Vacuum Arc Remelting (VAR)
6Pages

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table.main {} tr.row {} td.cell {} div.block {} div.paragraph {} .font0 { font:11.00pt "Impact", sans-serif; } .font1 { font:13.00pt "Impact", sans-serif; } .font2 { font:29.00pt "Impact", sans-serif; } Vacuum Arc Remelting (VAR) HR is widely used 1o improve the cleonliness and refno the structure of standard airmelted or vocuum induction mehed ingofs, then colled consumoble lectrodes. VAR steels and tuptrolloys as well as tilanium and zirconium and ifs alloys are used in a great number o( high-integrity applications wttere cleanlmess, homogenerty, improved fatigue ond fracture loughness of...

table.main {} tr.row {} td.cell {} div.block {} div.paragraph {} .font0 { font:11.00pt "Impact", sans-serif; } .font1 { font:13.00pt "Impact", sans-serif; } Metallirgy of the Vacuum Arc Remelting Process The VAR ingot's solidification structure ot a given matriel h o fundion of the locof solidf鯯calion rate ont) the temprature gradient at the liquid/solid interface. Ta achieve a direcled dendrrtfc primary structure, a relolively high temprature gradient at the solidification front must be moinloined during the entire remelting process. The growlh direction of the cellular dendrites conforms...

table.main {} tr.row {} td.cell {} div.block {} div.paragraph {} .font0 { font:11.00pt "Impact", sans-serif; } .font1 { font:68.00pt "Impact", sans-serif; } ■ Ff eckles ond white spots hove o much greoler effect on materiol properties as compared to Iree ring potterns. Both defects con represent o signifkant cause for prmatur foilure of turbine disks in aircraft engines. Freckles are dark-etching circuler or nearly circulor spots tha驯 are generolly rich in cor bides or carbide forming lments. The formation of freckles is usuolly a resuit of a high metol pool rfepth and somefimes of a...

table.main {} tr.row {} td.cell {} div.block {} div.paragraph {} .font0 { font:10.00pt "Impact", sans-serif; } .font1 { font:11.00pt "Impact", sans-serif; } .font2 { font:13.00pt "Impact", sans-serif; } Process Control Clote control of ail remelling paromelers is required for reproduable production of homogeneous ingots, which ore free of mocrosegregation ond show o controlled solidification structura and superior cleanliness. To fulfill todoy's most stringent molerial quality spcifications, VAR furnects make use of computer controlled process outomalion. Logic control fondions, continuous...

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