- Grade / Alloy
- Alloy 42
- EN / W.Nr.
- 1.3917
- AISI / SAE
- —
- UNS
- K94100
- Family
- Controlled expansion
Chemical composition
Chemical composition
Typical compositionTypical composition of the principal alloying elements; not a complete acceptance analysis.
| Element | Content (% by mass) |
|---|---|
| NiNickel | 41 |
| FeIron | 59 |
Values describe the grade, not the analysis of a specific batch. The applicable product specification and material certificate determine acceptance. A dash does not mean zero.
Why controlled expansion matters
Metal expands when heated and contracts when cooled. In a metal joined to glass, movement close to that of the glass is important. The controlled expansion of Alloy 42 is useful in such connections. Rather than exceptionally high mechanical strength, the main requirement is compatible movement between different materials as temperature changes. This physical property matters even in small electronic components.
Use in electronic components
Electronic packages, glass-to-metal feedthroughs and precision connections are established applications. The metal provides an electrical or mechanical connection while glass can supply insulation or closure. The expansion behaviour of the alloy supports their combined function. Compatibility with the particular glass or ceramic therefore explains its use as much as low expansion considered in isolation.
How it differs from Invar 36
Invar 36 and Alloy 42 are both iron-nickel alloys but are known for different purposes. Invar 36 is common in precision parts requiring very little dimensional movement. Alloy 42 serves expansion matching with certain glass and ceramic connections. The numbers indicate approximate nickel contents; the different compositions produce different dimensional responses to temperature.
The 1.3917 designation
Alloy 42 is also encountered as Ni42 and 1.3917. Flat products can serve planar electronic parts, while wire and rod suit connection geometries. Controlled expansion does not mean that the metal never expands. Its value lies in predictable movement over a particular temperature interval and compatibility with the material to which it is joined.
Typical application areas
Electronic packages, glass-to-metal connections, precision components.
Product and cutting options
Relevant product forms for this material are listed below. Availability varies with grade and dimensions.