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Precious Metal 14K vs 18K

Precious Metal · grade comparison

Precious Metal 14K and 18K are both precious metal grades. 18K is the stronger of the two: yield strength 240 MPa (34.8 ksi) against 220 MPa (31.9 ksi) for 14K, about 9% more; tensile strength follows at 450 MPa (65.3 ksi) vs 400 MPa (58 ksi). 18K is harder — 143 HB against 133 HB for 14K — which matters for wear surfaces and threads. 14K is lighter (13.07 g/cm³ vs 15.5 g/cm³ for 18K) and 18K runs hotter in service (300°C vs 250°C continuous).

14KChoose it when weight is the constraint.

18KChoose it when strength drives the design, or when surface hardness matters.

14K vs 18K: properties

14K18K

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Shear Modulus

30 GPa4.4 Msi
29 GPa4.2 Msi

Bulk Modulus

105 GPa15.2 Msi
135 GPa19.6 Msi

Poisson's Ratio

0.35
0.4

Tensile Strength (Ultimate)

400 MPa58 ksi
450 MPa65.3 ksi

Yield Strength (0.2% offset)

220 MPa31.9 ksi
240 MPa34.8 ksi

Elongation at Break

35%
38%

Reduction in Area

45%
48%

Compressive Strength

230 MPa33.4 ksi
245 MPa35.5 ksi

Shear Strength

250 MPa36.3 ksi
280 MPa40.6 ksi

Fatigue Strength (Endurance Limit)

180 MPa26.1 ksi
250 MPa36.3 ksi

Hardness, Brinell

133 HB
143 HB

Hardness, Rockwell B

75 HRB
80 HRB

Hardness, Vickers

140 HV
150 HV

Fracture Toughness (K_IC)

—
50 MPa·√m45.5 ksi·√in

Charpy V-Notch Impact (RT)

—
38 J28 ft·lbf

Same in both: Elastic (Young's) Modulus 80 GPa11.6 Msi

Physical

Density and transition temperatures.

Density

13.07 g/cm³0.47 lb/in³
15.5 g/cm³0.56 lb/in³

Melting Point (Solidus)

802°C1,476 °F
885°C1,625 °F

Liquidus Temperature

830°C1,526 °F
910°C1,670 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

75 W/m·K43.3 BTU/hr·ft·°F
150 W/m·K86.7 BTU/hr·ft·°F

Specific Heat Capacity

295 J/kg·K0.07 BTU/lb·°F
165 J/kg·K0.04 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

14.5 µm/m·K8.1 µin/in·°F
15.5 µm/m·K8.6 µin/in·°F

Latent Heat of Fusion

95 J/g40.8 BTU/lb
75 J/g32.2 BTU/lb

Max Service Temperature (continuous)

250°C482 °F
300°C572 °F

Min Service Temperature

-196°C-321 °F
-200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

14 % IACS
16 % IACS

Electrical Resistivity

1.23×10⁻⁷ Ω·m4.84 µΩ·in
1.08×10⁻⁷ Ω·m4.25 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

0.25 V
0.2 V

Corrosion Resistance

85 / 100
93 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

55 / 100
50 / 100

Machinability Rating (AISI 1212 = 100 %)

40%
45%

Weldability

80 / 100
82 / 100

Formability (cold)

95 / 100
92 / 100

Brazeability / Solderability

92 / 100
95 / 100

Polishability

95 / 100
98 / 100

Same in both: Castability 85 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

150,000 MJ/kg6.45×10⁷ BTU/lb
190,000 MJ/kg8.17×10⁷ BTU/lb

Embodied Carbon (primary production)

10,000 kg CO₂/kg
15,000 kg CO₂/kg

Embodied Water

140,000 L/kg16,776 gal/lb
200,000 L/kg23,965 gal/lb

Typical Recycled Content

40%
35%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

31 kN·m/kg
29 kN·m/kg

Specific Stiffness (E / density)

6.1 MN·m/kg
5.2 MN·m/kg

Modulus of Resilience

303 kJ/m³
360 kJ/m³

Thermal Diffusivity

19.5 mm²/s
58.7 mm²/s

Thermal Shock Resistance Index

26
54

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.

50100200500101520Density (g/cm³)Yield strength (MPa) — log scale18K14K

Manufacturing and finishing

Capability14K18K
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

14K vs 18K — frequently asked

Is 18K stronger than 14K?

Yes. 18K has a typical yield strength of 240 MPa (34.8 ksi) against 220 MPa (31.9 ksi) for 14K — about 9% more. Tensile strength is 450 MPa (65.3 ksi) vs 400 MPa (58 ksi).

Which is cheaper, 14K or 18K?

Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.

Which is easier to machine, 14K or 18K?

14K. Its machinability rates good (55/100) against fair (50/100) for 18K.

Ready to make it?

Upload a CAD file and FabDigit prices the part in 14K and 18K 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.