Dec 14 2012
Topics Covered
IntroductionChemical CompositionPhysical PropertiesMechanical PropertiesFabrication and Heat Treatment Annealing Cold Working Welding Forging Forming Machinability Aging Heat TreatmentApplications
Introduction
Super alloys or high performance alloys include iron-based, cobalt-based and nickel-based alloys. These alloys have 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.
Udimet 520™ is a nickel-chromium-cobalt alloy. Addition of tungsten and molybdenum result in age-hardening and strengthening of this alloy.
The following datasheet provides an overview of Udimet 520™.
Chemical Composition
The chemical composition of Udimet 520™ is outlined in the following table.
| Element |
Content (%) |
| Nickel, Ni |
52.18-59.976 |
| Chromium, Cr |
18.0-20.0 |
| Cobalt, Co |
11.0-14.0 |
| Molybdenum, Mo |
5.50-7.00 |
| Titanium, Ti |
2.90-3.25 |
| Aluminum, Al |
1.80-2.30 |
| Tungsten, W |
0.800-1.20 |
| Carbon, C |
0.0200-0.0600 |
| Boron, B |
0.00400-0.0100 |
Physical Properties
The following table shows the physical properties of Udimet 520™.
| Properties |
Metric |
Imperial |
| Density |
8.21 g/cm³ |
0.297 lb/in³ |
| Melting point |
1371°C |
2500°F |
Mechanical Properties
The mechanical properties of Udimet 520™ are displayed in the following table.
| Properties |
Metric |
Imperial |
| Tensile strength (@950°C/1740°F) |
350 MPa |
50800 psi |
| Yield strength (@strain 0.200%, temperature 850°C/@strain 0.200%, temperature 1560°F) |
500 MPa |
72500 psi |
| Elongation at break (@50°C/122°F) |
100% |
100% |
Fabrication and Heat Treatment
Annealing
Udimet 520™ is annealed at 1107°C (2025°F) and then cooled in air rapidly.
Cold Working
Standard cooling methods are used for cold forming Udimet 520™. Minimization of galling is possible with the usage of heavy duty lubricants and soft die materials though the die life is limited. Tooling is recommended in the cold working process to allow liberal radii and clearances.
Welding
Welding processes recommended for Udimet 520™ include gas-tungsten arc welding, gas metal-arc welding and shielded metal-arc welding. This alloy can be welded by the commonly used welding procedures, and the welding surfaces should be free from paint, crayon markings or oil.
Forging
Udimet 520™ is capable of being forged as it is ductile.
Forming
Conventional methods can be used to form Udimet 520™ with ease as it has good ductility. To obtain good forming results, a powerful equipment is used along with heavy- prevent embrittlement of this alloy at high temperatures.
Machinability
Udimet 520™ can be machined by conventional machining methods. and tThis alloy contains higher strength, gumminess and work-hardening qualities. Usage of water-based coolants is preferred for milling, turning or grinding. Usage of heavy lubricants is preferred for boring, drilling, broaching or tapping operations. Work-hardening of the alloy before the cutting process and chatter can be minimized by tooling and a heavy duty machining equipment.
Aging
Udimet 520™ is treated at three different temperatures to be air-hardened.
- Heat for 4 h at 1107°C (2025°F) and cool in air.
- Heat for 24 h at 843°C (1550°F) and cool in air.
- Heat for 16 h at 760°C (1400°F) and cool in air.
Heat Treatment
Udimet 520™ can be hardened when heat treated.
Applications
Udimet 520™ is used in gas turbine hot section components and industrial applications that need hot high heat strength with good quality.