PRELIMINARY INVESTIGATION OF MELTING, EXTRUDING, AND MECHANICAL PROPERTIES OF ELECTRON-BEAM-MELTED TUNGSTEN

摘要

Commercially sintered and arc-melted tungsten materials were melted and re melted in a 150-kilowatt electron-team furnace to form ingots 2,1/4 inches in diameter and ranging from 7 to 27 inches long. Remolding produced an improved surface over that of the first melting. During initial melting, purification of the tungsten was evidenced by outgassing of the melt. Chemical analysis of the melted tungsten provided primarily qualitative indication of increased purity.nMost of the billets machined from the electron-beam-melted ingots were extruded in a Dynapak press, and one was extruded in a 750-ton hydraulic extrusion press. Successful extrusions of 8 to 1 and of 10 to 1 reductions were obtained at 3000° or at 3200° F. The microstructures of the extruded bars indicated a predominantly hot-worked structure. The surface appearance of the low-velocity extrusion bars was good, whereas the surfaces of those bars obtained by highvelocity extrusion exhibited "raisin-type" defects.