High-strength ultra-thick H-beam steel

Patent metadata

Field	Value
Publication number	US-9863022-B2
Application number	US-201214357604-A
Country	US
Kind code	B2
Filing date	Dec 11, 2012
Priority date	Dec 15, 2011
Publication date	Jan 9, 2018
Grant date	Jan 9, 2018

Abstract

This H-beam steel has a composition including C, Si, Mn, Cu, Ni, V, Al, Ti, B, N, and O, and further including at least one of Mo and Nb, in which Ceq obtained in Equation 1 described below falls in a range of 0.37 to 0.50, the thickness of a flange falls in a range of 100 to 150 mm, and the area fraction of bainite at a depth of one quarter of the thickness of the flange from the external surface of the flange is 60% or more.

Ceq=C+Mn/6+(Mo+V)/5+(Ni+Cu)/15  Equation 1,

where C, Mn, Mo, V, Ni, and Cu represent the amount of each element contained.

First claim

The invention claimed is:

1. An H-beam steel with a composition comprising, in mass:
C: 0.110 to 0.15%;
Si: 0.20 to 0.50%;
Mn: 0.80 to 2.00%;
Cu: 0.04 to 0.25%;
Ni: 0.04 to 0.40%;
V: 0.01 to 0.10%;
Al: 0.005 to 0.040%;
Ti: 0.001 to 0.025%;
B: 0.0003 to 0.0012%;
N: 0.001 to 0.0090%;
O: 0.005 to 0.0035%,
at least one of Mo: 0.02 to 0.35% and Nb: 0.01 to 0.08%;
P: limited to not more than 0.03%; and
S: limited to not more than 0.02%,
with a balance including Fe and inevitable impurities; wherein
Ceq obtained with Equation 1 described below falls in a range of 0.37 to 0.50,
a thickness of a flange falls in a range of 100 to 150 mm, and
an area fraction of bainite at a depth of one quarter of the thickness of the flange from the external surface of the flange is not less than 60%,
Ceq=C+Mn/6+(Mo+V)/5+(Ni+Cu)/15  Equation 1.

2. The H-beam steel according to claim 1 , wherein the composition further comprises, in mass, Cr: not more than 0.20%, and
Ceq obtained with Equation 2 described below falls in a range of 0.37 to 0.50,
Ceq=C+Mn/6+(Cr+Mo+V)/5+(Ni+Cu)/15  Equation 2.

3. The H-beam steel according to claim 1 or 2 , wherein yield strength or 0.2% proof strength is not less than 450 MPa, and
tensile strength is not less than 550 MPa.

4. The H-beam steel according to claim 1 or 2 , wherein the amount of Mo is limited to not more than 0.20% in mass.

5. The H-beam steel according to claim 1 or 2 , wherein the amount of Mo is limited to not more than 0.10% in mass.

6. The H-beam steel according to claim 1 or 2 , wherein the area fraction of bainite at the depth of one quarter of the thickness of the flange from the external surface of the flange is not less than 90%.

7. The H-beam steel according to claim 1 or 2 , wherein the amount of Cu is 0.04% to 0.20% in mass.

8. The H-beam steel according to claim 1 or 2 , wherein the amount of Ni is 0.04% to 0.25% in mass.

9. The H-beam steel according to claim 1 or 2 , wherein the amount of Mo is 0% to limited to not more than 0.08% in mass.

Assignees

• Nippon Steel & Sumitomo Metal Corp

Inventors

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

Classifications

• C21D8/0226

  Hot rolling · CPC title

• C22C38/02

  containing silicon · CPC title

• C22C38/46

  with vanadium · CPC title

• C22C38/12

  containing tungsten, tantalum, molybdenum, vanadium, or niobium · CPC title

• C22C38/44

  with molybdenum or tungsten · CPC title