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Precious Metal 18K vs Dental Gold Type I

Precious Metal · grade comparison

Precious Metal 18K and Dental Gold Type I are both precious metal grades. 18K is the stronger of the two: yield strength 240 MPa (34.8 ksi) against 90 MPa (13.1 ksi) for Dental Gold Type I, about 167% more; tensile strength follows at 450 MPa (65.3 ksi) vs 250 MPa (36.3 ksi). 18K is the more ductile: elongation 38% versus 30% for Dental Gold Type I, and 18K is harder (143 HB vs 60 HB). 18K is lighter (15.5 g/cm³ vs 17.2 g/cm³ for Dental Gold Type I) and Dental Gold Type I is stiffer (85 GPa vs 80 GPa). On the shop floor, 18K machines more easily (50 vs 40 out of 100) and 18K welds better (very good vs good).

18KChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.

18K vs Dental Gold Type I: properties

18KDental Gold Type I

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

80 GPa11.6 Msi
85 GPa12.3 Msi

Shear Modulus

29 GPa4.2 Msi
31 GPa4.5 Msi

Bulk Modulus

135 GPa19.6 Msi
145 GPa21 Msi

Poisson's Ratio

0.4
0.37

Tensile Strength (Ultimate)

450 MPa65.3 ksi
250 MPa36.3 ksi

Yield Strength (0.2% offset)

240 MPa34.8 ksi
90 MPa13.1 ksi

Elongation at Break

38%
30%

Reduction in Area

48%
45%

Compressive Strength

245 MPa35.5 ksi
—

Shear Strength

280 MPa40.6 ksi
170 MPa24.7 ksi

Fatigue Strength (Endurance Limit)

250 MPa36.3 ksi
90 MPa13.1 ksi

Fracture Toughness (K_IC)

50 MPa·√m45.5 ksi·√in
—

Charpy V-Notch Impact (RT)

38 J28 ft·lbf
—

Hardness, Brinell

143 HB
60 HB

Hardness, Rockwell B

80 HRB
—

Hardness, Vickers

150 HV
65 HV

Physical

Density and transition temperatures.

Density

15.5 g/cm³0.56 lb/in³
17.2 g/cm³0.62 lb/in³

Melting Point (Solidus)

885°C1,625 °F
935°C1,715 °F

Liquidus Temperature

910°C1,670 °F
960°C1,760 °F

Thermal

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

Thermal Conductivity

150 W/m·K86.7 BTU/hr·ft·°F
115 W/m·K66.4 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

15.5 µm/m·K8.6 µin/in·°F
16 µm/m·K8.9 µin/in·°F

Latent Heat of Fusion

75 J/g32.2 BTU/lb
68 J/g29.2 BTU/lb

Same in both: Max Service Temperature (continuous) 300°C572 °F · Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

16 % IACS
25 % IACS

Electrical Resistivity

1.08×10⁻⁷ Ω·m4.25 µΩ·in
6.9×10⁻⁸ Ω·m2.72 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

0.2 V
0.28 V

Corrosion Resistance

93 / 100
96 / 100

Manufacturability

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

Machinability

50 / 100
40 / 100

Machinability Rating (AISI 1212 = 100 %)

45%
40%

Weldability

82 / 100
60 / 100

Formability (cold)

92 / 100
96 / 100

Castability

85 / 100
96 / 100

Same in both: Brazeability / Solderability 95 / 100 · Polishability 98 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Carbon (primary production)

15,000 kg CO₂/kg
13,000 kg CO₂/kg

Embodied Water

200,000 L/kg23,965 gal/lb
250,000 L/kg29,957 gal/lb

Typical Recycled Content

35%
60%

Same in both: Embodied Energy (primary production) 190,000 MJ/kg8.17×10⁷ BTU/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

29 kN·m/kg
15 kN·m/kg

Specific Stiffness (E / density)

5.2 MN·m/kg
4.9 MN·m/kg

Modulus of Resilience

360 kJ/m³
48 kJ/m³

Thermal Diffusivity

58.7 mm²/s
44.6 mm²/s

Thermal Shock Resistance Index

54
21

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 scale18KDental Gold Type I

Manufacturing and finishing

Capability18KDental Gold Type I
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

18K vs Dental Gold Type I — frequently asked

Is 18K stronger than Dental Gold Type I?

Yes. 18K has a typical yield strength of 240 MPa (34.8 ksi) against 90 MPa (13.1 ksi) for Dental Gold Type I — about 167% more. Tensile strength is 450 MPa (65.3 ksi) vs 250 MPa (36.3 ksi).

Which is cheaper, 18K or Dental Gold Type I?

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, 18K or Dental Gold Type I?

18K, by a small margin. Both rate fair for machinability — 50/100 against 40/100 for Dental Gold Type I; for welding the order is 18K first (very good, 82/100) then Dental Gold Type I (good, 60/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 18K and Dental Gold Type I 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.