Jan 2 2013
Topics Covered
IntroductionChemical CompositionPhysical PropertiesMechanical PropertiesThermal PropertiesFabrication and Heat Treatment Machinability Forming Welding Heat Treatment Forging Hot Working Cold Working AnnealingApplications
Introduction
Super alloys or high performance alloys have the ability to function at high temperatures and under mechanical stress. They have good creep and oxidation resistance, and are available in different forms. Solid-solution hardening, work hardening, and precipitation hardening are performed in order to enhance their strength. They are categorized into three groups such as cobalt-based, nickel-based, and iron-based super alloys.
Alumel™ is a high nickel alloy. The datasheet given below will discuss about Alumel™.
Chemical Composition
The chemical composition of Alumel™ is outlined in the following table.
| Elements |
Content (%) |
| Nickel, Ni |
95 |
| Aluminum, Al |
2 |
| Manganese, Mn |
2 |
Physical Properties
The physical properties of thermocouple wire type K – Std Alumel™ are given in the following table.
| Properties |
Metric |
Imperial |
| Density |
8.61 g/cm³ |
0.311 lb/in³ |
| Melting point |
1399°C |
2550°F |
Mechanical Properties
The following table shows the mechanical properties of Alumel™.
| Properties |
Metric |
Imperial |
| Tensile strength at break (annealed) |
586 MPa |
85000 psi |
| Tensile strength at break (stress relieved) |
1030 MPa |
150000 psi |
| Tensile strength at break (hard) |
1170 MPa |
170000 psi |
Thermal Properties
The thermal properties of Alumel™ are displayed in the following table.
| Properties |
Metric |
Imperial |
| Thermal expansion co-efficient (@ 20°C/68°F) |
12 µm/m°C |
6.67 µin/in°F |
| Thermal conductivity |
29.7 W/mK |
206 BTU in/hr.ft².°F |
Fabrication and Heat Treatment
Machinability
Alumel™ has good machinability.
Forming
Alumel™ has good formability.
Welding
Alumel™ can be welded using conventional methods.
Heat Treatment
Alumel™ is heat treated by annealing at 1066°C (1950°F) followed by cooling.
Forging
Alumel™ is forged at 1149°C (2100°F).
Hot Working
Alumel™ is hot worked at 705 to 1038°C (1300 to 1900°F).
Cold Working
Alumel™ has good cold working capacity.
Annealing
Alumel™ is annealed at 1066°C (1950°F) followed by cooling.
Applications
Alumel™ can be used with a chromel alloy to develop a thermocouple.