Lamp Grade Dumet Wire
MATERIAL DATA SHEET
Dumet Wire: Lamp Grade
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
- 24 ± 2% of the total weight
- 99.96% minimum copper with 0.00% Oxygen
Two other grades of are also available:
- Dumet with FeNi 42 core and Copperclad 28
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.