Jul 24 2013
Topics Covered
Introduction
Chemical Composition
Physical Properties
Thermal Properties
Other Designations
Fabrication and Heat Treatment
Machinability
Forming
Welding
Hot Working
Forging
Cold Working
Annealing
Hardening
Applications
Introduction
Super alloy Nicrofer 5120 CoTi is a nickel-cobalt-chromium alloy also containing molybdenum to provide heat strength. It is age-hardenable and has relatively easy forming characteristics with good high temperature performance.
It is a precipitation-hardening creep-resisting alloy. This alloy can be used in operations of up to 850°C (1562°F), and provides excellent oxidation and scaling resistance up to 1000°C (1832°F).
Super alloy Nicrofer 5120 CoTi is designed with good mechanical properties and good weldability without causing post-weld heat treatment cracking. The following sections will discuss in detail about super alloy Nicrofer 5120 CoTi.
Chemical Composition
The chemical composition of Nicrofer 5120 CoTi is outlined in the following table.
|
Element |
Content (%) |
|
Chromium, Cr |
21 |
|
Cobalt, Co |
21 |
|
Molybdenum, Mo |
6.1 |
|
Titanium, Ti |
2.8 |
|
Iron, Fe |
0.7 |
|
Manganese, Mn |
0.6 |
|
Aluminum, Al |
0.6 |
|
Silicon, Si |
0.4 |
|
Copper, Cu |
0.2 |
|
Carbon, C |
0.08 |
|
Phosphorus, P |
0.015 |
|
Sulfur, S |
0.007 |
|
Boron, B |
0.005 |
|
Nickel, Ni |
Remainder |
Physical Properties
The physical properties of Nicrofer 5120 CoTi are tabulated below.
|
Properties |
Metric |
Imperial |
|
Density |
8.35 g/cm3 |
0.302 lb/in3 |
|
Melting point |
1326°C |
2420°F |
Thermal Properties
The thermal properties of Nicrofer 5120 CoTi are tabulated below.
|
Properties |
Metric |
Imperial |
|
Thermal conductivity (@0°C/32°F) |
11.6 W/mK |
81 BTU in/hr.ft².°F |
Other Designations
Equivalent materials to Nicrofer 5120 CoTi are AMS 5872 and GE B50A774.
Fabrication and Heat Treatment
Machinability
Super alloy Nicrofer 5120 CoTi can be machined using the common processes applied to iron based alloys. This alloy does work-harden during machining and displays higher strength and "gumminess" unlike steels. It is recommended that heavy duty machining equipment and tooling should be used to reduce chatter or work-hardening of the alloy.
High quality water-based coolants should be used during the machining operations. Carbide tools and high-speed tools can be used for the machining operations.
Forming
Super alloy Nicrofer 5120 CoTi can be formed using any of the conventional methods.
Welding
Welding of super alloy Nicrofer 5120 CoTi can be performed using all the traditional welding methods. Matching alloy filler metal should be used. In case that is not available, it is advised that the nearest alloy closest to the chemical composition be used.
Hot Working
Hot working can be performed in the temperature range of 1149-954°C (2100-1750°F).
Forging
Forging can be performed at temperatures in the range of 1149-926°C (2100-1700°F).
Cold Working
Nicrofer 5120 CoTi can be cold formed using all the standard tools.
Annealing
Nicrofer 5120 CoTi can be annealed at 1149°C (2100°F) and rapidly air cooled and water quenched.
Hardening
Super alloy Nicrofer 5120 CoTi hardens by cold working and aging heat treatment.
Applications
Nicrofer 5120 CoTi is mainly used in high-temperature services as listed below:
-
Aircraft and industrial gas turbines
-
Combustion chambers
-
Exhaust cones and rings.