Super Alloy Pyromet CTX-3 (UNS N19907)

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
     Annealing
Applications

Introduction

Pyromet CTX-3 alloy is a high strength, precipitation hardenable superalloy that exhibits low thermal expansion coefficient over a broad temperature range. It also possesses good thermal fatigue resistance and notched stress-rupture strength over Pyromet CTX-1 alloy. The alloy is weldable, and remains unaffected by stress orientation.

The following section will provide an overview of Pyromet CTX-3 alloy.

Chemical Composition

The chemical composition of Pyromet CTX-3 alloy is outlined in the following table.

Element Content (%)
Nickel, Ni 35 - 40
Cobalt, Co 12-16
Niobium, Nb 4.3-5.2
Titanium, Ti 1.2-1.8
Manganese, Mn 1
Chromium, Cr 1
Copper, Cu 0.5
Silicon, Si 0.35
Aluminum, Al 0.2
Carbon, C 0.06
Sulfur, S 0.015
Boron, B 0.012
Iron, Fe Balance

Physical Properties

The following table shows the physical properties of Pyromet CTX-3 alloy.

Properties Metric Imperial
Density 8.28 g/cm3 0.299 lb/in3
Melting point 1385°C 2525°F

Mechanical Properties

The mechanical properties of Pyromet CTX-3 alloy are displayed in the following table.

Properties Metric Imperial
Tensile strength 1180 MPa 171000 psi
Yield strength 830 MPa 120000 psi
Elongation at break 14% 14%

Thermal Properties

The thermal properties of Pyromet CTX-3 alloy are given in the following table.

Properties Metric Imperial
Thermal expansion co-efficient (@25-416°C/77-781°F) 7.50 µm/m°C 4.17 µin/in°F

Fabrication and Heat Treatment

Machinability

Pyromet CTX-3 alloy can be machined using conventional techniques used for iron-based alloys.

Forming

The alloy has good formability, and can be formed using all conventional methods.

Welding

Pyromet CTX-3 alloy can be welded using common welding methods such as gas-tungsten arc welding, shielded metal arc welding and submerged arc welding.

Heat Treatment

Pyromet CTX-3 alloy can be solution annealed at 982°C (1800°F) and air cooled.

Forging

Forging is carried out in the temperature range of 927 to 1149°C (1700 to 2100°F).

Hot Working

Hot working of Pyromet CTX-3 alloy is carried out at 899 to1149°C (1650 to 2100°F).

Cold Working

The alloy is cold formed using standard tooling.

Annealing

The alloy is annealed at 982°C (1800°F) and air cooled.

Applications

The following are the list of applications of Pyromet CTX-3 alloy:

  • Glass to metal sealing
  • Gas turbine seals
  • Casings
  • Other hot section structural parts.

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