Ni-Span-C Alloy 902®

A precipitation hardenable Nickel-Iron-Chromium alloy having outstanding controllable thermoelastic coefficient characteristics and excellent oxidation resistance in high temperature atmospheres. The alloy can be processed to have a constant modulus of elasticity at temperatures ranging from -45 to +65oC (-50 to +150oF).

AMS 5225
AMS 5221
HS 261
UNS N09902
AWS 080
Outstanding controllable thermoelastic coefficient characteristics
Can be processed to have constant modulus of elasticity from from -45 to +65ºC (-50 to +150ºF)
Good for springs in watches and weighing equipment
Age hardenable
Springs in precise applications, such as watches and weighing machines
Specifications
AMS 5225
AMS 5221
HS 261
UNS N09902
AWS 080
Outstanding controllable thermoelastic coefficient characteristics
Can be processed to have constant modulus of elasticity from from -45 to +65ºC (-50 to +150ºF)
Good for springs in watches and weighing equipment
Age hardenable
Springs in precise applications, such as watches and weighing machines

Chemical Composition

Density

8.05 g/cm³ | 0.291 lb/in³

Melting Point

1480°C | 2700°F

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/mm² | 8993 – 10008 ksi

Modulus of Elasticity

165 – 200 kN/mm² | 23932 – 29008 ksi

Heat Treatment of Finished Parts

Condition as supplied by Alloy Wire Type Temperature Time (Hr) Cooling
°C °F
Spring Temper – For good all round properties Age Harden 650 1200 2 Air
Spring Temper – For max stability Stress Equalise
Age Harden
400
650
750
1200
2
2
Air
Air
Spring Temper – For minimum hysterisis & low thermoelastic coefficient Stress Equalise 400 750 2 Air

Properties

Condition Approx. tensile strength Approx. operating temperature
N/mm² ksi °C °F
Annealed 600 – 800 87 – 116 -45 to +65 -50 to +150
(for constant modulus applications)
Spring Tempered 900 – 1100 131 – 159 -45 to +65 -50 to +150
(for constant modulus applications)
Spring Temper + Aged 1300 – 1500 189 – 218 -45 to +65 -50 to +150
(for constant modulus applications)
The above tensile strength ranges are typical. If you require different please ask.

*Trade name of Special Metals Group

▲ Static applications