tantalum bar ASTM B365 standard:ASTM B365 RO5200,RO5400 RO5252 (Ta-2.5W) RO5255 (Ta-10W) ... purity:99.95%,99.99% ISO9001:2008 tantalum bar ASTM B365Introduction:Tantalum is dark, dense, ductile, very hard, easily fabricated ... including nut, screw ,ring ,wire, foil, sheet, rod, strip, plate, tube, alloys according to Standard ASTM AMS ASME MIL DMS JIS GB ...