Steel 18NiCrMo14-6 +H vs 18NiCrMo14-6 +U
Steel · 18NiCrMo14-6 temper comparison
18NiCrMo14-6 +H and 18NiCrMo14-6 +U are two conditions of the same steel grade, 18NiCrMo14-6: +H (supplied to specified hardenability (Jominy) band, carburize-and-harden…) versus +U (hot rolled). The chemistry is identical, so every difference below comes from the condition. 18NiCrMo14-6 +H is the stronger of the two: yield strength 1,050 MPa (152 ksi) against 650 MPa (94.3 ksi) for 18NiCrMo14-6 +U, about 62% more; tensile strength follows at 1,350 MPa (196 ksi) vs 950 MPa (138 ksi). 18NiCrMo14-6 +H is harder — 380 HB against 285 HB for 18NiCrMo14-6 +U — which matters for wear surfaces and threads. 18NiCrMo14-6 +U runs hotter in service (250°C vs 180°C continuous). On the shop floor, 18NiCrMo14-6 +U machines more easily (32 vs 22 out of 100), 18NiCrMo14-6 +U welds better (poor vs not recommended), and 18NiCrMo14-6 +U forms better (poor vs not recommended).
18NiCrMo14-6 +HChoose it when strength drives the design, or when surface hardness matters.
18NiCrMo14-6 +UChoose it when the part sees heat, or when the part is machined in volume.
18NiCrMo14-6 +H vs 18NiCrMo14-6 +U: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all steel 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 steel 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.
18NiCrMo14-6 +H18NiCrMo14-6 +U
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Hardness, Rockwell B 96 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,480°C2,696 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 34 W/m·K19.6 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -80°C-112 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7 % IACS · Electrical Resistivity 2.5×10⁻⁷ Ω·m9.84 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.65 V · Corrosion Resistance 12 / 100
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 30 / 100 · Brazeability / Solderability 45 / 100 · Polishability 75 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 34 MJ/kg14,617 BTU/lb · Embodied Carbon (primary production) 2.5 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 25%
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
18NiCrMo14-6 +H vs 18NiCrMo14-6 +U — frequently asked
Is 18NiCrMo14-6 +H stronger than 18NiCrMo14-6 +U?
Yes. 18NiCrMo14-6 +H has a typical yield strength of 1,050 MPa (152 ksi) against 650 MPa (94.3 ksi) for 18NiCrMo14-6 +U — about 62% more. Tensile strength is 1,350 MPa (196 ksi) vs 950 MPa (138 ksi).
Which condition does FabDigit quote by default, +H or +U?
+AC is the default 18NiCrMo14-6 condition in the FabDigit quote flow (neither +H nor +U). 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, 18NiCrMo14-6 +H or 18NiCrMo14-6 +U?
18NiCrMo14-6 +U, by a small margin. Both rate poor for machinability — 32/100 against 22/100 for 18NiCrMo14-6 +H; for welding the order is 18NiCrMo14-6 +U first (poor, 20/100) then 18NiCrMo14-6 +H (not recommended, 10/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 18NiCrMo14-6 +H and 18NiCrMo14-6 +U 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.