Introduction:
Kovar alloy has stable performance, mainly applying to the glass sealing of lead wire, chassis, shell holder, etc., in electrical vacuum components, transmitting valve, oscillating tube, ignitron, magnetron, transistor, sealing plug, electric relay and integrated circuit. The glass should match with the expansion coefficient of the alloy in application. Its cryogenic structural stability is strictly tested according to the use temperature. During the processing, proper heat treatment should be conducted to ensure that the material has good deep drawability and high elongation. When using forging material, its gas tightness should be tested strictly.
Supply of Kovar alloy
| Shape | Size |
| Wire | D=0.1~8mm | |
| Strip | W= 5~250mm | T= 0.1mm | |
| Foil | W= 10~100mm | T= 0.01~0.1mm | |
| Rod | D=8~100mm | L=50~1000mm | |
Grades
UNS K94610, ASTM F15, GB 4J29
Chemical composition (%)
| Ni | 28.5~29.5 | Fe | Bal. | Co | 16.8~17.8 | Si | ≤0.3 |
| Mo | ≤0.2 | Cu | ≤0.2 | Cr | ≤0.2 | Mn | ≤0.5 |
| C | ≤0.03 | P | ≤0.02 | S | ≤0.02 |
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Tensile strength, MPa
| State No. | State | Wire alloy | Strip alloy |
| R | Soft | ≤585 | ≤570 |
| 1/4I | 1/4 Hard | 585~725 | 520~630 |
| 1/2I | 1/2 Hard | 655~795 | 590~700 |
| 3/4I | 3/4 Hard | 725~860 | 600~770 |
| I | Hard | ≥850 | ≥700 |
Physical property
| Density (g/cm3) | 8.2 |
| Resistivity under 20℃(Ωmm2/m) | 0.48 |
| Resistance temperature coefficient (20℃~100℃)X10-5/℃ | 3.7~3.9 |
| Curie point, Tc/ ℃ | 430 |
| Elasticity modulus, E/ Gpa | 138 |
Expansion coefficient
| θ/℃ | α1/10-6℃-1 | θ/℃ | α1/10-6℃-1 |
| 20~60 | 7.8 | 20~500 | 6.2 |
| 20~100 | 6.4 | 20~550 | 7.1 |
| 20~200 | 5.9 | 20~600 | 7.8 |
| 20~300 | 5.3 | 20~700 | 9.2 |
| 20~400 | 5.1 | 20~800 | 10.2 |
| 20~450 | 5.3 | 20~900 | 11.4 |
Heat conductivity
| θ/℃ | 100 | 200 | 300 | 400 | 500 |
| λ/ W/(m*℃) | 20.6 | 21.5 | 22.7 | 23.7 | 25.4 |
Heat conductivity
| Stress-relief annealing | Be heated to 470~540℃ and preserve heat for 1~2 h. Be cooled in the furnace. |
| Anneal | Be heated to750~900℃ in vacuum |
| Holding time | 14 min~1h |
| Cooling methods | Be cooled to 200 ℃ at a speed of no more than 10 ℃/min |
Index
nickel alloy, alloy pipe
