Department Of Cu-Cr-Zr Alloy Thermodynamic Calculations And Experimental Study Of Non-vacuum Melting

Cu-Cr-Zr alloys has excellent strength and electroconductivity, strength of extension greaterthan600MPa, electroconductivity greater than80%IACS,and its softening temperature is relativehigh. Cu-Cr-Zr alloys is used for electric pole materials,such as for motor commutator, mashwelder, seam welder, butt welder and so on. These series alloys are made by vacuum meltingway,which has some shortcomings,for example being strict to tightness of furnace body,materialsmatching,and impurity control. Cu-Cr-Zr alloys can be made without vacuum melting way,whichcan solve the capital issues,so Cu-Cr-Zr alloys will be used widely.The factors impacting Cu-Cr-Zr alloys without vacuum melting way are calculated byFactSage in thermal aspect and the production technology of Contact line of Cu-Cr-Zr alloys areresearched by experiments.The results indicates the smelting of Cu-Cr-Zr alloys is influenced byN2,specially O2.The Cu and Cr in Cu-Cr-Zr alloys can react with N2or O2in multiple ways,suchas ZrN, Cr3O4,ZrO2.H2is unable to react with Cu-Cr-Zr alloys when the temperature more than800℃.we find graphite,alumina and quartz crucible have bad influence on the smelting ofCu-Cr-Zr alloys,but the magnesium oxide crucible not.The Zr in Cu-Cr-Zr alloys may react withC into ZrC4when using graphite crucible and covered by charcoal;The most probable reaction is3Mg+Al2O3=3MgO+2Al,when using alumina crucible;and3Zr+SiO2=Zr2Si+ZrO2,when usingquartz crucible and covered by glass;but magnesium oxide crucible and cover are unable to reactwith Cu-Cr-Zr alloys.The mathematical modeling of Cu-Cr-Zr alloys when using graphite crucible and covered bycharcoal is established;the results show the lose of Zr is more than Cr during smelting;the mainprecipitated phase of Cu-Cr-Zr alloys is Cu5Zr and Cr;the performance is excellent, brinellhardness112HB, electroconductivity86.8%IACS. in Cr, Zr and C reaction should generate Cr7C3,Cr3C2, ZrC when use graphite crucible smelting, in Cr, Zr don’t participate in MgO reaction whenusing magnesia crucible As the results, Reasonable smelting process:soaking zone is5-10min;smelt temperature is1150℃; crucible is magnesium oxide crucible; covering agent ismagnesia and borax cover.