Kovar Foil Kovar Plate Kovar Sheet
Kovar Foil (Alloy K) is used for high-power transmitting valves, transistor leads and headers, integrated-circuit lead frames, and photography flash bulbs. UNS K94610 Werkstoff Nr 1.3981 DIN 17745 ASTM F 15 AMS 7726 Wire AMS 7727 Bars and Forgings AMS 7728 Sheet, Strip and Plate MIL-I-23011 class 1 AFNOR NF A54-301 S.E.W 385 DILVER P
Description
Kovar foil (Alloy K) is used for high-power transmitting valves, transistor leads and headers, integrated-circuit lead frames, and photography flash bulbs.
Kovar Foil is also known as Kovar alloy. It was invented to meet the need for reliable glass-to-metal sealing, which is required in electronic equipment such as light bulbs, vacuum tubes, cathode ray tubes, and vacuum systems for chemical and other scientific research. Since the coefficient of thermal expansion is different from that of glass, most metals cannot be sealed with glass. Therefore, when the welded joint is cooled after processing, the stress caused by the difference in expansion rate of glass and metal causes the welded joint to crack
Kovar Foil Pictue:
Table 1Chemistry Composition (Weight Percent)
| Element | C≤ | P≤ | S≤ | Mn≤ | Si≤ | Cr≤ | Cu≤ | Mo≤ | Ni | Co | Fe |
| Composition% | 0.03 | 0.020 | 0.020 | 0.5 | 0.3 | 0.20 | 0.20 | 0.20 | 28.5-29.5 | 16.8-17.8 | Remainder |
Notes:
1.The shape and dimensions of the alloys are in compliance with ASTM F15
2.We offer kovar strip coil in custom Tempers from Annealed to Full Hard
Table 2Physical Properties
| Specific Gravity | 8.36 | |
| Density | 0.32 (Ib/cu in) | 8359 (kg/cu m) |
| Curie Temperature | 815(°F) | 435(°C) |
| Thermal Conductivity | 120(Btu-in/ft2/hr/°F) | 17.3 (W/m-K) |
| Melting Point | 2640 (°F) | 1450 (°C) |
| Electrical Resistivity | 294(ohm-cir mil/ft) | 490(microhm) |
| Modulus of Elasticity | 20(Psi x 106 ) | 138( MPa x 103) |
Table 3 Machanical Property
| Temper Designation | Temper name | Tensile Strength/MPa |
| A | Annealed | <585 |
| B | 1/4 Hard | 585-725 |
| C | 1/2 Hard | 655-795 |
| D | 3/4 Hard | 725-865 |
| E | Hard | >860 |
Table 4Tensile Strength Strip
| Temper Designation | Tamper Name | Tensile Strength/MPa |
| A | Annealed | <570 |
| B | 1/4 Unannealed | 520-700 |
| C | 1/2 Unanealed | 590-700 |
| D | 3/4 Unanealed | 600-770 |
| E | Hard | >700 |
Table 5 Hardness of Deep Stamping Strip
