Chromel® D
35-20 Nickel-Chromium Electrical Resistance Wire
Chromel D is an alloy used at operating temperatures up to 1850 °F (1030°C). It is a non-magnetic alloy made from nickel, chromium and iron that has a lower resistivity than Chromel C, but improved resistance to selective oxidation of chromium.
Nominal Chemical Composition
Ni 35%
Cr 20%
Fe 45%
Technical Specifications
Properties
| Property | Ch-A | Ch-C | Ch-D |
| Density | |||
| g/cm³ | 8.41 | 8.25 | 7.94 |
| #/in³ | .3039 | .2979 | .2870 |
| Electrical Resistivity, 20°C | |||
| µΩ·cm | 650 | 675 | 625 |
| Ω·circ.mil/ft | 108 | 112 | 104 |
| Ω·sq.mil/ft | 510 | 530 | 490 |
| Coefficient of Thermal Expansion | |||
| 20°C – 100°C, m/m/°C x 10-⁶ | 12 | 13 | 14 |
| 68°F – 212°F, in./in./°F x 10-⁶ | 6.7 | 7.2 | 7.8 |
| Max Operating Temp. (element) | |||
| °C | 1230 | 1065 | 1040 |
| °F | 2250 | 1950 | 1900 |
| Melting Point (approximate) | |||
| °C | 1400 | 1390 | 1390 |
| °F | 2250 | 2535 | 2535 |
Nominal Percent Change in Resistance with Temperature
| Temperature | ||||||||||
| °F | 200 | 400 | 600 | 800 | 1000 | 1200 | 1400 | 1600 | 1800 | 2000 |
| °C | 93 | 204 | 315 | 427 | 538 | 649 | 760 | 871 | 982 | 1093 |
| Ch-A* | 0.8 | 2.0 | 3.3 | 4.8 | 6.3 | 5.8 | 5.1 | 5.2 | 5.6 | 6.0 |
| Ch-A** | 0.43 | 0.93 | 1.46 | 1.94 | 1.90 | 1.04 | 0.71 | 0.79 | 1.18 | 1.66 |
| CH-C | 0.78 | 2.32 | 3.67 | 5.03 | 5.77 | 6.15 | 6.70 | 7.35 | 8.00 | 8.66 |
| Ch-D | 2.6 | 6.5 | 10.0 | 13.0 | 15.6 | 17.8 | 19.6 | 21.4 | 22.5 | 23.5 |
*Large diameter wire or small wire held above 250°C for extended time. This data should be used for heating element design purposes.
**Small diameter wire; rapidly cooled after annealing. Larger sizes may exhibit resistivity gains of up to 6%.