US 11,892,048 B2
Spring steel wire
Hiromu Izumida, Osaka (JP); Yoshiki Natsumeda, Osaka (JP); and Taichi Okada, Osaka (JP)
Assigned to Sumitomo Electric Industries, Ltd., Osaka (JP)
Appl. No. 17/058,282
Filed by Sumitomo Electric Industries, Ltd., Osaka (JP)
PCT Filed Jun. 15, 2020, PCT No. PCT/JP2020/023360
§ 371(c)(1), (2) Date Nov. 24, 2020,
PCT Pub. No. WO2021/255776, PCT Pub. Date Dec. 23, 2021.
Prior Publication US 2022/0186803 A1, Jun. 16, 2022
Int. Cl. C22C 38/02 (2006.01); F16F 1/02 (2006.01); C21D 6/00 (2006.01); C21D 9/52 (2006.01); C22C 38/04 (2006.01); C22C 38/18 (2006.01)
CPC F16F 1/021 (2013.01) [C21D 6/002 (2013.01); C21D 6/005 (2013.01); C21D 6/008 (2013.01); C21D 9/525 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/18 (2013.01); C21D 2211/009 (2013.01); F16F 2224/0208 (2013.01)] 7 Claims
OG exemplary drawing
 
1. A spring steel wire comprising:
a main body made of a steel and having a line shape; and
an oxidized layer covering an outer peripheral surface of the main body;
the steel constituting the main body containing not less than 0.5 mass % and not more than 0.7 mass % C, not less than 1 mass % and not more than 2.5 mass % Si, not less than 0.2 mass % and not more than 1 mass % Mn, and not less than 0.5 mass % and not more than 2 mass % Cr, with the balance being Fe and unavoidable impurities,
the steel constituting the main body having a pearlite structure,
the oxidized layer having an average thickness of more than 2 μm and not more than 5 μm,
the oxidized layer containing not less than 60 mass % Fe3O4.