# 3J21

> Co-Ni-Cr-Mo high-elasticity alloy for precision springs, diaphragms and watch hairsprings.

3J21 is a cobalt-nickel-chromium-molybdenum elastic alloy combining high elastic limit, excellent fatigue resistance and non-magnetic behavior. It is used for precision instrument springs, pressure sensor diaphragms, watch hairsprings and elastic sensing elements where high elastic performance and long-term dimensional stability are required.

## Key features

- High elastic limit
- Excellent fatigue life
- Non-magnetic
- Corrosion resistant
- Long-term dimensional stability

## Applications

- Precision instrument hairsprings
- Pressure sensor diaphragms
- Elastic sensing elements
- Watch and chronometer springs
- Aerospace elastic components

## Standards

- GB/T 14986
- YB/T 5253