Super Alloy Pyromet CTX-909 (UNS N11909)

Topics Covered

Introduction
Chemical Composition
Physical Properties
Mechanical Properties
Thermal Properties
Fabrication and Heat Treatment
     Machinability
     Forming
     Welding
     Heat Treatment
     Forging
     Hot Working
     Cold Working
     Hardening
Applications

Introduction

Pyromet CTX-909 alloy is a high-strength, precipitation hardenable superalloy that exhibits a low and relatively constant thermal expansion coefficient over a wide temperature range, good thermal fatigue resistance and high hot hardness. It offers excellent combination of tensile properties and stress rupture strength under the recrystallized condition.

The following datasheet will provide an overview of Pyromet CTX-909 alloy.

Chemical Composition

The chemical composition of Pyromet CTX-909 alloy is outlined in the following table.

Element Content (%)
Nickel, Ni 35 - 40
Cobalt, Co 12-16
Niobium, Nb 4.3 - 5.2
Chromium, Cr 1
Manganese, Mn 1
Copper, Cu 0.5
Phosphorus, P 0.015
Sulfur, S 0.015
Boron, B 0.012
Iron, F Balance

Physical Properties

The following table shows the physical properties of Pyromet CTX-909 alloy.

Properties Metric Imperial
Density 8.276 g/cm3 0.299 lb/in3
Melting point 1370-1400°C 743-760°F

Mechanical Properties

The mechanical properties of Pyromet CTX-909 alloy are displayed in the following table.

Properties Metric Imperial
Tensile strength 1158 MPa 167954 psi
Yield strength 1034 MPa 149969 psi
Elongation at break 15% 42%

Thermal Properties

The thermal properties of Pyromet CTX-909 alloy are given in the following table.

Properties Metric Imperial
Thermal expansion co-efficient (@25-93°C/77-200°F) 8.1 µm/m°C 4.5 µin/in°F
Thermal conductivity 16 W/mK 110.93 BTU.in/hrft².°F

Fabrication and Heat Treatment

Machinability

Conventional machining techniques that are used for machining iron-based alloys can be used.

Forming

Pyromet CTX-909 alloy has excellent ductility, and can be readily formed by all conventional techniques.

Welding

The alloy can be welded using commonly used welding techniques such as gas-tungsten arc welding, shielded metal-arc welding, gas metal-arc welding and submerged-arc welding.

Heat Treatment

The alloy is heat-treated at 982°C (1800°F) and air cooled.

Forging

Forging of Pyromet CTX-909 alloy can be done at the temperature range of 1060 to 1121°C (1940 to 2050°F).

Hot Working

The alloy is hot-worked at 982 to 1038°C (1800 to 1900°F) and then air cooled.

Cold Working

Cold working of the alloy can be performed using standard tooling.

Hardening

Pyromet CTX-909 alloy can be hardened using cold working.

Applications

The following are the list of applications of Pyromet CTX-909 alloy:

  • Gas turbine shrouds
  • High temperature bolting
  • Gauge blocks.

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