Copper and copper alloys · Alloy 25 / C17200
Engineering Reference for Beryllium Copper Alloy 25 (UNS C17200)
Engineering Analysis of Alloy 25 (UNS C17200)
UNS C17200 alloy, also known by the trade name Alloy 25, is a benchmark representative of the class of precipitation-hardening copper-beryllium alloys. Its uniqueness lies in the synergy of mechanical properties, reaching the level of alloyed steels (high strength and hardness), with the inherent physical characteristics of copper: high thermal and electrical conductivity, as well as excellent corrosion resistance. EV Group China technologists confirm its indispensability for manufacturing critical components operating under extreme mechanical stresses and in corrosive environments.
| Forms of Supply | International Designations | Alloy Classification | Standards and Specifications | Equivalent Grades (Analogs) | ||
|---|---|---|---|---|---|---|
| Forms of Supply | International Designations | Alloy Classification | ASTM | ASME | W.Nr. | EN |
| Bars, Plates, Strips | Alloy 25, UNS C17200, CDA172 | High-Strength Copper-Beryllium Alloy | B194, B196, B197, B570, B643, B888 | SB194, SB196, SB570, SB888 | 2.1247 | CW101C, CuBe2 |
Chemical Composition of C17200 Alloy according to Specifications (%)
Precise control of the chemical composition is a key factor for achieving the specified mechanical and physical properties of EV Group China products. The content of alloying elements is strictly regulated.
| Al (Aluminum) | <0.2 |
|---|---|
| Be (Beryllium) | 1.8-2.0 |
| Co (Cobalt) | <0.2 |
| Si (Silicon) | <0.2 |
| Cu (Copper) | Balance |
| Impurities (total) | <0.5 |
Engineering Note: Copper (Cu) concentration is defined as the sum of Cu + Ag. The total Co+Ni content must be at least 0.2%, while the sum of Co+Fe+Ni must not exceed 0.6%.
Mechanical Characteristics of Alloy C17200 in Various Supply Conditions
The table presents the minimum guaranteed values of mechanical properties, determined according to ASTM B194. These parameters directly depend on the material's condition, which is achieved through various heat treatment and cold deformation regimes.
| Parameters according to ASTM B194 | Condition of Supply (Temper) | Code | TF00 | TF01 | TH02 | TH04 | TH05 | TH06 | TH08 |
|---|---|---|---|---|---|---|---|---|---|
| Parameters according to ASTM B194 | Condition of Supply (Temper) | Form | AM | 1/4 HM | 1/2 HM | HM | SHM | XHM | XHMS |
| Parameters according to ASTM B194 | Ultimate Tensile Strength (UTS), MPa | 690-760 | 780-825 | 825-930 | 930-1035 | 1035-1105 | 1070-1205 | 1210-1310 | |
| Parameters according to ASTM B194 | Yield Strength (0.2% Yield Strength), MPa | 485-655 | 550-760 | 655-860 | 760-930 | 860-965 | 930-1170 | 1035-1240 | |
| Parameters according to ASTM B194 | Elongation, % (min.) | 16 | 15 | 12 | 9 | 9 | 4 | 3 | |
| Parameters according to ASTM B194 | Rockwell Hardness | Scale C | 95 | 20 | 23 | 28 | 31 | 32 | 33 |
| Parameters according to ASTM B194 | Rockwell Hardness | Scale 30N | 37 | 42 | 44 | 48 | 52 | 52 | 53 |
| Parameters according to ASTM B194 | Rockwell Hardness | Scale 15N | 67.5 | 70 | 72 | 75 | 75.5 | 76 | 76.5 |
Key Physical Properties of Alloy 25 (C17200)
The physical constants of the alloy are defining for its application in electrical engineering, heat exchange equipment, and components requiring dimensional stability under temperature changes.
| Melting Range (Solidus) | Density at 20°C (68°F) | Relative Density (Specific Gravity) | Electrical Conductivity at 20°C (relative to IACS) | Thermal Conductivity at 20°C (68°F) | Average CTE in the range 20–300°C (68–572 °F) | Specific Heat at 20°C (68°F) | Young's Modulus (Elasticity) | Shear Modulus |
|---|---|---|---|---|---|---|---|---|
| 1800°F (982°C) | 0.304 lb/in³ (8.41 g/cm³) | 8.26 | 22% | 62 BTU/ft·h·°F | 9.9 x 10⁻⁶ /°F | 0.1 BTU/lb/°F | 18500 ksi | 7300 ksi |