Steel Böhler S390 Annealed vs Böhler S390 HT 68-70HRC
Steel · Böhler S390 temper comparison
Böhler S390 Annealed and Böhler S390 HT 68-70HRC are two conditions of the same steel grade, Böhler S390: Annealed versus HT 68-70HRC (hardened & triple tempered). The chemistry is identical, so every difference below comes from the condition. Böhler S390 HT 68-70HRC is the stronger of the two: yield strength 2,000 MPa (290 ksi) against 700 MPa (102 ksi) for Böhler S390 Annealed, about 186% more; tensile strength follows at 2,100 MPa (305 ksi) vs 1,000 MPa (145 ksi). In exchange, Böhler S390 Annealed is the more ductile: elongation 10% versus 0% for Böhler S390 HT 68-70HRC, and Böhler S390 HT 68-70HRC is harder (69 HRC vs 31 HRC). Böhler S390 HT 68-70HRC runs hotter in service (600°C vs 500°C continuous) and Böhler S390 Annealed conducts heat better (24 W/m·K vs 21 W/m·K). On the shop floor, Böhler S390 Annealed machines more easily (poor vs not recommended) and Böhler S390 Annealed welds better (poor vs not recommended).
Böhler S390 AnnealedChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
Böhler S390 HT 68-70HRCChoose it when strength drives the design, or when the part sees heat.
Böhler S390 Annealed vs Böhler S390 HT 68-70HRC: 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.
Böhler S390 AnnealedBöhler S390 HT 68-70HRC
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
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, Rockwell C
Hardness, Vickers
Same in both: Shear Modulus 94 GPa13.6 Msi · Bulk Modulus 200 GPa29 Msi · Poisson's Ratio 0.29 · Hardness, Brinell 300 HB · Hardness, Rockwell B 104 HRB
Physical
Density and transition temperatures.
Same in both: Density 8 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,260°C2,300 °F · Liquidus Temperature 1,420°C2,588 °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 420 J/kg·K0.1 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.5 µm/m·K5.8 µin/in·°F · Min Service Temperature -60°C-76 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Corrosion Resistance 15 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Polishability
Same in both: Brazeability / Solderability 40 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 70 MJ/kg30,095 BTU/lb · Embodied Carbon (primary production) 5.5 kg CO₂/kg · Embodied Water 200 L/kg24 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.
Böhler S390 Annealed vs Böhler S390 HT 68-70HRC — frequently asked
Is Böhler S390 HT 68-70HRC stronger than Böhler S390 Annealed?
Yes. Böhler S390 HT 68-70HRC has a typical yield strength of 2,000 MPa (290 ksi) against 700 MPa (102 ksi) for Böhler S390 Annealed — about 186% more. Tensile strength is 2,100 MPa (305 ksi) vs 1,000 MPa (145 ksi).
Which condition does FabDigit quote by default, Annealed or HT 68-70HRC?
Annealed is the default Böhler S390 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, Böhler S390 Annealed or Böhler S390 HT 68-70HRC?
Böhler S390 Annealed. Its machinability rates poor (25/100) against not recommended (3/100) for Böhler S390 HT 68-70HRC; for welding the order is Böhler S390 Annealed first (poor, 20/100) then Böhler S390 HT 68-70HRC (not recommended, 3/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in Böhler S390 Annealed and Böhler S390 HT 68-70HRC 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.