Global Patent Index - EP 2071044 A1

EP 2071044 A1 20090617 - A method for producing high-carbon steel rails excellent in wear resistance and ductility

Title (en)

A method for producing high-carbon steel rails excellent in wear resistance and ductility

Title (de)

Verfahren zur Herstellung von Hartstahlschienen, die eine hervorragende Verschleißfestigkeit und Duktilität aufweisen

Title (fr)

Procédé de production de rails en acier à forte teneur en carbone ayant une excellente résistante à l'usure et ductilité

Publication

EP 2071044 A1 20090617 (EN)

Application

EP 09004035 A 20050309

Priority

  • EP 05726643 A 20050309
  • JP 2004065676 A 20040309
  • JP 2004285934 A 20040930

Abstract (en)

Disclosed are methods of producing steel rails having a high carbon content and being excellent in wear resistance and ductility from the slabs for rails. One method involves producing a steel rail having a high content of carbon, comprising finish rolling the rail in two consecutive passes, with a reduction rate per pass of a cross-section of the rail of 2-30%, wherein the conditions of the finish rolling satisfy the following relationship: S ‰¦ 800 / (C × T), wherein S is the maximum rolling interval time (seconds), C is the carbon content of the steel, wherein the carbon content is 0.85-1.40 mass%, and T is the maximum surface temperature (°C) of the rail head. Another method involves producing a steel rail with a high content of carbon, comprising: finish rolling the rail in three or more passes, with a reduction rate per pass of a cross-section of the rail of 2-30%, wherein the conditions of the finish rolling satisfy the following relationship: S ‰¦ 2400 / (C × T × P), wherein S is the maximum rolling interval time (seconds), C is the carbon content of the steel rail, wherein the carbon content is 0.85ˆ¼1.40 mass%, T is the maximum surface temperature (°C) of a rail head, and P is the number of passes, which is 3 or more. In addition to above, controlled additional amounts of V, Nb, N may be added to the steel rail and/or controlled rapid cooling of the rail after rolling may be accomplished to provide further improvements.

IPC 8 full level

C21D 8/00 (2006.01); B21B 1/08 (2006.01); C22C 38/00 (2006.01); C22C 38/58 (2006.01); B21B 1/085 (2006.01)

CPC (source: EP)

C21D 9/04 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/18 (2013.01); C22C 38/24 (2013.01); B21B 1/085 (2013.01); C21D 2211/009 (2013.01)

Citation (applicant)

Citation (search report)

  • [A] EP 0685566 A1 19951206 - NIPPON STEEL CORP [JP]
  • [DA] PATENT ABSTRACTS OF JAPAN vol. 2002, no. 12 12 December 2002 (2002-12-12)

Designated contracting state (EPC)

AT DE FR GB LU

DOCDB simple family (publication)

WO 2005085481 A1 20050915; AT 435308 T 20090715; BR PI0508533 A 20070814; BR PI0508533 B1 20131008; CA 2558850 A1 20050915; CA 2558850 C 20140218; DE 602005015199 D1 20090813; EP 1730317 A1 20061213; EP 1730317 B1 20090701; EP 2071044 A1 20090617; JP 2005290544 A 20051020; JP 4469248 B2 20100526; US 2007181231 A1 20070809

DOCDB simple family (application)

JP 2005004582 W 20050309; AT 05726643 T 20050309; BR PI0508533 A 20050309; CA 2558850 A 20050309; DE 602005015199 T 20050309; EP 05726643 A 20050309; EP 09004035 A 20050309; JP 2004285934 A 20040930; US 59084605 A 20050309