High energy beam welding of single-crystal superalloys and assemblies formed thereby
AssigneeGeneral Electric Company
InventorsGanjiang Feng, Daniel Anthony Nowak
Life of this patent
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Abstract
A method of welding articles formed of single-crystal superalloys, particularly single-crystal nickel-base superalloys containing 10 weight percent or more of refractory metals, and welded assemblies formed thereby. A shim is positioned between the articles, and a backing strip is preferably positioned to contact both articles and bridge the gap between the articles. The articles are then welded together using a high energy beam with a low current pulse frequency and low travel speed.
Claims35
A method of high-energy beam welding at least two single-crystal superalloy articles, the method comprising the steps of:
- placing a shim in a gap between the articles so that the shim contacts faying surfaces of the articles, the shim being formed of a superalloy that is more ductile than the superalloys of the articles;
- welding the articles together with a high-energy beam operated at a pulsed current frequency of about 10 to 50 Hz, a travel speed of about 0.85 to about 1.5 cm/s, a voltage level of about 100 to about 150 kV, and a current level of about 10 to 40 milliamps, the high-energy beam melting the shim and portions of the articles contacting the shim to cause mixing of the superalloys of the shim and articles;
- and then
- cooling the articles to yield a weld joint having a W-shaped joint root.
A method of forming a component of a gas turbine engine by electron beam welding at least two articles formed of gamma prime-strengthened single-crystal nickel-base superalloys containing at least ten weight percent of one or more refractory metals, the method comprising the steps of:
- providing a shim formed of a nickel-base superalloy that does not contain gamma-prime precipitates and is more ductile than the nickel-base superalloys of the articles, the shim having a thickness of about 0.5 to 2.5 mm;
- placing the shim in a gap between the articles so that the shim contacts faying surfaces of the articles and protrudes beyond adjacent outer surfaces of the articles, and placing a single-crystal superalloy backing strip that contacts surfaces of the articles opposite the outer surfaces thereof so that the backing strip bridges the gap between the articles;
- welding the articles together with an electron beam operated at a current pulse frequency of about 10 to about 50 Hz, a travel speed of about 0.85 to about 1.5 cm/s, a voltage level of about 100 to about 150 kV, and a current level of about 10 to 40 milliamps, the electron beam melting the shim and portions of the articles contacting the shim to cause mixing of the superalloys of the shim and articles;
- and then
- cooling the articles to yield a butt weld joint containing gamma-prime precipitates and having a W-shaped joint root that extends into the backing strip.
An assembly formed by high-energy beam welding at least two single-crystal superalloy articles, the articles being welded together at a weld joint having a W-shaped joint root.
A component of a gas turbine engine comprising:
- at least two articles formed of gamma prime-strengthened single-crystal nickel-base superalloys containing at least ten weight percent of one or more refractory metals, the articles being joined together by a butt weld joint containing gamma-prime precipitates;
- and
- a single-crystal superalloy backing strip that contacts adjacent surfaces of the articles and bridges the weld joint between the articles, the weld joint having a W-shaped joint root that extends into the backing strip.
Dependencies are inferred from the claim text.