US 9,005,520 B2Granted

Steel compositions for special uses

AssigneesV & M France, Annie Fouquet, Catheline Petelot, Emilie Petelot, Adeline Petelot

InventorsDaniel Petelot, Jean Leyer, Bruno Vandenberghe, Viviane Lepingle, Ghislain Louis

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Abstract

The invention concerns steels having excellent resistance over time, in a corrosive atmosphere due to oxidizing environments such as, for example, fumes or water vapor, under high pressure and/or temperature. The invention concerns a steel composition for special applications, said composition containing, by weight, about 1.8 to 11% of chromium (and preferably between about 2.3 and 10% of chromium), less than 1% of silicon, and between 0.20 and 0.45% of manganese. It has been found that it is possible to adjust the contents of the composition based on a predetermined model, selected to obtain substantially optimal properties with respect to corrosion in specific conditions of high temperature performances. Said model can involve as additive of as residue at least one element selected among molybdenum, tungsten, cobalt, and nickel.

Claims8

Dependent claims

A steel composition comprising chromium (Cr), manganese (Mn), silicon (Si), molybdenum (Mo), tungsten (W), nickel (Ni), cobalt (Co) such that the content by weight of each component satisfies at least one relationship selected from the group consisting of 1 and 2 in the Table below:

1
2
according to specifications ASTM A213
T22/P22
T92/P92
and A335 defining respectively grades . . .
comprising
chromium (Cr)
2.3-2.6
8.9-9.5
(in % by weight)
manganese (Mn)
0.20-0.45
0.3-0.45
silicon (Si)
≦0.5
≦0.5
molybdenum (Mo)
0.87-1
0.3-0.45
Nickel (Ni)
0.1-0.2
0.02-0.20
Vanadium (V),
No
Titanium (Ti), and
voluntary
Boron (B)
addition
tungsten (W)
≦0.01
1.5-1.75
being such that the corrosion value Vcor is
≦0.9
≦0.08
wherein said corrosion value Vcor is calculated based on the following Equation (21)
V
COR
650
⁢
°
⁢
⁢
C
.
=
α
⁢
1
Cr
2
+
β
⁢
1
A
+
δ
⁢
⁢
B
+
C
(
21
)
wherein the variable in Equation (21) are defined in Equations (31) to (36):
Alpha=2.828 (31)
Beta=0.237 (32)
A=Cr—(Mo+W+Ni+Co) (33)
Delta=0.091 (34)
B=1.40−0.12*Cr+0.007/Si (35)
C=1.2*Mn*Mn−0.53*Mn+0.02*(W+Ni)−0.012 (36)

70 more elements

Dependencies are inferred from the claim text.