Material Comparison
Compare verified engineering materials side by side with condition-specific mechanical properties.
| Parameter | Britannia Silver 958 | Sterling Silver 925 |
|---|---|---|
| Material Family | Silver & Silver Alloys | Silver & Silver Alloys |
| Subfamily | Alloyed Silver | Sterling Silver |
| UK-HALLMARK Designation | 958 | 925 |
| ISO Designation | Ag958 | Ag925 |
| DIN Designation | Ag958 | Ag925 |
| EN Designation | AgCu4.2 | — |
| SPECIFICATION Designation | British Hallmarking Act 1973 Schedule 2 Standards of Fineness | ASTM B742 Standard Specification for Fine Silver Contact Material (Grade 92.5) |
| UNS Designation | — | P07925 |
| ASTM Designation | — | B742 Grade 92.5 |
| W-Nr Designation | — | 2.1213 |
| Element | Britannia Silver 958 | Sterling Silver 925 |
|---|---|---|
| Ag (Silver) | ≥ 95.84% | ≥ 92.5% |
| Cu (Copper) | 4 – 4.16% | 7.2 – 7.5% |
| Property | Britannia Silver 958 | Sterling Silver 925 |
|---|---|---|
| Density · TYPICAL · 20 °CUnit: g/cm³ | 10.4 g/cm³ | 10.36 g/cm³ |
| Mechanical Parameter | Britannia Silver 958Annealed (Soft) | Sterling Silver 925Annealed (O Temper) |
|---|---|---|
| Modulus of Elasticity · TYPICALUnit: GPa | 78 GPa | 82 GPa |
| Yield Strength (0.2% Offset) · Strip, Sheet, Wire · Annealed (Soft) · TYPICALUnit: MPa | ≥ 80 MPa | — MPa |
| Yield Strength (0.2% Offset) · Strip, Sheet, Wire · Annealed (O Temper) · TYPICALUnit: MPa | — MPa | ≥ 125 MPa |
| Ultimate Tensile Strength · Strip, Sheet, Wire · Annealed (Soft) · TYPICALUnit: MPa | ≥ 185 MPa | — MPa |
| Ultimate Tensile Strength · Strip, Sheet, Wire · Annealed (O Temper) · TYPICALUnit: MPa | — MPa | ≥ 220 MPa |
| Elongation at Break · Strip, Sheet, Wire · Annealed (Soft) · TYPICALUnit: % | ≥ 35 % | — % |
| Elongation at Break · Strip, Sheet, Wire · in 50 mm (2 in) · Annealed (O Temper) · TYPICALUnit: % | — % | ≥ 28 % |
| Poisson's Ratio · TYPICALUnit: dimensionless | — dimensionless | 0.36 dimensionless |
| Property | Britannia Silver 958 | Sterling Silver 925 |
|---|---|---|
| Electrical Conductivity · TYPICAL · 20 °CCategory: ELECTRICAL • Unit: % IACS | 92 % IACS | 84 % IACS |
| Electrical Resistivity · TYPICAL · 20 °CCategory: ELECTRICAL • Unit: nΩ·m | — nΩ·m | 20.5 nΩ·m |
| Thermal Conductivity · TYPICAL · 20 °CCategory: THERMAL • Unit: W/(m·K) | 420 W/(m·K) | 410 W/(m·K) |
| Melting Range (Solidus-Liquidus) · RANGECategory: THERMAL • Unit: °C | 870–940 °C | 779–893 °C |
| Hardness Scale | Britannia Silver 958 | Sterling Silver 925 |
|---|---|---|
| HV Hardness · Annealed (Soft) · TYPICAL | 48–62 HV | 62–78 HV |
Machinability: Rated at approximately 35% relative to C36000. Softer and more ductile than sterling silver; tends to form continuous chips requiring chip-breaker tool geometries.
Weldability: Readily brazed using silver-bearing filler metals. Less prone to deep firescale oxidation than sterling silver due to lower copper fraction.
Formability / Cold Working: Superb spinning and deep drawing performance; requires fewer intermediate annealing steps than 925 sterling.
Heat Treatment & Annealing: Annealed at 450°C to 550°C for 20 minutes, followed by water quench. Demonstrates minor precipitation hardening capability due to copper supersaturation.
Machinability: Rated at approximately 45% relative to C36000. Chips shear more cleanly than fine silver; tool life is good when using positive rake carbide inserts and flood oil/emulsion coolant.
Weldability: Readily brazed using silver solder (AWS BAg-1 to BAg-7). Subject to firescale (subsurface cuprous oxide Cu2O formation) when heated in oxidizing atmospheres without flux.
Formability / Cold Working: Excellent cold working characteristics; readily stamped, coined, and rolled with periodic annealing at 600°C.
Heat Treatment & Annealing: Precipitation hardenable: Solution heat treat at 740°C to 760°C for 15-30 minutes and rapid water quench; artificial age at 280°C to 300°C for 45-60 minutes to achieve peak hardness of 110-140 HV.