Specification for Niobium Bar
Standard: As per ASTM B392
Material: R04200-Type 1 -Reactor grade unalloyed niobium
R04210-Type 2 -Commercial grade unalloyed niobium
R04251-Type 3—Reactor grade niobium alloy containing 1 % zirconium
R04261-Type 4—Commercial grade niobium alloy containing 1 % zirconium
R40220-Type 5 -RRR grade pure niobium
Size: 5x5mm to 120mm x 120mm x L<1400mm Wider bars will be named niobium plate and block.
Niobium is a rare, soft, malleable, ductile, gray-white metal. It has a body-centered cubic crystalline structure and in its physical and chemical properties, it resembles tantalum. It must be placed in a protective atmosphere when processed at even moderate temperatures because it tends to react with oxygen, carbon, halogens, nitrogen, and sulfur. The metal is inert to acids, even to aqua regia at room temperatures, but is attacked by hot, concentrated acids, and especially by alkalis and oxidizing agents.
Chemical compositions for Niobium
|Gr||Main Content||Impurities (≤ %)|
Mechanical requirements (annealed condition) for Niobium bar
|Grade||Tensile strength,δb psi (MPa), ≥||Yield strength,δ0.2, psi (MPa), ≥||Elongation in 1″/2″ gage length, %, ≥|
|R04200-1 R04210-2||18000 (125)||10500 (73)||25|
|Special requirements of niobium ingot to be agreed on negotiations|