A cobalt-based alloy, Alloy 188 has excellent high temperature strength.

Alloy 188 combines excellent strength at high temperature, superb resistance to oxidising environments and good resistance to sulphate deposit hot corrosion. It is readily weldable with good hot and cold forming characteristics.

  • UNS Number: UNS R30188
  • Werkstoff Number: 2.4683
  • AMS: 5608, 5801, 5772

Product availability

Round Bar
Welding Wire

Chemical analysis



  • Gas turbine engine combuster cans
  • Spray bars
  • Flame holders
  • Afterburner liners

About Alloy 188

Alloy 188 is a cobalt-based superalloy with a unique combination of high temperature strength and oxidation resistance up to 1093°C, along with good post-aging. The alloy maintains its ductility after prolonged exposure to high temperatures.

Alloy 188 is also particularly resistant to sulphate-deposit hot corrosion.

Alloy 188 is readily fabricated, being welded by both manual and automatic methods including electron beam, gas tungsten arc and resistance welding.

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  • Density: 8.97 g/cm³
  • Melting range: 1302-1410°C

Mechanical & Physical Properties

Mechanical & Physical Properties21°C427°C538°C649°C760°C871°C982°C1093°C
Ultimate Tensile Strength /MPa944.6--710.2620.5413.7241.3131
0.2% Yield Strength /MPa462--275.8268.9248.213162.1
Elongation %53--59636459-
Coefficient of Thermal Expansion µm/m⁰C-1414.815.516.216.917.8-
Thermal Conductivity /kcal/(hr.m.°C)-15.517.118.920.721.623.5-
Modulus of Elasticity/ x105 MPa2.3421.931.791.721.651.52-

Typical Stress Rupture Strength

14001500160017001800Temperature, °F
32221495100 hours, ksi
23159621000 hours, ksi
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