Nov 15 2012
Topics Covered
IntroductionChemical CompositionPhysical PropertiesMechanical PropertiesOther DesignationsFabrication and Heat Treatment Annealing Cold Working Welding Forming Hardening Heat Treatment AgingApplications
Introduction
Super alloys or high performance alloys are of three types namely iron-based, cobalt-based and nickel-based alloys. These alloys can be strengthened by precipitation hardening, solid-solution hardening and work hardening methods.
Super alloys contain good oxidation and creep resistance and are available in varied shapes. These alloys can function under high mechanical stress and high temperatures and also in places that require high surface stability.
Super alloy 35N is a cobalt-nickel-chromium alloy. This alloy is age-hardenable and also contains molybdenum that makes it corrosion resistant. Very high strength can be obtained when a combination of aging and cold-working processes are performed on this alloy.
The following datasheet provides an overview of super alloy 35N.
Chemical Composition
The chemical composition of super alloy 35N is outlined in the following table.
| Element |
Content (%) |
| Cobalt, Co |
35 |
| Nickel, Ni |
35 |
| Chromium, Cr |
20 |
| Molybdenum, Mo |
9.80 |
| Carbon, C |
0.013 |
Physical Properties
The following table shows the physical properties of super alloy 35N.
| Properties |
Metric |
Imperial |
| Density |
8.41 g/cm3 |
0.304 lb/in3 |
| Melting point |
1416°C |
2580°F |
Mechanical Properties
The mechanical properties of super alloy 35N are displayed in the following table.
| Properties |
Metric |
Imperial |
| Tensile strength |
897 MPa |
130000 psi |
| Yield strength (@strain 0.200 %) |
517 MPa |
75000 psi |
| Elongation at break |
30% |
30% |
| Reduction of area |
35% |
35% |
| Hardness, Brinell (estimated from Rockwell C value for Brinell test with 3000 kg load/10 mm diameter ball) |
278 |
278 |
| Hardness, Knoop (estimated from Rockwell C value) |
301 |
301 |
| Hardness, Rockwell C |
28 |
28 |
| Hardness, Vickers (estimated from Rockwell C value) |
292 |
292 |
Other Designations
Equivalent materials to super alloy 35N are provided below:
- AMS 5758
- AMS 5844
- AMS 5845
- SPS M646
Fabrication and Heat Treatment
Annealing
Super alloy 35N can be annealed at 1066°C (1950°F) followed by cooling in a rapid manner.
Cold Working
Super alloy 35N has good ductility and can thus be cold formed by conventional cold working methods.
Welding
Super alloy 35N is capable of being welded using TIG method. Welding in the annealed state and low heat inputs provide good welding results for this alloy.
Forming
The high work hardening rate of super alloy 35N will reduce ductility during the forming process.
Hardening
Cold working and aging result in hardening of super alloy 35N.
Heat Treatment
Super alloy 35N is annealed at 1066°C (1950°F) followed by rapid air cooling. Age-hardening of this alloy takes place for 4 h at 566°C (1050°F) followed by air cooling.
Aging
Super alloy 35N is capable of being age-hardened.
Applications
Super alloy 35N is suitable for use in seawater applications, oil and gas well components containing hydrogen sulfide, and chemical process equipment.