Welding method for stainless steel weld overlay
First Claim
1. In a method for the overlay welding of at least one weld layer onto the inner surfaces of pressure vessels made of carbon and low alloy steels as a base metal and used in processes in which hydrogen is contained within the vessels at elevated temperatures and under high pressure, the improvement which comprises welding a first layer weld overlay onto the inner surface of a pressure vessel, consisting essentially of up to 0.1 wt% C, up to 1.0 wt% Si, up to 2.0 wt% Mn, 7 to 12 wt% Ni, 12 to 17 wt% Cr, up to 1.0 wt% Mo, up to 0.1 wt% Al, the balance being Fe, said first layer weld overlay being welded at a welding current within the range of 1000-2800 amperes and at a welding speed varying between 5 to 50 cm/min. so as to produce a weld structure selected from (1) a martensite structure in an amount of 4% to 40% by area in an austenite matrix or (2) a martensite structure in an amount of 4% to 40% by area and a ferrite structure in an amount below 8% by area both within an austenite matrix.
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Abstract
A method for overlay welding of stainless steel on the inner surfaces of pressure vessels as used for treating hydrogen at elevated temperature, e.g. below 450° C. and under high pressure, e.g. below 150 kg/cm2, is provided wherein, in order to prevent the disbonding of the welded stainless steel, as the 1st layer weld overlay including martensitic structure of 4 to 40% by area or additionally including ferritic structure of up to 8% by area is used. For this purpose the chemical composition of the stainless steel weld metal is defined as essentially comprising of up to 0.1% C, up to 1.0% Si, up to 2.0% Mn, 7 to 12% Ni, 12 to 18% Cr, up to 1.0% Mo, and up to 0.1% Al, the balance being Fe. The stainless steel weld overlay may further include Nb of above 8 times the carbon content but up to 1.0%.
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Citations
4 Claims
- 1. In a method for the overlay welding of at least one weld layer onto the inner surfaces of pressure vessels made of carbon and low alloy steels as a base metal and used in processes in which hydrogen is contained within the vessels at elevated temperatures and under high pressure, the improvement which comprises welding a first layer weld overlay onto the inner surface of a pressure vessel, consisting essentially of up to 0.1 wt% C, up to 1.0 wt% Si, up to 2.0 wt% Mn, 7 to 12 wt% Ni, 12 to 17 wt% Cr, up to 1.0 wt% Mo, up to 0.1 wt% Al, the balance being Fe, said first layer weld overlay being welded at a welding current within the range of 1000-2800 amperes and at a welding speed varying between 5 to 50 cm/min. so as to produce a weld structure selected from (1) a martensite structure in an amount of 4% to 40% by area in an austenite matrix or (2) a martensite structure in an amount of 4% to 40% by area and a ferrite structure in an amount below 8% by area both within an austenite matrix.
Specification
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- Resources
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Current AssigneeJapan Steel Works Limited, Chiyoda Chemical Engineering & Construction Company Limited (Mitsubishi Corporation)
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Original AssigneeJapan Steel Works Limited, Chiyoda Chemical Engineering & Construction Company Limited (Mitsubishi Corporation)
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InventorsNaitoh, Katsuyuki, Adachi, Takao, Okada, Hachiro, Fuji, Akiyoshi, Onishi, Keizo, Chiba, Ryuichi
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Primary Examiner(s)Rubinson, Gene Z.
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Assistant Examiner(s)George, Keith E.
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Application NumberUS06/119,772Time in Patent Office1,040 DaysField of Search219/76.1, 219/76.12, 219/76.14, 219/146.23, 219/146.41US Class Current219/76.12CPC Class CodesB23K 35/004 at least one of the workpie...B23K 9/04 Welding for other purposes ...
