Precious Metal Gold 18K-1/2 Hard vs Gold 18K-O
Precious Metal · Gold 18K temper comparison
Gold 18K-1/2 Hard and Gold 18K-O are two conditions of the same precious metal grade, Gold 18K: 1/2 Hard (half hard) versus O (annealed). The chemistry is identical, so every difference below comes from the condition. Gold 18K-1/2 Hard is the stronger of the two: yield strength 500 MPa (72.5 ksi) against 200 MPa (29 ksi) for Gold 18K-O, about 150% more; tensile strength follows at 640 MPa (92.8 ksi) vs 450 MPa (65.3 ksi). In exchange, Gold 18K-O is the more ductile: elongation 40% versus 10% for Gold 18K-1/2 Hard, and Gold 18K-1/2 Hard is harder (190 HB vs 140 HB). Gold 18K-O runs hotter in service (400°C vs 250°C continuous). On the shop floor, Gold 18K-1/2 Hard machines more easily (very good vs good).
Gold 18K-1/2 HardChoose it when strength drives the design, or when the part is machined in volume.
Gold 18K-OChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
Gold 18K-1/2 Hard vs Gold 18K-O: 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
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Shear Modulus 28 GPa4.1 Msi · Bulk Modulus 135 GPa19.6 Msi · Poisson's Ratio 0.39
Physical
Density and transition temperatures.
Same in both: Density 15.5 g/cm³0.56 lb/in³ · Melting Point (Solidus) 895°C1,643 °F · Liquidus Temperature 920°C1,688 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 165 J/kg·K0.04 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 16 µm/m·K8.9 µin/in·°F · Latent Heat of Fusion 80 J/g34.4 BTU/lb · Min Service Temperature -200°C-328 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) 0.25 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Same in both: Castability 85 / 100 · Brazeability / Solderability 95 / 100 · Polishability 98 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 180,000 MJ/kg7.74×10⁷ BTU/lb · Embodied Carbon (primary production) 11,000 kg CO₂/kg · Embodied Water 100,000 L/kg11,983 gal/lb · Typical Recycled Content 30%
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.
Gold 18K-1/2 Hard vs Gold 18K-O — frequently asked
Is Gold 18K-1/2 Hard stronger than Gold 18K-O?
Yes. Gold 18K-1/2 Hard has a typical yield strength of 500 MPa (72.5 ksi) against 200 MPa (29 ksi) for Gold 18K-O — about 150% more. Tensile strength is 640 MPa (92.8 ksi) vs 450 MPa (65.3 ksi).
Which condition does FabDigit quote by default, 1/2 Hard or O?
O is the default Gold 18K condition in the FabDigit quote flow. The other condition is available on request or by drawing note — specify it in the material field or the part notes and the quote is priced for it.
Which is easier to machine, Gold 18K-1/2 Hard or Gold 18K-O?
Gold 18K-1/2 Hard. Its machinability rates very good (70/100) against good (60/100) for Gold 18K-O; for welding the order is Gold 18K-O first (excellent, 85/100) then Gold 18K-1/2 Hard (very good, 78/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Gold 18K-1/2 Hard and Gold 18K-O 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.