Controlled Expansion Property Comparisons
| Physical Properties | Kovar | Alloy 52 | Alloy 48 | Alloy 46 | Alloy 42 | Alloy 42-6 | Invar 36 | Super Invar 32-5 |
|---|---|---|---|---|---|---|---|---|
| Density lb/cu in | 0.302 | 0.3 | 0.298 | 0.295 | 0.293 | 0.293 | 0.291 | 0.294 |
| Specific Gravity | 8.36 | 8.3 | 8.25 | 8.17 | 8.12 | 8.12 | 8.05 | 8.15 |
| Curie Temp °F | 815 | 986 | 880 | 860 | 716 | 560 | 535 | 470 |
| Curie Temp °C | 435 | 530 | 471 | 460 | 380 | 293 | 279 | 245 |
| Melting Point °F | 2640 | 2600 | 2600 | 2600 | 2600 | 2600 | 2600 | 2600 |
| Melting Point °C | 1449 | 1427 | 1427 | 1427 | 1427 | 1427 | 1427 | 1427 |
| Electrical Resistivity micro-ohm-cm | 49 | 44 | 49 | 47 | 68 | 97 | 84 | 82 |
| Electrical Resistivity ohm-cir mil/ft | 294 | 258 | 290 | 277 | 400 | 570 | 495 | 481 |
| Thermal Conductivity W/cm °C | 0.17 | 0.14 | 0.13 | 0.11 | 0.11 | 0.13 | 0.10 | 0.10 |
| Thermal Conductivity BTU- in/ sq. ft hr- °F | 120 | 97 | 90 | 79.2 | 74.5 | 87 | 72.6 | 72.6 |
| Specific Heat Cal/g- °C | 0.11 | 0.12 | 0.12 | 0.12 | 0.12 | 0.12 | 0.123 | 0.12 |
| Specific Heat BTU/lbm- °F | 0.11 | 0.12 | 0.12 | 0.12 | 0.12 | 0.12 | 0.123 | 0.12 |
| Thermal Expansion ppm/°F (75°F to 842°F) | 2.9 | 5.5 | 5.0 | 4.4 | 3.9 | 5.9 | 4.9 | 4.5 |
| Thermal Expansion ppm/°C (25°C to 450°C) | 5.3 | 9.9 | 9.0 | 7.9 | 7.0 | 10.6 | 8.9 | 8.0 |
| Mechanical Properties | Kovar | Alloy 52 | Alloy 48 | Alloy 46 | Alloy 42 | Alloy 42-6 | Invar 36 | Super Invar 32-5 |
|---|---|---|---|---|---|---|---|---|
| Tensile Strength ksi | 75 | 80 | 79 | 80 | 82 | 80 | 75 | 70 |
| Tensile Strength MPa | 518 | 552 | 545 | 552 | 566 | 552 | 518 | 483 |
| Yield Strength ksi | 40 | 40 | 36 | 35 | 34 | 40 | 40 | 40 |
| Yield Strength MPa | 276 | 276 | 248 | 242 | 235 | 276 | 276 | 276 |
| Elongation % in 2 in. | 30 | 35 | 30 | 30 | 30 | 30 | 34 | 40 |
| Typical Hardness Ann. Rockwell | HRB 80 | HRB 80 | HRB 80 | HRB 80 | HRB 80 | HRB 80 | HRB 80 | HRB 75 |
| Modulus of Elasticity Mpsi | 30 | 23 | 23 | 23 | 21.5 | 23 | 20.5 | 21.0 |
| Modulus of Elasticity kMPa | 207 | 159 | 159 | 159 | 148 | 159 | 141 | 145 |
| Chemistry | Kovar | Alloy 52 | Alloy 48 | Alloy 46 | Alloy 42 | Alloy 42-6 | Invar 36 | Super Invar 32-5 |
|---|---|---|---|---|---|---|---|---|
| maximum % unless noted | ||||||||
| Iron | Bal | Bal | Bal | Bal | Bal | Bal | Bal | Bal |
| Nominal Nickel | 29 | 50.5 | 48 | 46 | 41 | 42 | 36 | 32 |
| Nominal Cobalt | 17 | - | - | - | - | - | 0.5 | 5 |
| Carbon | 0.02 | 0.05 | 0.05 | 0.05 | 0.05 | 0.07 | 0.05 | 0.05 |
| Silicon | 0.20 | 0.30 | 0.30 | 0.30 | 0.30 | 0.30 | 0.40 | 0.25 |
| Sulfur | - | 0.025 | 0.025 | 0.025 | 0.025 | 0.025 | 0.015 | 0.015 |
| Chromium | 0.20 | 0.025 | 0.025 | 0.025 | 0.025 | 5.6 nom. | 0.25 | 0.25 |
| Titanium | - | - | - | - | - | - | - | |
| Magnesium | - | - | - | - | - | - | - |
| Specifications | Kovar | Alloy 52 | Alloy 48 | Alloy 46 | Alloy 42 | Alloy 42-6 | Invar 36 |
|---|---|---|---|---|---|---|---|
| ASTM | F-15/ F-1466 | F-30 | F-30 | F-30 | F-30 | F-31 | F-1684 |
| MIL | I-23011 CI 1 | I-23011 CI 2 | I-23011 CI 3 | I-23011 CI 4 | I-23011 CI 5 | I-23011 CI 6 | I-23011 CI 7 |
| AMS | I-23011 CI 1 | I-23011 CI 2 | I-23011 CI 3 | I-23011 CI 4 | I-23011 CI 5 | I-23011 CI 6 | I-23011 CI 7 |
References
1Trademark Carpenter Technology Corp., Reading PA
2Trademark ThyseenKrupp-VDM, Germany
3Trademark Aperam Alloys, France
4Trademark Special Metals Corporation, USA
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