Invar 42 (also known as Alloy 42 or Nilo 42), designated as UNS K94100 and W.Nr. 1.3917, is a nickel-iron alloy known for its low coefficient of thermal expansion. This makes it an ideal choice for electronic components and glass-to-metal seals where dimensional stability is crucial under varying temperatures.
Invar 42 is widely used in semiconductor lead frames, hermetic seals, electronic connectors, and precision instruments. Its ability to maintain its shape and size despite thermal changes makes it a preferred material in the aerospace, telecommunications, and microelectronics industries.
| Grade | C | Mn | Si | S | Co | Fe | Mo | Al |
| Invar 42 | .50 max | .40 max | .15 max | .20 max | .35 max | Bal | .02 max | .03 max |
| Density | lb/cu in | 0.293 |
| Specific Gravity | 8.12 | |
| Curie Temp | °F | 716 |
| °C | 380 | |
| Melting Point | °F | 2600 |
| °C | 1425 | |
| Electrical Resistivity | ohm-cir mil/ft | 430 |
| Microhms-cm | 71 | |
| Thermal Conductivity | BTU-in/sq. ft-hr-°F | 74.5 |
| W/cm °C | 0.11 | |
| Specific Heat | BTU/lb °F | 0.12 |
| Tensile Strength | ksi | 75 |
| MPa | 517 | |
| Yield Strength | ksi | 40 |
| MPa | 276 | |
| Elongation | % in 2 in. | 30 |
| Hardness Ann. | Rockwell B | 76 |
| Modulus of Elasticity | ksi | 21.5 x 103 |
| ASTM F30 | MIL-I-23011 CL 5 | AMS 1-23011 CL 5 | UNS K94100 |
Standard product forms of Invar 42/alloy 42/Nilo 42/1.3917/UNS K94100 are pipe, tube, sheet, strip, plate, round bar, flat bar, forging stock, hexagon and wire. The products are available in a wide variety of sizes. Please contact us at [email protected] for full information.
English 
Korean 
Japanese 
Arabic 
Spanish 
German 
Portuguese 
French 
Russian 
Italian