Grade : Kovar nickel-cobalt ferrous alloy/ 29HK/ 4J29
Classification : the alloy of expansion characteristics
Application: Kovar (trademark of CRS Holdings, inc., Delaware[1]) is a nickel-cobalt ferrous alloy compositionally identical to Fernico 1, designed to be compatible with the thermal expansion characteristics of borosilicate glass (~5 × 10？6 /K between 30 and 200 °C, to ~10 × 10？6 /K at 800 °C) in order to allow direct mechanical connections over a range of temperatures. It finds application in electroplated conductors entering glass envelopes of electronic parts such as vacuum tubes (valves), X-ray and microwave tubes and some lightbulbs.
Chemical Composition in % Kovar
Ni
28,5-29,5% |
Fe
51,14-54,5% |
C
0.03% |
Si
0.3% |
Mn
0,4 % |
S
o 0.015% |
P
0.015% |
o
17-18% |
Ti
0.1% |
Al
0.2% |
Cu
0.2% |
Cr
0,1 % |
The thermal properties of alloy
| Temperature coefficient of linear expansion αsr ？ 10-6 K-1 in the temperature range, ° C | inflection point temperature, ° C
No less | Heat treatment regime blanks and samples |
| 20-80 | 20-100 | 20-300 | 20-400 | 20-450 | 20-500 | 20-800 |
| - | - | 4,6-5,6 | 4,6-5,2 | - | 5,9-6,4 | - | 420 | samples and blanks annealing in hydrogen, a vacuum or protective atmosphere at a temperature (960 ± 20) ° C, holding 1 hr., cooling with the furnace or container to 200 ° C at a rate not exceeding 10 ° C / min |
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| Property | sintered | HIPed |
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| Density / g cm3 | 8.0 | 8.35 |
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| Hardness / HV1 | 160 | 150 |
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| Youngs Modulus / GPa | 138 | 138 |
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| reduction of area at fracture / % | 30 | 30 |
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| yield strength / MPa | 270 | 270 |
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| thermal conductivity / W/Km | 17 |
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| Curie Temperature / °C | 435 |
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| electrical resistivity Ω mm2 / m | 0.49 |
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| specific heat J/gK | 0.46 |
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| thermal expansion coefficient/10？6 K？1 (25 - 200 °C) | 5.5 |
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| (25-300 °C) | 5.1 |
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| (25-400 °C) | 4.9 |
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| (25-450 °C) | 5.3 |
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| (25-500 °C) | 6.2 |
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The name Kovar is often used as a general term for Fe-Ni alloys with these particular thermal expansion properties. Note the related particular Fe-Ni alloy Invar which exhibits minimum thermal expansion.
TANKII, referring to the presence of high-power production, offers customers buy alloy Kovar in the required quantities and ensures minimum time shipments of rolled metal products, made on the basis of Kovar.
Shanghai Tankii Alloy Material Co., Ltd. Has been specializing in the production of Resistance Heating Alloy, Nickel Chromium Alloys, FeCrAl Alloys, thermocouple wire, Copper Nickel Alloys, Manganin, pure nickel and other precision alloy materials in the form of round wire, ribbon wire, rod, sheet, tape and strip.
We' Ve already got ISO9001 quality system certificate and approval of ISO14001 environmental protection system.
We own a complete set of advanced production flow of refining, cold reduction, drawing and heat treating etc. We also proudly have independent R&D capacity.
Shanghai Tankii Alloy Material Co., Ltd. Has accumulated lots of experiences over nine years in this field. During nine years, more than 60 management elites and high science and technology talents were employed. They participated in every walk of the company life, which make our company keep blooming and invincible in the competitive market.
Based on the principle of "first quality, sincere service", our managing ideology is pursuing technology innovation and creating the top brand in the alloy field. We persist in Quality - the foundation of the survival. It is our forever ideology to serve you with full heart and soul. We committed to provide customers all over the world with high-quality, competitive products and perfect service.
Our products have been exported to Europe, India, South America, United States, Southest Asia, South America, etc. We are willing to establish strong and long-time partnership with our customers.
Shanghai TANKII ALLOY IS THE MOST PROFESSIONAL PRODUCER OF NICKEL CHROMIUM ALLOYS, THERMOCOUPLE WIRE, FECRAL ALLOYS AND COPPER NICKEL ALLOYS IN China.
