Beryllium Copper Alloy B25 UNS-C17200
Chemical Composition
(% maximum, unless shown as range or minimum)
| Copper(1) | Aluminium | Beryllium | Cobalt(2) | Silicon |
|
| Min / Max | Remainder | 0.20 | 1.80 – 2.00 | 0.20 min | 0.20 |
| Nominal | 98.1 | – | 1.90 | – | – |
(1) Copper value includes Silver
(2) Ni + Co, 20% min: Ni + Fe + Co, 0.6% max Ni +
Note: Copper + Sum of Named Elements, 99.5% min)
Applicable Specifications
| Product | Specification |
| AMS | ASTM | MILITARY | SAE |
| Bar | 4533, 4650, 4651 | B194, B196 | MIL-C-21657 | J461, J463 |
| Extrusions |
| B570 |
|
|
| Forgings | 4650 | B570 |
|
|
| Plate |
| B194 |
|
|
| Rod | 4533, 4651, 4534, 4650 | B196 | MIL-C-21657 | J461, J463 |
| Rod, Forging | 4650 |
|
|
|
| Sheet |
| B194 |
|
|
| Strip |
| B194 |
| J461, J463 |
| Tube, Seamless | 4535 | B643 |
|
|
| Wire | 4725 | B197 |
| J461, J463 |
Common Fabrication Processes
Blanking, Drawing, Drilling, Forming and Bending, Tapping, Turning
Fabrication Properties
| Joining Technique | Suitability |
| Soldering | Good |
| Brazing | Good |
| Oxy-Acetylene Welding | Not Recommended |
| Gas Shielded Arc Welding | Good |
| Coated Metal Arc Welding | Good |
| Forgeability Rating | 40 |
| Joining Technique | Suitability |
| Spot Weld | Good |
| Seam Weld | Fair |
| Butt Weld | Fair |
| Capacity for Being Cold Worked | Good |
| Capacity for Being Hot Formed | Excellent |
| Machinability Rating | 20 |
Mechanical Properties
Typical Room Temperature 20°C
| Temper | Former Temper | Section Size | Yield Strength(0.2% offset) | Tensile Strength | Elongation | Rockwell Hardness | Vickers Hardness(approx) | Fatigue Strength@ 108 cycles |
|
| mm | MPa | MPa | % | B | C | F | 30T |
| MPa |
| TB00 | SHT | All | 221 | 483 | 45 | 60 | – | – | 58 | 108 | – |
| TD01 | 1/4 Hard | 4.78 | 483 | 552 | 25 | 80 | – | – | 70 | 151 | – |
| TD02 | 1/2 Hard | 4.78 | 565 | 634 | 15 | 92 | – | – | 77 | 198 | – |
| TD04 | Hard | 4.78 | 717 | 758 | 5 | 99 | – | – | 81 | 240 | – |
| TF00 | Precipitation Hardened | 4.78 | 1,069 | 1,207 | 6 | – | 38 | – | – | 362 | 248 |
| TH01 | 1/4 Hard + PHT | 4.78 | 1,138 | 1,276 | 4 | – | 41 | – | – | 382 | 276 |
| TH02 | 1/2 Hard + PHT | 4.78 | 1,207 | 1,344 | 3 | – | 41 | – | – | 393 | 303 |
| TH04 | Hard + PHT | 4.78 | 1,241 | 1,379 | 2 | – | 42 | – | – | 404 | 307 |
| TM00 | Mill Hardened | 4.78 | 565 | 724 | 20 | – | 27 | – | – | 275 | – |
| TM01 | 1/4 Hard (mill) | 4.78 | 634 | 793 | 17 | – | 23 | – | – | 250 | – |
| TM02 | 1/2 Hard (mill) | 4.78 | 724 | 883 | 15 | – | 27 | – | – | 275 | – |
| TM04 | Hard (mill) | 4.78 | 841 | 979 | 12 | – | 32 | – | – | 309 | – |
| TM06 | Extra Hard (mill) | 4.78 | 1,020 | 1,158 | 7 | – | 37 | – | – | 353 | – |
| TM08 | Spring Hard (mill) | 4.78 | 1,103 | 1,255 | 6 | – | – | – | – | – | – |
| TB00 | Annealed |
| 138 | 496 | 20 | 65 | – | – | – | 117 | – |
| TD04 | SHT & Cold Worked: Hard (H) | 9.53 | 517 | 758 | 8 | 95 | – | – | – | 214 | – |
| TD04 | 25.4 | 517 | 745 | 8 | 95 | – | – | – | 214 | – |
| TD04 | 76.2 | 517 | 710 | 8 | 94 | – | – | – | 209 | – |
| TF00 | SHT & Precipitation Hardened | 76.2 | 896 | 1,255 | 3 | – | – | – | – |
| – |
| TF00 | All | 1000 | 1,255 | 4 | – | – | – | – |
| – |
| TH04 | SHT, Cold Worked, PHT: Hard (H) | 9.53 | 2,172 | 2,792 | 4 | – | – | – | – |
| – |
| TH04 | 76.2 | 1000 | 1,344 | 4 | – | – | – | – |
| – |
| TB00 | SHT |
| 193 | 469 | 35 | – | – | – | – |
| – |
| TD01 | SHT & Cold Worked: 1/4 Hard |
| 565 | 703 | 10 | – | – | – | – |
| – |
| TD02 | SHT & Cold Worked: 1/2 Hard |
| 689 | 841 | 5 | – | – | – | – |
| – |
| TD03 | SHT & Cold Worked: 3/4 Hard |
| 827 | 979 | 2 | – | – | – | – |
| – |
| TD04 | SHT & Cold Worked: Hard |
| 862 | 1,048 | 1 | – | – | – | – |
| – |
| TF00 | Precipitation Hardened |
| 1,103 | 1,227 | 3 | – | – | – | – |
| – |
| TH01 | 1/4 Hard & PHT (1/4HT) |
| 1,207 | 1,310 | 2 | – | – | – | – |
| – |
| TH02 | 1/2 Hard & PHT (1/2HT) |
| 1,276 | 1,379 | 1 | – | – | – | – |
| – |
| TH03 | 3/4 Hard & PHT (3/4HT) |
| 1,310 | 1,448 | 1 | – | – | – | – |
| – |
| TH04 | Hard & PHT (HT) |
| 1,344 | 1,462 | 1 | – | – | – | – |
| – |
PHT = Precipitation Heat Treated
SHT = Solution Heat Treated
Physical Properties
| Property | Metric Units | Imperial Units |
| Melting Point (Liquidus) | 982°C | 1800°F |
| Melting Point (Solidus) | 866°C | 1590°F |
| Density | 8.25 gm/cm³ @ 20°C | 0.298 lb/in³ @ 68°F |
| Specific Gravity | 8.26 | 8.26 |
| Coefficient of Thermal Expansion | 17.8 x 10 -6 / °C (20-300°C) | 9.9 x 10 -6 / °F (68-392°F) |
| Themal Conductivity * | 107.3 W/m. °K @ 20°C | 62.0 BTU/ft²/ft/hr/°F @ 68°F |
| Thermal Capacity (Specific Heat) | 418.64 J/kg. °K @ 293°K | 0.1 BTU/lb/°F @ 68°F |
| Electrical Resistivity | 7.68 microhm.cm @ 20°C | 46.2 ohms (circ mil/ft) @ 68°F |
| Electrical Conductivity** | 0.129 MegaSiemens/cm @ 20°C | 22% IACS@ 68°F |
| Modulus of Elasticity (tension) | 128,000 MPa | 18,500ksi |
| Modulus of Rigidity (shear) | 50,330 MPa | 7,300 ksi |
Actual value is 62-75
In the Precipitation Hardened Condition
Tempers Most Commonly Used
| Flat Products |
| Bar, Drawn | H02, O60 |
| Bar, Rolled | H02, O60 |
| Plate | O60 |
| Strip, Rolled | H01, H02, H03, H04, H10, O60 |
| Other Products |
| Rod | H04, O60 |
| Shapes | O60 |
| Tube | H58, O60 |
| Wire | H01, H02, H03, H04, O60 |
Typical Uses
Electrical – Electrical Switch and Relay Blades, Contact Bridges, Clips, Spring Connectors, Current Carrying, Relay Parts, Switch Parts, Fuse Clips, Navigational Instruments, Connectors, Belleville Washers
Fasteners – Bolts, Screws, Fasteners, Washers, Lock Washers, Roll Pins, Retaining Rings
Industrial – Diaphragms, Valve Stems, Flexible Metal Hose, Shafts, Springs, Electrochemical, Bourdon Tubes, Bellows, Wear Plates on Heavy Equipment, Springs, Welding Equipment, Rolling Mill Parts, Spline Shafts, Pump Parts, Valves, Pumps, Non Sparking Safety Tools, Valve Seats, Housings for Instruments, Bushings, Bearings