Ni-Span-C Alloy 902• • Trade name of Special Metals Group
UNS N09902
AWS 080
AWS 080
A precipitation hardenable Nickel-Iron-Chromium alloy having
outstanding controllable thermoelastic coefficient
characteristics and excellent strength and oxidation
resistance in high temperature atmospheres. The alloy
can be processed to have a constant modulus of elasticity at
temperatures ranging from -45oC to +65oC
(-50 to +150oF).
Applications include:
Springs in precise applications, such as watches and
weighing machines
| Approximate Chemical Composition | |
| Ni | 41-43.5% |
| Cr | 4.9-5.75% |
| Ti | 2.2-2.75% |
| Fe | 48% |
| DENSITY | 8.05 g/cm3 | 0.291 lb/in3 |
| MELTING POINT | 1480oC | 2700oF |
| COEFFICIENT OF EXPANSION | 7.6 µm/m °C ( 20 - 100°C) |
4.2 x 10-6 in/in
°F ( 70 - 212°F) |
| MODULUS OF RIGIDITY | 62-69 kN/m2 | 8993-10008 ksi |
| MODULUS OF ELASTICITY | 165-200 kN/m2 | 23932-29008 ksi |
| CONDITION OF SUPPLY | HEAT TREATMENT (AFTER FORMING) |
| Spring Temper For good all round properties: |
Age harden at 650°C (1200°F) for 2 hours and air cool. |
| For maximum stability: | Stress equalise at 400°C (750°F) for 2
hours and air cool and age harden at 650°C (1200°F) for 2 hours and air cool. |
| For min. hysterisis & low thermo elastic coefficient: | Stress equalise at 400°C (750°F) for 2 hours and air cool. |
(Very high precision applications will require each batch to be pilot tested to
determine
the specific heat treatment necessary to produce the required thermo elastic coefficient).
the specific heat treatment necessary to produce the required thermo elastic coefficient).
| CONDITION |
APPROX TENSILE STRENGTH |
APPROX SERVICE TEMPERATURE |
||||
| Annealed | 450-650 N/mm2 | 65-94 ksi | -45 to +65°C | -50 to 150°F | ||
| (for constant modulus applications) | ||||||
| Spring Tempered | 900-1100 N/mm2 | 131-159 ksi | -45 to +65°C | -50 to 150°F | ||
| (for constant modulus applications) | ||||||
| Spring Temper + Aged | 1300-1500 N/mm2 | 189-218 ksi | -45 to +65°C | -50 to 150°F | ||
| (for constant modulus applications) | ||||||
| STANDARDS |
| AMS 5255 |
