2.For protecting flow-conducting component constructed of stainless steel containing less than about 15 weight percent nickel used in geothermal brine service from chloride stress corrosion caused by contact of geothermal brine having temperature of at least about 150° F. with an exterior surface of said component comprising thermally-spraying onto an exterior surface thereof metal selected from the group consisting of mild steel, aluminum, zinc, magnesium, and mixtures thereof to provide metal coating of at least about 5 mils.
3.The protective method as claimed in claim 2 wherein said stainless steel is selected from austenitic stainless steel and chrome-duplex types of stainless steels.
4.For protecting stainless steel flow-conducting component used in geothermal brine service from stress corrosion cracking caused by contact of geothermal brine with an exterior surface of said component comprising thermally-spraying onto said exterior surface in region of residual stress metal having an electrode potential more negative than that of the stainless steel being protected.
5.Method for protecting stainless steel flow-conducting component through which is flowed corrosive geothermal brine having temperature of at least about 150° F. from stress corrosion cracking caused by contact of geothermal brine with an exterior surface of said component comprising thermally-spraying mild steel onto said exterior surface in region of residual stress to provide thereon mild steel coating of at least about 5 mils.
6.The protective method as claimed in claim 5 wherein the stainless steel flow-conducting component is constructed of stainless steel selected from austenitic stainless steel and chrome-duplex types of seamless pipe.
7.An article consisting of stainless steel having surface thereof coated with metal having an electrode potential more negative than that of said stainless steel, said stainless steel being selected from austenitic stainless steel and chrome-duplex stainless steel, said metal being coated upon said surface to thickness of at least about 5 mils.
8.An article for use in hot geothermal brine service consisting of stainless steel flow-conducting component having nickel content less than about 18 percent, an exterior surface of said component having thereon coating of metal selected from the group consisting of mild steel, aluminum, magnesium, zinc and mixtures thereof, said coating having thickness of about 5 to about 40 mils.
9.The article as claimed in claim 8 wherein said stainless steel is selected from the group consisting of austenitic steel and chrome-duplex steel.
10.A stainless steel component having an interior surface for conducting flow of hot geothermal brine through said component and an external surface, at least portion of which is coated with metal having an electrode potential more negative than said stainless steel.
11. The component as claimed in claim 10 wherein said stainless steel pipe is selected from the group consisting of austenitic stainless steel and chrome-duplex stainless steel.
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