Material description
Dumet wire consists of a nickel-iron core in an oxygen-free-high-conductivity copper sheath. It is available in various surface finishes: electrically oxidised, borax coated, nickel plated, bare (uncoated).
Borated surface finish Dumet is used in Lead-in-wires for lamps. Dumet forms a glass-to-metal seal while manufacturing these lamps. The oxidised Dumet is used in Lead-in-wires, diodes and capacitor slug leads application.
Composition:
Core
| Ni | C | Mn | Si | S | P | Fe |
|---|
| 41 - 43 | 0.05 max | 1.0 max | 0.30 max | 0.02 max | 0.02 max | Rest |
Copper Sheath
Two other grades of are also available:
- Dumet with FeNi 42 core and Copperclad 28
- Dumet with FeNi 47 core and Copperclad 17
Mechanical Properties
| Co-efficient of Linear expansion (20 - 400°C) Radial | 8.5 - 10.0 x 10-6/°C |
|---|
| Co-efficient of Linear expansion (20 - 400°C) Axial | 5.5 - 7.0 x 10-6/°C |
|---|
| Electrical Resistivity µOhm-cm | 6 to 9 |
|---|
| Tensile Strength (Annealed) | 50 - 65 Kg/mm² |
|---|
| Elongation Upon Fracture | 20 min |
|---|
Surface Finish
For Borated and Oxidised Dumet, colour is as per ASTM colour standard F-29-63T. The colours have been divided into three parts.
| Light | Medium | Dark |
|---|
| 0.5YR - 8.5R | 7.5R - 5.5R | 4.5R - 2.5R |
For Nickel-Plated Dumet wire, standard plating thickness is 2 microns and 4 microns.
Available Dimensions
| Diameter (D) (mm) | Tolerance (mm) | Max out-of-roundness |
|---|
| 0.20 - 1.0 | ±0.010 | 0.010 |
| 1.0 - 2.0 | ±1% of D | 1% of D |
Packaging :
Available on many types of spools. Common spool in use has following dimensions (mm) :
| Spool Type | Traverse (mm) | Bore (mm) | Flange (mm) | Tare (gm.) |
|---|
| Dumet-SP | 52 | 48 | 100 | 60 gms |
|---|
Barrel/drum packaging and other standard DIN spools are also available upon request.
Dumet spools are individually sealed with plastic film and put in an air-tight plastic container with activated desiccant.
Dumet Wire: Copper-Clad Ni-Fe Wire
