US20170283895A1 - Rail manufacturing method and rail manufacturing apparatus - Google Patents

Rail manufacturing method and rail manufacturing apparatus Download PDF

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Publication number
US20170283895A1
US20170283895A1 US15/511,431 US201515511431A US2017283895A1 US 20170283895 A1 US20170283895 A1 US 20170283895A1 US 201515511431 A US201515511431 A US 201515511431A US 2017283895 A1 US2017283895 A1 US 2017283895A1
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Prior art keywords
rail
temperature
cooling
rolling
head portion
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US15/511,431
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English (en)
Inventor
Kenji Okushiro
Hideo Kijima
Hiroyuki Fukuda
Moriyasu YAMAGUCHI
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JFE Steel Corp
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JFE Steel Corp
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Assigned to JFE STEEL CORPORATION reassignment JFE STEEL CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: YAMAGUCHI, Moriyasu, KIJIMA, HIDEO, OKUSHIRO, Kenji, FUKUDA, HIROYUKI
Publication of US20170283895A1 publication Critical patent/US20170283895A1/en
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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
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
    • B21B—ROLLING OF METAL
    • B21B1/00—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations
    • B21B1/08—Metal-rolling methods or mills for making semi-finished products of solid or profiled cross-section; Sequence of operations in milling trains; Layout of rolling-mill plant, e.g. grouping of stands; Succession of passes or of sectional pass alternations for rolling structural sections, i.e. work of special cross-section, e.g. angle steel
    • B21B1/085—Rail sections
    • 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
    • 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
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • 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
    • C22C38/24—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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel 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
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel 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
    • C22C38/60—Ferrous alloys, e.g. steel alloys containing lead, selenium, tellurium, or antimony, or more than 0.04% by weight of sulfur
    • 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

Definitions

  • the present invention relates to a method and an apparatus for manufacturing a pearlitic steel rail with excellent ductility obtained by performing rough rolling, finish rolling, and heat treatment of a heated bloom and particularly relates to a method and an apparatus for manufacturing a rail having ductility improved by refining the pearlite block or colony size.
  • a rail in which the structure of a head portion forms a pearlite structure is generally manufactured by the following manufacturing method.
  • a bloom cast by a continuous casting method is heated to 1100° C. or more, and then hot-rolled into a predetermined rail shape by rough rolling and finish rolling.
  • a rolling method in each rolling process is performed combining caliber rolling and universal rolling.
  • the rolling is performed in a plurality of passes in the rough rolling or in a plurality of passes or a single pass in the finish rolling.
  • crops at end portions of the hot-rolled rail are sawn.
  • the length of the hot-rolled rail is 50 to 200 m. Therefore, when a heat treatment apparatus has a length limitation, the rail is sawn into a predetermined length, e.g., 25 m, simultaneously with the sawing of the crops.
  • the rail when the rail is required to have wear resistance, the rail is subjected to heat treatment by the heat treatment apparatus (heat treatment process) subsequent to the hot-rolling process.
  • heat treatment process heat treatment process
  • the wear resistance improves when the heat treatment start temperature is higher. Therefore, a re-heating process of heating the rail may be provided before the heat treatment process.
  • the rail In the heat treatment process, the rail is fixed with a restraining device, such as a clamp, and then a head portion, a foot portion, and, as necessary, an web portion are forcibly cooled using a cooling medium, such as air, water, and mist.
  • the forcible cooling is usually performed until the temperature of the head portion reaches 650° C. or less.
  • the restraint of the rail by the clamp is released, and then the rail is conveyed to a cooling bed.
  • the rail is cooled until the temperature reaches 100° C. or less.
  • a rail to be used under severe environments such as mining sites of natural resources, such as coal
  • a rail to be used under severe environments is demanded to have high wear resistance and high toughness. Therefore, when the rail to be used under severe environments is manufactured, the above-described heat treatment process is required.
  • processing such as bending processing, for example, later
  • the processing becomes difficult to achieve in some cases because the rail is excessively hardened when subjected to heat treatment, so that the ductility decreases. Therefore, a rail with high hardness and excellent ductility has been demanded.
  • Patent Document 1 discloses a method including setting the rolling temperature in finish rolling in a temperature range of Ar3 transformation point to 900° C., and then performing accelerated cooling of a rail to at least 550° C. at a cooling rate of 2 to 30/sec within 150 sec after the end of the finish rolling to thereby increase the ductility of the rail.
  • Patent Document 2 discloses a method including performing rolling at an area reduction ratio of 10% or more in a temperature range 800° C. or less in hot-rolling to thereby improve the ductility of a rail.
  • Patent Document 1 has had a problem in that the temperature control for a foot portion of a rail is not performed, and therefore the ductility of the foot portion does not improve.
  • Patent Document 2 has had a problem in that the temperature adjustment conditions in rolling for a foot portion of a rail are not specified, and therefore the ductility of the foot portion does not improve.
  • the present invention has been made focusing on the problems described above. It is an object of the present invention to provide a method and an apparatus for manufacturing a rail having high ductility in both a head portion and a foot portion.
  • a method for manufacturing a rail includes hot-rolling a heated steel rail material, adjusting the temperature by cooling the hot-rolled steel rail material, processing the steel rail material subjected to the temperature adjustment into a rail shape by means of temperature-adjusted rolling at an area reduction ratio of 20% or more, and, in adjusting the temperature of the steel rail material, cooling the surface portions of the steel rail material corresponding to a head portion and a foot portion of the rail shape to 500° C. or more and 1,000° C. or less.
  • An apparatus for manufacturing a rail has at least one first rolling mill rolling a steel rail material, a cooling device adjusting a temperature by cooling the steel rail material rolled with the first rolling mill, and at least one second rolling mill processing the steel rail material subjected to the temperature adjustment into a rail shape by means of temperature-adjusted rolling at an area reduction ratio of 20% or more, in which the cooling device cools the surface portions of the steel rail material corresponding to a head portion and a foot portion of the rail shape so that the temperatures of the surface portions reach 500° C. or more and 1,000° C. or less.
  • a rail having high ductility in both a head portion and a foot portion is able to be manufactured.
  • FIG. 1 is a schematic view illustrating an apparatus for manufacturing a rail according to one embodiment of the present invention
  • FIG. 2 is a cross-sectional view illustrating a rough cooling device of one embodiment of the present invention
  • FIG. 3 is a schematic view illustrating a heat treatment apparatus of one embodiment of the present invention.
  • FIG. 4 is a cross-sectional view illustrating each portion of a rail
  • FIG. 5 is an explanatory view illustrating collection positions of tensile test pieces evaluated in Examples.
  • FIG. 6 is an explanatory view illustrating positions where a Brinell hardness test evaluated in Examples is carried out.
  • % for chemical composition means % by mass.
  • the rail manufacturing apparatus 1 is a rolling line having a heating furnace 2 , a roughing mill 3 A, a finishing mill 3 B, a rough cooling device 4 , a finish cooling device 5 , a re-heating device 6 , a heat treatment apparatus 7 , and a cooling bed 8 .
  • the rail 9 is manufactured by rolling and heat-treating a steel rail material, such as a continuously cast bloom, by the manufacturing apparatus 1 .
  • the rail 9 extends in the width direction viewed in a cross section perpendicular to the longitudinal direction and has a head portion 91 and a foot portion 93 facing each other in the vertical direction and an web portion 92 connecting the head portion 91 disposed on the upper side and the foot portion 93 disposed on the lower side and extending in the vertical direction.
  • steel containing the following chemical composition is usable, for example.
  • C carbon
  • the lower limit is preferably set to 0.60% and more preferably set to 0.70% or more.
  • excessive content of C causes an increase in the cementite amount, and therefore an increase in hardness and strength is expectable but, contrarily, the ductility decreases.
  • the increase in the C content extends the temperature range of a ⁇ + ⁇ zone and promotes softening of a weld heat affected zone. Considering these adverse effects, the upper limit of the C content is preferably set to 1.05% and more preferably set to 0.97% or less.
  • Si 0.1% or more and 1.5% or less
  • Si silicon
  • the Si content is preferably 0.1% or more and more preferably 0.2% or more.
  • the upper limit of the Si content is preferably set to 1.5% and more preferably 1.3% or less.
  • Mn 0.01% or more and 1.5% or less
  • Mn manganese
  • Mn has an effect of lowering the pearlite transformation temperature and densifying the pearlite lamella intervals, and therefore Mn is effective for maintaining high hardness up to a rail inner region.
  • the Mn content is preferably 0.01% or more and more preferably 0.3% or more.
  • the upper limit of the Mn content is preferably set to 1.5% and more preferably set to 1.3% or less.
  • the content of P phosphorus
  • the toughness and the ductility are lowered. Therefore, the P content is preferably suppressed to 0.035% or less and more preferably limited to 0.025% or less.
  • the lower limit is preferably set to 0.001%.
  • the S content is preferably suppressed to 0.030% or less and more preferably suppressed to 0.015% or less.
  • the lower limit is preferably set to 0.0005%.
  • Cr chromium
  • TE equilibrium transformation temperature
  • the use of Cr in combination with Sb is effective for inhibition of the generation of a decarburized layer. Therefore, when Cr is compounded, the content is preferably set to 0.1% or more and more preferably set to 0.2% or more.
  • the Cr content exceeds 2.0%, a possibility of the generation of welding defects increases, the quenching properties increase, and the generation of martensite is promoted. Therefore, the upper limit of the Cr content is preferably set to 2.0%, and more preferably set to 1.5% or less.
  • the total content of Si and Cr is desirably set to 2.0% or less. This is because, when the total content of Si and Cr exceeds 2.0%, the adhesiveness of a scale increases, and therefore the peeling of the scale may be inhibited and decarburization may be promoted.
  • Sb antimony
  • the content is preferably 0.005% or more and more preferably 0.01% or more .
  • the upper limit is preferably set to 0.5% and more preferably set to 0.3% or less.
  • one or two or more elements of Cu 0.01% or more and 1.0% or less, Ni: 0.01% or more and 0.5% or less, Mo: 0.01% or more and 0.5% or less, V: 0.001% or more and 0.15% or less, and Nb: 0.001% or more and 0.030% or less may be compounded.
  • Cu copper
  • Cu is an element capable of further increasing the hardness by solid solution strengthening. Cu is effective also for decarburization control.
  • the Cu content is preferably 0.01% or more and more preferably 0.05% or more.
  • the upper limit of the Cu content is preferably set to 1.0% and more preferably set to 0.6% or less.
  • Ni 0.01% or more and 0.5% or less
  • Ni nickel
  • Ni nickel
  • the lower limit is preferably set to 0.01% and more preferably set to 0.05% or more.
  • the upper limit is preferably set to 0.5% and more preferably set to 0.3% or less.
  • Mo mobdenum
  • the lower limit is preferably set to 0.01% and more preferably set to 0.05% or more.
  • the upper limit of the Mo content is preferably set to 0.5% and more preferably set to 0.3% or less.
  • V 0.001% or more and 0.15% or less
  • V vanadium
  • VN vanadium
  • V content is preferably 0.001% or more and more preferably 0.005% or more.
  • the upper limit is preferably set to 0.15% and more preferably set to 0.12% or less.
  • Nb 0.001% or more and 0.030% or less
  • Nb niobium
  • the Nb content is preferably 0.001% or more and more preferably 0.003% or more.
  • the upper limit is preferably set to 0.030% and more preferably set to 0.025% or less.
  • the remainder other than the components described above includes Fe (iron) and inevitable impurities.
  • Fe iron
  • inevitable impurities the mixing of N (nitrogen) up to 0.015%, the mixing of O (oxygen) up to 0.004%, and the mixing of H (hydrogen) up to 0.0003% are acceptable.
  • the Al content is desirably set to 0.001% or less and the Ti content is desirably set to 0.001% or less.
  • the heating furnace 2 is a continuation type or batch type heating furnace and heats steel rail materials, such as a continuously cast bloom, to a predetermined temperature.
  • the roughing mill 3 A is a universal mill which hot-rolls a steel material at a predetermined area reduction ratio and two or more of the roughing mills 3 A are provided.
  • the manufacturing apparatus 1 has n pieces of roughing mills 3 A 1 to 3 An.
  • the rough cooling device 4 is provided between a k-th roughing mill 3 Ak and a (K+1)-th roughing mill 3 Ak+1 among the roughing mills 3 A 1 to 3 An along the conveyance direction of the rail 9 .
  • the finishing mill 3 B is a universal mill which further hot-rolls the rough-rolled rail 9 to thereby finally process the same into a target rail shape.
  • the area reduction ratio of the rail 9 to be rolled from the (k+1)-th roughing mill 3 Ak+1 to the finishing mill 3 B as the rolling process after the rough cooling device 4 is set to 20% or more.
  • the area reduction ratio in this embodiment shows the area reduction ratio of a cross-sectional area perpendicular to the longitudinal direction of the steel rail material and shows the ratio of the reduction in the cross-sectional area during the rolling to the cross-sectional area before the rolling of the bloom and the like.
  • the rough cooling device 4 has a head portion cooling nozzle 41 , a foot portion cooling nozzle 42 , a head portion thermometer 43 , a foot portion thermometer 44 , a conveyance table 45 , guides 46 a and 46 b, and a control unit 47 as illustrated in FIG. 2 .
  • the head portion cooling nozzle 41 cools the head portion 91 of the rail 9 by ejecting a cooling medium to the head portion 91 .
  • the foot portion cooling nozzle 42 cools the foot portion 93 of the rail 9 by ejecting a cooling medium to the foot portion 93 .
  • the cooling medium ejected from the head portion cooling nozzle 41 and the foot portion cooling nozzle 42 is spray water.
  • the head portion cooling nozzle 41 and the foot portion cooling nozzle 42 are provided above the head portion 91 and the foot portion 93 , respectively, on the y-axis positive direction side and eject a cooling medium to each of the head portion 91 and the foot portion 93 with an inclination with respect to the y axial direction.
  • two or more of the head portion cooling nozzles 41 and the foot portion cooling nozzles 42 are provided along the z axis direction perpendicular to the x-y plane as the longitudinal direction of the rail 9 .
  • the head portion thermometer 43 and the foot portion thermometer 44 are noncontact thermometers which measure the surface temperature of each of the head portion 91 and the foot portion 93 of the rail 9 , respectively, to which the cooling medium is ejected and are provided facing the head portion 91 and the foot portion 93 , respectively, in the x axis direction.
  • the measurement results of the head portion thermometer 43 and the foot portion thermometer 44 are transmitted to the control unit 47 .
  • the conveyance table 45 is a conveyance roll extending in the x axis direction and two or more of the conveyance tables 45 are provided side by side along the z axis direction.
  • the guides 45 a and 46 b are plate-like members and are provided extending in the z axis direction.
  • the guides 46 a and 46 b are individually disposed on the upper side relative to the conveyance table 45 on the y-axis positive direction side and on both end sides in the longitudinal direction of the conveyance table 45 .
  • the guides 46 a and 46 b are further provided with openings 461 a and 461 b at the positions where the head portion thermometer 43 and the foot portion thermometer 44 are disposed, respectively.
  • the control unit 47 controls the conditions of the cooling medium ejected from the head portion cooling nozzle 41 and the foot portion cooling nozzle 42 based on the measurement results of the head portion thermometer 43 and the foot portion thermometer 44 to thereby cool the rail 9 to a predetermined surface temperature.
  • the ejection conditions of the cooling medium include the ejection amount, the ejection pressure, the moisture amount, the ejection time, and the like of the cooling medium, for example.
  • the rough cooling device 4 of the configuration described above is provided between the k-th roughing mill 3 Ak and the (k+1)-th roughing mill 3 Ak+1 among the plurality of roughing mills 3 A located side by side in the rolling direction of the rail 9 and controls the surface temperature of the head portion 91 and the foot portion 93 of the rail 9 to be rolled with the k-th roughing mill 3 Ak.
  • the finish cooling device 5 is provided immediately before the finishing mill 3 B and controls the surface temperature of the head portion 91 and the foot portion 93 of the rail 9 to be rolled with the finishing mill 3 B.
  • the finish cooling device 5 has the same configuration as that of the rough cooling device 4 illustrated in FIG. 2 .
  • the rail 9 is conveyed and rolled with an overturned state as illustrated in FIG. 2 when rolled or cooled with the roughing mills 3 A, the rough cooling device 4 , the finish cooling device 5 , and the finishing mill 3 B.
  • the re-heating device 6 is an induction heating type heating device and heats the head portion 91 of the rail 9 to a predetermined temperature.
  • the heat treatment apparatus 7 has head portion cooling headers 71 a to 71 c, a foot portion cooling header 72 , a head portion thermometer 73 , and a control unit 74 as illustrated in FIG. 3 .
  • the head portion cooling headers 71 a to 71 c are provided facing each of the head top surface and both head side surfaces of the head portion 91 and cool the head portion 91 by ejecting a cooling medium to the head top surface and both the head side surfaces.
  • the foot portion cooling header 72 is provided facing the underside of the foot portion 93 and cools the foot portion 93 by ejecting a cooling medium to the underside of the foot.
  • the head portion thermometer 73 is a non-contact-type thermometer and measures the surface temperature of the head portion 91 . The temperature measurement results of the head portion thermometer 73 are transmitted to the control unit 74 .
  • the control unit 74 controls the ejection conditions of the cooling medium ejected from the head portion cooling headers 71 a to 71 c and the foot portion cooling header 72 according to the temperature measurement results of the head portion thermometer 73 to thereby control the cooling rate of the rail 9 .
  • the heat treatment apparatus 7 of the configuration described above cools the rail 9 at a predetermined cooling rate until the surface temperature reaches a predetermined surface temperature.
  • the heat treatment apparatus 7 has a clamp (not illustrated). The clamp is a device restraining the foot portion of the rail 9 by holding the same.
  • the cooling bed 8 is a device which naturally cools the rail 9 and contains, for example, a base supporting the rail 9 .
  • a bloom which is a steel rail material cast by a continuous casting method is carried into the heating furnace 2 to be heated to reach 1100° C. or more.
  • the heated steel rail material is rolled to have an almost rail shape by the roughing mills 3 Aa to 3 Ak on the upstream side in the conveyance direction relative to the rough cooling device 4 .
  • a steel material in the hot-rolling process is also referred to as a steel rail material.
  • the steel rail material rolled with the roughing mills 3 Aa to 3 Ak is cooled (temperature adjustment) with the rough cooling device 4 until the surface temperature of portions corresponding to the head portion 91 and the foot portion 93 of the rail 9 reaches 500° C. or more and 1000° C. or less.
  • the control unit 47 controls the ejection amount, the ejection pressure, the moisture amount, the ejection time, and the like of the cooling medium to thereby cool the steel rail material.
  • the entire structure is transformed into austenite.
  • the austenite structure of 1000° C. or more the grain boundary easily moves and re-crystallization occurs, so that the crystal grains are coarsened.
  • strain is generated in the crystal grains, and thus the crystal grains are divided, and then refined.
  • the temperature in the rolling is 1000° C. or less, the re-crystallization and the coarsening of the crystal grains are difficult to occur. Therefore, by setting the temperature of the steel rail material in the rolling to 1000° C. or less, the coarsening of the crystal grains refined by the rolling is difficult to occur.
  • the temperature adjustment is preferably performed until the surface temperature of the portions corresponding to the head portion 91 and the foot portion 93 reach 500° C. or more and 730° C. or less.
  • the structure partially causes pearlite transformation. Therefore, the structure of the steel rail material has a two phase structure containing untransformed austenite and pearlite.
  • the yield strength of the austenite is lower, and therefore most of strain is introduced in the austenite grains and the structure in the rolling is refined as compared with the case where the structure in the rolling is an austenite single phase.
  • the colony size and the block size of the pearlite as the final structure are affected by the crystal grain diameter of the austenite which is the structure before transformation. Therefore, when the austenite grains are coarse, the colony size and the block size of the pearlite are also coarsened, and therefore the ductility decreases. On the other hand, when the austenite grains are fine, the colony size and the block size of the pearlite are refined, and therefore the ductility improves.
  • the steel rail material rough-rolled with the roughing mills 3 A 1 to 3 An is cooled with the finish cooling device 5 as necessary, and then rolled with the finishing mill 3 B to be formed into the rail 9 of a desired shape.
  • the rolling in the roughing mills 3 Ak+1 to 3 An and the finishing mill 3 B after the temperature adjustment is also referred to as temperature-adjusted rolling.
  • the area reduction ratio of the steel rail material to be subjected to the temperature-adjusted rolling is 20% or more. By setting the area reduction ratio to 20% or more, strain can be generated also in the steel rail material, and therefore the inside structure of the rail 9 can be refined.
  • the rail 9 hot-rolled with the roughing mills 3 A and the finishing mill 3 B is conveyed to the re-heating device 6 o be heated until the surface temperature of the head portion 91 reaches 730° C. or more and 900° C. or less.
  • the heated rail 9 is conveyed to the heat treatment apparatus 7 to be forcibly cooled (heat treatment) with the heat treatment apparatus 7 in the state of being restrained by the clamp until the surface temperature of the head portion 91 reaches 600° C. or less.
  • the control unit 74 calculates the cooling rate of the rail 9 from the temperature measurement results of the head portion thermometer 73 , and then controls the ejection conditions of the cooling medium ejected from the head portion cooling headers 71 a to 71 c so that the average cooling rate is 1° C./s or more and 10° C./s or less.
  • control unit 74 controls the ejection conditions of the cooling medium ejected from the foot portion cooling header 72 in such a manner as to be the same as any one of the ejection conditions of the cooling medium ejected from the head portion cooling headers 71 a to 71 c.
  • the structure When the surface temperature of the head portion 91 is less than 730° C. before the heat treatment, the structure partially or entirely causes pearlite transformation. Before the heat treatment, the rail 9 is naturally cooled and the cooling rate is low. Therefore, the pearlite lamella intervals is coarse. Therefore, by performing re-heating so that the surface temperature of the head portion 91 reaches 730° C. or more before the heat treatment, the pearlite structure is reversely transformed to the austenite structure, and thus the lamella structure is able to be formed again. On the other hand, when the surface temperature of the head portion 91 is higher, the hardening of the decarburized layer on the surface and the hardening due to an improvement of the cooling rate inside the rail are achieved, so that the wear resistance is improved.
  • the upper limit of the surface temperature in the re-heating before the heat treatment is preferably set to 900° C.
  • the reduction in the pearlite lamella intervals is effective.
  • heat treatment at a high cooling rate is required. Therefore, the heat treatment is preferably performed at a surface temperature and at an average cooling rate within the ranges mentioned.
  • the cooling rate is less than 1° C./s, the pearlite lamella intervals are coarse and the wear resistance decreases.
  • the cooling rate exceeds 10° C./s, the structure after transformation is such as bainite and martensite that are poor in toughness and ductility, and this is not preferable.
  • the average cooling rate is a cooling rate determined from the temperature changes and the heat treatment time from the start of the heat treatment to the end of the heat treatment. Therefore, the thermal history from the start of the heat treatment to the end of the heat treatment also includes the heat generation of the phase transformation heat and isothermal-holding by patenting treatment.
  • the surface temperature of the head portion 91 at the end of the heat treatment exceeds 600° C., the lamella structure is partially spheroidized after the end of the heat treatment, and therefore the lamella intervals are coarse and the wear resistance decreases.
  • the rail 9 subjected to accelerated cooling is conveyed to the cooling bed 8 , and then naturally cooled until the temperature reaches about 100° C. or less.
  • shape correction of the rail 9 is performed as necessary when the rail 9 is bent or the like.
  • the cooling method in the rough cooling device 4 and the finish cooling device 5 is spray cooling employing spray water for the cooling medium in the embodiment described above but the present invention is not limited to the example.
  • mist cooling as spray cooling employing mist as a cooling medium or mixed cooling of mist cooling and air blast cooling employing mist and air as a cooling medium may be used for the cooling method in the rough cooling device 4 and the finish cooling device 5 .
  • natural cooling, immersion cooling, air blast cooling, water column cooling, and the like may be performed in place of the spray cooling with the rough cooling device 4 and the finish cooling device 5 . In the natural cooling and the air blast cooling, the cooling rate is low, and therefore the time until the rail 9 is cooled to a predetermined temperature is prolonged.
  • the rolling pitch is to be increased, other cooling methods, such as spray cooling, immersion cooling, and water column cooling, are able to be employed.
  • the cooling rate in the water column cooling is excessively high, and therefore the cooling rate is difficult to adjust.
  • the structure may be transformed to a structure having low toughness and ductility, such as bainite and martensite.
  • the spray cooling has advantages in that a somewhat high cooling rate is able to be secured and the cooling portion is easily localized. Therefore, the spray cooling is preferably used for the cooling method in the rough cooling device 4 and the finish cooling device 5 .
  • the temperature-adjusted rolling is performed in the rolling pass after the roughing mill 3 Ak+1 in the embodiment described above but the present invention is not limited to the example.
  • the temperature-adjusted rolling may be performed after any roughing mill 3 A insofar as an area reduction ratio of 20% or more is able to be secured.
  • the rough cooling device 4 is provided immediately before the roughing mill 3 A with which the temperature-adjusted rolling is started.
  • the temperature-adjusted rolling may be performed in finish rolling by the finishing mill 3 B.
  • the rough cooling device 4 may not be provided in the rail manufacturing apparatus 1 and the temperature adjustment may be performed only the finish cooling device 5 .
  • the temperature-adjusted rolling is preferably performed in the rolling with some of the roughing mills 3 A and with the finishing mill 3 B.
  • the roughing mills 3 A and the finishing mill 3 B are universal mills in the embodiment described above but the present invention is not limited to the example.
  • the roughing mills 3 A and the finishing mill 3 B may be caliber rolling mills.
  • a universal rolling method rolling from a plurality of directions is achieved as compared with a caliber rolling method, and therefore the rolling load can be reduced.
  • a rolling operation capable of obtaining a large area reduction ratio at a low temperature is performed, and therefore rolling is performed under an overload and the load to the rolling mills becomes high, so that the risk of a facility trouble becomes high. Therefore, at least any one of the roughing mills 3 A and two or more of the finishing mills 3 B is preferably a universal mill.
  • finishing mills 3 B may be provided.
  • the re-heating device 6 is the induction heating type heating device in the embodiment described above but the present invention is not limited to the example.
  • the re-heating device 6 may be a burner type heating device.
  • the size of the facility is able to be made small as compared with the burner type. Therefore, the induction heating type re-heating device 6 is preferable when disposed in-line.
  • the re-heating device 6 heats the head portion 91 in the embodiment described above but the present invention is not limited to the example.
  • the re-heating device 6 may have a configuration of heating the entire rail 9 .
  • portions contacting wheels are worn out, and therefore particularly the head portion 91 is required to have wear resistance. Therefore, a configuration of re-heating only the head portion 91 in re-heating is economically excellent because energy required for the heating is able to be reduced.
  • the re-heating is performed with the re-heating device 6 after the hot-rolling in the embodiment described above but the re-heating with the re-heating device 6 may not be performed.
  • the hot-rolled rail 9 is conveyed to the heat treatment apparatus 7 , and then heat-treated with the heat treatment apparatus 7 . Even when the re-heating is not performed, the ductility improvement effect of the head portion 91 and the foot portion 93 is able to be obtained.
  • the temperature of the rail 9 after the end of the hot-rolling (after the end of the temperature-adjusted rolling) is low, the hardness decreases as compared with the case where the temperature is high.
  • the heat treatment with the heat treatment apparatus 7 is also omissible.
  • the hot-rolled rail 9 is conveyed to the cooling bed 8 , and then cooled until the temperature reaches about 100° C. or less. Even when the re-heating and the heat treatment are not performed, the ductility improvement effect of the head portion 91 and the foot portion 93 is able to be obtained. However, the hardness decreases as compared with the case where the re-heating and the heat treatment are performed.
  • the method for manufacturing the rail 9 according to the embodiment described above includes hot-rolling a heated steel rail material, adjusting the temperature by cooling the hot-rolled steel rail material, processing the steel rail material subjected to the temperature adjustment into a rail shape by means of temperature-adjusted rolling at an area reduction ratio of 20% or more, and, in adjusting the temperature of the steel rail material, cooling the surface portions of the steel rail material corresponding to a head portion and a foot portion of the rail shape so that the temperatures of the surface portions reach 500° C. or more and 1,000° C. or less.
  • crystal grains are able to be divided and refined while preventing the coarsening of the crystal grains due to the re-crystallization in the austenite temperature range in the temperature-adjusted rolling. Therefore, the toughness and the ductility of the head portion 91 and the foot portion 93 of the rail 9 are able to be increased.
  • the rail 9 is heat-treated until the surface temperature of the head portion of the rail 9 reaches 600° C. or less at an average cooling rate of 1° C./s or more and 10° C./s or less.
  • the pearlite lamella intervals of the head portion 91 of the rail 9 can be refined and the wear resistance is able to be increased. Moreover, the spheroidization of the lamella structure after the end of the heat treatment is able to be prevented, and therefore the wear resistance improves.
  • the rail Before heat-treating the rail 9 , the rail is re-heated to 730° C. or more when the surface temperature of the head portion of the rail 9 is less than 730° C.
  • the pearlite structure is able to be reversely transformed to the austenite structure, so that the lamella structure is able to be re-created again. Therefore, the hardness and the wear resistance of the rail 9 are able to be increased.
  • the energy required for the heating is able to be reduced as compared with the case where the entire rail 9 is re-heated.
  • the apparatus 1 for manufacturing the rail 9 has at least one first rolling mills 3 A 1 to 3 AK rolling a steel rail material, a cooling device 4 adjusting a temperature by cooling the steel rail material rolled with the first rolling mills 3 A 1 to 3 AK, and at least one second rolling mills 3 AK+1 to 3 An and 3 B processing the steel rail material subjected to the temperature adjustment into a rail shape by means of temperature-adjusted rolling at an area reduction ratio of 20% or more, in which the cooling device 4 cools the surface portions of the steel rail material corresponding to the head portion 91 and the foot portion 93 of the rail shape so that the temperatures of the surface portions reach 500° C. or more and 1,000° C. or less.
  • rails 9 were manufactured using the rail manufacturing apparatus 1 described in FIG. 1 under various chemical composition conditions and rolling conditions, and then the total elongation of the manufactured rails 9 was measured.
  • Table 1 shows the chemical composition of the rail 9 used in Examples 1. The remainder includes iron and inevitable impurities.
  • Table 2 shows the rolling conditions and the measurement results of the total elongation in Examples 1.
  • Examples 1 first, a continuously cast bloom was heated with the heating furnace 2 until the temperature reached 1100° C.
  • the chemical composition of the bloom used in Examples 1 was any one of the composition A to the composition G of Table 1 as shown in Table 2.
  • the heated bloom was collected from the heating furnace 2 , and then hot-rolled with the roughing mills 3 A and the finishing mill 3 B.
  • the roughing mills 3 A a plurality of rolling mills in which a universal mill and a caliber rolling mill were combined was used.
  • the rail 9 during the rolling was rolled and conveyed with an overturned state.
  • the temperature adjustment was performed until the surface temperatures of the head portion 91 and the foot portion 93 reached 500° C. or more and 1000° C. or less with either the rough cooling device 4 or the finish cooling device 5 .
  • the temperature adjustment method the time from the start of the temperature-adjusted rolling to the end of the hot-rolling, and the number of temperature-adjusted rolling passes are individually shown in Table 2.
  • the temperature-adjusted rolling refers to hot-rolling after the temperature adjustment was performed.
  • the temperature adjustment was performed by anyone of the spray cooling, air blast cooling, and naturally cooling methods.
  • the surface temperatures of the head portion 91 and the foot portion 93 were adjusted by adjusting the water amount density and the cooling time in the case of the spray cooling or by controlling the cooling time without using the rough cooling device 4 and the finish cooling device 5 in the case of the natural cooling.
  • the number of the temperature-adjusted rolling passes shown in Table 2 shows the number of rolling passes after the temperature adjustment was performed by any one of the methods described above.
  • the number of times of the temperature-adjusted rolling passes was 1 time indicates that, after the temperature adjustment, only the finish rolling was performed and the number of times of the temperature-adjusted rolling passes was n (n ⁇ 2) times indicates that, after the temperature adjustment, n ⁇ 1 times of rough rolling and one finish rolling were performed.
  • the number of times of the temperature-adjusted rolling passes was 1 time the temperature adjustment was performed using the finish cooling device 5 .
  • the number of times of the temperature-adjusted rolling passes was n times the temperature adjustment was performed using the rough cooling device 4 .
  • the rail 9 was forcibly cooled with the heat treatment apparatus 7 .
  • the surface temperatures of the head portion 91 and the foot portion 93 in starting the forcible cooling were set as shown in the conditions shown in Table 2.
  • the average cooling rate was set to 3° C./s.
  • the cooling was performed until the surface temperature reached 400° C.
  • mist was used for a cooling medium.
  • the re-heat treatment employing the re-heating device 6 was not performed after the hot-rolling.
  • the forcibly cooled rail 9 was conveyed to the cooling bed 8 , the temperature was reduced to 100° C. or less by cooling, and then the rail was straightened.
  • test pieces were collected from four places of an end portion, the 1 ⁇ 4 position, the 1 ⁇ 2 position, and the 3 ⁇ 4 position in the longitudinal direction of the rail 9 , and then various physical properties were measured. As illustrated in FIG. 5 , a sample 9 a was collected from the head portion 91 and a sample 9 b was collected from the foot portion 93 of the test pieces collected at each position in the longitudinal direction.
  • the sample 9 a is a JIS No.
  • Example 1 as examples different in the chemical composition, the temperature adjustment method, the number of temperature-adjusted rolling passes, the surface temperature, and the area reduction ratio, rails 9 were manufactured under 28 kinds of conditions of Examples 1-1 to 1-28, and then the total elongation was evaluated.
  • rails 9 were manufactured as comparative examples under the same conditions as those of Examples 1-1 to 1-28, and then the total elongation was evaluated also for Comparative Examples 1-1 to 1-5 with the surface temperature and the area reduction ratio in the temperature-adjusted rolling outside the ranges of the embodiment described above.
  • the total elongation values shown in Table 2 show the average value of the four samples, i.e., the sum of one sample collected from each of the test pieces collected from each of the four places.
  • Comparative Example 1-1 in which the surface temperature of the foot portion 93 in the temperature-adjusted rolling exceeded 1000° C. and Comparative Example 1-2 in which the area reduction ratio of the foot portion 93 in the temperature-adjusted rolling was less than 20%, the elongation of the foot portion 93 was less than 12% and decreased as compared with those of Examples 1-1 to 1-28.
  • Comparative Examples 1-3 and 1-4 in which the surface temperature in the temperature-adjusted rolling was less than 500° C. or exceeded 1000° C.
  • Comparative Example 1-5 in which the rolling reduction of the head portion 91 in the temperature-adjusted rolling was less than 20%, the elongation of the head portion 91 was less than 12% and decreased as compared with those of Examples 1-1 to 1-28.
  • Examples 2 influences on the total elongation, the hardness, and the surface structure depending on the heat treatment conditions were confirmed by varying the chemical composition and the conditions in the temperature-adjusted rolling and the heat treatment.
  • Table 3 shows the chemical composition, the surface temperature in temperature-adjusted rolling, the conditions of heat treatment (forcible cooling), the measurement results of the total elongation, the measurement results of the hardness, and the observation results of a head portion surface structure in Examples 2.
  • Example 2 as the temperature-adjusted rolling, rolling in four passes in total containing three universal mills and one caliber rolling mill was performed so that the area reduction ratios of the head portion 91 and the foot portion 93 were 30%.
  • the surface temperatures of the head portion 91 and the foot portion 93 in the temperature-adjusted rolling and the start temperature, the cooling rate, and the end temperature in the heat treatment were set as shown in the conditions shown in Table 3.
  • air was used for a cooling medium under the condition where the cooling rate was 3° C./s or less and a mixture of air and mist was used for a cooling medium under the condition where the cooling rate exceeded 3° C./s.
  • the other manufacturing conditions were the same as those of Examples 1.
  • test pieces were collected, and then the total elongation was measured by the same method as that of Examples 1.
  • a sample 9 c was collected from a position of the head portion surface illustrated in FIG. 6 and a sample 9 d was collected from a position inside the head portion from the test pieces of about 20 mm thickness sawn from four places of an end portion, the 1 ⁇ 4 position, the 1 ⁇ 2 position, and the 3 ⁇ 4 position in the longitudinal direction of the rail 9 .
  • the sample 9 c was collected from the center of the upper end surface of the head portion 91 of the test pieces polished in order to remove surface unevenness.
  • the hardness of the collected samples 9 c and 9 d was measured by a Brinell hardness test. With respect to the surface structure, the surface structure of the collected samples 9 c was observed.
  • Examples 2 as examples different in the chemical composition, the surface temperature in the temperature-adjusted rolling, and conditions in the heat treatment, rails 9 were manufactured under 21 kinds of conditions of Examples 2-1 to 2-21, and then the total elongation and the hardness were measured and further the surface structure was observed.
  • Example 2-13 the heat treatment was not performed and the rail 9 after the hot-rolling was conveyed to the cooling bed 8 , and then cooled until the temperature reached 100° C. or less. After the rail 9 reached 100° C. or less, the rail was straightened.
  • Example 2-2 and 2-3 the surface temperature of the head portion 91 in the temperature-adjusted rolling was lower than that in other conditions, the surface temperature in starting the heat treatment was also low and the total elongation of the head portion 91 was 15% or more, which was higher than that in other conditions.
  • the hardness of the head portion 91 was 380 HB or less, which was lower than that in Example 2-1.
  • Examples 2-1, 2-7 to 2-10, and 2-14 to 2-21 in which the conditions except the cooling rate in the heat treatment were the same and, further, in Examples 2-14 to 2-21 in which the composition is different, the hardness of the surface and inside of the head portion 91 improved when the cooling rate was higher.
  • Examples 2-1, 2-7 to 2-10, and 2-14 to 2-21 and Comparative Examples 2-1 to 2-3 in which the conditions except the cooling rate in the heat treatment were the same and, further, in Comparative Examples 2-1 to 2-3 in which the cooling rate exceeded 10° C./s, the cooling rate was excessively high, and therefore the structure was partially transformed into a martensite and the total elongation was as very low as 3%.
  • Example 2-13 in which the heat treatment was not performed, the total elongations of the head portion 91 and the foot portion 93 were 12% or more but the hardness of the surface and inside of the head portion 91 was the lowest in all the conditions.
  • the pearlite structure was partially spheroidized.
  • Example 3 in order to confirm influences on the hardness and the surface structure by re-heat treatment, re-heating was performed before the heat treatment with respect to the condition of Example 2-3 in which the hardness was low.
  • manufacturing conditions other than the surface temperature of the head portion 91 in the temperature-adjusted rolling and performing re-heating were the same as those of Example 2-3.
  • Table 4 individually shows the chemical composition, the surface temperature in the temperature-adjusted rolling, the conditions in the re-heating and the heat treatment, the measurement results of the total elongation, the measurement results of the hardness, and the observation results of the head portion surface structure in Example 3.
  • the total elongation values and the hardness shown in Table 4 show the average value of the four samples, i.e., the sum of one sample collected from each of the test pieces collected from each of the four places.
  • the head portion 91 or the entire rail 9 was re-heated with the re-heating device 6 after the hot-rolling.
  • the re-heating device 6 is an induction heating type heating device and is able to heat the head portion 91 or the entire rail 9 according to the conditions shown in Table 4.
  • the surface temperature of the head portion 91 after the re-heating is the start temperature in the heat treatment shown in Table 4.
  • Examples 3 rails 9 were manufactured under 9 kinds of conditions of Examples 3-1 to 3-9 different in the surface temperature of the head portion 91 in the temperature-adjusted rolling and the re-heating conditions, and then the total elongation and the hardness were measured and further the surface structure was observed.
  • a method for collecting samples for the total elongation and the hardness and a method for collecting samples for observing the surface structure are the same as those of Examples 2.
  • Example 3-1 is the condition in which the re-heating was not performed and has the same manufacturing conditions as those of Example 2-3.
  • Example 3-1 in which the re-heating was not performed, the surface temperature in starting the temperature-adjusted rolling was low, and therefore the surface temperature of the head portion 91 in starting the heat treatment was as low as 630° C. and the hardness of the surface and inside of the head portion 91 was low.
  • Example 3-2 and 3-6 the re-heating was performed and the surface temperature of the head portion 91 in starting the heat treatment was set to 700° C. but the surface temperature was as low as 730° C. or less, and therefore the hardness of the surface and inside of the head portion 91 was low as in Example 3-1.

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10233512B2 (en) * 2014-05-29 2019-03-19 Nippon Steel & Sumitomo Metal Corporation Rail and production method therefor

Families Citing this family (5)

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Publication number Priority date Publication date Assignee Title
PL442341A1 (pl) * 2022-09-21 2024-03-25 Firma Codogni Spółka Jawna Sposób walcowania kul
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PL442343A1 (pl) * 2022-09-21 2024-03-25 Firma Codogni Spółka Jawna Sposób walcowania kul
WO2024202406A1 (fr) * 2023-03-24 2024-10-03 Ｊｆｅスチール株式会社 Rail et son procédé de fabrication
WO2024202408A1 (fr) * 2023-03-24 2024-10-03 Ｊｆｅスチール株式会社 Rail et son procédé de fabrication

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4486248A (en) * 1982-08-05 1984-12-04 The Algoma Steel Corporation Limited Method for the production of improved railway rails by accelerated cooling in line with the production rolling mill
US5209792A (en) * 1990-07-30 1993-05-11 Nkk Corporation High-strength, damage-resistant rail
US5762723A (en) * 1994-11-15 1998-06-09 Nippon Steel Corporation Pearlitic steel rail having excellent wear resistance and method of producing the same
JP2002226915A (ja) * 2001-02-01 2002-08-14 Nippon Steel Corp 高耐摩耗・高靭性レールの製造方法
US20040187981A1 (en) * 2002-04-05 2004-09-30 Masaharu Ueda Pealite base rail excellent in wear resistance and ductility and method for production thereof
US20110139320A1 (en) * 2009-12-14 2011-06-16 Bramfitt Bruce L Method of making a hypereutectoid, head-hardened steel rail
US20110155821A1 (en) * 2008-10-31 2011-06-30 Masaharu Ueda Pearlite rail having superior abrasion resistance and excellent toughness
US20110226389A1 (en) * 2009-08-18 2011-09-22 Nippon Steel Corporation Pearlite rail
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
US20130133784A1 (en) * 2011-11-29 2013-05-30 Cf&I Steel L.P., D/B/A Evraz Rocky Mountain Steel Method and apparatus for treatment of a rail weld
US20140182751A1 (en) * 2012-12-31 2014-07-03 Pangang Group Panzhihua Steel & Vanadium Co., Ltd. Heat treatment method of turnout track and the turnout track

Family Cites Families (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3336006A1 (de) * 1983-10-04 1985-04-25 Krupp Stahl Ag, 4630 Bochum Schiene mit hoher verschleissfestigkeit im kopf und hoher bruchsicherheit im fuss
JPS62127453A (ja) * 1985-11-26 1987-06-09 Nippon Kokan Kk <Nkk> 延性及び靭性に優れた高性能レールの製造方法
JP3950212B2 (ja) * 1997-11-20 2007-07-25 新日本製鐵株式会社 耐摩耗性に優れた高強度パーライト系レールの製造法
JP2001040415A (ja) * 1999-07-30 2001-02-13 Nippon Steel Corp 靭性および延性に優れた高強度パーライト系レールの製造方法
JP2001234238A (ja) * 2000-02-18 2001-08-28 Nippon Steel Corp 高耐摩耗・高靭性レールの製造方法
JP4267334B2 (ja) * 2002-11-12 2009-05-27 新日本製鐵株式会社 高炭素鋼パーライトレールの熱処理方法
JP4469248B2 (ja) * 2004-03-09 2010-05-26 新日本製鐵株式会社 耐摩耗性および延性に優れた高炭素鋼レールの製造方法
JP5472418B2 (ja) * 2006-07-24 2014-04-16 新日鐵住金株式会社 耐摩耗性および延性に優れたパーライト系レールの製造方法
JP4994928B2 (ja) * 2007-04-17 2012-08-08 新日本製鐵株式会社 耐折損性に優れたレールの製造方法

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4486248A (en) * 1982-08-05 1984-12-04 The Algoma Steel Corporation Limited Method for the production of improved railway rails by accelerated cooling in line with the production rolling mill
US5209792A (en) * 1990-07-30 1993-05-11 Nkk Corporation High-strength, damage-resistant rail
US5762723A (en) * 1994-11-15 1998-06-09 Nippon Steel Corporation Pearlitic steel rail having excellent wear resistance and method of producing the same
JP2002226915A (ja) * 2001-02-01 2002-08-14 Nippon Steel Corp 高耐摩耗・高靭性レールの製造方法
US20040187981A1 (en) * 2002-04-05 2004-09-30 Masaharu Ueda Pealite base rail excellent in wear resistance and ductility and method for production thereof
US20110155821A1 (en) * 2008-10-31 2011-06-30 Masaharu Ueda Pearlite rail having superior abrasion resistance and excellent toughness
US20110226389A1 (en) * 2009-08-18 2011-09-22 Nippon Steel Corporation Pearlite rail
US20110139320A1 (en) * 2009-12-14 2011-06-16 Bramfitt Bruce L Method of making a hypereutectoid, head-hardened steel rail
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
US20130133784A1 (en) * 2011-11-29 2013-05-30 Cf&I Steel L.P., D/B/A Evraz Rocky Mountain Steel Method and apparatus for treatment of a rail weld
US20140182751A1 (en) * 2012-12-31 2014-07-03 Pangang Group Panzhihua Steel & Vanadium Co., Ltd. Heat treatment method of turnout track and the turnout track

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10233512B2 (en) * 2014-05-29 2019-03-19 Nippon Steel & Sumitomo Metal Corporation Rail and production method therefor

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CN106714990A (zh) 2017-05-24
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CA2962031A1 (fr) 2016-03-31
AU2018271236A1 (en) 2018-12-13
WO2016047076A1 (fr) 2016-03-31
BR112017005296A2 (pt) 2017-12-12
EP3199255B1 (fr) 2020-07-22
EP3199255A1 (fr) 2017-08-02
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CA2962031C (fr) 2019-05-14
JPWO2016047076A1 (ja) 2017-04-27

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