Material Comparison
Compare verified engineering materials side by side with condition-specific mechanical properties.
| Parameter | Fine Silver 999 | Sterling Silver 925 |
|---|---|---|
| Material Family | Silver & Silver Alloys | Silver & Silver Alloys |
| Subfamily | Fine Silver | Sterling Silver |
| UNS Designation | P07010 | P07925 |
| ISO Designation | Ag99.9 | Ag925 |
| ASTM Designation | Grade 99.90 | B742 Grade 92.5 |
| DIN Designation | Ag99.9 | Ag925 |
| W-Nr Designation | 2.1211 | 2.1213 |
| UK-HALLMARK Designation | 999 | 925 |
| SPECIFICATION Designation | ASTM B742 Standard Specification for Fine Silver Contact Material | ASTM B742 Standard Specification for Fine Silver Contact Material (Grade 92.5) |
| Element | Fine Silver 999 | Sterling Silver 925 |
|---|---|---|
| Ag (Silver) | ≥ 99.9% | ≥ 92.5% |
| Cu (Copper) | ≤ 0.08% | 7.2 – 7.5% |
| Fe (Iron) | ≤ 0.01% | — |
| Pb (Lead) | ≤ 0.015% | — |
| Bi (Bismuth) | ≤ 0.005% | — |
| Property | Fine Silver 999 | Sterling Silver 925 |
|---|---|---|
| Density · TYPICAL · 20 °CUnit: g/cm³ | 10.49 g/cm³ | 10.36 g/cm³ |
| Mechanical Parameter | Fine Silver 999Annealed (Soft) | Sterling Silver 925Annealed (O Temper) |
|---|---|---|
| Modulus of Elasticity · TYPICALUnit: GPa | 76 GPa | 82 GPa |
| Poisson's Ratio · TYPICALUnit: dimensionless | 0.37 dimensionless | 0.36 dimensionless |
| Yield Strength (0.2% Offset) · Strip, Sheet, Wire, Bar · Annealed (Soft) · TYPICALUnit: MPa | ≥ 40 MPa | — MPa |
| Yield Strength (0.2% Offset) · Strip, Sheet, Wire · Annealed (O Temper) · TYPICALUnit: MPa | — MPa | ≥ 125 MPa |
| Ultimate Tensile Strength · Strip, Sheet, Wire, Bar · Annealed (Soft) · TYPICALUnit: MPa | ≥ 125 MPa | — MPa |
| Ultimate Tensile Strength · Strip, Sheet, Wire · Annealed (O Temper) · TYPICALUnit: MPa | — MPa | ≥ 220 MPa |
| Elongation at Break · Strip, Sheet, Wire, Bar · in 50 mm (2 in) · Annealed (Soft) · TYPICALUnit: % | ≥ 40 % | — % |
| Elongation at Break · Strip, Sheet, Wire · in 50 mm (2 in) · Annealed (O Temper) · TYPICALUnit: % | — % | ≥ 28 % |
| Property | Fine Silver 999 | Sterling Silver 925 |
|---|---|---|
| Electrical Conductivity · TYPICAL · 20 °CCategory: ELECTRICAL • Unit: % IACS | 106 % IACS | 84 % IACS |
| Electrical Resistivity · TYPICAL · 20 °CCategory: ELECTRICAL • Unit: nΩ·m | 15.9 nΩ·m | 20.5 nΩ·m |
| Thermal Conductivity · TYPICAL · 20 °CCategory: THERMAL • Unit: W/(m·K) | 429 W/(m·K) | 410 W/(m·K) |
| Melting Point · TYPICALCategory: THERMAL • Unit: °C | 962 °C | — °C |
| Melting Range (Solidus-Liquidus) · RANGECategory: THERMAL • Unit: °C | — °C | 779–893 °C |
| Specific Heat Capacity · TYPICAL · 20 °CCategory: THERMAL • Unit: J/(kg·K) | 235 J/(kg·K) | — J/(kg·K) |
| Hardness Scale | Fine Silver 999 | Sterling Silver 925 |
|---|---|---|
| HV Hardness · Annealed (Soft) · TYPICAL | 25–35 HV | 62–78 HV |
Machinability: Rated at approximately 30% relative to free-cutting brass (C36000). Highly ductile and gummy; produces long continuous chips. Requires sharp high-rake carbide or diamond tooling, light feed rates, and continuous flood coolant to prevent tearing and galling.
Weldability: Weldable with gas tungsten arc (GTAW/TIG) and resistance welding; requires significant preheat and higher heat input due to extremely high thermal diffusivity (1.74 cm²/s). Readily brazed with silver-bearing fluxed fillers.
Formability / Cold Working: Exceptional cold workability. Capable of severe deep drawing, spinning, wire drawing down to micro-diameters, and cold swaging without intermediate annealing.
Heat Treatment & Annealing: Full recrystallization annealing occurs between 200°C and 300°C (392°F to 572°F) for 30 minutes, followed by rapid water quench or air cooling to preserve soft annealed ductility.
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.