| 简介 |
FIELD : metallurgy.SUBSTANCE : procedure consists in melting charge materials in vacuum and in decarbonisation refining in two stages. At the first stage there is introduced oxidant in atmosphere of inert gas at pressure 20-150 mm of m. c. with successive withdrawal of inert gas. Upon removing inert gas carbon is additionally introduced into melt at amount of 0.001-0.010 % of charge materials weight at pressure of gas (1-10)×10-2 mm m. c. At the second stage there are introduced rare earth metals amount of which 2.0-20.0 times exceeds amount of carbon left in melt upon the first stage of refining. Upon the second stage of refining chromium and active alloying elements are introduced into melt.EFFECT : upgraded purity of carbon-free cast heat resistant alloys; increased operational properties of alloys and increased output of acceptable product at casting items with mono-crystal structure.2 tbl |
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