Overlay welding method
First Claim
1. In an overlay welding method of the type including overlay welding a surface layer of stainless steel or nickel alloy on a base metal of carbon steel or low alloy steel, the improvement comprising previously overlay welding an austenitic stainless steel welded metal layer having a ratio of chromium equivalent (Creq), given by the following equation, to nickel equivalent (Nieq), given by the following equation, being more than 1.85, the chromium equivalent of less than 26%, and delta-ferrite phase of less than 20%, and no martensite phase, on the base metal as an intermediate layer and then overlay welding the surface layer thereon:
- Creq=%Cr+%Mo+1.5×
%Si+0.5×
%NbNieq=%Ni+30×
%C+0.5×
%Mn.
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Accused Products
Abstract
An austenitic stainless steel welded metal layer having the given composition containing delta-ferrite phase is previously overlay welded as an intermediate layer prior to overlay welding of a surface layer of stainless steel, nickel alloy or the like on a base metal of carbon steel or low alloy steel. In the said composition, by making the ratio of Creq/Nieq to be more than 1.85, the disbonding is prevented and by making Creq to be less than 26% and the content of delta-ferrite phase to be less than 20%, the deterioration of flexural elongation is prevented. The present invention is applicable to the lining on an inner surface of a chemical reactor vessel, such as a desulfurizing reactor for petroleum-refining to be used under a high-temperature, high-pressure hydrogen environment.
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Citations
1 Claim
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1. In an overlay welding method of the type including overlay welding a surface layer of stainless steel or nickel alloy on a base metal of carbon steel or low alloy steel, the improvement comprising previously overlay welding an austenitic stainless steel welded metal layer having a ratio of chromium equivalent (Creq), given by the following equation, to nickel equivalent (Nieq), given by the following equation, being more than 1.85, the chromium equivalent of less than 26%, and delta-ferrite phase of less than 20%, and no martensite phase, on the base metal as an intermediate layer and then overlay welding the surface layer thereon:
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Creq=%Cr+%Mo+1.5×
%Si+0.5×
%NbNieq=%Ni+30×
%C+0.5×
%Mn.
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Specification
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- Resources
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Current AssigneeKawasaki Steel Corporation (JFE Holdings Incorporated)
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Original AssigneeKawasaki Steel Corporation (JFE Holdings Incorporated)
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InventorsYasuda, Koichi, Nishiyama, Noboru, Nakano, Syozaburo
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Primary Examiner(s)Godici, Nicholas P.
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Assistant Examiner(s)Heinrich, Samuel M.
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Application NumberUS06/585,274Time in Patent Office1,005 DaysField of Search228/263.15, 219/76.12, 219/76.14, 219/146.41, 220/3, 220/456US Class Current228/262.41CPC Class CodesB23K 35/004 at least one of the workpie...B23K 35/3086 containing Ni or MnB23K 9/04 Welding for other purposes ...Y10S 220/917 Corrosion resistant container
