Nikrothal® 70 is an austenitic nickel-chromium alloy (NiCr alloy) for use at temperatures up to 1250°C (2280°F). The alloy is characterized by high resistivity and good oxidation resistance. It has good ductility after use and excellent weldability.
Nikrothal® 70 is particularly well suited for reducing atmospheres, as it is not subject to 'green rot'.
Nikrothal® 70 is used in electrical heating elements in industrial furnaces. The alloy is particularly well suited for reducing atmospheres, as it is not subject to 'green rot'.
Chemical composition
|
C % |
Si % |
Mn % |
Cr % |
Fe % |
Ni % |
Trace elements |
| Nominal composition |
|
|
|
|
|
Bal. |
Added |
| Min |
- |
0.5 |
- |
29.0 |
- |
- |
|
| Max |
0.15 |
2.0 |
1.0 |
32.0 |
5.0 |
- |
|
Mechanical properties
| Wire size |
Yield strength |
Tensile strength |
Elongation |
Hardness |
| Ø |
Rp0.2 |
Rm |
A |
|
| mm |
MPa |
MPa |
% |
Hv |
| 1.0 |
430 |
820 |
30 |
185 |
| 4.0 |
425 |
800 |
30 |
185 |
Physical properties
| Density g/cm3 |
8.10 |
|---|
| Electrical resistivity at 20°C Ω mm2/m |
1.18 |
|---|
Temperature factor of resistivity
| Temperature °C | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | 1000 | 1100 | 1200 |
|---|
| Ct |
1.01 |
1.02 |
1.03 |
1.04 |
1.05 |
1.05 |
1.04 |
1.04 |
1.04 |
1.05 |
1.05 |
1.06 |
|---|
Coefficient of thermal expansion
| Temperature °C | Thermal Expansion x 10-6/K |
|---|
| 20 - 250 |
13.7 |
|---|
| 20 - 500 |
14.6 |
|---|
| 20 - 750 |
15.8 |
|---|
| 20 - 1000 |
17.1 |
|---|
Thermal conductivity
| Temperature °C | 20 | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | 1000 | 1100 |
|---|
| W m-1 K-1 |
13 |
13 |
14 |
15 |
17 |
19 |
20 |
22 |
24 |
26 |
28 |
29 |
|---|
Specific heat capacity
| Temperature °C | 20 | 100 | 200 | 300 | 400 | 500 | 600 | 700 | 800 | 900 | 1000 | 1100 |
|---|
| kJ kg-1 K-1 |
0.46 |
0.46 |
0.48 |
0.50 |
0.53 |
0.55 |
0.58 |
0.60 |
0.63 |
0.65 |
0.67 |
0.71 |
|---|
| Melting point °C |
1380 |
|---|
| Max continuous operating temperature in air °C |
1250 |
|---|
| Magnetic properties |
The material is non-magnetic |
|---|
| Emissivity - fully oxidized material |
0.88 |
|---|
