Granted Patent B2

US 12,247,358 · App. 17/432,607 · Granted Mar 11, 2025

Inventors: Masaharu Ueda (Tokyo, JP); Teruhisa Miyazaki (Tokyo, JP); Takuya Tanahashi (Tokyo, JP); Yusuke Maeda (Tokyo, JP)

Assignee: NIPPON STEEL CORPORATION

E01B5/08C21D6/001C21D6/002C21D6/005C21D6/007C21D6/008C21D8/005C21D9/04C22C38/001C22C38/002C22C38/005C22C38/02C22C38/04C22C38/06C22C38/08C22C38/10C22C38/12C22C38/14C22C38/16C22C38/18C21D2211/009

Abstract

Claims (64)

1. A rail comprising steel composition including, by mass %:

C: 0.75 to 1.20%;

Si: 0.10 to 2.00%;

Mn: 0.10 to 2.00%;

Cr: 0 to 2.00%;

Mo: 0 to 0.50%;

Co: 0 to 1.00%;

B: 0 to 0.0050%;

Cu: 0 to 1.00%;

Ni: 0 to 1.00%;

V: 0 to 0.50%;

Nb: 0 to 0.050%;

Ti: 0 to 0.0500%;

Mg: 0 to 0.0200%;

Ca: 0 to 0.0200%;

REM: 0 to 0.0500%;

Zr: 0 to 0.0200%;

N: 0 to 0.0200%;

Al: 0 to 1.00%;

P: 0.0250% or less;

S: 0.0250% or less; and

a remainder including Fe and impurities,

wherein 90 area % or greater of a metallographic structure in a cross section of a rail web portion is a pearlite structure,

a minimum value of a hardness in the cross section of the rail web portion is Hv 300 or greater, and

a difference between a maximum value and the minimum value of the hardness in the cross section of the rail web portion is Hv 40 or less.

2. The rail according to claim 1 ,

wherein the difference between the maximum value and the minimum value of the hardness in the cross section of the rail web portion is Hv 20 or less.

3. The rail according to claim 2 ,

wherein the steel composition includes, by mass %, one or two or more selected from the group consisting of:

Cr: 0.01 to 2.00%;

Mo: 0.01 to 0.50%;

Co: 0.01 to 1.00%;

B: 0.0001 to 0.0050%;

Cu: 0.01 to 1.00%;

Ni: 0.01 to 1.00%;

V: 0.005 to 0.50%;

Nb: 0.0010 to 0.050%;

Ti: 0.0030 to 0.0500%;

Mg: 0.0005 to 0.0200%;

Ca: 0.0005 to 0.0200%;

REM: 0.0005 to 0.0500%;

Zr: 0.0001 to 0.0200%;

N: 0.0060 to 0.0200%; and

Al: 0.0100 to 1.00%.

4. The rail according to claim 1 ,

wherein the steel composition includes, by mass %, one or two or more selected from the group consisting of:

Cr: 0.01 to 2.00%;

Mo: 0.01 to 0.50%;

Co: 0.01 to 1.00%;

B: 0.0001 to 0.0050%;

Cu: 0.01 to 1.00%;

Ni: 0.01 to 1.00%;

V: 0.005 to 0.50%;

Nb: 0.0010 to 0.050%;

Ti: 0.0030 to 0.0500%;

Mg: 0.0005 to 0.0200%;

Ca: 0.0005 to 0.0200%;

REM: 0.0005 to 0.0500%;

Zr: 0.0001 to 0.0200%;

N: 0.0060 to 0.0200%; and

Al: 0.0100 to 1.00%.

5. The rail according to claim 1 , wherein

the rail includes a rail head portion, a rail foot portion, and the raid web portion extending between the rail head portion and the rail foot portion, and

the web portion has a cross-sectional hardness distribution within a range of 0 to 40 Hv, the cross-sectional hardness distribution being a distribution of a hardness at a cross section in a thickness direction of the rail web portion that is perpendicular to a direction in which the web portion extends.

Assignments (1)

Priority Claims (1)

Continuity (1)

References Cited (30)