	US 12,104,234 B2
	Steel material
Akira Shiga, Tokyo (JP); and Yutaka Neishi, Tokyo (JP)
Assigned to NIPPON STEEL CORPORATION, Tokyo (JP)
Appl. No. 17/311,543
Filed by NIPPON STEEL CORPORATION, Tokyo (JP)
PCT Filed Dec. 27, 2019, PCT No. PCT/JP2019/051470 § 371(c)(1), (2) Date Jun. 7, 2021, PCT Pub. No. WO2020/138432, PCT Pub. Date Jul. 2, 2020.
Claims priority of application No. 2018-246367 (JP), filed on Dec. 28, 2018.
Prior Publication US 2022/0106671 A1, Apr. 7, 2022
Int. Cl. C22C 38/54 (2006.01); C22C 38/00 (2006.01); C22C 38/02 (2006.01); C22C 38/04 (2006.01); C22C 38/06 (2006.01); C22C 38/42 (2006.01); C22C 38/44 (2006.01); C22C 38/46 (2006.01); C22C 38/48 (2006.01); C22C 38/50 (2006.01)

CPC C22C 38/54 (2013.01) [C22C 38/001 (2013.01); C22C 38/002 (2013.01); C22C 38/005 (2013.01); C22C 38/02 (2013.01); C22C 38/04 (2013.01); C22C 38/06 (2013.01); C22C 38/42 (2013.01); C22C 38/44 (2013.01); C22C 38/46 (2013.01); C22C 38/48 (2013.01); C22C 38/50 (2013.01)]

2 Claims

1. A steel material having a chemical composition consisting of, in mass %:

C: 0.07 to 0.13%;

Si: 0.15 to 0.35%;

Mn: 0.60 to 0.80%;

S: 0.005 to 0.050%;

Cr: 1.90 to 2.50%;

B: 0.0005 to 0.0100%;

Ti: 0.010 to less than 0.050%;

Al: 0.010 to 0.100%;

Ca: 0.0002 to 0.0030%;

N: 0.0080% or less;

P: 0.050% or less;

O: 0.0030% or less;

Nb: 0 to 0.100%;

V: 0 to 0.300%;

Mo: 0 to 0.500%;

Ni: 0 to 0.500%;

Cu: 0 to 0.500%;

Mg: 0 to 0.0035%; and

rare earth metal (REM): 0 to 0.005%,

with the balance being Fe and impurities, and

satisfying Formula (1) to Formula (5):

0.140<C+0.194×Si+0.065×Mn+0.012×Cr+0.033×Mo+0.067×Ni+0.097×Cu+0.078×Al<0.235 (1)

1.35<(1.33×C−0.1)+(0.23×Si+0.01)+(0.42×Mn+0.22)+(0.27×Cr+0.22)+(0.77×Mo+0.03)+(0.12×Ni+0.01)<1.55 (2)

0.004<Ti−N×(48/14)<0.030 (3)

0.03≤Ca/S≤0.15 (4)

Mn/(Si+Cr+Mo+Ni)<0.30 (5)

where a symbols of each element in Formula (1) to Formula (5) is to be substituted by contents of the corresponding element (mass %) or to be substituted by “0” when the corresponding element is not contained.