Description

UDIMET® alloy 188 (UNS R30188)

 

good oxidation resistance to 2000°F (1093°C). The high chromium level coupled with small additions of lanthanum produce an extremely tenacious and protective scale. The alloy also has good sulfidation resistance and excellent metallurgical stability as displayed by its good ductility after prolonged exposure to elevated temperatures. Good fabricability and weldability combine to make the alloy useful in gas turbine applications such as combustors, flame holders, liners and transition ducts.

 

 

Mechanical Properties

Carbon……………………………………………………………. 0.05-0.15

Manganese…………………………………………………….. 1.25 max.

Silicon…………………………………………………………….. 0.20-0.50

Chromium………………………………………………………. 20.0-24.0

Nickel…………………………………………………………….. 20.0-24.0

Tungsten………………………………………………………… 13.0-16.0

Lanthanum………………………………………………………. 0.02-0.12

Boron…………………………………………………………… 0.015 max.

Iron…………………………………………………………………. 3.0 max.

Cobalt……………………………………………………………. Balance*

*Reference to the ‘balance’ of a composition does not guarantee this is exclusively of the element mentioned but that it predominates and others are present only in minimal quantities.

 

Yield Strength Tensile Strength Elongation ksi MPa ksi MPa % 65 446 140 963 55

Table 3 – Typical Room Temperature Mechanical Properties of annealed UDIMET alloy 188 Sheet

 

 

Table 4 – Rupture Strength of UDIMET alloy 188 Sheet (1000-hr)

Physical Constants and Thermal Properties

 

Table 2 – Physical Constants

Density, lb/in³………………………………………………………… 0.330

g/cm³………………………………………………………… 9.14

Melting Range, °F……………………………………………. 2375-2425

Temperature Rupture Strength ksi MPa 1300°F / 704°C 35 240 1400°F / 760°C 24 165 1500°F / 816°C 16 110 1600°F / 871°C 10 69 1700°F / 927°C 5.9 41 1800°F / 982°C 3.6 25 1900°F / 1038°C 2.2 15 2000°F / 1093°C 1.3 9

°C…………………………………………… 1300-1330

Specific Heat at 70°F, Btu/lb°F…………………………………. 0.097

at 21 °C, J/kg°C……………………………………. 405

Permeability at 200 oersted……………………………………. 1.0007

Coefficient of Expansion, 0 – 200°F, 10^-6 in/in•°F…………… 6.6

21 – 93°C, µm/m•°C……………… 11.9

Thermal Conductivity, Btu•in/ft²•h•°F……………………………. 84

W/m•°C…………………………………… 12.1

Electrical Resistivity, ohm•circ mil/ft……………………………… 613

microhm-cm……………………………. 102.0