	US 12,352,309 B2
	Crankshaft
Tatsuhiko Abe, Tokyo (JP); Manabu Kubota, Tokyo (JP); Satoru Okawa, Tokyo (JP); Motoichi Murakami, Gotenba (JP); Takashi Koyama, Mishima (JP); Yusuke Morita, Mishima (JP); Takeshi Fukui, Aichi-ken (JP); Yusuke Inukai, Aichi-ken (JP); and Yuichiro Kajiki, Aichi-ken (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP); and TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP)
Appl. No. 18/005,877
Filed by NIPPON STEEL CORPORATION, Tokyo (JP); and TOYOTA JIDOSHA KABUSHIKI KAISHA, Toyota (JP)
PCT Filed Sep. 24, 2021, PCT No. PCT/JP2021/035059 § 371(c)(1), (2) Date Jan. 18, 2023, PCT Pub. No. WO2022/065425, PCT Pub. Date Mar. 31, 2022.
Claims priority of application No. 2020-162443 (JP), filed on Sep. 28, 2020.
Prior Publication US 2023/0304528 A1, Sep. 28, 2023
Int. Cl. C22C 38/04 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/06 (2006.01); C22C 38/38 (2006.01); C22C 38/60 (2006.01); F16C 3/06 (2006.01); C21D 9/30 (2006.01)

CPC F16C 3/06 (2013.01) [C22C 38/00 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/38 (2013.01); C22C 38/60 (2013.01); C21D 9/30 (2013.01)]

6 Claims

1. A crankshaft comprising a journal and a pin, the crankshaft having a chemical composition of, in mass %:

0.35 to 0.40% C;

up to 0.70% Si;

1.00 to 2.00% Mn;

up to 0.50% Cr;

up to 0.050% Al;

up to 0.020% N;

up to 0.020% P;

0.005 to 0.200% S; and

balance Fe and impurities,

for each of the journal and the pin, a microstructure of a surface containing tempered martensite in not less than 80 volume % and a hardness of the surface being not higher than HV 450.