188

188

Alloy 188 is a cobalt base superalloy with a unique combination of high temperature strength and oxidation resistance, along with adequate ductility after prolonged exposure to the 1400-1600°F temperature range.

Cobalt alloys have an inherent advantage over the nickel base grades in high temperature creep. Alloy 188 is solid solution strengthened by a 14% tungsten addition, and further by M6C and M23C6 carbides. Alloy 188 is readily fabricated, being welded by both manual and automatic methods including electron beam, gas tungsten arc and resistance welding.

Chemistry

 CrNiCoWLaBCFeMnSiPS
MIN 20.0 20.0 - 13.0 0.02 - 0.05 - - 0.2 - -
MAX 24.0 24.0 Balance 16.0 0.12 0.015 0.015 3.0 1.25 0.5 0.02 0.015

Specifications

AMS 5608, AMS 5801
EN 2.4683
PWA 1042
UNS R30188
Werkstoff 2.4683

Inventory

188 Coil, 188 Sheet, 188 Welding Products

Common Trade Names

Alloy 188

Features

  • Strength and oxidation resistant to 2000°F
  • Good post-aging ductility
  • Resistant to sulfate deposit hot corrosion

Applications

  • Gas turbine engine combustor cans, spray bars, flame-holders and afterburner liners

Physical Properties

Density: 0.324 lb/in3
Melting Range: 2375 -2570°F

Temperature, °F 70 800 1000 1200 1400 1600 1800
Coefficient* of Thermal Expansion, in/in°F x 10-6 - 7.8 8.2 8.6 9.0 9.4 9.9
Thermal Conductivity
Btu • ft/ft2 • hr • °F
- 10.4 11.5 12.7 13.9 14.5 15.8
Modulus of Elasticity Dynamic, psi x 106 34 29 28 26 25 24 22

* 70°F to indicated temperature.

Mechanical Properties

Representative Tensile Properties, Sheet

Temperature, °F 70 1200 1400 1600 1800 2000
Ultimate Tensile Strength, ksi 137 103 90 60 35 19
0.2% Yield Strength, ksi 67 40 39 36 19 9
Elongation, % 53 59 63 64 59 32

Typical Stress-Rupture Strength

Temperature, °F 1400 1500 1600 1700 1800
100 Hours, ksi 32 22 14 9 5
1,000 Hours, ksi 23 15 9 6 2

188 is a Trademark of Haynes International