Special alloys / UNS K94100
Nilo® 42 is an iron-nickel alloy with about 42% nickel and a low, controlled coefficient of thermal expansion from room temperature to about 300 °C, used to match glass and ceramics in sealing applications.
- UNS K94100
- Spec ASTM F30
Also known as / equivalents
| System | Designation |
|---|---|
| UNS | K94100 |
| Also known as | Alloy 42, Invar 42, Ni42 |
Available forms & specifications
| Form | Specification | Size range |
|---|---|---|
| Sheets & plates | ASTM B575 (Alloy 59), B625 (926), B688 / A240 (AL-6XN), ASTM F30 (Nilo) | 0.3 mm – 6 mm |
| Pipe & tube | ASTM B619 / B622 (Alloy 59), B673 / B674 / B677 (926), B675 / B676 / B690 (AL-6XN) | 1/8" – 24" NB |
| Bars & rods | ASTM B574 (Alloy 59), B649 (926), B691 (AL-6XN) | 3 mm – 500 mm |
| Flanges & forgings | ASTM B564, B462 | 1/2" – 48" NB (larger on request) |
Corrosion & temperature resistance
Alloy 59, 926 and AL-6XN offer very high pitting and crevice resistance in chloride media; Nilo alloys are chosen for dimensional stability rather than corrosion resistance.
Applications
Nilo® 42: Glass-to-metal seals, lead frames, thermostats. Glass-to-metal and ceramic-to-metal seals, lead frames and thermostat bimetals (Nilo); seawater cooling, desalination, FGD and chemical process equipment (59, 926, AL-6XN).
Nilo® 42 vs Nilo® 48
| Nilo® 42 | Nilo® 48 | |
|---|---|---|
| UNS | K94100 | K94800 |
| Key property | Controlled low expansion (~42% Ni) | Controlled expansion (~48% Ni) |
| Typical use | Glass-to-metal seals, lead frames, thermostats | Soft-glass seals, thermostat bimetals |
| Cr (wt %) | — | — |
| Ni (wt %) | — | — |
| Mo (wt %) | — | — |
| C (wt %) | — | — |
| Tensile / yield (min, MPa) | — | — |
Frequently asked questions
What is the UNS number of Nilo® 42?
Nilo® 42 is designated UNS K94100.
What is Nilo® 42 used for?
Controlled low expansion (~42% Ni). Typical uses: glass-to-metal seals, lead frames, thermostats.
In which forms can I buy Nilo® 42 from Rajkamal Metals?
Coils & Strips, Sheets & Plates, Pipes & Tubes, Round Bars & Rods, Flanges, Buttweld Fittings, Socket Weld & Threaded Fittings. Sizes as per standard; other sizes on request.
Do you supply a Mill Test Certificate with Nilo® 42?
Yes. Actual values are given in the Mill Test Certificate (EN 10204 3.1) supplied with each order.
What is the difference between Nilo® 42 and Nilo® 48?
Nilo® 42: controlled low expansion (~42% ni). Nilo® 48: controlled expansion (~48% ni). See the comparison table on this page.
Last updated: 30 October 2026. Grade names identify the supply range; designations are not engineering equivalents. Availability, make, origin and documentation are confirmed at quotation.
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