Title:
METHOD FOR PRODUCING RAIL WHEEL AND RAIL WHEEL
Document Type and Number:
WIPO Patent Application WO/2018/181862
Kind Code:
A1
Abstract:
The present invention makes it possible to consistently produce rail wheels for which generation of pro-eutectoid cementite has been curbed. In the invention, an intermediate product having 0.80 to 1.15% C in mass% is heated to an Acm transformation point or higher, and then cooled so that the rate of cooling (°C/sec) of the intermediate product from 800°C to 500°C meets the following conditions. Surfaces other than a tread surface and flange surface: ≤ Fn1 as defined in formula (1). Rate of cooling of a region where the rate of cooling is the slowest: ≥ Fn2 as defined in formula (2). Tread surface and flange surface: ≥ Fn2.
Formula (1): Fn1=-5.0+exp(5.651-1.427×C-1.280×Si-0.7723×Mn-1.815×Cr-1.519×Al-7.798×V)
Formula (2): Fn2=0.515+exp(-24.816+24.121×C+1.210×Si+0.529×Mn+2.458×Cr-15.116×Al-5.116×V)
Inventors:
MAEJIMA TAKETO (JP)
KUBOTA MANABU (JP)
KUBOTA MANABU (JP)
Application Number:
PCT/JP2018/013538
Publication Date:
October 04, 2018
Filing Date:
March 30, 2018
Export Citation:
Assignee:
NIPPON STEEL & SUMITOMO METAL CORP (JP)
International Classes:
C21D9/34; C22C38/00; C22C38/24
Domestic Patent References:
| WO2015190088A1 | 2015-12-17 |
Foreign References:
| JP2004315928A | 2004-11-11 | |||
| JPH09202937A | 1997-08-05 | |||
| JP2012107295A | 2012-06-07 | |||
| JP2013231212A | 2013-11-14 | |||
| JP2004315928A | 2004-11-11 |
Other References:
F. WEVER ET AL.: "Zur Frage der Warmebehandlung der Stahle auf Grund ihrer Zeit-Temperatur-Umwandlungs-Schaubilder", STAHL U EISEN, vol. 74, 1954, pages 749 - 761
Attorney, Agent or Firm:
ASCEND IP LAW FIRM (JP)
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