1992 Volume 32 Issue 5 Pages 656-663
Electron beam cold hearth melting and refining (EB-CHR) of refractory metals (Nb, Mo, Ta) and an alloy (Nb-1%Zr) was examined for its ability to produce homogeneous materials in the 2 000 and 400 kW EB-CHR furnaces and the 70 kW EB furnace.
Behavior of gaseous elements was discussed with taking the volatile parameter R into the consideration.
In the production of Nb-1%Zr in the 400 kW EB-CHR furnace, zirconium content was controllable. No serious segregation was found. These results show that the mechanism of zirconium loss in the EB-CHR process depends on both the evaporation and segregation of zirconium.
Heat balance in molybdenum melting was measured in the 2 000 kW EB-CHR furnace. The obtained heat efficiency was about 70% and energy loss of EB agreed with the ratio of backscattered electron energy to whole EB well energy input, which is about 30%.
Mechanical processing tests involving forging, hot-rolling and cold-rolling were carried out. Material property such as workability was evaluated. EB-CHR processed materials gave better workability than others. Plates and sheets of some refractory metals were successfully produced.
