US3846183A - Method of treating steel rail - Google Patents

Method of treating steel rail Download PDF

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Publication number
US3846183A
US3846183A US00356535A US35653573A US3846183A US 3846183 A US3846183 A US 3846183A US 00356535 A US00356535 A US 00356535A US 35653573 A US35653573 A US 35653573A US 3846183 A US3846183 A US 3846183A
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United States
Prior art keywords
rail
pearlite
cooling
steel
spacing
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Expired - Lifetime
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US00356535A
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English (en)
Inventor
R Henry
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Bethlehem Steel Corp
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Bethlehem Steel Corp
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Publication date
Application filed by Bethlehem Steel Corp filed Critical Bethlehem Steel Corp
Priority to US00356535A priority Critical patent/US3846183A/en
Priority to AU68002/74A priority patent/AU484483B2/en
Priority to GB1672474A priority patent/GB1457061A/en
Priority to ZA00742497A priority patent/ZA742497B/xx
Priority to CA198,249A priority patent/CA1024422A/en
Priority to FR7415123A priority patent/FR2228112B1/fr
Priority to JP49049632A priority patent/JPS5047808A/ja
Priority to DE2421109A priority patent/DE2421109A1/de
Application granted granted Critical
Publication of US3846183A publication Critical patent/US3846183A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • 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

Definitions

  • said method includes hot forming a rail whose chemistry falls within the ranges, by weight, 0.64 to 0.82% carbon, up to about 1.50% manganese, up to about 0.04% phosphorus, up to about 0.05% sulfur, up to about 1.25% silicon, up to about 2.5% chromium, balance essentially iron, and rapidly cooling from a temperature above about 1800 F. to about 700 F.
  • the rate of cooling is such as to produce a fully pearlitic microstructure and a mean interlamellar spacing of pearlite no greater than about 1500 A., preferably no greater than about 1100 A., as determined by a plurality of measurements at random locations on a polished and etched surface.
  • the invention herein' is concerned with the production of formed steel rail having a high rolling contact fatigue life, or resistance to deformation and shelling.
  • shelling as defined in the Proceedings of A.-R.E.A., vol. 61, 1960, p. 832 is a phenomenon observed on the surface of steel rails in use, where small pieces, on the order of up to several inches by /2 inch, of the rail head fall off. Typically these failures are noted on inside corners.
  • the prior art introduced heat treatments to the conventional hot rolled and air cooled rails which were characterized by a coarse pearlitic microstructure and a hardness ranging between about R 25 to 30. Through heat treatment it was possible to refine the pearlitic microstructure, raise the hardness to a level between about R 35 to 40, with the result that the resistance to deformation and shelling improved. As a consequence of said additional treatment, costs increased resulting in a premium rail.
  • a fully heat treated rail and a partially heat treated rail.
  • the former is produced by reaustenitizing a batch of rails at about 1550 F., oil quenching, followed by tempering.
  • the partially heat treated rails have an induction or flame treated head portion only so that the microstructure of the rail is heterogeneous. That is, as a result of the localized heat treatment, a portion of the head is characterized by a fine pearlite, with the remainder of the head, the web, and base a coarse pearlite.
  • said portion of the head of the rail must be reaustenitized before refinement of the microstructure takes place.
  • the invention herein resides in the recognition that the deformation and shelling resistance, or rolling contact fatigue life, of a rail steel can be improved by controlling or minimizing the interlamellar spacing of pearlite.
  • the invention further resides in the discovery that control of such a microstructure can be achieved directly off the forming or rolling mill without the need of costly post treatments and supplementary equipment.
  • the rail steels to which this invention relates are those whose chemistry fall within the following ranges; by weight: carbon 0.64 to 0.82%, manganese up to about 1.50%, phosphorus up to about 0.04%, sulfur up to about 0.05%, silicon up to about 1.25%, chromium up to about 2.5%, balance essentially iron.
  • the steel is melted, cast and finally rolled in a conventional manner at a temperature between about 2100 to 23 50 F. While still hot and at a temperature above about 1800 F., the formed steel rail is rapidly cooled to a temperature between about 1000 to 700 F, followed by controlled cooling to prevent hydrogen flaking. Under such conditions, upon examination, the microstructure will be characterized as fully pearlitic, having a mean interlamellar spacing of pearlite no greater than about 1500 A., and preferably no greater than about 1100 A.
  • FIG. 1 is a perspective view of apparatus capable of carrying out the method of this invention.
  • FIG. 2 is a sectional view of the apparatus of FIG. 1 taken along a plane perpendicular to the axis of the rail being treated according to this invention.
  • FIG. 3 is a plan view of the apparatus described above.
  • FIG. 4 is a graph showing approximate cooling rates and mean pearlite spacing of a rail steel of this invention subjected to a Jominy bar test.
  • FIG. 5 is a reproduction of a fine grain pearlitic microstructure at approximately 20,700 showing the interlamellar spacing of the cementite lamellar.
  • This invention is directed in particular to the treatment of railroad rails to increase their shelling resistance or rolling contact fatigue life. While present day rails are rolled in various sizes ranging from 81 lb./yd. up to 155 lb./yd. one of the common rails in main line use is the 140 lb./ yd. rail. According to the standards established by the American Railway Engineering Association, a representative chemical composition for such a rail is one falling within the following ranges, by weight:
  • a ferrous alloy having a rail steel chemistry as noted above, is suitably melted and cast into ingots.
  • the ingots are processed hot by rolling into blooms and/or directly to shaped rails by such methods as the tongue-and-groove or diagonal method.
  • the rail is formed hot at a temperature of about 2l00 to 2350 F.
  • the temperature at finishing is typically above about 1800 F.
  • the method of this invention is employed to secure optimum rail steel properties.
  • the rail while still hot from the forming operation, is rapidly cooled to a temperature above about 700 F. so as to produce a fully pearlitic microstructure having a mean interlamellar spacing of pearlite no greater than about 1500 A., preferably no greater than about 1100 A.
  • a rapid cooling is used, it can not be so rapid as will result in martensite, or a mixed phase of martensite-pearlite.
  • the apparatus of FIGS. 1-3 illustrate equipment capable of achieving the proper cooling rate needed to optimize properties.
  • FIG. 1 is a perspective view of a preferred cooling system which can be used in conjunction with a conventional roll out table.
  • FIGS. 2 and 3 are different views of the said cooling system.
  • Each said side is characterized by an upstanding wall 16 and top and bottom flanges, 18 and 20 respectively.
  • the top flange 18 of each side 14 is joined to the other by cross members 22.
  • one end 24 of the cross member 22 is adapted to slide along slot 26 and be firmly secured by fastener 28 at any point therealong.
  • a plurality of nozzles 30, connected to a common manifold 32 or pipe, are secured and directed toward the rail to be cooled.
  • the rate or pressure of the cooling medium such as steam, may be monitored by gages 34 and may be modified as conditions and steel chemistry may dictate.
  • a broad range of cooling rates can be attained by this system using a combination of different cooling medium, rates and distance from nozzle to rail.
  • the method of this invention is directed to a procedure that will produce a relatively small mean interlamellar spacing of pearlite. It is therefore difiicult to select a specific cooling rate, or range thereof, as the rate will vary with the alloy used.
  • a specific cooling rate or range thereof, as the rate will vary with the alloy used.
  • FIG. 4 is a Jominy bar test of an alloy whose chemistry, by weight, is 0.73% carbon, 0.84% manganese, 0.019% phosphorus, 0.022% sulfur, 0.25% silicon, balance iron.
  • a cooling rate within vertical zones X and Y is too severe and will result in a microstructure containing martensite.
  • zone Z a cooling rate falling within zone Z, would result in a fully pearlite microstructure, but one whose mean interlamellar pearlite spacing is too great.
  • zones X and Y will be broadened.
  • slower cooling rates may be used.
  • the Jominy bar test represents a convenient method for preselecting a suitable cooling rate for the chemistry of the rail.
  • microstructure for the steel will develop similar to that shown in FIG. 5.
  • the microstructure is a graphic reproduction of a 0.69%, by weight, carbon steel, magnified about 20,700X.
  • the cementite lamellae which are generally pancake shaped, form in colonies within the prior austenite grains.
  • the colonies, containing a plurality of generally parallel lamellae, are randomly oriented within the prior austenite grain and hence throughout the steel.
  • some sets of lamellae will appear thin and in close proximity to each other, while an adjacent set might appear flattened with broad spacings between lamellae.
  • the interlamellar pearlite spacing is generally about the same throughout, so the differences are due to the angle the lamellae assume with the polished surface.
  • the lamellae illustrated at M are at an oblique angle to the polished surface.
  • the lamellae illustrated at N approach an angle normal to the polished surface.
  • the spacings N N are clearly more representative of the actual interlamellar spacing of pearlite.
  • the ladle chemistry, by weight, for said steel is listed in Table I.
  • the simple expedient herein of rapidly cooling olf the rolling mill results in a rail having properties superior to that of the air cooled, and properties at least comparable to those of the costly heat treated rails.
  • rapid cooling has been defined functionally as a rate sufficient to produce a fine pearlite having a mean interlamellar spacing of pearlite no greater than about 1500 A., preferably no greater than about 1100 A. It is obvious that the cooling rate used is not so severe as to produce martensite, or a mixed martensitepearlite.
  • a series of tests were conducted comparing the present invention to a rail isothermally transformed using a fluidized bed for cooling purposes.
  • a method of treating a rolled steel railroad rail to improve its shelling resistance comprising the steps of forming the said rail from a steel whose composition, by weight, comprises carbon between about 0.64 to 0.82%, manganese up to about 1.50%, phosphorus up to about 0.04%, sulfur up to about 0.05%, silicon up to about 1.25%, chromium up to about 2.5%, balance essentially iron, at a temperature above about 2000 F. and rapidly cooling said rail from a temperature above 1800 F. to at least a temperature between about 700 to 1000 F. at a rate sufiicient to produce a fully pearlitic microstructure and an average pearlite spacing of less than about 1500 A.
  • the method according to Claim 1 including the step of slowly cooling the rail from a temperature between 700 to 1000 F. to ambient temperature to prevent hydrogen flaking.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Heat Treatment Of Articles (AREA)
  • Heat Treatment Of Steel (AREA)
US00356535A 1973-05-02 1973-05-02 Method of treating steel rail Expired - Lifetime US3846183A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US00356535A US3846183A (en) 1973-05-02 1973-05-02 Method of treating steel rail
AU68002/74A AU484483B2 (en) 1973-05-02 1974-04-17 Method of treating steel rail
GB1672474A GB1457061A (en) 1973-05-02 1974-04-17 Method of heat treating steel rail
ZA00742497A ZA742497B (en) 1973-05-02 1974-04-18 Method of treating steel rail
CA198,249A CA1024422A (en) 1973-05-02 1974-04-26 Method of treating steel rail
FR7415123A FR2228112B1 (enrdf_load_stackoverflow) 1973-05-02 1974-04-30
JP49049632A JPS5047808A (enrdf_load_stackoverflow) 1973-05-02 1974-05-02
DE2421109A DE2421109A1 (de) 1973-05-02 1974-05-02 Verfahren zur behandlung von schienen

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00356535A US3846183A (en) 1973-05-02 1973-05-02 Method of treating steel rail

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US3846183A true US3846183A (en) 1974-11-05

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US00356535A Expired - Lifetime US3846183A (en) 1973-05-02 1973-05-02 Method of treating steel rail

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US (1) US3846183A (enrdf_load_stackoverflow)
JP (1) JPS5047808A (enrdf_load_stackoverflow)
CA (1) CA1024422A (enrdf_load_stackoverflow)
DE (1) DE2421109A1 (enrdf_load_stackoverflow)
FR (1) FR2228112B1 (enrdf_load_stackoverflow)
GB (1) GB1457061A (enrdf_load_stackoverflow)
ZA (1) ZA742497B (enrdf_load_stackoverflow)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4222260A (en) * 1978-05-15 1980-09-16 Wsp Industries Corporation Warm forging of connecting rod caps
EP0049004A1 (fr) * 1980-07-23 1982-04-07 CENTRE DE RECHERCHES METALLURGIQUES CENTRUM VOOR RESEARCH IN DE METALLURGIE Association sans but lucratif Perfectionnements aux procédés de fabrication de rails, et rails obtenus au moyen de ces procédés
US4375995A (en) * 1978-05-12 1983-03-08 Nippon Steel Corporation Method for manufacturing high strength rail of excellent weldability
US20040187981A1 (en) * 2002-04-05 2004-09-30 Masaharu Ueda Pealite base rail excellent in wear resistance and ductility and method for production thereof
US20050078901A1 (en) * 2002-03-06 2005-04-14 Kazutoshi Toda Bearing device and method of manufacturing the bearing device
US20100116381A1 (en) * 2007-03-28 2010-05-13 Jfe Steel Corporation Internal high hardness type pearlitic rail with excellent wear resistance and rolling contact fatigue resistance and method for producing same

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5818966B2 (ja) * 1978-06-23 1983-04-15 日本鋼管株式会社 レ−ルの製造方法
JPS57198216A (en) * 1981-05-27 1982-12-04 Nippon Kokan Kk <Nkk> Manufacture of high-strength rail
GB2118579A (en) * 1982-01-29 1983-11-02 British Steel Corp Heat treatment of rails
CA1193176A (en) * 1982-07-06 1985-09-10 Robert J. Ackert Method for the production of improved railway rails by accelerated colling in line with the production rolling mill
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
LU84417A1 (fr) * 1982-10-11 1984-05-10 Centre Rech Metallurgique Procede perfectionne pour la fabrication de rails et rails obtenus par ce procede
DE3446794C1 (de) * 1984-12-21 1986-01-02 BWG Butzbacher Weichenbau GmbH, 6308 Butzbach Verfahren zur Waermebehandlung perlitischer Schienenstaehle
EP0186373B1 (en) * 1984-12-24 1990-09-12 Nippon Steel Corporation Method of and apparatus for heat treating rails
US4886558A (en) * 1987-05-28 1989-12-12 Nkk Corporation Method for heat-treating steel rail head
US4895605A (en) * 1988-08-19 1990-01-23 Algoma Steel Corporation Method for the manufacture of hardened railroad rails
US5762723A (en) 1994-11-15 1998-06-09 Nippon Steel Corporation Pearlitic steel rail having excellent wear resistance and method of producing the same
CA2687438C (en) * 2007-10-10 2012-12-18 Jfe Steel Corporation Internal high hardness type pearlitic rail with excellent wear resistance, rolling contact fatigue resistance, and delayed fracture property and method for producing same
CA2948297C (en) * 2014-06-11 2019-08-20 Jfe Steel Corporation Railway vehicle wheel and method for manufacturing railway vehicle wheel

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2109121A5 (enrdf_load_stackoverflow) * 1970-10-02 1972-05-26 Wendel Sidelor

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4375995A (en) * 1978-05-12 1983-03-08 Nippon Steel Corporation Method for manufacturing high strength rail of excellent weldability
US4426236A (en) 1978-05-12 1984-01-17 Nippon Steel Corporation Method for manufacturing high strength rail of excellent weldability
US4222260A (en) * 1978-05-15 1980-09-16 Wsp Industries Corporation Warm forging of connecting rod caps
EP0049004A1 (fr) * 1980-07-23 1982-04-07 CENTRE DE RECHERCHES METALLURGIQUES CENTRUM VOOR RESEARCH IN DE METALLURGIE Association sans but lucratif Perfectionnements aux procédés de fabrication de rails, et rails obtenus au moyen de ces procédés
US20050078901A1 (en) * 2002-03-06 2005-04-14 Kazutoshi Toda Bearing device and method of manufacturing the bearing device
US7690846B2 (en) * 2002-03-06 2010-04-06 Koyo Seiko Co., Ltd. Bearing device and method of manufacturing the bearing device
US20040187981A1 (en) * 2002-04-05 2004-09-30 Masaharu Ueda Pealite base rail excellent in wear resistance and ductility and method for production thereof
US20100116381A1 (en) * 2007-03-28 2010-05-13 Jfe Steel Corporation Internal high hardness type pearlitic rail with excellent wear resistance and rolling contact fatigue resistance and method for producing same
US7955445B2 (en) 2007-03-28 2011-06-07 Jfe Steel Corporation Internal high hardness type pearlitic rail with excellent wear resistance and rolling contact fatigue resistance and method for producing same

Also Published As

Publication number Publication date
GB1457061A (en) 1976-12-01
AU6800274A (en) 1975-10-23
JPS5047808A (enrdf_load_stackoverflow) 1975-04-28
ZA742497B (en) 1975-04-30
CA1024422A (en) 1978-01-17
FR2228112B1 (enrdf_load_stackoverflow) 1978-04-21
DE2421109A1 (de) 1974-11-21
FR2228112A1 (enrdf_load_stackoverflow) 1974-11-29

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