Precious Metal B631 Class C vs Silver 999
Precious Metal · grade comparison
Precious Metal B631 Class C and Silver 999 are both precious metal grades. B631 Class C is the stronger of the two: yield strength 420 MPa (60.9 ksi) against 55 MPa (7.98 ksi) for Silver 999, about 7.6 times as much; tensile strength follows at 550 MPa (79.8 ksi) vs 140 MPa (20.3 ksi). In exchange, Silver 999 is the more ductile: elongation 48% versus 1.2% for B631 Class C, and B631 Class C is harder (205 HB vs 25 HB). Silver 999 is lighter (10.49 g/cm³ vs 16.4 g/cm³ for B631 Class C) and B631 Class C is stiffer (260 GPa vs 76 GPa). On the shop floor, Silver 999 machines more easily (fair vs poor), Silver 999 welds better (good vs poor), and B631 Class C sits in a lower cost tier (high, $$$$) than Silver 999 (specialty, $$$$$).
B631 Class CChoose it when strength drives the design, or when the part sees heat.
Silver 999Choose it when the part is bent, formed or impact-loaded, or when weight is the constraint.
B631 Class C vs Silver 999: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all precious metal grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
How to read these bars
- One bar per material. A full bar is the highest value among all precious metal grades in the FabDigit library; each bar is drawn as a share of that.
- The better value (by the usual engineering direction) is in bold. Rows with no direction — density, thermal conductivity — have no bold.
- Values are typical room-temperature figures for the condition named on each card.
- Confirm against the certified mill or resin datasheet before design release.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Shear Modulus
Bulk Modulus
Poisson's Ratio
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Hardness, Brinell
Hardness, Vickers
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Physical
Density and transition temperatures.
Density
Melting Point (Solidus)
Liquidus Temperature
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Min Service Temperature
Latent Heat of Fusion
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Galvanic Potential (seawater, vs SCE)
Corrosion Resistance
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Brazeability / Solderability
Polishability
Castability
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Same in both: Typical Recycled Content 30%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
Strength versus weight
Yield strength against density for every precious metal grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
Manufacturing and finishing
| Capability | B631 Class C | Silver 999 |
|---|---|---|
| Default condition | — | O |
| Relative cost | $$$$ High | $$$$$ Specialty |
| Min. machined wall | — | — |
| Best machined surface | — | — |
B631 Class C vs Silver 999 — frequently asked
Is B631 Class C stronger than Silver 999?
Yes. B631 Class C has a typical yield strength of 420 MPa (60.9 ksi) against 55 MPa (7.98 ksi) for Silver 999 — about 7.6 times as much. Tensile strength is 550 MPa (79.8 ksi) vs 140 MPa (20.3 ksi).
Which is cheaper, B631 Class C or Silver 999?
B631 Class C is the lower-cost material: it sits in the high tier ($$$$) while Silver 999 is specialty ($$$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, B631 Class C or Silver 999?
Silver 999. Its machinability rates fair (40/100) against poor (22/100) for B631 Class C; for welding the order is Silver 999 first (good, 60/100) then B631 Class C (poor, 15/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in B631 Class C and Silver 999 side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.
Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.