more and more high-end, higher requirements are placed on the purity and homogenization of steel raw materials. Summary of the Invention

[0003] One of the objects of the present invention is to provide a high-quality guide rail steel, wherein the composition range of the guide rail steel is C: 0.53-0.60%, Si: 0.20-0.30%, Mn: 0.70-1.10%, Cr: 0.10-0.25%, Mo≤0.05%, Cu: 0.06-0.09%, Ni≤0.15%, Al: 0.020-0.030%, P≤0.022%, S≤0.005%, Ca≤0.0002%, Ti≤0.0010%, O≤6ppm, N: 80-110ppm, Al / N: 1.7-2.7; the rest is iron.

[0004] The second object of the present invention is to provide a method for preparing high-quality guide rail steel, the process flow is: KR desulfurization, electric furnace smelting, argon station, LF refining, RH vacuum treatment, billet continuous casting, rolling. The specific steps are:

[0005] KR: The temperature of molten iron arriving at the station is ≥1380℃. 6-8kg of desulfurizer is added to each ton of steel for mechanical stirring and desulfurization. The sulfur content in the steel is controlled to be ≤0.001%.

[0006] Electric furnace smelting: The raw material is pure molten iron, high carbon drawing is performed, and steel is tapped from an EBT eccentric bottom. During the tapping process, 50% deoxidizer, carbon powder, 50% deoxidizer, a low-calcium, low-titanium alloy, and top slag are added in sequence. The deoxidizer is aluminum block. The low-calcium, low-titanium alloy is added after the converter according to target values. The low-calcium, low-titanium alloy includes low-calcium, low-titanium ferrosilicon, low-calcium, low-titanium ferromanganese, or low-calcium, low-titanium ferrochrome. The top slag ratio is 400kg lime + 800kg furnace protection agent. The low-calcium, low-titanium alloy contains ≤0.010% titanium and ≤0.008% calcium.

[0007] Argon station: After the molten steel arrives at the argon station, samples are taken for analysis of aluminum content. Based on the sample analysis results, the aluminum content is adjusted to 0.055%-0.070% using aluminum wire;

[0008] LF refining: In the early stage of refining, high-speed power supply and strong argon stirring are used to melt the slag, lime is added in an appropriate amount, and silicon carbide is used for deoxidation to produce white slag. In the middle and late stages of refining, the power supply level and argon flow rate are reduced, and silicon carbide is scattered to protect the slag. The refining cycle is 25-50 minutes. Furthermore, in the early stage of refining, high-speed voltage is used for power supply and the bottom-blowing argon flow rate is 200-500Nl / min. In the middle and late stages of refining, medium-low speed voltage is used for power supply and the bottom-blowing argon flow rate is 50-200Nl / min.

[0009] RH furnace: maintain RH vacuum degree ≤ 67Pa for 20-30min; feed calcium silicon wire after breaking the air. Since secondary oxidation is inevitable during the continuous casting process, feed 100 meters / furnace in the first furnace to avoid the stopper rod rising due to secondary oxidation. Feed 25 meters / furnace in the continuous casting furnace to ensure stable continuous casting and control the calcium content in the steel at an extremely low level. Soft blowing operation is carried out after breaking the air, and the soft blowing time is 15-25min; among them, the feeding rate of calcium silicon wire is about 4.5m / s.

[0010] Billet continuous casting: Continuous casting utilizes tightly protected pouring, using a 225mm x 275mm cross-section, a casting speed of 0.67-0.73m / min, a specific water volume of 0.18L / kg, and a secondary cooling water distribution ratio of 25:40:35. Three-stage electromagnetic stirring is employed: mold electromagnetic stirring, pulsed electromagnetic stirring, and end-stage electromagnetic stirring. Mold electromagnetic stirring is 280A x 2.5Hz, pulsed magneto-oscillation (PMO) voltage is 145V, and end-stage electromagnetic stirring is 150A x 5Hz. This significantly increases the proportion of equiaxed grains in the billet and significantly improves steel homogeneity. Tightly protected pouring during continuous casting includes measures such as argon sealing of the sprue nozzle, long shroud lengths in the ladle, and argon blowing in the tundish, primarily to prevent secondary oxidation during the pouring process.

[0011] Rolling: The ingot is sprayed with high-temperature anti-decarburization coating. The heating process for steel rolling is as follows: preheating section temperature 750-900℃, heating section temperature 980-1220℃, heating section temperature 2 and soaking section temperature 1150-1230℃, total heating time 250-370min, starting rolling temperature 1050℃-1140℃, and the bar is rolled into products through multiple passes on the bar production line. The final rolling temperature is controlled by a water tank at 850℃-920℃.

[0012] The beneficial effects of the present invention are: 1. Optimizing the process flow, strictly controlling the amount of sulfur and calcium brought into the molten steel, reducing the generation of low-melting-point inclusions, and at the same time, RH micro-calcium treatment can not only ensure that the steel has ultra-high purity, but also effectively increase the number of continuous casting furnaces and reduce production costs. 2. Adjusting the composition control of the steel, increasing the corrosion-resistant element Cu and controlling the aluminum-nitrogen ratio in the steel, using appropriate pouring parameters and stirring parameters for continuous casting, and using a high-temperature diffusion process in the rolling process to make the low-multiple structure more uniform, which is more conducive to improving the hardening performance. 3. Guide rail steels with similar compositions are extremely sensitive to decarburization, and considering the cost impact, customers often have extremely high requirements for the decarburization layer, so a low-temperature heating process is often used to ensure that the decarburization layer meets customer requirements. The present application uses high-temperature anti-decarburization and dematerialization before heating the ingot, and uses a high-temperature diffusion process for steel rolling. While being able to meet the customer's requirements for the decarburization layer, the steel structure is more uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a low-magnification photograph of the round steel in Example 1;

[0014] Figure 2 This is a low-magnification photograph of the round steel of Comparative Example 4;

[0015] Figure 3 This is the purity C scan image of the water immersion flaw detection in Example 2 (SEP19275 level accuracy);

[0016] Figure 4 This is the purity C scan diagram of the water immersion flaw detection of comparative example 3 (SEP19275 level accuracy). DETAILED DESCRIPTION

[0017] The present invention is further described in detail below in conjunction with production examples:

[0018] The steel composition range is C: 0.53-0.60%, Si: 0.20-0.30%, Mn: 0.70-1.10%, Cr: 0.10-0.25%, Mo≤0.05%, Cu: 0.06-0.09%, Ni≤0.15%, Al: 0.020~0.030%, P≤0.022%, S≤0.005%, Ca≤0.0002%, Ti≤0.0010%, O≤6ppm, N: 80-110ppm, Al / N: 1.7-2.7; the rest is iron.

[0019] The process flow is: KR desulfurization, electric furnace smelting, argon station, LF refining, RH vacuum treatment, small square billet continuous casting, and rolling.

[0020] Example 1

[0021] The specific steps of production using the above process are as follows:

[0022] KR: The temperature of molten iron arriving at the station is 1400℃. 6.5kg of desulfurizer is added to each ton of steel for mechanical stirring and desulfurization. The sulfur content of the molten iron is ≤0.001%.

[0023] Electric furnace smelting: The raw material is pure molten iron, high carbon drawing operation, and EBT eccentric bottom tapping is adopted. During the tapping process, 110kg deoxidizer, 700kg carbon powder, 110kg deoxidizer, alloy, and top slag are added; the deoxidizer is aluminum block, and the alloy types are low-calcium and low-titanium ferrosilicon, low-calcium and low-titanium ferromanganese, and low-calcium and low-titanium ferrochrome. Low-calcium and low-titanium ferrosilicon is added at the end of the furnace according to the target value. The top slag ratio is 400kg lime + 800kg furnace protective agent;

[0024] Argon station: After the molten steel arrives at the argon station, samples are taken for analysis of aluminum content. Based on the sample analysis results, the aluminum content is adjusted to 0.60% using an aluminum wire;

[0025] LF refining: In the early stage of refining, high voltage is used for power supply, 400Nl / min bottom blowing argon is used for strong stirring and slag dissolution, lime is added in appropriate amount, and silicon carbide is used for deoxidation to produce white slag. In the middle and late stages of refining, the power supply is reduced to medium-low voltage, the bottom blowing argon flow rate is reduced to 100Nl / min, and silicon carbide is frequently added for slag preservation. The refining cycle is 45 minutes.

[0026] RH furnace: maintain RH vacuum degree ≤ 67Pa for 22 minutes; feed calcium silicon wire after breaking the vacuum. Since secondary oxidation is inevitable during the continuous casting process, feed 100 meters / furnace in the first furnace to avoid the stopper rod rising due to secondary oxidation. Feed 25 meters / furnace in the next continuous casting furnace to ensure stable continuous casting and control the calcium content in the steel at an extremely low level. After breaking the vacuum, soft blowing operation is carried out, and the soft blowing time is 20 minutes;

[0027] Billet continuous casting: Continuous casting adopts strict protection pouring, 225mm*275mm cross-section pouring, casting speed 0.70 / min, specific water volume 0.18L / kg, secondary cooling water distribution ratio of 25:40:35, and three-stage electromagnetic stirring of crystallizer electromagnetic stirring + pulse electromagnetic stirring + end electromagnetic stirring. The crystallizer electromagnetic stirring is 280A*2.5Hz, PMO voltage is 145V, and the end electromagnetic stirring is 150A*5Hz.

[0028] Rolling: The ingot is sprayed with high-temperature anti-decarburization coating. The heating process for steel rolling is as follows: preheating section temperature 750-890℃, heating section temperature 1000-1180℃, heating section temperature 2 and soaking section temperature 1170-1210℃, total heating time 310min, starting rolling temperature 1070℃-1100℃, and the bar is rolled into products through multiple passes on the bar production line. The final rolling temperature is controlled by a water tank at 850℃-890℃.

[0029] The main components and gas content of the high-quality guide rail steel smelted by the above method are: C: 0.55%, Si: 0.24%, Mn: 0.89%, Cr: 0.18%, Mo: 0.002%, Cu: 0.07%, Ni: 0.02%, Al: 0.025%, P: 0.010%, S: 0.001%, Ca: 0.0001%, Ti: 0.0008%, O: 5.5ppm, N: 100ppm; Al / N: 2.5. Specific indicators are shown in Appendix 1 and Table 2.

[0030] Example 2

[0031] The specific steps of production using this process are as follows:

[0032] KR: The temperature of molten iron arriving at the station is 1400℃. 6.5kg of desulfurizer is added per ton of steel for mechanical stirring and desulfurization.

[0033] Electric furnace: The raw material is pure molten iron, high carbon drawing operation, and EBT eccentric bottom tapping. During the tapping process, 100kg deoxidizer, 730kg carbon powder, 100kg deoxidizer, alloy, and top slag are added; the deoxidizer is aluminum block, and the alloy types are low-calcium and low-titanium ferrosilicon, low-calcium and low-titanium ferromanganese, and low-calcium and low-titanium ferrochrome. Low-calcium and low-titanium ferrosilicon is added at the end of the furnace according to the target value. The top slag ratio is 400kg lime + 800kg furnace protective agent;

[0034] Argon station: After the molten steel arrives at the argon station, samples are taken for analysis of aluminum content. Based on the sample analysis results, the aluminum content is adjusted to 0.58% using aluminum wire;

[0035] LF refining: In the early stage of refining, high voltage is used for power supply, 450Nl / min bottom blowing argon is used for strong stirring and slag dissolution, lime is added in appropriate amounts, and silicon carbide is used for deoxidation to produce white slag. In the middle and late stages of refining, the power supply is reduced to medium-low voltage, the bottom blowing argon flow rate is reduced to 120Nl / min, and silicon carbide is frequently added for slag preservation. The refining cycle is 46 minutes.

[0036] RH furnace: maintain RH vacuum degree ≤ 67Pa for 25 minutes; feed calcium silicon wire after breaking the vacuum. Since secondary oxidation is inevitable during the continuous casting process, feed 100 meters / furnace in the first furnace to avoid the stopper rod rising due to secondary oxidation. Feed 25 meters / furnace in the next continuous casting furnace to ensure stable continuous casting and control the calcium content in the steel at an extremely low level. After breaking the vacuum, soft blowing operation is carried out, and the soft blowing time is 18 minutes;

[0037] Billet continuous casting: Continuous casting adopts strict protection pouring, 225mm*275mm cross-section pouring, casting speed 0.70 / min, specific water volume 0.18L / kg, secondary cooling water distribution ratio of 25:40:35, and three-stage electromagnetic stirring of crystallizer electromagnetic stirring + pulse electromagnetic stirring + end electromagnetic stirring. The crystallizer electromagnetic stirring is 280A*2.5Hz, PMO voltage is 145V, and the end electromagnetic stirring is 150A*5Hz.

[0038] Rolling: The ingot is sprayed with high-temperature anti-decarburization coating. The heating process for steel rolling is as follows: preheating section temperature 780-900℃, heating section temperature 980-1180℃, heating section temperature 2 and soaking section temperature 1180-1220℃, total heating time 320min, starting rolling temperature 1080℃-1120℃, and the bar is rolled into products through multiple passes on the bar production line. The final rolling temperature is controlled by a water tank at 850℃-890℃.

[0039] The main components and gas content of the high-quality guide rail steel smelted by the above method are: C: 0.57%, Si: 0.25%, Mn: 0.86%, Cr: 0.17%, Mo: 0.002%, Cu: 0.07%, Ni: 0.01%, Al: 0.024%, P: 0.010%, S: 0.001%, Ca: 0.0001%, Ti: 0.0007%, O: 5.4ppm, N: 95ppm; Al / N: 2.5. Specific indicators are shown in Appendix 1 and Table 2.

[0040] Comparative Example 1

[0041] Compared with Example 1, the main difference is that the process flow does not include KR desulfurization treatment.

[0042] The main components and gas content of the high-quality guide rail steel smelted by the above method are: C: 0.56%, Si: 0.23%, Mn: 0.87%, Cr: 0.17%, Mo: 0.003%, Cu: 0.08%, Ni: 0.01%, Al: 0.023%, P: 0.010%, S: 0.003%, Ca: 0.0003%, Ti: 0.0009%, O: 6.5ppm, N: 88ppm; Al / N: 2.6. Specific indicators are shown in Appendix 1 and Table 2.

[0043] Comparative Example 2

[0044] Compared with Example 1, the main differences are: the alloy is not a low-calcium, low-titanium alloy, but ordinary ferrosilicon, ferromanganese and ferrotitanium; the timing of addition is not after the furnace, but a conventional addition method is adopted, with part added during the steelmaking process of the primary furnace and part added during the refining process.

[0045] The main components and gas content of the high-quality guide rail steel smelted by the above method are: C: 0.57%, Si: 0.25%, Mn: 0.89%, Cr: 0.14%, Mo: 0.001%, Cu: 0.07%, Ni: 0.01%, Al: 0.025%, P: 0.011%, S: 0.003%, Ca: 0.0003%, Ti: 0.0015%, O: 6.6ppm, N: 98ppm; Al / N: 2.55. Specific indicators are shown in Appendix 1 and Table 2.

[0046] Comparative Example 3

[0047] Compared with Example 1, the main difference is that all the calcium silicon wires in the RH furnace are fed at a rate of 100 meters per furnace.

[0048] The main components and gas content of the high-quality guide rail steel smelted by the above method are: C: 0.57%, Si: 0.25%, Mn: 0.89%, Cr: 0.15%, Mo: 0.003%, Cu: 0.06%, Ni: 0.01%, Al: 0.026%, P: 0.010%, S: 0.003%, Ca: 0.0006%, Ti: 0.0009%, O: 6.2ppm, N: 101ppm; Al / N: 2.57. Specific indicators are shown in Appendix 1 and Table 2.

[0049] Comparative Example 4

[0050] Compared with Example 1, the main differences are: the continuous casting process adopts 225mm*275mm cross-section casting, the casting speed is 0.85 / min, the specific water volume is 0.25L / kg, the secondary cooling water distribution ratio is 25:40:35, and the crystallizer electromagnetic stirring + end electromagnetic stirring are adopted, the crystallizer electromagnetic stirring is 150A*2.5Hz, and the end electromagnetic stirring is 100A*5Hz.

[0051] The main components and gas content of the high-quality guide rail steel smelted by the above method are: C: 0.54%, Si: 0.26%, Mn: 0.88%, Cr: 0.15%, Mo: 0.002%, Cu: 0.08%, Ni: 0.01%, Al: 0.021%, P: 0.010%, S: 0.001%, Ca: 0.0001%, Ti: 0.0010%, O: 5.9ppm, N: 86ppm; Al / N: 2.44. Specific indicators are shown in Appendix 1 and Table 2.

[0052] Comparative Example 5

[0053] Compared with Example 1, the main difference is that the steel rolling adopts a low-temperature heating process, that is, the steel rolling heating process is a preheating section temperature of 750-880°C, a heating section temperature of 960-1040°C, a heating section temperature of 1080-1130°C, and a total heating time of 200 minutes. The starting rolling temperature is 1000℃-1040℃, and the steel is rolled into products through multiple passes on the bar production line. The final rolling temperature is controlled at 850℃-890℃ by a water tank. The main components and gas content of the high-quality guide rail steel smelted by the above method are: C: 0.56%, Si: 0.26%, Mn: 0.88%, Cr: 0.16%, Mo: 0.002%, Cu: 0.07%, Ni: 0.01%, Al: 0.022%, P: 0.009%, S: 0.001%, Ca: 0.0001%, Ti: 0.0008%, O: 5.8ppm, N: 86ppm; Al / N: 2.56. Specific indicators are shown in Appendix 1 and Table 2.

[0054] Table 1. Rating of non-metallic inclusions in steel (assessed according to GB / T 10561)

[0055]

[0056] Table 2. Ratings of various indicators

[0057]

Claims

1. A high-quality guide rail steel, characterized by: The steel has a composition range of C: 0.53-0.60%, Si: 0.20-0.30%, Mn: 0.70-1.10%, Cr: 0.10-0.25%, Mo≤0.05%, Cu: 0.06-0.09%, Ni≤0.15%, Al: 0.020-0.030%, P≤0.022%, S≤0.005%, Ca≤0.0002%, Ti≤0.0010%, O≤6ppm, N: 80-110ppm, Al / N ratio: 1.82-2.7; the remainder is iron; The process of preparing high-quality guide rail steel is as follows: KR desulfurization, electric furnace smelting, argon station, LF refining, RH vacuum treatment, billet continuous casting and rolling; wherein, Electric furnace smelting: The raw material is pure molten iron, high carbon drawing operation, and EBT eccentric bottom tapping is adopted. During the tapping process, 50wt% deoxidizer, carbon powder, 50wt% deoxidizer, low calcium and low titanium alloy and top slag are added in sequence; the low calcium and low titanium alloy contains ≤0.010wt% titanium and ≤0.008wt% calcium; RH vacuum treatment: maintain RH vacuum degree ≤ 67Pa for 20-30min, feed calcium silicon wire after breaking the vacuum, feed 100 meters / furnace for the first furnace, and feed 25 meters / furnace for the continuous casting furnace, and perform soft blowing operation after breaking the vacuum, and the soft blowing time is 15-25min; Billet continuous casting: Continuous casting adopts strict protection pouring, adopts 225mm*275mm cross-section pouring, casting speed 0.67-0.73m / min, specific water volume 0.18L / kg, and secondary cooling water distribution ratio of 25:40:35; adopts three-stage electromagnetic stirring: crystallizer electromagnetic stirring, pulse electromagnetic stirring and end electromagnetic stirring. The crystallizer electromagnetic stirring is 280A*2.5Hz, the pulse magneto-oscillation voltage is 145V, and the end electromagnetic stirring is 150A*5Hz; Rolling: The ingot is sprayed with high-temperature anti-decarburization coating. The heating process for steel rolling is as follows: preheating section temperature 750-900℃, heating section temperature 980-1220℃, heating section temperature 2 and soaking section temperature 1150-1230℃, total heating time 250-370min, starting rolling temperature 1050℃-1140℃, and the bar is rolled into products through multiple passes on the bar production line. The final rolling temperature is controlled by a water tank at 850℃-920℃.

2. A method for preparing high-quality guide rail steel according to claim 1, characterized in that: The process flow is: KR desulfurization, electric furnace smelting, argon station, LF refining, RH vacuum treatment, billet continuous casting and rolling; specifically includes the following steps: KR desulfurization: When the temperature of molten iron at the station is ≥1380℃, add desulfurizer and stir to desulfurize, and control the sulfur content in the steel to ≤0.001wt%; Electric furnace smelting: The raw material is pure molten iron, high carbon drawing operation, and EBT eccentric bottom tapping is adopted. During the tapping process, 50 wt% deoxidizer, carbon powder, 50 wt% deoxidizer, low calcium and low titanium alloy and top slag are added in sequence; the low calcium and low titanium alloy contains ≤0.010 wt% titanium and ≤0.008 wt% calcium; Argon station: After the molten steel arrives at the argon station, samples are taken for analysis of aluminum content. Based on the sample analysis results, the aluminum content is adjusted to 0.055wt%-0.070wt% using aluminum wire; LF refining: In the early stage of refining, high voltage is used for power supply, argon is used for strong stirring to dissolve slag, lime is added in appropriate amount, and silicon carbide is used for deoxidation to produce white slag; in the middle and late stages of refining, the power supply voltage and argon flow are reduced, silicon carbide is scattered to maintain slag, and the refining cycle is 25-50 minutes; RH vacuum treatment: maintain RH vacuum degree ≤ 67Pa for 20-30min, feed calcium silicon wire after breaking the vacuum, feed 100 meters / furnace for the first furnace, and feed 25 meters / furnace for the continuous casting furnace, and perform soft blowing operation after breaking the vacuum, and the soft blowing time is 15-25min; Billet continuous casting: Continuous casting adopts strict protection pouring, adopts 225mm*275mm cross-section pouring, casting speed 0.67-0.73m / min, specific water volume 0.18L / kg, and secondary cooling water distribution ratio of 25:40:35; adopts three-stage electromagnetic stirring: crystallizer electromagnetic stirring, pulse electromagnetic stirring and end electromagnetic stirring. The crystallizer electromagnetic stirring is 280A*2.5Hz, the pulse magneto-oscillation voltage is 145V, and the end electromagnetic stirring is 150A*5Hz; Rolling: The ingot is sprayed with high-temperature anti-decarburization coating. The heating process for steel rolling is as follows: preheating section temperature 750-900℃, heating section temperature 980-1220℃, heating section temperature 2 and soaking section temperature 1150-1230℃, total heating time 250-370min, starting rolling temperature 1050℃-1140℃, and the bar is rolled into products through multiple passes on the bar production line. The final rolling temperature is controlled by a water tank at 850℃-920℃.

3. The method for preparing high-quality guide rail steel according to claim 2, characterized in that: The amount of desulfurizer added in the KR process is 6-8kg / ton of steel.

4. The method for preparing high-quality guide rail steel according to claim 2, characterized in that: The deoxidizer is an aluminum block.

5. The method for preparing high-quality guide rail steel according to claim 2, characterized in that: Low-calcium, low-titanium alloy is added after the electric furnace according to the target value. The low-calcium, low-titanium alloy is selected from one or more of low-calcium, low-titanium ferrosilicon, low-calcium, low-titanium ferromanganese, and low-calcium, low-titanium ferrochrome; the top slag ratio is 400kg lime + 800kg furnace protective agent.

6. The method for preparing high-quality guide rail steel according to claim 2, characterized in that: During the LF refining process, in the early stage of refining, the high-speed voltage is turned on and the bottom-blowing argon flow rate is 200-500NL / min; in the middle and late stages of refining, the medium-low-speed voltage is turned on and the bottom-blowing argon flow rate is 50-200NL / min.

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