Blog
  2. ASTM
  3. Washers
  4. ASTM B708 Specification

ASTM B708 Specification

Forgings, Fasteners, Boltings, Stud Bolts, Screws, Nuts

Scope

ASTM B708 specification covers unalloyed and alloyed tantalum plate, sheet, and strip as follows.
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 of vacuum-arc melt, or both, 1.1.4 R05252, tantalum alloy, 97.5 % tantalum, 2.5 % tungsten, electron-beam furnace or vacuum-arc melt, or both, and R05240, tantalum alloy, 60 % tantalum, 40 % niobium, electron-beam furnace or vacuum-arc melt.

Related Specifications of ASTM B708

ASTM B708 Chemical Composition

Content, max, weight % Element
C O N H Fe Mo Nb Ni Si Ti W Ta
Electron-Beam Cast (R05200) Vacuum-Arc Cast (R05200) Unalloyed Tantalum 0.010 0.015 0.010 0.0015 0.010 0.020 0.100 0.010 0.005 0.010 0.05 remainder
Sintered (R05400) Unalloyed Tantalum 0.010 0.03 0.010 0.0015 0.010 0.020 0.100 0.010 0.005 0.010 0.05 remainder
Electron-Beam Cast (R05255) Vacuum-Arc Cast (R05255) 90 % Tantalum 10 % Tungsten 0.010 0.015 0.010 0.0015 0.010 0.020 0.100 0.010 0.005 0.010 9.0-11.0 remainder
Electron-Beam Cast (R05252) Vacuum-Arc Cast (R05252) 97.5 % Tantalum 2.5 % Tungsten 0.010 0.015 0.010 0.0015 0.010 0.020 0.50 0.010 0.005 0.010 2.0-3.5 remainder
Electron Beam Cast (R05240) Vacuum-Arc Cast (R05240) 60 % Tantalum 40 % Niobium 0.010 0.020 0.010 0.0015 0.010 0.020 35.0-42.0 0.010 0.005 0.010 0.050 remainder
 
Content, max, weight % Element
O N H C
Electron-Beam Cast (R05200) VacuumArc Cast (R05200) Unalloyed Tantalum 0.025 0.010 0.0015 0.020
Sintered (R05400) Unalloyed Tantalum 0.035 0.010 0.0015 0.020
Electron-Beam Cast (R05255) VacuumArc Cast (R05255) 90 % Tantalum 10 % Tungsten 0.025 0.010 0.0015 0.020
Electron-Beam Cast (R05252) Vacuum-Arc Cast (R05252) 97.5 % Tantalum 2.5 % Tungsten 0.025 0.010 0.0015 0.020
Electron Beam Cast (R05240) Vacuum-Arc Cast (R05240) 60 % Tantalum 40 % Niobium 0.025 0.010 0.0015 0.020

ASTM B708 Mechanical Requirements

Grade and Form Annealed Condition
  Ultimate Tensile Strength, min, psi (MPa) Yield Strength, min, psi (MPa) (2 % Offset) Elongation, min, % (1-in. Gage Length)
Unalloyed tantalum (R05200) (R05400) Plate, Sheet and Strip <0.060 in. thick 30 000 (207) 20 000 (138) 20
≥0.060 in. thick 25 000 (172) 15 000 (103) 30
90 % tantalum - 10 % tungsten (R05255) Sheet and strip 70 000 (482) 60 000 (414) 15
Plate 70 000 (482) 55 000 (379) 20
97.5 % tantalum - 2.5 % tungsten (R05252) <0.125 in. thick 40 000 (276) 30 000 (207) 20
≥0.125 in. thick 40 000 (276) 22 000 (152) 25
60 % tantalum - 40 % niobium (R05240 <0.060 in. thick 35 000 (241) 20 000 (138) 25
≥0.060 in. thick 35 000 (241) 15 000 (103) 25

ASTM B708 Dimensional Tolerances

Thickness of Tantalum in. (mm) Tolerance on Thickness,A plus or minus, in. (mm) Tolerance on Width (Slit),B plus or minus, in. (mm) Tolerance on Sheared Lengths, in. (mm)
Width under 6 in (152.4 mm) Width 6 to 24 in. (152.4 to 609.6 mm) Width under 6 in. (152.4 mm) Width 6 to 24 in. (152.4 to 609.6 mm) Length 12 in. (304.8 mm) and Under Length over 12 in. (304.8 mm)
Plus Minus Plus Minus
0.0051 to 0.010 (0.129 to 0.254) 0.0005 (0.0127) ... 0.012 (0.305) ... 1⁄16 (1.59) 0 1⁄4 (6.35) 0
0.011 to 0.015 (0.279 to 0.381) 0.0007 (0.0178) 0.001 (0.0254) 0.015 (0.381) 0.015 (0.381) 1⁄16 (1.59) 0 1⁄4 (6.35) 0
0.016 to 0.020 (0.406 to 0.508) 0.0008 (0.0203) 0.0015 (0.0381) 0.015 (0.381) 0.015 (0.381) 1⁄16 (1.59) 0 1⁄4 (6.35) 0
0.021 to 0.030 (0.533 to 0.762) 0.0015 (0.0381) 0.0025 (0.0635) 0.020 (0.508) 0.025 (0.635) 1⁄16 (1.59) 0 1⁄4 (6.35) 0
0.031 to 0.060 (0.787 to 1.524) 0.0025 (0.0635) 0.0035 (0.0889) 0.025 (0.635) 0.030 (0.762) 1⁄16 (1.59) 0 1⁄4 (6.35) 0
0.061 to 0.090 (1.549 to 2.286) 0.004 (0.1016) 0.005 (0.1270) 0.025 (0.635) 0.035 (0.889) 1⁄16 (1.59) 0 1⁄4 (6.35) 0
0.091 to 0.125 (2.311 to 3.175) 0.006 (0.1524) 0.007 (0.1778) ... ... 1⁄16 (1.59) 0 1⁄4 (6.35) 0
0.126 to 0.187 (3.200 to 4.750) 0.010 (0.2540) 0.010 (0.2540) ... ... 1⁄16 (1.59) 0 1⁄4 (6.35) 0
  • A Tolerance on thickness of sheet over 24 in. (609.6 mm) wide shall be ±10 % of the thickness.
    B Tolerance on width of sheared sheet shall be + 1⁄4 in. (6.35 mm), − 0 in. (0 mm).

ASTM B708 Certifications

  • EN 10204 3.1
  • EN 10204 3.2
  • PED 2014/68/EC
  • MERKBLATT AD 2000 W2/W7/W10
  • API 20 E BSL 1/ BSL 2
  • NACE MR 0175
  • NACE MR 0103

ASTM B708 Supplementary Requirements

S1  Special Flatness Requirement for Explosive Bonding
S2  Tantalum Plate for Sputtering Target Applications (R05200 or R05400 only)
S3  Metallurgical Properties