| 摘要 |
PURPOSE:To improve toughness, fatigue strength, workability and resistance to stress corrosion cracking by irradiating the ray flux having a high energy density to a large-sized casting ingot consisting of a metal or alloy to effect continuously local remelting and solidification thereby forming finer structure and increasing the solid solubility limit of the additive elements. CONSTITUTION:A large-sized casting ingot of a metal or alloy is generally low in cooling rate and therefore the crystal grain size is large and in the case of an alloy, an intermetallic compd. is crystallized by which the workability in rolling, extruding, casting, etc. is deteriorated and various physical characteristics are deteriorated. The ray flux having a high energy density such as electron beam, plasma arc or the like is irradiated from the surface to the large-sized casting ingot in this case to effect local remelting and succeeding quick cooling. The crystal grain size of the casting ingot is made fine and in the case of the alloy, the solid solubility limit of the alloy elements is increased, by which the hot and cold workability is improved and the toughness, fatigue strength, corrosion resistance, etc. of the worked product are improved.
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