Compressor impeller and method of manufacturing the same
AssigneesHitachi Metals Precision, Ltd., Hitachi Metals, Ltd.
InventorsYasuhiro Kubota, Hirokazu Itoh, Mikio Sasaki
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Abstract
A compressor impeller and a method of manufacturing the compressor impeller. The magnesium alloy compressor impeller as a die-cast part comprises a hub shaft part, a hub disk part having a hub surface extending from the hub shaft part in the radial direction, and a plurality of vane parts disposed on the hub surface. The impeller can be manufactured by a die-cast method in which a magnesium alloy heated to a liquidus temperature or higher is supplied into molds with cavities corresponding to the shape of the impeller for a filling time of 1 sec. or shorter, a pressure of 20 MPa or higher is applied to the magnesium alloy in the cavities, and the pressurized state is maintained for a time of 1 sec. or longer.
Claims9
A compressor impeller comprising a hub shaft part, a hub disk part having a hub surface extending from the hub shaft part in a radial direction, and a plurality of blade parts provided on the hub surface, wherein
- the compressor impeller is made of a magnesium alloy and is a die-cast product, and
- the hub disk part comprises a surface layer having a solidification structure having an average grain size of 15 μm or less, and a core having a solidification structure having an average grain size of 50 μm or less, which is larger than that of the surface layer, in the vicinity of the core.
A method of manufacturing a compressor impeller by a die-casting process, in which the dies used define a cavity corresponding to the shape of the compressor impeller, and the compressor impeller comprising a hub shaft part, a hub disk part having a hub surface extending from the hub shaft part in a radial direction, and a plurality of blade parts provided on the hub surface, wherein
- a molten magnesium alloy heated to a higher temperature by 10 to 80° C. than a liquidus temperature of the magnesium alloy is supplied into the cavity for a filling time of 1 sec. or shorter, the cavity being previously pressure-reduced to 0.005 MPa or lower thereby causing the cavity to have an atmosphere from which oxygen is excluded,
- a pressure of not less than 20 MPa is consecutively applied to the molten magnesium alloy in the cavity, and
- the pressurized state is maintained for a time of not less than 1 sec, and
- wherein the hub disk part comprises a surface layer having a solidification structure having an average grain size of 15 μm or less, and a core having a solidification structure having an average grain size of 50 μm or less, which is larger than that of the surface layer, in the vicinity of the core.
Dependencies are inferred from the claim text.