General Description

Alloy 42 is a low expansion alloy which is very similar to Invar 36. It has a low expansion up to about 300℃. Principally used as strip for semiconductor lead frames in integrated circuits and bi-metal strip, the alloy can be also used in ceramic to metal seals with alumina and the glass bulb envelope to metal seals.

Chemical Composition

Grade C% P% S% Mn% Si% Al% Co% Ni% Fe%
Alloy 42 Max 0.05 Max 0.02 Max 0.02 Max 0.8 Max 0.3 Max 0.1 Max 1.0 41.0-42.5 Bal.


UNS K94100

Werkstoff Nr. 1.3917


Wire/Strip/Sheet/Bar  ASTM F30

Physical Properties

Density: 8.12 g/cm3

Melting Point: 1440°C

Electric Resistivity: 0.61μΩ·m

Mechanical Properties

Alloy 42 Strip: <590 MPa (Soft)

Alloy 42 Strip: >700 Mpa(Hard)

Linear Coefficient of Thermal Expansion ā,10-6/℃

Grade 20-100℃ 20-200℃ 20-300℃ 20-400℃ 20-450℃ 20-500℃ 20-600℃
Alloy 42 5.6 4.9 4.8 5.9 6.9 7.8 9.2

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