Expansion Alloy 29HK Kovar Uns K94610 Tube Ni29co18 FeNi29 pipe for Sealing Process
| Controlled Expansion and Glass Sealing Alloys |
| German standard number |
Tradename |
DIN |
UNS |
| 1.3912 |
Alloy 36 |
17745 |
K93600/93601 |
| 1.3917 |
Alloy 42 |
17745 |
K94100 |
| 1.3922 |
Alloy 48 |
17745 |
K94800 |
| 1.3981 |
Pernifer2918 |
17745 |
K94610 |
| 2.4478 |
NiFe 47 |
17745 |
N14052 |
| 2.4486 |
NiFe47Cr |
17745 |
- |
General Description
Kovar is a nominal 29%Ni-17%Co-54%Fe alloy that is a well-known glass-sealing alloy suitable for sealing to hard glasses. Kovar has a nominal expansion coefficient of approximately 5 ppm/°C and inflection temperature of ~450 °C (840 °F).
4J29 also known as Fe-Ni-Co Glass Sealing Alloy. it was invented to meet the need for a reliable glass-to-metal seal, which is required in electronic devices such as light bulbs, vacuum tubes, cathode ray tubes, and in vacuum systems in chemistry and other scientific research.
Kovar (ASTM F15) has been used for making hermetic seals with the harder Pyrex glasses and ceramic materials. This alloy has found wide application in power tubes, microwave tubes, transistors, and diodes. In integrated circuits, it has been used for the flat pack and the dual-in-line package.
Mainly used in electric vacuum components and emission control, shock tube, igniting tube, glass magnetron, transistors, seal plug, relay, integrated circuits lead, chassis, brackets and other housing sealing.
Chemical Domposition
| alloy |
C |
Mn |
Si |
P |
S |
Ni |
Cr |
Co |
Cu |
Mo |
Fe |
| 4J29 |
≤0.03 |
≤0.50 |
≤0.30 |
≤0.020 |
≤0.020 |
28.5~29.5 |
≤0.20 |
16.8~17.8 |
≤0.2 |
≤0.2 |
balance |
Tensile Strength, MPa
| Code of condition |
Condition |
Wire |
Strip |
| 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 |
Typical Physical properties
| Density (g/cm3) |
8.2 |
| Electrical resistivity at 20ºC(OMmm2/m) |
0.48 |
| Temperature factor of resistivity(20ºC~100ºC)X10-5/ºC |
3.7~3.9 |
| Curie point Tc/ ºC |
430 |
| Elastic Modulus, E/ Gpa |
138 |
The heat treatment process
| Annealing for stress relief |
Heated to 470~540ºC and hold 1~2 h. Cold down |
| annealing |
In vacuum heated to 750~900ºC |
| Holding time |
14 min~1h. |
| Cooling rate |
No more than 10 ºC/min cooled to 200 ºC |
Coefficient of expansion
| θ/ºC |
α1/10-6ºC-1 |
θ/ºC |
α1/10-6ºC-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 |
Thermal conductivity
| θ/ºC |
100 |
200 |
300 |
400 |
500 |
| λ/ W/(m*ºC) |
20.6 |
21.5 |
22.7 |
23.7 |
25.4 |
Style of supply
| Alloys Name |
Type |
Dimension |
|
| 4J29 |
Wire |
D= 0.1~8mm |
|
| 4J29 |
Strip |
W= 5~250mm |
T= 0.1mm |
| 4J29 |
Foil |
W= 10~100mm |
T= 0.01~0.1mm |
| 4J29 |
Bar |
Dia= 8~100mm |
L= 50~1000mm |
Audited Supplier 
){kind=link}
){kind=link}