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Precious Metal 18K-H02 vs 18K-H04

Precious Metal · 18K temper comparison

18K-H02 and 18K-H04 are two conditions of the same precious metal grade, 18K: H02 (half hard) versus H04 (full hard). The chemistry is identical, so every difference below comes from the condition. 18K-H04 is the stronger of the two: yield strength 680 MPa (98.6 ksi) against 480 MPa (69.6 ksi) for 18K-H02, about 42% more; tensile strength follows at 760 MPa (110 ksi) vs 600 MPa (87 ksi). In exchange, 18K-H02 is the more ductile: elongation 12% versus 3% for 18K-H04, and 18K-H04 is harder (204 HB vs 176 HB). 18K-H02 runs hotter in service (200°C vs 170°C continuous).

18K-H02Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

18K-H04Choose it when strength drives the design.

18K-H02 vs 18K-H04: properties

18K-H0218K-H04

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

80 GPa11.6 Msi
81 GPa11.7 Msi

Tensile Strength (Ultimate)

600 MPa87 ksi
760 MPa110 ksi

Yield Strength (0.2% offset)

480 MPa69.6 ksi
680 MPa98.6 ksi

Elongation at Break

12%
3%

Reduction in Area

30%
14%

Compressive Strength

490 MPa71.1 ksi
700 MPa102 ksi

Shear Strength

360 MPa52.2 ksi
440 MPa63.8 ksi

Fatigue Strength (Endurance Limit)

290 MPa42.1 ksi
330 MPa47.9 ksi

Fracture Toughness (K_IC)

45 MPa·√m41 ksi·√in
38 MPa·√m34.6 ksi·√in

Charpy V-Notch Impact (RT)

22 J16.2 ft·lbf
9 J6.6 ft·lbf

Hardness, Brinell

176 HB
204 HB

Hardness, Rockwell B

90 HRB
96 HRB

Hardness, Vickers

185 HV
215 HV

Same in both: Shear Modulus 29 GPa4.2 Msi · Bulk Modulus 135 GPa19.6 Msi · Poisson's Ratio 0.4

Physical

Density and transition temperatures.

Same in both: Density 15.5 g/cm³0.56 lb/in³ · Melting Point (Solidus) 885°C1,625 °F · Liquidus Temperature 910°C1,670 °F

Thermal

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

Thermal Conductivity

146 W/m·K84.4 BTU/hr·ft·°F
143 W/m·K82.6 BTU/hr·ft·°F

Max Service Temperature (continuous)

200°C392 °F
170°C338 °F

Same in both: Specific Heat Capacity 165 J/kg·K0.04 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 15.5 µm/m·K8.6 µin/in·°F · Latent Heat of Fusion 75 J/g32.2 BTU/lb · Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

15 % IACS
14.5 % IACS

Electrical Resistivity

1.15×10⁻⁷ Ω·m4.53 µΩ·in
1.19×10⁻⁷ Ω·m4.69 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

93 / 100
92 / 100

Same in both: Galvanic Potential (seawater, vs SCE) 0.2 V

Manufacturability

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

Machinability

60 / 100
65 / 100

Machinability Rating (AISI 1212 = 100 %)

55%
60%

Weldability

75 / 100
70 / 100

Formability (cold)

65 / 100
30 / 100

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) 190,000 MJ/kg8.17×10⁷ BTU/lb · Embodied Carbon (primary production) 15,000 kg CO₂/kg · Embodied Water 200,000 L/kg23,965 gal/lb · Typical Recycled Content 35%

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 scale18K

18K-H02 vs 18K-H04 — frequently asked

Is 18K-H04 stronger than 18K-H02?

Yes. 18K-H04 has a typical yield strength of 680 MPa (98.6 ksi) against 480 MPa (69.6 ksi) for 18K-H02 — about 42% more. Tensile strength is 760 MPa (110 ksi) vs 600 MPa (87 ksi).

Which condition does FabDigit quote by default, H02 or H04?

O is the default 18K condition in the FabDigit quote flow (neither H02 nor H04). 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, 18K-H02 or 18K-H04?

18K-H04, by a small margin. Both rate good for machinability — 65/100 against 60/100 for 18K-H02; for welding the order is 18K-H02 first (very good, 75/100) then 18K-H04 (very good, 70/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in 18K-H02 and 18K-H04 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.