Corrosion-resistant coatings for steel tubes
AssigneeSurface Engineered Products Corporation
InventorsChinnia Gounder Subramanian, David Aaron Easton
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Abstract
A method of providing a protective, corrosion-resistant thin coating of a MCrX alloy on a carbon or low-alloy steel pipe or tube where M is one of nickel, cobalt or iron or combination thereof and X is one of molybdenum, silicon, tungsten or combination thereof, and heat treating the coating to metallurgically bond the coating onto a steel substrate of the pipe or tube. The coating may be deposited in one or two layers by plasma transferred arc deposition or may be deposited as a slurry coating or thermal spray coating with sintering of the coating. The steel substrate is prepared for coating by at least one of boring, honing, bright finishing, grit blasting, grinding, chemical pickling or electro-polishing of the substrate.
Claims48
A method of providing a protective coating on an inner steel substrate of a carbon or low-alloy steel pipe or tube comprising preparing the steel substrate by at least one of boring, honing, bright finishing, grit blasting, grinding, chemical pickling or electro-polishing the steel substrate, depositing a continuous thin coating on the substrate of a MCrX alloy where M=one of nickel, cobalt, iron or combination thereof and X=one of molybdenum, silicon, tungsten or combination thereof, having about 45 to 91 wt % M, about 9 to 40 wt % Cr and 0 to about 20 wt % Mo, 0 to about 20 wt % Si and 0 to about 10 wt % W, and heat treating the coating to metallurgically bond the coating onto the steel substrate.
A method of providing a protective coating on an inner surface substrate of a carbon or low-alloy steel pipe or tube comprising roughening the steel substrate by wet or dry grit blasting, knurling or abrasive cleaning and depositing a MCrSiX coating powder on the substrate, where M=one of nickel, cobalt, iron or combination thereof and X=one of molybdenum, boron, tungsten or combination thereof, having about 45 to 91 wt % M, about 9 to 40 wt % chromium, about 0.8 to about 20 wt % Si, 0 to about 20 wt % Mo, 0 to about 8 wt % B and 0 to about 10 wt % W, and heat treating the coating at a temperature in the range of 600 to 1200° C. for sintering and metallurgically bonding the coating to the substrate.
A protective coating on an inner steel substrate of a carbon or low-alloy steel pipe or tube comprising a continuous thin coating having a thickness of 0.5 to 10 mm deposited on the substrate of a MCrX alloy where M=one of nickel, cobalt, iron or combination thereof and X=one of molybdenum, silicon, tungsten or combination thereof, having about 45 to 91 wt % M, about 9 to 40 wt % Cr and 0 to about 20 wt % Mo, 0 to about 20 wt % Si and 0 to about 10 wt % W, the coating heat-treated to metallurgically bond the coating onto the steel substrate.
A protective coating on an inner steel substrate of a carbon or low-alloy steel pipe or tube comprising a coating powder deposited on the substrate of a MCrSiX alloy where M=one of nickel, cobalt, iron or combination thereof and X=one of molybdenum, tungsten or combination thereof, having about 45 to 91 wt % M, about 9 to 40 wt % chromium, about 2 to about 20 wt % Si, 0 to about 20 wt % Mo, 0 to about 8 wt % B and 0 to about 10 wt % W, the coating heat-treated at a temperature in the range of 600 to 1200° C. for sintering and metallurgically bonding the coating to the substrate.
Dependencies are inferred from the claim text.