3J21 High-Elasticity Alloy Specification
Cobalt-Based Superalloy for Precision Elastic Components
Product Specification
| Standard | GB/T 15018 (China), ASTM B439 (USA), AMS 5770 (Aerospace) |
| Material Designation | 3J21 (Co-Cr-Ni-Mo), Phynox, UNS R30003 |
| Tolerance | h7-h11 (on request) |
| Melt Method | Vacuum Induction Melting (VIM) + Electroslag Remelting (ESR) |
| Available Forms & Sizes | Strip: 0.05-2.0mm thick (width ≤300mm) Wire: φ0.10mm – φ5.0mm Bar: 15-100mm diameter Custom profiles upon request |
Chemical Composition (wt%)
| Element | Min | Max |
| Cobalt (Co) | 39.0 | 41.0 |
| Chromium (Cr) | 19.0 | 21.0 |
| Nickel (Ni) | 14.0 | 16.0 |
| Molybdenum (Mo) | 6.5 | 7.5 |
| Manganese (Mn) | 1.7 | 2.3 |
| Carbon (C) | – | 0.03 |
| Cerium (Ce) | 0.10 | 0.15 |
| Iron (Fe) | Balance | |
| Impurity Control: P≤0.01%, S≤0.01%, Si≤0.6% | ||
Physical & Mechanical Properties
| Property | Value | Condition/Notes |
| Density | 8.4 g/cm³ | Room temperature |
| Melting Point | 1372-1405°C | |
| Elastic Modulus | 195-215 GPa | Maintains >95% at 300°C |
| Tensile Strength | 1400-1600 MPa | Peak-aged condition |
| Yield Strength | ≥1300 MPa | Aged condition |
| Elongation | 8-35% | Varies with processing condition |
| Fatigue Strength | ≥550 MPa | 10⁷ cycles |
| Thermal Expansion | 12×10⁻⁶/°C | 20-200°C |
Key Characteristics
- Non-magnetic properties
- Operating temperature range: -150°C to +400°C
- Excellent corrosion resistance in acids/alkalines/salts
- Hardness: 180-220 HV (as-processed)
- Electrical resistivity: 0.9-1.0 µΩ·m
- Oxidation resistance stable to 900°C
- Suitable for nuclear applications
Applications
- Aerospace: Fuel regulator diaphragms, solar wing deployment mechanisms
- Precision instruments: Optical focus mechanism springs, atomic clock components
- Medical devices: Artificial heart valve supports, minimally invasive surgical tools
- 5G technology: RF switch contacts, antenna components
- Nuclear energy: Control rod drive strips in reactors
- Industrial equipment: High-stress springs for valves and pumps
Special Processing Notes
- Recommended heat treatment: Solution annealing at 1100°C/1.5h (water quench) + aging at 700°C/2h + 600°C/4h
- Cold working reduction should not exceed 70% without intermediate annealing
- Surface polishing (Ra≤0.05μm) or PVD coating recommended for critical applications
- Store in dry environment to prevent surface oxidation
