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PRODUCT DATA of Wolfram (Tungsten)
MaterialWolfram (Tungsten)
PrecautionsTungsten is likely to be brittle at to be brittle at room tempearture or at lower temperatures and therefore requires careful handling to avoid fracture.
Chemical Composition100W
CAS Registry ID7440-33-7
EXPERIENCE IN PRACTICE
Development StatusSpecial Commercial Product
Equivalent DesignationsW
Space ExperienceFair
PHYSICAL PROPERTIES
Atomic Number74
Atomic Weight184 amu
Work Function4.55 eV
Crystal StructureBody centered cubic (bcc)
Specific Gravity19.2
Magnetic PropertiesNonmagnetic
ELASTIC PROPERTIES
Tensile Modulus411 GPa
Bulk Modulus311 GPa
Poisson Ratio0.28
Speed of Sound (longitudinal)5180 m/s
Speed of Sound (transverse)2870 m/s
Acoustic Impedance99.7 MRayls
ELECTRICAL PROPERTIES
Electrical Volume Resistivity5.5e-8 ohm.m
Electrical Conductivity31 %IACS
Superconductivity Critical Temperature-273 °C
THERMAL PROPERTIES
Thermal Conductivity167 W/m.K
Thermal Expansion Coefficient4.44 μstrain/°C
Melting Range3400 °C
Specific Heat0.138 J/g.K
RELEVANT PROPERTIES FOR USE IN SPACE COMMUNITY
Corrosion/ThermalTungsten resists water and water vapour at room temperature, but at red heat the metal is oxidised rapidly to WO3 and blue oxide
Atmospheric CorrosionTungsten is not affected by air at room temperature when the metal is in other than the powder form. Fine-powdered Tungsten is pyrophoric. At 400C to 500C, Tungsten begin to oxidise in air.
EMF vs SCE-0.3 V
Remark: Measured in 3.5% NaCl solution
Data Quality: Design Data
MachinabilityAbrasive wheels of silicon carbide are used to machine Tungsten. Light pressure, high tool speed, and an abundance of coolant facilitate the grinding of cutting operations
WeldingOxidation is a problem in the welding of Tungsten
BrazingTungsten can be brazed using copper, copper-nickel alloys and tantalum (for high T use)
SolderingSilver and soft solder are used to solder Tungsten