公开(公告)号：US20240271262A1

公开(公告)日：2024-08-15

申请号：US18681571

申请日：2022-08-19

申请人： NIPPON STEEL CORPORATION

发明人： Yusuke MIYAKOSHI

IPC分类号： C22C38/60 ,  C21D1/32 ,  C21D6/00 ,  C21D8/06 ,  C21D9/52 ,  C22C38/00 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/44

CPC分类号： C22C38/60 ,  C21D1/32 ,  C21D6/002 ,  C21D6/004 ,  C21D6/005 ,  C21D6/008 ,  C21D8/065 ,  C21D9/525 ,  C22C38/002 ,  C22C38/005 ,  C22C38/02 ,  C22C38/04 ,  C22C38/06 ,  C22C38/20 ,  C22C38/22 ,  C22C38/24 ,  C22C38/26 ,  C22C38/28 ,  C22C38/32 ,  C22C38/44

摘要： A steel material contains, in mass %, C: 0.30 to 0.50%, Si: 0.40% or less, Mn: 0.10 to 0.60%, P: 0.030% or less, S: 0.030% or less, Cr: 0.90 to 1.80%, Mo: 0.30 to 1.00%, Al: 0.005 to 0.100%, and N: 0.003 to 0.030%, with the balance comprising Fe and impurities. When a Cr concentration in an extraction residue obtained by electrolyzing and removing a region from a surface of the steel material to a depth position of 100±20 μm by performing a preliminary constant current electrolysis and thereafter further electrolyzing a region from a surface of the steel material to a depth position of 100±20 μm by performing a main constant current electrolysis is defined as “[Cr]” (mass %), and a Mo concentration in the extraction residue is defined as “[Mo]” (mass %), the steel material satisfies Formula (1).







10.
≤


[
Cr
]

+

[
Mo
]


≤
30.




(
1
)