Nov 29 2012
Topics Covered
IntroductionChemical CompositionPhysical PropertiesMechanical PropertiesThermal PropertiesFabrication and Heat Treatment Cold Working Welding Forming MachinabilityApplications
Introduction
Super alloys or high performance alloys include iron-based, cobalt-based and nickel-based alloys. These alloys contain good oxidation and creep resistance and are available in different shapes.
Super alloys can be strengthened by precipitation hardening, solid-solution hardening and work hardening methods. These alloys can function under high mechanical stress and high temperatures and also in places that require high surface stability.
Nimonic 86™ is a nickel-chromium-molybdenum alloy comprising good weldability, hot creep strength and ductility.
The following datasheet provides an overview of Nimonic 86™.
Chemical Composition
The chemical composition of Nimonic 86™ is outlined in the following table.
| Element |
Content (%) |
| Nickel, Ni |
65 |
| Chromium, Cr |
25 |
| Molybdenum, Mo |
10 |
| Carbon, C |
0.050 |
| Cerium, Ce |
0.030 |
Physical Properties
The following table shows the physical properties of Nimonic 86™.
| Properties |
Metric |
Imperial |
| Density |
8.54 g/cm³ |
0.309 lb/in³ |
| Melting point |
1357°C |
2475°F |
Mechanical Properties
The mechanical properties of Nimonic 86™ are displayed in the following table.
| Properties |
Metric |
Imperial |
| Tensile strength (solution annealed, value at room temperature) |
825 MPa |
120000 psi |
| Yield strength (solution annealed, value at room temperature, @strain 0.200%) |
410 MPa |
59500 psi |
| Elastic modulus
| 210 GPa
| 30500 ksi |
| Elongation at break (solution annealed) |
42% |
42% |
Thermal Properties
The thermal properties of Nimonic 86™ are given in the following table.
| Properties |
Metric |
Imperial |
| Thermal expansion co-efficient (@20-100°C/68-212°F) |
12.7 µm/m°C |
7.06 µin/in°F |
Fabrication and Heat Treatment
Cold Working
Standard tooling methods are used for cold working Nimonic 86™. Usage of plain carbon steels is not recommended as they may produce galling. However, galling can be reduced by the usage of soft die materials and heavy duty lubricants.
Welding
Welding techniques recommended for Nimonic 86™ include gas-tungsten arc welding, gas metal-arc welding, submerged-arc welding and shielded metal-arc welding. Usage of a matching alloy filler metal is recommended for the welding process, and an alloy rich in Ni, Co, Cr, Mo is used during the absence of a matching filler metal.
Forming
Conventional methods and heavy-duty lubricants have to be used for the forming process of Nimonic 86™ due to its good ductility. Powerful equipment is recommended for this alloy as it is stronger than the commonly available steels.
Machinability
Nimonic 86™ is machined by conventional machining methods. This alloy has higher levels of gunniness and strength, and is work-hardened during the machining process. Tooling and usage of a heavy duty machining equipment during the machining process enables minimizing work-hardening or chatter of this alloy before the cutting process. Heavy lubricants are suitable for boring, tapping, drilling or broaching, and coolants that are water-based are recommended for high-speed operations like milling, grinding or turning.
Applications
Nimonic 86™ is used in industrial furnaces and gas turbine components in the hot section.