US4224062A — High temperature creep resistant structural steel

Claim 1

Independent Claim 144 words

A structural member having improved high temperature creep resistance such that it exhibits only about 1% creep when subjected to a load of 16 Newtons per square millimeter for 1000 hours at a temperature of up to about 900° C., said member being formed from a fully austenitic steel alloy consisting of the following ingredients in percentages by weight: 0.002-0.12% total content of two elements, the first element being selected from the group consisting of the alkaline earth metals, calcium, strontium and barium and the second element being selected from the group consisting of the rare earth metals, lanthanum and other lanthanides, at least some portion of each element being present; 0.0-0.20% Carbon; 1.0-3.0% Silicon; 0.2-2.0% Manganese; 15.0-25.0% Chromium; 5.0-20.0% Nickel; 0.12-0.22% Nitrogen, said Nitrogen being added in amounts sufficient to assure that said alloy is fully austenitic; and remainder iron and incidental impurities.

Claim 2

Dependent Claim 144 words

A structural member having improved high temperature creep resistance such that it exhibits only about 1% creep when subjected to a load of 16 Newtons per square millimeter for 1000 hours at a temperature of up to about 900° C., said member being formed from a fully austenitic steel alloy consisting of the following ingredients in percentages by weight: 0.002-0.12% total content of two elements, the first element being selected from the group consisting of the alkaline earth metals, calcium, strontium and barium and the second element being selected from the group consisting of the rare earth metals, lanthanum and other lanthanides, at least some portion of each element being present; 0.0-0.20% Carbon; 1.0-3.0% Silicon; 0.2-2.0% Manganese; 15.0-25.0% Chromium; 5.0-20.0% Nickel; 0.12-0.22% Nitrogen, said Nitrogen being added in amounts sufficient to assure that said alloy is fully austenitic; and remainder iron and incidental impurities.

Claim 3

Dependent Claim 26 words

A structural member as claimed in claim 1 wherein said structural member exhibits the high temperature creep resistance at constant temperatures up to about 1200° C.

Claim 4

Dependent Claim 31 words

A structural member as claimed in claim 1 wherein said structural member exhibits the high temperature creep resistance during repeated temperature variations from normal ambient temperatures up to about 1200° C.

Claim 5

Dependent Claim 70 words

A structural member as claimed in claim 1 wherein said total content of said two members is 0.03 to 0.07% by weight, said carbon content is from 0.08 to 0.12% by weight, said silicon content is from 1.5 to 2.3% by weight, said manganese is from 0.3 to 0.7% by weight, said chromium is from 19 to 22% by weight, and said nickel is from 8 to 12% by weight.

Claim 6

Dependent Claim 17 words

A structural member as claimed in claims 1 and 4 wherein said second member is misch metal.

Claim 7

Dependent Claim 16 words

A structural member as claimed in claims 1 and 4 wherein said second member is cerium.

Claim 8

Dependent Claim 16 words

A structural member as claimed in claims 1 and 4 wherein said first member is calcium.

Claim 9

Dependent Claim 37 words

A structural member as claimed in claims 1 and 4 wherein said first member is calcium and its content is 0.002-0.006% by weight, and wherein said second member is cerium and its content is 0.03-0.07% by weight.

Claim 10

Dependent Claim 111 words

A structural member having improved high temperature creep resistance such that it exhibits only about 1% creep when subjected to a load of 16 Newtons per square millimeter for 1000 hours at a temperature of up to about 900° C., said member being formed from a fully austenitic steel alloy consisting of the following ingredients in percentages by weight: 0.002-0.12% total content of two elements, the first element being selected from the group consisting of the alkaline earth metals, calcium, strontium and barium and the second member being selected from the group consisting of the rare earth metals, lanthanum and other lanthanides, at least some portion of each element being present;

Claim 11

Dependent Claim 111 words

A structural member having improved high temperature creep resistance such that it exhibits only about 1% creep when subjected to a load of 16 Newtons per square millimeter for 1000 hours at a temperature of up to about 900° C., said member being formed from a fully austenitic steel alloy consisting of the following ingredients in percentages by weight: 0.002-0.12% total content of two elements, the first element being selected from the group consisting of the alkaline earth metals, calcium, strontium and barium and the second member being selected from the group consisting of the rare earth metals, lanthanum and other lanthanides, at least some portion of each element being present;

Claim 12

Dependent Claim 50 words

0-0.2% Carbon; 1.0-3.0% Silicon; 0.2-2.0% Manganese; 15.0-25.0% Chromium; 5.0-20.0% Nickel; 0.12-0.22% Nitrogen, said Nitrogen being added in amounts sufficient to assure that said alloy is fully austenitic; 0.0-2.0% total content of high oxygen affinity elements selected from the group consisting of yttrium and zirconium; and remainder iron and incidental impurities.

Claim 13

Dependent Claim 50 words

0-0.2% Carbon; 1.0-3.0% Silicon; 0.2-2.0% Manganese; 15.0-25.0% Chromium; 5.0-20.0% Nickel; 0.12-0.22% Nitrogen, said Nitrogen being added in amounts sufficient to assure that said alloy is fully austenitic; 0.0-2.0% total content of high oxygen affinity elements selected from the group consisting of yttrium and zirconium; and remainder iron and incidental impurities.

Claim 14

Dependent Claim 59 words

A structural member having improved high temperature creep resistance such that it exhibits only about 1% creep when subjected to a load of 16 Newtons per square millimeter for 1000 hours at a temperature of up to about 900° C., said member being formed from a fully austenitic steel alloy consisting of the following ingredients in percentages by weight:

Claim 15

Dependent Claim 59 words

A structural member having improved high temperature creep resistance such that it exhibits only about 1% creep when subjected to a load of 16 Newtons per square millimeter for 1000 hours at a temperature of up to about 900° C., said member being formed from a fully austenitic steel alloy consisting of the following ingredients in percentages by weight:

Claim 16

Dependent Claim 102 words

02-0.07% total content of two elements, the first element being selected from the group consisting of the alkaline earth metals, calcium, strontium and barium and the second element being selected from the group consisting of the rare earth metals, lanthanum and other lanthanides, at least some portion of each element being present; 0.08-0.12% Carbon; 1.5-2.3% Silicon; 0.3-0.7% Manganese 19.0-22.0% Chromium; 8.0-12.0% Nickel; 0.12-0.22% Nitrogen, said Nitrogen being added in amounts sufficient to assure that said alloy is fully austenitic, 0.0-2.0% total content of high oxygen affinity elements selected from the group consisting of yttrium and zirconium; and remainder iron and incidental impurities.

Claim 17

Dependent Claim 102 words

02-0.07% total content of two elements, the first element being selected from the group consisting of the alkaline earth metals, calcium, strontium and barium and the second element being selected from the group consisting of the rare earth metals, lanthanum and other lanthanides, at least some portion of each element being present; 0.08-0.12% Carbon; 1.5-2.3% Silicon; 0.3-0.7% Manganese 19.0-22.0% Chromium; 8.0-12.0% Nickel; 0.12-0.22% Nitrogen, said Nitrogen being added in amounts sufficient to assure that said alloy is fully austenitic, 0.0-2.0% total content of high oxygen affinity elements selected from the group consisting of yttrium and zirconium; and remainder iron and incidental impurities.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	1983-09-23	1984-03-24	1984-09-23	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	1987-09-23	1988-03-24	1988-09-23	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	1991-09-23	1992-03-24	1992-09-23	$7700.00	Window Closed / Lapsed

High temperature creep resistant structural steel

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