ULTRA-HIGH STRENGTH ALLOY
A steel alloy having very high strength in combination with good ductility, impact toughness, and fracture toughness is disclosed. The alloy has the following weight percent composition. C 0.30-0.46 Mn 0.04 max. Si 0.03 max. P 0.003 max S 0.0010 max. Cr 1.65-2.90 Ni 10.5-13.0 Mo 1.2-3.4 Co 15.4-18.6 Al 0.01 max Ti 0.02 max. O 0.0010 max. N 0.0010 max. The balance is iron and usual impurities.
1 . A steel alloy having very high strength in combination with good ductility and toughness, said alloy consisting essentially of, in weight percent:
C
about 0.30-about 0.46
Mn
about 0.04 max.
Si
about 0.03 max.
P
about 0.003 max
S
about 0.0010 max.
Cr
about 1.65-about 2.90
Ni
about 10.5-about13.0
Mo
about 1.2-about 3.4
Co
about 15.4-about 18.6
Al
about 0.01 max
Ti
about 0.02 max.
O
about 0.0010 max.
N
about 0.0010 max.
one or both of Ce up to about 0.01% and La up to about 0.04%, wherein the ratio Ce/S or La/S is about 4 to about 20; and the balance of the alloy is iron and usual impurities.
2 . The alloy as claimed in claim 1 wherein molybdenum is about 1.8% to about 3.4%.
3 . The alloy as claimed in claim 1 wherein carbon is about 0.35% to about 0.46%.
4 . The alloy as claimed in claim 1 wherein carbon is about 0.38% to about 0.42%, chromium is about 1.8% to about 2.5%, nickel is about 11.0% to about 13.0%, and molybdenum is about 1.3% to about 1.9%.
5 . The alloy as claimed in claim 1 wherein carbon is about 0.32% to about 0.46%, chromium is about 1.8% to about 2.8%, nickel is about 11.0% to about 12.0%, and molybdenum is about 1.3% to about 2.4%.
6 . The alloy as claimed in claim 1 wherein carbon is about 0.32% to about 0.40%, chromium is about 1.7% to about 2.0%, nickel is about 10.5% to about 12.0%, molybdenum is about 2.2% to about 2.4%, and cobalt is about 16.0% to about 18.0%.
7 . A steel alloy having very high strength in combination with good ductility and toughness, said alloy consisting essentially of, in weight percent:
C
about 0.30-about 0.46
Mn
about 0.04 max.
Si
about 0.03 max.
P
about 0.003 max
S
about 0.0010 max.
Cr
about 1.65-about 2.90
Ni
about 10.5-about13.0
Mo
about 1.8-about 3.4
Co
about 15.4-about 18.6
Al
about 0.01 max
Ti
about 0.02 max.
O
about 0.0010 max.
N
about 0.0010 max.
one or both of Ce up to about 0.01% and La up to about 0.04%, wherein the ratio Ce/S or La/S is about 4 to about 20; and the balance of the alloy is iron and usual impurities.
8 . The alloy as claimed in claim 7 wherein carbon is about 0.35% to about 0.46%.
9 . The alloy as claimed in claim 7 wherein carbon is about 0.38% to about 0.42%, chromium is about 1.8% to about 2.5%, nickel is about 11.0% to about 13.0%, and molybdenum is about 1.3% to about 1.9%.
10 . The alloy as claimed in claim 7 wherein carbon is about 0.32% to about 0.46%, chromium is about 1.8% to about 2.8%, nickel is about 11.0% to about 12.0%, and molybdenum is about 1.3% to about 2.4%.
11 . The alloy as claimed in claim 7 wherein carbon is about 0.32% to about 0.40%, chromium is about 1.7% to about 2.0%, nickel is about 10.5% to about 12.0%, molybdenum is about 2.2% to about 2.4%, and cobalt is about 16.0% to about 18.0%.
12 . A steel alloy having very high strength in combination with good ductility and toughness, said alloy consisting essentially of, in weight percent:
C
about 0.32-about 0.46
Mn
about 0.04 max.
Si
about 0.03 max.
P
about 0.003 max
S
about 0.0010 max.
Cr
about 1.65-about 2.90
Ni
about 10.5-about13.0
Mo
about 1.2-about 3.4
Co
about 15.4-about 18.6
Al
about 0.01 max
Ti
about 0.02 max.
O
about 0.0010 max.
N
about 0.0010 max.
one or both of Ce up to about 0.01% and La up to about 0.04%, wherein the ratio Ce/S or La/S is about 4 to about 20; and the balance of the alloy is iron and usual impurities.
13 . The alloy as claimed in claim 12 wherein carbon is about 0.38% to about 0.42%, chromium is about 1.8% to about 2.5%, nickel is about 11.0% to about 13.0%, and molybdenum is about 1.3% to about 1.9%.
14 . The alloy as claimed in claim 12 wherein chromium is about 1.8% to about 2.8%, nickel is about 11.0% to about 12.0%, and molybdenum is about 1.3% to about 2.4%.
15 . The alloy as claimed in claim 12 wherein carbon is about 0.32% to about 0.40%, chromium is about 1.7% to about 2.0%, nickel is about 10.5% to about 12.0%, molybdenum is about 2.2% to about 2.4%, and cobalt is about 16.0% to about 18.0%.