초록 ▼

A method for repairing an environmental protective coated article portion of a gas turbine engine article made of a Ni base superalloy including Cr and at least about 6 wt. % total of Al and Ti comprises removing the coating, exposing the article portion to a reducing mixture of gases including, by

A method for repairing an environmental protective coated article portion of a gas turbine engine article made of a Ni base superalloy including Cr and at least about 6 wt. % total of Al and Ti comprises removing the coating, exposing the article portion to a reducing mixture of gases including, by weight, greater than 6% up to about 20% hydrohalogen gas with the balance principally hydrogen gas, and preferably about 10-15 wt. % hydrogen fluoride gas. Exposure is at a temperature in the range of about 1600.degree.-2000.degree. F. for a time, greater than about 2 hours, and preferably about 2-10 hours, sufficient to remove from within the article portion metal sulfides, Al, Ti, oxides of Al or Ti, or their combinations. Then the article portion is recoated. One form relates to weld repairing the article portion by removing Al or Ti or both to a depth up to about 0.003". Another form removes metal sulfides, resulting from or relating to combustion, from within the body of the article portion to a depth up to about 0.005".

대표청구항 ▼

[ We claim:] [1.] In a method for repairing an article portion of a gas turbine engine article which has experienced high temperature operation in an engine, the article being made of a Ni base superalloy including Cr and at least about 6 wt % total of Al and Ti, the article portion including an out

[ We claim:] [1.] In a method for repairing an article portion of a gas turbine engine article which has experienced high temperature operation in an engine, the article being made of a Ni base superalloy including Cr and at least about 6 wt % total of Al and Ti, the article portion including an outer surface on which is deposited a high temperature environmental resistant coating, in which method the environmental resistant coating is removed from the outer surface of the article portion and the article portion is recoated, the step after the coating is removed and before the article portion is recoated, of:exposing at least the article portion to a reducing mixture of gases including, by weight, greater than 6% up to about 20% hydrohalogen gas, with the balance principally hydrogen gas, at a temperature in the range of about 1600.degree.-2000.degree. F. for a time greater than about 2 hours, sufficient to remove from beneath the outer surface of the article portion to a depth of about 0.005" at least one material selected from the group consisting of metal sulfides. Al, and Ti, and to avoid excessive intergranular attack and alloy depletion.