Data Sheet: Dumet

Learn more about each nickel speciality alloy

  • Bare Dumet Wire, Oxidized Dumet Wire, Borated Dumet Wire, Nickel-Plated Dumet Wire Alloys

Dumet: Wire \ Ribbon

Dumet is a glass-to-metal sealing alloy. It is a bimetal made of a nickel-iron core encased in an oxygen-free-high- conductivity (OFHC) copper sheath. Dumet wire is used as a glass-to-metal seal in manufacturing of lamps, diodes, and capacitor slug leads. It is used as the pinch-lead in Lead-in-Wires that are used in incandescent, fluorescent tube, automotive, halogens, HID, decorative, and other special purpose lamps. JLC boasts of being the world's largest producer of lamp grade Dumet wire.

Grades of Supply

  • Bare Dumet Wire
  • Oxidized Dumet Wire
  • Borated Dumet Wire
  • Nickel-Plated Dumet Wire

All grades are supplied as annealed wire.
Grade selection depends on the lamp type and the manufacturing process of the lamp maker.

Nominal Chemical Composition (%)

Alloy Ni C Mn Si S P Fe
NiFe42 Core 41-43 Max 0.05 Max 1.0 Max 0.30 Max 0.02 Max 0.02 Balance

Two grades are available which are identified with Copper sheath as follows:

Copper* Sheath 24 ± 2 % of the total weight
26 ± 2 % of the total weight

* Min 99.99% OFHC Copper

Nominal Physical & Electrical Properties (for cold drawn & annealed wire)

Alloy Density Electrical Resistivity at 20°C
g/cm³ µΩ-cm
Dumet wire 8.35 6-9

Nominal Mechanical Properties (for cold drawn & annealed wire)

Alloy Coeff. of Linear Expansion
between 20-400°C
Tensile strength
% at L0=100 mm
Nominal dia in mm
Radial Axial Min Max Min Max
Dumet wire 8.5-10.0 5.5-7.0 400 600 20 30

Surface Finish

For Borated and Oxidized Dumet, color of the wire surface is as per ASTM color standard F29-63T.
The color has been divided into three parts:

Light Medium Dark
7.5R - 0.5YR 3.5R - 7.5R 2.5R - 3.5R

For Nickel plated Dumet wire, standard plating thickness is min 2 microns.


Available in different types of spools or drums/barrels based on customer specification. Common spool used has the following dimensions:

Spool Type Traverse Bore Flange Tare weight
mm mm mm gm
Dumet-SP 52 48 100 60

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 an activated dessicant material.

It is advisable to use the wire within six months from the date of manufacturing for best performance. The shelf life of borated, oxidised and bare dumet is only six months from the date of manufacturing.

Click here to download this data sheet in PDF format.

Related Links


Nickel Alloys

Standard Nickel Grades:

Nickel-Manganese Alloys:

Nickel-Copper Alloys:

Welding Alloys Heating & Resistance

Nickel-Chromium Alloys:

Iron-Chrome-Aluminum Alloys

Nickel Chrome Iron Alloys Low Resistance & Shunt Alloys

Cu-Ni Low Resistance Alloys:

Cu-Mn-Ni Alloys:

Lamp Components & Alloys Thermocouple Alloys

Thermocouple Grade Alloys:

Extension and Compensating Grade Alloys:

Automotive Alloys

Alloys for Earth and Central Electrodes:

  • NiSi
  • NiCr15Fe
  • NiCr5SiMn
  • NiCr2SiMn
  • NiSi1Al1Y
Soft Magnetic Alloys

Temperature Compensating Alloys:

  • Ni30Fe
  • Ni31Fe
  • Ni32Fe

High Permeability Alloys:

  • SMA 50 (Ni50Fe)
Controlled Expansion Alloys
Dumet Wires
Clad Wires
  • Copper-Clad FeNi42
  • Copper-Clad FeNi60
  • Iron-Clad Nickel
  • Nickel-Clad Iron