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ASTM B365, ASTM B708: 
Additional Chemical Requirements for Finished Product*
(When specified by the purchaser)
Content, Maximum % Weight Grades
Element Electron-Beam Cast  Sintered Electron-Beam Cast  Electron-Beam Cast  Electron-Beam Cast 
(R05200) (R05400) (R05255) (R05252) (R05240)
Unalloyed Tantalum Unalloyed Tantalum 90% Tantalum 97% Tantalum 60% Tantalum
    10% Tungsten 2.5% Tungsten 40% Niobium
Oxygen 0.025 0.035 0.025 0.025 0.025
Nitrogen 0.01 0.01 0.01 0.01 0.01
Carbon 0.0015 0.0015 0.0015 0.0015 0.0015
Hydrogen 0.02 0.02 0.02 0.02 0.02
*Certifiable per ASTM B365 and B708, report values for ASTM B521
ASTM B364, ASTM B365, ASTM B521, ASTM B708:
Chemical Requirements for Tantalum and Tantalum Alloy Ingots
(Content, Maximum Weight %)
Element Electron Beam Cast (R05200) Sintered (R05400) Electron Beam Cast (R05255) Electron Beam Cast (R05252) Electron Beam Cast (R05240)
Unalloyed   Tantalum Unalloyed Tantalum 90% Ta 10% W 97.5% Ta 2.5% W 60% Ta 40% Nb
Carbon 0.01 0.01 0.01 0.01 0.01
Oxygen 0.015 0.03 0.015 0.015 0.02
Nitrogen 0.01 0.01 0.01 0.01 0.01
Hydrogen 0.0015 0.0015 0.0015 0.0015 0.0015
Niobium 0.1 0.1 0.1 0.5 35.0-42.0
Fe (Iron) 0.01 0.01 0.1 0.01 0.01
Titanium 0.01 0.01 0.1 0.01 0.01
W(Tungsten) 0.05 0.05 9.0-11.0 2.0-3.5 0.05
Molybdenum 0.02 0.02 0.02 0.02 0.02
Silicon 0.005 0.005 0.005 0.005 0.005
Nickel 0.01 0.01 0.01 0.01 0.01
Tantalum remainder remainder remainder remainder remainder
   
ASTM B 364 covers unalloyed and alloyed tantalum ingots prepared by vacuum-arc 
melting, electron-beam melting, or powder-metallurgy consolidation to 
produce consolidated metal for processing to various mill shapes.
ASTM B 365   covers unalloyed and alloyed tantalum rod, tantalum wire.
ASTM B 521  covers tantalum and tantalum alloy seamless and welded tubes.
ASTM F 560 covers the chemical, mechanical, and metallurgical requirements for 
unalloyed tantalum plate, tantalum sheet, tantalum strip, tantalum rod, 
and tantalum wire used in the manufacture of surgical implants; 
referenced Practice for Assessment of Compatibility of Biomaterials for 
Surgical Implants with Respect to Effect of Materials on Muscle and Bone.
ASTM B 708  covers unalloyed and alloyed tantalum plate, tantalum sheet;
   
The materials covered by this specification are:  
R05200 unalloyed tantalum, electron-beam furnace or vacuum-arc melt, or both;
R05400 unalloyed tantalum, powder-metallurgy consolidation;
R05255 tantalum alloy, 90 % tantalum 10 % tungsten, electron-beam furnace or vacuum-arc melt, or both;
 
R05252 tantalum alloy, 97.5 % tantalum 2.5 % tungsten, electron-beam furnace or vacuum-arc melt, or both;
 
R05240 tantalum alloy, 60 % tantalum 40 % columbium,electron-beam furnace or vacuum-arc melt, or both;

ASTM B391, B392, B393, B394:
Chemical Requirements for Nb and Nb Alloy Nb1Zr
(Maximum Weight %)
Element Type 1 Type 2 Type 3 Type 4
Reactor Grade Commercial Grade  Reactor Grade Commercial Grade
Unalloyed Niobium  Unalloyed Niobium  Nb 1% Zirconium Nb 1% Zirconium
R04200 R04210 R04251 R04261
Carbon  0.01 0.01 0.01 0.01
Nitrogen 0.01 0.01 0.01 0.01
Oxygen 0.015 0.025 0.015 0.025
Hydrogen 0.0015 0.0015 0.0015 0.0015
Zirconium 0.02 0.02 0.8 to 1.2 0.8 to 1.2
Tantalum  0.01 0.2 0.1 0.5
Iron 0.005 0.01 0.005 0.01
Silicon 0.005 0.005 0.005 0.005
Tungsten 0.03 0.05 0.03 0.05
Nickel 0.005 0.005 0.005 0.005
Molybdenum 0.01 0.1 0.1 0.05
Hafnium  0.02 0.02 0.02 0.02
When Specified
Boron 0.0002          - 0.0002          -
Aluminium 0.002 0.005 0.002 0.005
Beryllium  0.005          - 0.005          -
Chromium  0.002          - 0.002          -
Cobalt  0.002          - 0.002          -
ASTM B 391 covers unalloyed and alloyed niobium ingots prepared by vacuum- or plasma-arc melting or electronbeam melting to produce consolidated metal for  processing to various mill shapes.
(NOTE 1—Committee B10 has adopted “niobium” as the designation for Element No. 41, formerly named “columbium.” )

ASTM B 392 covers four grades of wrought niobium and niobium alloy bar, niobium rod, niobium alloy bar, niobium wire, niobium alloy wire.
ASTM B 393 covers five grades of wrought niobium and niobium alloy strip, niobium sheet, niobium alloy sheet, niobium plate, niobium alloy plate.
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;
R0xxxx-Type 5—RRR grade pure niobium.  (This grade of niobium is used in superconducting applications that require the ultra high purity. Because of the high purity the product is conducive to very large grains that can adversely affect formability. It is not recommended for other applications).

ASTM B 394 covers wrought niobium and niobium alloy seamless tube, niobium tube, niobium alloy welded tube, niobium welded tube, niobium seamless tube.

The materials covered by this specification are :
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.