Method of manufacture of a heat resistant alloy useful in heat recuperator applications and product

Claim 3

The method according the claim 1 wherein the final anneal causes the form to have an ASTM grain size number ranging from 10 to 8.

Claim 4

The method according to claim 1 wherein the final anneal is conducted at about 1900°-2050° F. (1038°-1121° C.) for about 10-90 seconds.

Claim 5

The method according to claim 1 wherein the alloy includes about 30-80% nickel, about 1.5-20% iron, about 12-30% chromium, about 0-10% molybdenum, about 0-15% cobalt, about 0-5% columbium plus tantalum, and additional minor constituents.

Claim 6

The method according to claim 4 wherein the alloy includes about 50-75% nickel, about 1.5-20% iron, about 14-25% chromium, about 0-10% molybdenum, about 0-15% cobalt, about 0-5% columbium plus tantalum, and additional minor constituents.

Claim 7

The method according to claim 1 wherein the form is cold worked 30-60%.

Claim 8

The method according to claim 1 wherein the alloy form is fabricated into a recuperator.

Claim 9

The method according to claim 1 wherein the intermediate anneal occurs at a temperature approximately 50° F. (28° C.) less than the final anneal and for approximately the same time.

Claim 10

A recuperator consisting essentially of about 30-80% nickel, about 1.5-20% iron, about 12-30% chromium, about 0-10% molybdenum, about 0-15% cobalt, about 0-5% columbium plus tantalum and additional minor constituents having an isotropic structure, high temperature corrosion resistance, high thermal conductivity, a low coefficient of expansion and a high level of ductility and strength made by: (a) processing an alloy heat of the above composition to a form of near net shape; (b) intermediately annealing the form; (c) cold working the form 20-80%; (d) finally annealing the form to retain a 20-80% increase in yield strength over that of a solution annealed material of similar composition as well as retaining at least 60% of the solution annealed ductility; and (e) fabricating the alloy into a recuperator.

Claim 11

A recuperator consisting essentially of about 30-80% nickel, about 1.5-20% iron, about 12-30% chromium, about 0-10% molybdenum, about 0-15% cobalt, about 0-5% columbium plus tantalum and additional minor constituents having an isotropic structure, high temperature corrosion resistance, high thermal conductivity, a low coefficient of expansion and a high level of ductility and strength made by: (a) processing an alloy heat of the above composition to a form of near net shape; (b) intermediately annealing the form; (c) cold working the form 20-80%; (d) finally annealing the form to retain a 20-80% increase in yield strength over that of a solution annealed material of similar composition as well as retaining at least 60% of the solution annealed ductility; and (e) fabricating the alloy into a recuperator.

Claim 12

The recuperator according to claim 9 wherein the final anneal is conducted at about 1900°-2050° F. (1038°-1121° C.) for about 10-90 seconds.

Claim 13

The recuperator according to claim 9 wherein the recuperator has an ASTM alloy grain size number ranging from 10-8.

Claim 14

The recuperator according to claim 9 wherein the form is cold worked 30-60%.

Claim 15

The recuperator according to claim 9 including about 50-75% nickel, about 1.5-20% iron, about 14-25% chromium, about 0-10% molybdenum, about 0-15% cobalt, about 0-5% columbium plus tantalum and additional minor constituents.

Claim 16

The recuperator according to claim 9 wherein the intermediate anneal occurs at a temperature approximately 50° F. (28° C.) less than the final anneal and for approximately the same time.

Claim 17

The recuperator according to claim 9 wherein the recuperator operates at a temperature range of about 600°-1500° F. (316°-816° C.).