High Strength, High Toughness Steel Alloy
Abstract
A high strength, high toughness steel alloy is disclosed. The alloy has the following broad weight percent composition. Element Broad C 0.35-0.55 Mn 0.6-1.2 Si 0.9-2.5 P 0.01 max. S 0.001 max. Cr 0.75-2.0 Ni 3.5-7.0 Mo + ½ W 0.4-1.3 Cu 0.5-0.6 Co 0.01 max. V + (5/9) × Nb 0.2-1.0 Fe Balance Included in the balance are the usual impurities found in commercial grades of steel alloys produced for similar use and properties. Also disclosed is a hardened and tempered article that has very high strength and fracture toughness. The article is formed from the alloy having the broad weight percent composition set forth above. The alloy article according to this aspect of the invention is further characterized by being tempered at a temperature of about 500° F. to 600° F.
Claims
exact text as granted — not AI-modified1 - 86 . (canceled)
87 . A steel alloy comprising, in weight percent, about:
Carbon 0.35-0.5 Manganese 0.6-1.2 Silicon 0.9-2.5 Phosphorus 0.01 max. Sulfur 0.001 max. Chromium 1.0-1.5 Nickel 3.5-4.5 Molybdenum 0.4-1.3 Copper 0.5-0.6 Cobalt 0.01 max. Vanadium 0.25-0.35 Titanium 0.01 max. Calcium up to 0.005
the balance being iron and usual impurities, and wherein
2≦(% Si+% Cu)/% V≦14.
88 . The alloy claimed in claim 87 which contains at least 0.37% carbon.
89 . The alloy claimed in claim 88 which contains not more than 0.45% carbon.
90 . The alloy claimed in claim 87 which contains at least 1.3% silicon.
91 . The alloy claimed in claim 87 which contains at least 3.7% nickel.
92 . The alloy claimed in claim 91 which contains not more than 4.2% nickel.
93 . The alloy claimed in claim 87 which contains at least 0.5% molybdenum.
94 . The alloy claimed in claim 93 which contains not more than 1.1% molybdenum.
95 . The alloy claimed in claim 87 which contains at least 1.2% chromium.
96 . The alloy claimed in claim 95 which contains not more than 1.35% chromium.
97 . The alloy claimed in claim 87 wherein 6≦(% Si+% Cu)/% V≦12.
98 . The steel alloy claimed in claim 87 wherein the alloy comprises, in weight percent, about
Carbon
0.37-0.45
Manganese
0.7-0.9
Silicon
1.3-2.5
Phosphorus
0.005 max.
Sulfur
0.0005 max.
Chromium
1.2-1.35
Nickel
3.7-4.5
Molybdenum
0.5-1.1
and wherein
6≦(% Si+% Cu)/% V≦12.
99 . A quenched and tempered steel article formed from the alloy claimed in claim 87 , said article providing a tensile strength of at least 280 ksi and a K Ic fracture toughness of at least 90 ksi√in after having been tempered at a temperature of 500° F.
100 . The quenched and tempered article claimed in claim 99 wherein the article is a structural component of an aircraft.
101 . The quenched and tempered article claimed in claim 100 wherein the article is a landing gear component.
102 . A steel alloy comprising, in weight percent, about:
C
0.35-0.55
Mn
0.6-1.2
Si
0.9-2.5
P
0.01 max.
S
0.001 max.
Cr
0.75-2.0
Ni
3.5-7.0
Mo + ½ W
0.4-1.3
Cu
0.5-0.6
Co
0.01 max.
V + (5/9)Nb
0.2-1.0
Ti
0.01 max.
Ca
up to 0.005
the balance being iron and usual impurities, and wherein
2≦(% Si+% Cu)/(% V+(5/9)% Nb)≦14.
103 . The alloy claimed in claim 102 which contains at least 0.37% carbon.
104 . The alloy claimed in claim 103 which contains not more than 0.5% carbon.
105 . The alloy claimed in claim 102 which contains at least 1.3% silicon.
106 . The alloy claimed in claim 102 which contains at least 3.7% nickel.
107 . The alloy claimed in claim 106 which contains not more than 4.5% nickel.
108 . The alloy claimed in claim 102 which contains at least 0.5% (Mo+½W).
109 . The alloy claimed in claim 108 which contains not more than 1.1% (Mo+½W).
110 . The alloy claimed in claim 102 which contains not more than about 0.01% molybdenum and about 0.8-2.6% tungsten.
111 . The alloy claimed in claim 110 which contains about 1.0-2.2% tungsten.
112 . The alloy claimed in claim 102 which contains not more than about 0.01% vanadium.
112 . The alloy claimed in claim 102 wherein
6≦(% Si+% Cu)/(% V+(5/9)% Nb)≦12.
113 . The steel alloy claimed in claim 102 wherein the alloy comprises, in weight percent, about
C
0.37-0.50
Mn
0.7-0.9
Si
1.3-2.5
P
0.005 max.
S
0.0005 max.
Cr
1.0-1.5
Ni
3.7-4.5
Mo + ½ W
0.5-1.1
and wherein
2≦(% Si+% Cu)/(% V+(5/9)% Nb)≦14.
114 . A quenched and tempered steel article formed from the alloy claimed in claim 102 , said article providing a tensile strength of at least 280 ksi and a K Ic fracture toughness of at least 90 ksi√in after having been tempered at a temperature of 500° F.
115 . The quenched and tempered article claimed in claim 114 wherein the article is a structural component of an aircraft.
116 . The quenched and tempered article claimed in claim 115 wherein the article is a landing gear component.Join the waitlist — get patent alerts
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