Data Sheet: ontrolled Expansion Alloys

Learn more about each nickel speciality alloy

  • Controlled Expansion and Glass Sealing Nickel Iron Alloy Grades

Controlled Expansion: Glass Sealing Alloys

These are nickel-iron based alloys that are required for applications where a hermetic seal is required between metal and glass or ceramic. They are also used for applications where a certain thermal expansion is required over a given temperature range. Examples of such applications are light bulbs, vacuum tubes, optoelectronics, etc.

Alloy 36 This grade exhibits near zero coefficient of thermal expansion from room temperature to 100 °C. It is used for applications that cannot tolerate any dimensional changes due to temperature changes. It finds use in precision laser measurement equipment, electronic devices, instrumentation, thermostats, and in antenna/aerial technologies. Another common usage is for making the low expansion part of bimetallic thermostats.

Alloy 42 has a constant low rate of thermal expansion up to temperatures approaching 350 °C. The thermal coefficient of expansion of this alloy matches that of soft glass. As a result, it is used for glass-sealing applications in microelectronic components and vacuum devices. Alloy 42 is also used as the core of Dumet wire, which forms the glass-sealing component of the lead-in-wires used in electric light bulbs. This alloy is also used for thermostats and thermo switches.

Alloy 48 has a thermal expansion coefficient which matches that of soda-lime glass. It is widely used for electric wiring in glass-to-metal connections. It is also used in thermostats for industrial applications up to 450 °C.

Alloy 52 is also a glass-to-metal sealing alloy that is used in compact fluorescent lamps (CFL) and other electronic applications.

Alloy 54 is also a glass-to-metal sealing alloy that is used in compact fluorescent lamps (CFLs), special auto lamps, and other electronic applications.

Note: Other variants with customer specified Nickel content can also be manufactured. Please contact JLC for more details.

Specifications & Nominal Chemical Composition (%)

Alloy Werkstoff Nr UNS designation ASTM Ni Fe
Alloy 36 1.3912 K93600/K93603 B753 36 Balance
Alloy 42 1.3917 K94100 F29 42 Balance
Alloy 48 1.3922 K98000 F30 48 Balance
Alloy 52 2.4478 N14052 F30 52 Balance
Alloy 54 2.4475 - - 54 Balance

Nominal Physical, Electrical & Mechanical Properties (at room temperature)

Alloy Density Electrical Resistivity at 20 °C Tensile Strength Elongation
  g/cm³ µΩ-cm N/mm² % at L0=100 mm
Alloy 36 8.11 80 490 30
Alloy 42 8.11 61 510 30
Alloy 48 8.20 47 520 30
Alloy 52 8.30 43 540 30
Alloy 54 8.30 43 550 30

Mean Coefficient of Thermal Expansion in Annealed Condition (µm/m-°C)

Alloy Temperature Range (°C)
20-100 20-200 20-300 20-400 20-500
Alloy 36 1.5 2.6 5.5 8.4 10.1
Alloy 42 5.3 5.3 5.3 6.2 8.0
Alloy 48 8.5 8.6 8.7 8.8 9.1
Alloy 52 10.3 10.2 10.2 10.1 9.9
Alloy 54 10.3 10.3 10.2 10.1 10.2

Size Range

Form Dia Length
mm mm
Alloy 36 1.5 - 2.0 Supplied in custom lengths
Wire 0.3 - 10.0 -

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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 48 (Ni48Fe)
  • SMA 50 (Ni50Fe)
  • SMA 80 (Ni80Mo5Fe)
Controlled Expansion Alloys
Dumet Wires
Clad Wires
  • Copper-Clad FeNi42
  • Copper-Clad FeNi60
  • Iron-Clad Nickel
  • Nickel-Clad Iron