# US 2009/0014099 A1 · Rail manufacturing method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 2009/0014099 A1 - Document ID: US20090014099A1 - Status: Published application - Kind: A1 - Application number: 10/585,472 - Filed: 2005-01-07 - Published: 2009-01-15 - Earliest claimed: 2004-01-09 - Assignees: Nippon Steel Corporation - Inventors: Noriaki Onodera; Takuya Satoh; Masaharu Ueda; Kazuo Fujita; Akira Kobayashi - Web page: https://patentgrep.com/patent/US20090014099A1 ## CPC - C21D 9/06: with diminished tendency to become wavy - C21D 9/04: for rails - B21B 1/085: Rail sections - B21B 2045/0254: {for structural sections, e.g. H-beams} - C21D 1/84: Controlled slow cooling (cooling-beds for metal rolling B21B43/00) - 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 (surface treatment of metallic material involving at least one process provided for in class C23 and at least one process covered by this subclass C23F17/00; unidirectional solidification of eutectic materials or unidirectional demixing of eutectoid materials C30B) - B21B: ROLLING OF METAL (auxiliary operations used in connection with metal-working operations covered in B21, see B21C; bending by rolling B21D; manufacture of particular objects, e.g. screws, wheels, rings, barrels, balls, by rolling B21H; pressure welding by means of a rolling mill B23K20/04) ## Abstract A rail manufacturing method is provided, in which a billet is hot-rolled into a rail form and the rail is cooled to ambient temperature. The foot part of the rail can be mechanically restrained to improve the straightness of the rail during at least the period of cooling where the surface temperature is between 800° C. and 400° C. In the subsequent cooling process, at least while the surface temperature of the foot of the rail is between 400° C. and 250° C., the rail is kept in an upright state, and cooled naturally without using insulation or accelerated cooling. ## Claims ### Claim 1 A rail manufacturing method, comprising: a) hot-rolling a billet into a form of a rail having a high temperature; and b) after step (a), cooling the high-temperature rail is cooled to ambient temperature, wherein the rail is maintained in an upright position until a temperature of a surface of a head of a rail reaches a temperature range of substantially 400° C. to 250° C., and where the rail is cooled naturally without a use of at least one of an insulation and an accelerated cooling procedure. ### Claim 2 (depends on 1) The rail manufacturing method according to claim 1, wherein step (b) comprises, while mechanically restraining the foot of the rail and while at the same time maintaining the rail in the upright position, performing accelerated cooling of the head and a foot of the rail at a speed of substantially 1° C. per second to 20° C. per second, wherein the accelerated cooling is performed until one of (i) a surface temperature of at least the head reaches a temperature range of substantially 550° C. to 450° C., and (ii) the surface temperature of the foot of the rail reaches a temperature range of substantially 500° C. to 450° C. ### Claim 3 (depends on 2) The rail manufacturing method according to claim 2, wherein one of the surface temperature of the head of the rail which begins the accelerated cooling and the surface temperature of the foot part of the rail which begins the accelerated cooling is the temperature at which a structure of the rail is austenitic. ### Claim 4 (depends on 1) The rail manufacturing method according to claim 1, wherein, after step (a), the rail is maintained in the upright position until an ambient temperature is reached. ### Claim 5 (depends on 4) The rail manufacturing method according to claim 4, wherein a cross-sectional shape of the rail is measured online during a conveyance of the rail that has been placed into the upright position after step (a). ### Claim 6 (depends on 1) The rail manufacturing method according to claim 1, wherein the length of the rail is between substantially 80 meters and 250 meters. ### Claim 7 A rail manufacturing method, comprising: a) hot-rolling a billet into a form of a rail having a high temperature; and b) after step (a), cooling the high-temperature rail is cooled to ambient temperature, wherein the rail is maintained in an upright position until a temperature of a surface of a foot of a rail reaches a temperature range of substantially 800° C. to 400° C. while the foot of the rail is mechanically restrained. ### Claim 8 (depends on 7) The rail manufacturing method according to claim 7, wherein step (b) comprises, while mechanically restraining the foot of the rail and while at the same time maintaining the rail in the upright position, performing accelerated cooling of a head and the foot of the rail at a speed of substantially 1° C. per second to 20° C. per second, wherein the accelerated cooling is performed until one of (i) a surface temperature of at least the head reaches a temperature range of substantially 550° C. to 450° C., and (ii) the surface temperature of the foot of the rail reaches a temperature range of substantially 500° C. to 450° C. ### Claim 9 (depends on 8) The rail manufacturing method according to claim 8, wherein one of the surface temperature of the head of the rail which begins the accelerated cooling and the surface temperature of the foot part of the rail which begins the accelerated cooling is the temperature at which a structure of the rail is austenitic. ### Claim 10 (depends on 7) The rail manufacturing method according to claim 7, wherein, after step (a), the rail is maintained in the upright position until an ambient temperature is reached. ### Claim 11 (depends on 10) The rail manufacturing method according to claim 10, wherein a cross-sectional shape of the rail is measured online during a conveyance of the rail that has been placed into the upright position after step (a). ### Claim 12 (depends on 11) The rail manufacturing method according to claim 11, wherein the length of the rail is between substantially 80 meters and 250 meters.