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AssigneeSurface Engineered Products Corporation
InventorsJuan Manuel Mendez Acevedo, Chinnia Gounder Subramanian
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A method for protecting high temperature stainless steel from coking and corrosion at elevated temperatures in corrosive environments, such as during ethylene production by pyrolysis of hydrocarbons or the reduction of oxide ores, by coating the stainless steel with a coating of MCrAlX in which M is nickel, cobalt, iron or a mixture thereof and X is yttrium, hafnium, zirconium, lanthanum or combination thereof deposited onto and metallurgically bonded to the stainless steel by plasma transferred arc deposition of atomized powder of MCrAlX. The coating has a thick, dense, continuous and smooth transition region providing an effective metallurgically bond of the coating with the stainless steel. The coating retains a relatively high aluminum content which permits generation of an adherent alumina layer on the surface, providing good resistance to high temperature oxidation together with good anti-coking and hot erosion resistance properties.
A method for providing a protective an inert coating on high temperature stainless steel comprising metallurgically bonding a continuous coating of a MCrAlX alloy, where M=nickel, cobalt or iron or mixture thereof and X=yttrium, hafnium, zirconium, lanthanum or combination thereof, having about 10 to 40 wt % chromium, about 3 to 30 wt % aluminum and up to about 5 wt % X, the balance M, by plasma transferred arc deposition of the coating onto a high temperature stainless steel substrate.
A method as claimed in 4 in which the MCrAlX is NiCrAlY and has, by weight, about 12 to 25% chromium, about 4 to 15% aluminum and about 0.5 to 1.5% yttrium, the balance nickel.
A surface alloyed component comprising a stainless steel base alloy substrate and a continuous coating deposited thereon by plasma transfer arc deposition of MCrAlX alloy in which fed is nickel, cobalt, iron or a mixture thereof and X=yttrium, hafnium, zirconium, lanthanum or combination thereof and comprising about 10 to 25 wt % chromium, about 4 to 20 wt % aluminum and up to about 3 wt % X, the balance M, wherein the MCrAlX alloy coating has a thickness of about 80 to 500 μm, and an aluminum surface layer having a thickness up to about 50% of the coating thickness metallurgically bonded to the coating.
A coking and corrosion resistant reactor tube for use in high temperature environments comprising an elongated tube formed from a high temperature stainless steel and a continuous coating metallurgically bonded on an inner surface of the elongated tube comprising a MCrAlX alloy wherein M is Ni, Co, Fe or a mixture thereof and X is yttrium, hafnium, zirconium, lanthanum or combination thereof and comprising, by weight, about 10 to 25% chromium, about 4 to 20% aluminum and up to about 3% yttrium, hafnium, zirconium or lanthanum by plasma transferred arc deposition of the coating onto the inner surface of the elongated tube, and wherein the MCrAlX coating has a thickness of about 20 to 6000 μm and is metallurgically bonded to the stainless steel substrate.
A furnace for the production of ethyl including a plurality of reactor tubes each comprising an elongated tube formed from a high temperature stainless steel and a continuous coating of a MCrAlX alloy wherein M is Ni, Co, Fe or a mixture thereof and X is yttrium, hafnium, zirconium, lanthanum or combination thereof and comprising, by weight, about 10 to 40% chromium, about 3 to 30% aluminum and up to 5% yttrium, hafnium, zirconium and/or lanthanum, the balance M, deposited in a thickness of about 20 to 6000 μm and metallurgically bonded to the inner surface of the elongated tube by plasma transfer arc deposition.
Dependencies are inferred from the claim text.