WO2022209293A1 - レールおよびその製造方法 - Google Patents
レールおよびその製造方法 Download PDFInfo
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- WO2022209293A1 WO2022209293A1 PCT/JP2022/004530 JP2022004530W WO2022209293A1 WO 2022209293 A1 WO2022209293 A1 WO 2022209293A1 JP 2022004530 W JP2022004530 W JP 2022004530W WO 2022209293 A1 WO2022209293 A1 WO 2022209293A1
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- Prior art keywords
- cooling
- rail
- temperature
- transformation
- pearlite
- Prior art date
Links
- 238000000034 method Methods 0.000 title claims abstract description 25
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 23
- 238000001816 cooling Methods 0.000 claims abstract description 144
- 230000009466 transformation Effects 0.000 claims abstract description 57
- 229910001566 austenite Inorganic materials 0.000 claims abstract description 22
- 229910001562 pearlite Inorganic materials 0.000 claims description 45
- 229910001563 bainite Inorganic materials 0.000 claims description 29
- 238000003303 reheating Methods 0.000 claims description 23
- 230000015572 biosynthetic process Effects 0.000 claims description 9
- 235000019362 perlite Nutrition 0.000 abstract description 2
- 239000010451 perlite Substances 0.000 abstract description 2
- 230000007423 decrease Effects 0.000 description 7
- 238000010438 heat treatment Methods 0.000 description 7
- 230000020169 heat generation Effects 0.000 description 5
- 239000002826 coolant Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 238000009434 installation Methods 0.000 description 3
- 229910000734 martensite Inorganic materials 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 2
- 239000003570 air Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000003595 mist Substances 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000005855 radiation Effects 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 238000005096 rolling process Methods 0.000 description 2
- 239000010959 steel Substances 0.000 description 2
- 230000003187 abdominal effect Effects 0.000 description 1
- 238000005299 abrasion Methods 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- 238000009529 body temperature measurement Methods 0.000 description 1
- 229910052804 chromium Inorganic materials 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 238000012937 correction Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 210000002683 foot Anatomy 0.000 description 1
- 238000007429 general method Methods 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 238000007689 inspection Methods 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
- 229910052758 niobium Inorganic materials 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 210000003371 toe Anatomy 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
Images
Classifications
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D9/00—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor
- C21D9/04—Heat treatment, e.g. annealing, hardening, quenching or tempering, adapted for particular articles; Furnaces therefor for rails
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D1/00—General methods or devices for heat treatment, e.g. annealing, hardening, quenching or tempering
- C21D1/18—Hardening; Quenching with or without subsequent tempering
- C21D1/19—Hardening; Quenching with or without subsequent tempering by interrupted quenching
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D6/00—Heat treatment of ferrous alloys
- C21D6/002—Heat treatment of ferrous alloys containing Cr
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/005—Modifying the physical properties by deformation combined with, or followed by, heat treatment of ferrous alloys
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
-
- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/009—Pearlite
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium with copper
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/26—Ferrous alloys, e.g. steel alloys containing chromium with niobium or tantalum
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
Definitions
- the present invention accelerates cooling with a cooling medium (air, water, mist, etc.) to a high-temperature rail that has been hot-rolled at or above the austenite region temperature, or heated at or above the austenite region temperature, thereby increasing the durability of the head.
- a cooling medium air, water, mist, etc.
- the present invention relates to a rail with improved abrasion resistance and a manufacturing method thereof.
- Rails that have been hot-rolled at or above the austenite range temperature or heated above the austenite range temperature are brought into the heat treatment equipment in an upright state (the top of the head is up and the sole is down). .
- it may be carried into the heat treatment apparatus with a length of about 100 m, or it may be divided (hereinafter referred to as sawing) so that the length per piece becomes, for example, about 25 m. It is sometimes brought in from If it is based on sawing and then cooling, the heat treatment apparatus may also be divided into zones of corresponding length.
- the toes of the rail are restrained, for example, by clamps, and the top of the head, the side of the head, the sole of the foot, and, if necessary, the abdominal surface are forcibly cooled with a cooling medium (air, water, mist, etc.).
- a cooling medium air, water, mist, etc.
- Patent Literature 1 describes a method of controlling temperature history while monitoring transformation behavior with a thermometer installed in a cooling device.
- Fig. 2 shows a model of the pressure schedule of the top air header and the history of the rail head surface temperature for performing the desired cooling in Patent Document 1.
- cooling starts at the cooling start temperature in the austenite region, and temperature rise due to transformation heat starts at timing t1 in the figure. If the temperature rise is too large, the steel transforms at a high temperature, resulting in a decrease in hardness. In order to prevent this, it is necessary to increase the header pressure almost at the same time as the temperature rises or slightly before that to increase the cooling capacity. This makes it possible to reduce temperature rise due to transformation heat generation and increase hardness.
- temperature variations include variations due to materials and variations within the cross section of the head. Due to variations in temperature and time during heating, rolling, and transportation to the accelerated cooling device, temperature variations occur depending on the material. In addition, since the rails are transported from rolling to the accelerated cooling device in an overturned state, the heat dissipation state of the rail heads is different, and a temperature difference occurs in the cross section of the heads.
- the present invention has been made to solve the above-described problems, and an object of the present invention is to manufacture a high-hardness, high-quality rail by a simple cooling method irrespective of rail temperature variations before the start of cooling. It provides a method to Here, “high hardness” means a surface hardness of HB430 or higher and an internal hardness of HB385 or higher. Also, “high quality” means that the bainite production rate at a position 5 mm deep from the cooling surface of the rail head, which reduces wear resistance, is 15% or less.
- the pearlite transformation is incomplete at the end of accelerated cooling, austenite remains, and even if the temperature is in the bainite formation temperature range, it reaches the pearlite transformation temperature range again during the reheating process. Most of the remaining austenite undergoes pearlite transformation during the reheating process and subsequent natural cooling. It was found that the desired pearlite structure was obtained by this.
- a rail manufacturing method comprising a step of accelerated cooling of a rail having a temperature equal to or higher than the temperature of the austenite region, wherein the area 70 at a depth of 5 mm from the cooling surface of the rail head when the accelerated cooling is completed % or less is austenite, and the temperature of the rail head surface at the completion of reheating after accelerated cooling is within the pearlite transformation temperature range.
- FIG. 1 is a schematic diagram showing the relationship between the temperature history of the rail head surface from the start of accelerated cooling and the transformation rate in the range from the cooling surface of the rail head to a depth of 5 mm, according to the present invention.
- FIG. 2 is a schematic diagram of the pressure schedule of the top air header for cooling the rail head surface and the history of the rail head surface temperature according to Patent Document 1.
- FIG. 3 shows the temperature history of the rail head surface and the transformation rate in the range up to 5 mm deep from the cooling surface when the temperature at the time of completion of reheating that occurs after the end of accelerated cooling is in the bainite transformation temperature range, according to the comparative example. It is a schematic diagram showing the relationship of.
- a small amount of bainite may be generated in the bainite generation temperature range during accelerated cooling and reheating. If the bainite production rate in the region at a depth of 5 mm from the cooling surface of the rail head is 15% or less, the difference from full pearlite, ie, 100% pearlite, is negligible in terms of wear resistance. It should be noted that the fact that pearlite transformation is incomplete and austenite remains after accelerated cooling can be confirmed by measurement using a transformation rate meter, reproduction of the actual temperature measured during cooling by Thermec, or the like. Alternatively, a method such as comparison with a rail in which the cooling time is intentionally extended and the temperature range after reheating is set to the bainite transformation temperature range may be adopted.
- bainite transformation temperature range refers to a temperature range in which bainite is formed when held in an isothermal state. By preparing an isothermal transformation curve using a test piece or the like in advance, the transformation temperature range of bainite or pearlite can be grasped.
- the temperature of the rail head surface is the value obtained by measuring the temperature of the corner of the rail head with a radiation thermometer.
- the temperature in the cross section of the rail head becomes almost the same during the reheating process. position is no problem.
- the area at a depth of 5 mm from the cooling surface of the rail head means the average value of the microstructure of the area at a depth of 5 mm from the central surface and both sides of the rail head.
- the maximum temperature of the rail head in the reheating process after the end of accelerated cooling is +75°C or less from the lower limit of the pearlite transformation temperature range, the pearlite that is generated becomes finer and the hardness of the rail becomes higher, which is preferable. More preferably, it is +50° C. or less from the lower limit of the pearlite transformation temperature.
- the rail head surface cool until the temperature reaches 200°C or less, and then cool it at a rate of 1°C/s or more. If the rail temperature is 200° C. or less, all the rails have completed their transformation, so the cooling time can be shortened without affecting the characteristics. Also, there is no effect on rail warpage due to cooling in the cooling bed. Further, when the temperature is allowed to cool to 200° C. or less, the temperature difference from the room temperature becomes small, so it takes one hour or more to cool to room temperature. By setting the cooling rate to 1° C./s or more, it is possible to greatly shorten the processing time in the cooling bed.
- the timing of cooling in the cooling bed it is possible to determine in advance the time at which the temperature will be 200°C or less, and start cooling after a predetermined time. Also, after measuring the temperature of the rail head surface with a thermometer and confirming that it is 200° C. or less, cooling may be started.
- the cooling method in the cooling bed there is no problem with a known method such as water spray cooling from above.
- the temperature should be measured at a timing of 30 seconds or more and 150 seconds or less after the end of accelerated cooling. If it is less than 30 seconds, the heat recovery is not yet completed, and it is not possible to determine whether the temperature of the rail head surface is within the desired pearlite transformation temperature range, and the hardness of the rail may be reduced. . On the other hand, if it is longer than 150 seconds, the amount of temperature drop in natural cooling after the reheating process becomes large, making it difficult to grasp the temperature during the reheating process, and there is a risk that the hardness of the rail will decrease. .
- the rail After accelerated cooling, the rail is generally transferred to a cooling bed and allowed to naturally cool to near room temperature. Therefore, it is preferable to measure the temperature during transportation to the cooling bed for 30 seconds or more and 150 seconds or less after the end of accelerated cooling. This makes it possible to measure the total length of the rail with a single thermometer.
- the cooling amount should be adjusted for the rails after the next material. That is, if the temperature is high, in order to increase the amount of cooling, the flow rate of the coolant to be injected should be increased to increase the cooling capacity, or the cooling time should be extended. If the temperature is low, the amount of cooling can be reduced by reducing the flow rate of the coolant to be injected to lower the cooling capacity, or by shortening the cooling time.
- the rail head surface is cooled at 1° C./s or more and 7° C./s or less, and pearlite transformation is started in the vicinity of the surface, that is, in the range from the cooling surface of the rail head surface to a depth of 5 mm. is preferred. More preferably, it is 4°C/s or more and 6°C/s or less.
- the temperature decreases and the cooling capacity also decreases. Therefore, it is preferable to increase the air volume as the temperature of the rail decreases.
- the temperature rise due to transformation heat generation is preferably 50° C. or less. More preferably, it is 30°C or less.
- the temperature rise due to transformation heat generation near the surface is completed, it is preferable to cool at 1°C/s or more and 5°C/s or less. More preferably, it is 1.5°C/s or more and 2.5°C/s or less. If it is higher than 5°C/s, a larger cooling device will be required, resulting in increased equipment costs. In addition, the variation in the adjustment amount of the cooling amount also becomes large, and the control of the cooling measures with higher accuracy is required, which increases the facility cost.
- the bainite formation rate must be 15% or less in the range from the cooling surface of the rail head cooled by the above cooling method to a depth of 5 mm.
- the remaining structure preferably has a pearlite production rate of 85% or more. This is because if the bainite production rate is greater than 15%, the wear resistance is inferior to that of full pearlite.
- the bainite production rate referred to here is the area ratio of bainite that can be visually recognized by observing the structure with a normal optical microscope.
- the generation rate of structures other than bainite also means the area ratio.
- the composition of the rail may be within a conventionally known range. Mn content: 0.20 to 1.50%, P content: 0.035% or less, S content: 0.012% or less, Cr content: 0.20 to 1.50% %, and optionally at least one selected from Cu, Ni, Mo, V, Nb, Al, Ti, and Sb in an amount of 0.01 to 1.00%, B, Ca, Mg, and REM At least one of them may be contained in an amount of 0.001 to 0.10%, and the balance is preferably iron and unavoidable impurities.
- the steel structure of the region other than the region from the cooling surface of the rail head to a depth of 5 mm, and conventional structures may be used.
- a long rail having the chemical composition shown in Table 1 and hot-rolled at 900°C was inserted into the cooling device almost at the same time over the entire length, and the header was brought closer when the surface temperature of the rail head was 770°C. Cooled by air. The temperature of the corner of the rail head during cooling was measured with a radiation thermometer, and the cooling rate of the rail head surface was measured. From the start of accelerated cooling until the temperature rise due to transformation heat generation near the rail surface occurs, the temperature is cooled at 5.5°C/s, and after the temperature rise due to transformation heat generation near the surface ends, the speed is 1.5°C/s. cooled. After accelerated cooling, the rail was removed from the cooling device and transported to the cooling bed.
- the temperature of the head surface of the rail during transportation to the cooling bed was measured and used as the temperature of the rail head surface at the completion of reheating.
- the cooling time after the end of the temperature rise due to the heat generated by the transformation near the surface was adjusted so that the temperature reached a predetermined value.
- a sample was cut from the rail at room temperature according to JIS Z 2243, the hardness was measured at the center of the head surface and 23 mm inside, and the average pearlite formation at a depth of 5 mm from the center of the head and both sides of the head surface. rate was investigated. Table 2 shows the results. In addition, the history of the measured surface temperature was reproduced by Thermec, and the transformation behavior during cooling was investigated. All the structures other than pearlite were bainite. Incidentally, when an isothermal transformation curve for the components shown in Table 1 was created, the transformation temperature range of pearlite was 750 to 525°C. A surface hardness of HB430 or more was judged to have a good surface hardness.
- the internal hardness was HB385 or more
- the internal hardness was judged to be good.
- the scope of the present invention is defined as 85% or more of pearlite formation rate at room temperature, and it was determined that the higher the pearlite formation rate at room temperature, the better the structure.
- a value obtained by subtracting each pearlite production rate at the end of accelerated cooling from 100% is regarded as the remaining amount of austenite.
- Example 1 the temperature of the rail head surface at the completion of reheating was 610°C, so the hardness and structure were good.
- Example 2 the temperature of the rail head surface at the time of completion of reheating was set to 550° C., so compared with Example 1, the hardness was further increased.
- the pearlite transformation rate on the rail surface immediately after the end of accelerated cooling was 35%, but the pearlite transformation occurred during the subsequent reheating process.
- the pearlite transformation rate on the rail surface immediately after the end of accelerated cooling was 35%, and the temperature of the rail head surface at the end of reheating was set to 450°C. perlite did not transform.
- a large amount of bainite was generated in the vicinity of the surface, resulting in a significant decrease in surface hardness.
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Abstract
Description
[1] オーステナイト域温度以上の温度を有するレールを加速冷却する工程を有する、レールの製造方法であって、前記加速冷却が終了した時点のレール頭部の冷却面から5mm深さにおける領域の70%以下がオーステナイトであり、加速冷却終了後に生じる復熱の完了時のレール頭部表面の温度がパーライト変態温度域である、レールの製造方法。
[2] 前記加速冷却終了後に生じる復熱過程における前記レール頭部表面の最高温度が、パーライト変態温度域下限以上パーライト変態温度域下限+75℃以下である、[1]に記載のレールの製造方法。
[3] 前記加速冷却終了後に前記レールを放冷し、前記レール頭部表面の温度が200℃以下となった後は1℃/s以上の速度で冷却する、[1]又は[2]に記載のレールの製造方法。
[4] レール頭部の冷却面から5mm深さまでの範囲において、ベイナイト生成率が15%以下である、レール。
Claims (4)
- オーステナイト域温度以上の温度を有するレールを加速冷却する工程を有する、レールの製造方法であって、
前記加速冷却が終了した時点のレール頭部の冷却面から5mm深さにおける領域の70%以下がオーステナイトであり、
加速冷却終了後に生じる復熱の完了時のレール頭部表面の温度がパーライト変態温度域である、レールの製造方法。 - 前記加速冷却終了後に生じる復熱過程における前記レール頭部表面の最高温度が、パーライト変態温度域下限以上パーライト変態温度域下限+75℃以下である、請求項1に記載のレールの製造方法。
- 前記加速冷却終了後に前記レールを放冷し、前記レール頭部表面の温度が200℃以下となった後は1℃/s以上の速度で冷却する、請求項1または2に記載のレールの製造方法。
- レール頭部の冷却面から5mm深さまでの範囲において、ベイナイト生成率が15%以下である、レール。
Priority Applications (2)
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EP22779522.6A EP4282991A4 (en) | 2021-03-31 | 2022-02-04 | RAIL AND ITS MANUFACTURING METHOD |
JP2022527100A JP7405250B2 (ja) | 2021-03-31 | 2022-02-04 | レールの製造方法 |
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JP2021060122 | 2021-03-31 | ||
JP2021-060122 | 2021-03-31 |
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Citations (5)
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JPH09316598A (ja) * | 1996-03-27 | 1997-12-09 | Nippon Steel Corp | 耐摩耗性および溶接性に優れたパーライト系レールおよびその製造法 |
JP2001020040A (ja) * | 1999-07-08 | 2001-01-23 | Nippon Steel Corp | 耐摩耗性、耐内部疲労損傷性に優れたパーライト系レールおよびその製造法 |
JP2003129182A (ja) * | 2001-10-22 | 2003-05-08 | Nippon Steel Corp | 耐表面損傷性に優れたパーライト系レールおよびその製造法 |
US20110253268A1 (en) * | 2010-04-16 | 2011-10-20 | Pangang Group Co., Ltd. | High carbon content and high strength heat-treated steel rail and method for producing the same |
WO2015182759A1 (ja) * | 2014-05-29 | 2015-12-03 | 新日鐵住金株式会社 | レールおよびその製造方法 |
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WO2014157252A1 (ja) * | 2013-03-27 | 2014-10-02 | Jfeスチール株式会社 | パーライトレールおよびパーライトレールの製造方法 |
AU2016210107B2 (en) * | 2015-01-23 | 2018-10-18 | Nippon Steel Corporation | Rail |
JP6459623B2 (ja) * | 2015-02-25 | 2019-01-30 | 新日鐵住金株式会社 | パーライト鋼レール |
EP3851549A4 (en) * | 2018-09-10 | 2022-07-13 | Nippon Steel Corporation | RAIL AND RAIL MANUFACTURING METHOD |
CN113966406B (zh) * | 2019-06-20 | 2022-09-16 | 杰富意钢铁株式会社 | 钢轨及其制造方法 |
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JPH09316598A (ja) * | 1996-03-27 | 1997-12-09 | Nippon Steel Corp | 耐摩耗性および溶接性に優れたパーライト系レールおよびその製造法 |
JP2001020040A (ja) * | 1999-07-08 | 2001-01-23 | Nippon Steel Corp | 耐摩耗性、耐内部疲労損傷性に優れたパーライト系レールおよびその製造法 |
JP2003129182A (ja) * | 2001-10-22 | 2003-05-08 | Nippon Steel Corp | 耐表面損傷性に優れたパーライト系レールおよびその製造法 |
US20110253268A1 (en) * | 2010-04-16 | 2011-10-20 | Pangang Group Co., Ltd. | High carbon content and high strength heat-treated steel rail and method for producing the same |
WO2015182759A1 (ja) * | 2014-05-29 | 2015-12-03 | 新日鐵住金株式会社 | レールおよびその製造方法 |
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JP7405250B2 (ja) | 2023-12-26 |
EP4282991A1 (en) | 2023-11-29 |
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