H-Section steel

Patent metadata

Field	Value
Publication number	US-9482005-B2
Application number	US-201314416403-A
Country	US
Kind code	B2
Filing date	Nov 13, 2013
Priority date	Nov 26, 2012
Publication date	Nov 1, 2016
Grant date	Nov 1, 2016

Abstract

There is provided an H-section steel in which a number density of oxide particles having an equivalent circle diameter of 0.005 μm to 2.0 μm per unit area is 100 pieces/mm 2 to 5000 pieces/mm 2 , the oxide particles includes Ca, Al, and O as a composition, the amount of Ca is 5% or more, the amount of Al is 5% or more, and a total amount of Ca and Al is 50% or more by mass ratio excluding O in the oxide particles, a thickness of the flange is 100 mm to 150 mm, a bainite fraction in a metallographic structure of the flange is 80% or more at a strength evaluation position, and an average prior austenite grain size in the metallographic structure of the flange is 200 μm or less at a toughness evaluation position.

First claim

The invention claimed is:

1. An H-section steel comprising:
a flange; and
a web,
wherein the steel includes, as a chemical composition, by mass %,
C: 0.05% to 0.16%,
Si: 0.01% to 0.50%,
Mn: 0.80% to 2.00%,
Ni: 0.05% to 0.50%,
V: 0.01% to 0.20%,
Al: 0.005% to 0.100%,
Ti: 0.005% to 0.030%,
N: 0.0010% to 0.0200%,
O: 0.0001% to 0.0100%,
Ca: 0.0003% to 0.0040%,
Cr: 0% to 0.50%,
Cu: 0% to 0.50%,
Mo: 0% to 0.20%,
Nb: 0% to 0.05%, and
a balance consisting of Fe and impurities,

a carbon equivalent Ceq obtained by the following expression (1) is 0.35% to 0.50%,
a number density of oxide particles having an equivalent circle diameter of 0.005 μm to 2.0 μm per unit area is 100 pieces/mm 2 to 5000 pieces/mm 2 ,
the oxide particle includes Ca, Al, and O as a composition,
an amount of Ca is 5% or more, an amount of Al is 5% or more, and a total amount of Ca and Al is 50% or more by mass ratio excluding O in the oxide particle,
a thickness of the flange is 100 mm to 150 mm,
a bainite fraction in a metallographic structure of the flange is 80% or more at a strength evaluation position which is a ⅙ position from a surface of the flange in a length direction and is a ¼ position from the surface of the flange in a thickness direction, and
an average prior austenite grain size in the metallographic structure of the flange is 200 μm or less at a toughness evaluation position which is a ½ position from the surface of the flange in the length direction and is a ¾ position from the surface of the flange in the thickness direction,
Ceq=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15  Expression (1),

here, C, Mn, Cr, Mo, V, Ni, and Cu in the expression represent an amount (mass %) of each element, and elements which are not added are indicated as 0.

2. The H-section steel according to claim 1 ,
wherein, the steel includes as a chemical composition, by mass %:
Cr: 0.01% to 0.50%;
Cu: 0.01% to 0.50%;
Mo: 0.001% to 0.20%; and
Nb: 0.001% to 0.05%.

3. The H-section steel according to claim 1 ,
wherein a yield strength or a 0.2% proof stress is 450 MPa or more, a tensile strength is 550 MPa or more, and a Charpy absorbed energy at 21° C. is 100 J or more at the strength evaluation position.

4. The H-section steel according to claim 1 , wherein the oxide particle contains Ti.

5. The H-section steel according to claim 1 , wherein the steel is produced by universal rolling.

6. The H-section steel according to claim 2 ,
wherein a yield strength or a 0.2% proof stress is 450 MPa or more, a tensile strength is 550 MPa or more, and a Charpy absorbed energy at 21° C. is 100 J or more at the strength evaluation position.

7. The H-section steel according to claim 2 , wherein the oxide particle contains Ti.

8. The H-section steel according to claim 3 , wherein the oxide particle contains Ti.

9. The H-section steel according to claim 6 , wherein the oxide particle contains Ti.

10. The H-section steel according to claim 2 , wherein the steel is produced by universal rolling.

11. The H-section steel according to claim 3 , wherein the steel is produced by universal rolling.

12. The H-section steel according to claim 4 , wherein the steel is produced by universal rolling.

13. The H-section steel according to claim 6 , wherein the steel is produced by universal rolling.

14. The H-section steel according to claim 7 , wherein the steel is produced by universal rolling.

15. The H-section steel according to claim 8 , wherein the steel is produced by universal rolling.

16. The H-section steel according to claim 9 , wherein the steel is produced by universal rolling.

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

• Mizoguchi Masaki
• Ichikawa Kazutoshi
• MITSUYASU Kazuaki
• Sugiyama Hirokazu

Classifications

• C21D8/00

  Modifying the physical properties of ferrous metals or ferrous alloys by deformation combined with, or followed by, heat treatment (hardening articles or materials formed by forging or rolling with no further heating beyond that required for the formation C21D1/02) · CPC title

• C21D1/60

  Aqueous agents · CPC title

• C21D2211/004

  Dispersions; Precipitations · CPC title

• C22C38/16

  containing copper · CPC title

• C22C38/46

  with vanadium · CPC title