Overview

INCOLOY alloy 909 (UNS N19909) is a nickel-ironcobalt alloy whose outstanding characteristics are a constant low coefficient of thermal expansion, a constant modulus of elasticity, and high strength. The alloy is strengthened by a precipitation-hardening heat treatment made possible by additions of niobium and titanium.

The combination of low expansion and high strength makes INCOLOY alloy 909 especially useful for gas turbines. The low expansion enables closer control of clearances and tolerances for greater power output and fuel efficiency. The high strength increases strength-to-weight ratios for lower weight in aircraft engines. For those reasons, INCOLOY alloy 909 is used for gas-turbine vanes, casings, shafts, and shrouds. The properties of INCOLOY alloy 909 are attractive also for rocket-engine thrust chambers, ordnance hardware, springs, steam-turbine bolts, gauge blocks, instrumentation, and glass-sealing applications.

Limiting Chemical Composition, %

Nickel..................................................................................................................................35.0-40.0

Cobalt.................................................................................................................................12.0-16.0

Niobium..................................................................................................................................4.3-5.2

Titanium.................................................................................................................................1.3-1.8

Silicon.................................................................................................................................0.25-0.50

Aluminum.............................................................................................................................0.15 max.

Carbon.................................................................................................................................0.06 max.

Copper...................................................................................................................................0.5 max.

Iron .......................................................................................................................................Balance.

Physical Constants

Mechanical properties

In the age-hardened condition, INCOLOY alloy 909 has high mechanical properties at room temperature and retains much of its strength at temperatures to about 1200°F (650°C). All mechanical properties reported here are for material given the standard heat treatment:

Solution treat at 1800°F (980°C)/1 hr, air cool, plus age harden at 1325°F (720°C)/8 h, furnace cool at 100°F (55°C)/h to 1150°F (620°C)/8 h, air cool.

Previously developed low-expansion superalloys may be susceptible to grain-boundary oxygen embrittlement at high temperatures and consequent poor notch-bar rupture strength. Special processing or long, over-aging heat treatments are needed to alleviate the problem. INCOLOY alloy 909 achieves, primarily through its silicon content, good notch-rupture properties with conventional processing and heat treatment. The notch-bar tests, conducted at 1000°F (540°C), showed strength levels comparable to those obtained with smooth-bar tests.

Corrosion Resistance

INCOLOY alloy 909 contains no chromium because the presence of that element would increase thermal expansion rate. The absence of chromium, however, makes the alloy more susceptible to oxidation in high-temperature atmospheres. In some applications, INCOLOY alloy 909 may require a protective coating to prevent excessive oxidation. A characteristic of INCOLOY alloy 909 is that, unlike other materials of comparable strength, it resists embrittlement by high-pressure hydrogen.

Available Forms

We provide you with a variety of product forms, including but not limited to

● Bar & Rod

● Pipe &Tube

● Coil & Strip

● Plate & Sheet/Circle

● Wire & Welding

● Fitting (Flange, Bolts ,Elbow, Tee...)

● Customize