US 12,186,822 B2
Method for manufacturing rail, and rail
Naoki Iizuka, Tokyo (JP); Ryo Matsuoka, Tokyo (JP); Minoru Honjo, Tokyo (JP); and Shigeo Okamoto, Tokyo (JP)
Assigned to JFE STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/431,838
Filed by JFE STEEL CORPORATION, Tokyo (JP)
PCT Filed Feb. 13, 2020, PCT No. PCT/JP2020/005536
§ 371(c)(1), (2) Date Aug. 18, 2021,
PCT Pub. No. WO2020/170930, PCT Pub. Date Aug. 27, 2020.
Claims priority of application No. 2019-027604 (JP), filed on Feb. 19, 2019.
Prior Publication US 2022/0145546 A1, May 12, 2022
Int. Cl. B23K 11/16 (2006.01); B23K 11/04 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/20 (2006.01); C22C 38/22 (2006.01); C22C 38/24 (2006.01); C22C 38/26 (2006.01); C22C 38/28 (2006.01); C22C 38/32 (2006.01); C22C 38/40 (2006.01); E01B 5/08 (2006.01); B23K 101/26 (2006.01)
CPC B23K 11/16 (2013.01) [B23K 11/04 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/20 (2013.01); C22C 38/22 (2013.01); C22C 38/24 (2013.01); C22C 38/26 (2013.01); C22C 38/28 (2013.01); C22C 38/32 (2013.01); C22C 38/40 (2013.01); E01B 5/08 (2013.01); B23K 2101/26 (2018.08)] 4 Claims
OG exemplary drawing
 
1. A method of manufacturing a rail, comprising joining a plurality of pieces of rail base metal via welds formed by flash-butt welding, wherein
the rail base metal comprises a chemical composition containing
C: 0.60 mass % to 1.20 mass %,
Si: 0.10 mass % to 1.50 mass %,
Mn: 0.10 mass % to 1.50 mass %, and
Cr: 0.10 mass % to 1.50 mass %,
with the balance being Fe and inevitable impurities,
the flash-butt welding is performed with an amount of welding heat input of 1.50×105 kA2×sec or more and 4.50×105 kA2×sec or less,
an absolute value of difference in hardness between the rail base metal and the welds in a surface layer from a surface of a rail head to a depth of 2.5 mm after the welding is 20 or less in Vickers hardness, and
deflection of the welds is 20 mm or more.