Steel S7 Annealed vs S7 Nitrided
Steel · S7 temper comparison
S7 Annealed and S7 Nitrided are two conditions of the same steel grade, S7: Annealed versus Nitrided. The chemistry is identical, so every difference below comes from the condition. S7 Nitrided is the stronger of the two: yield strength 1,600 MPa (232 ksi) against 530 MPa (76.9 ksi) for S7 Annealed, about 3.0 times as much; tensile strength follows at 1,950 MPa (283 ksi) vs 830 MPa (120 ksi). In exchange, S7 Annealed is the more ductile: elongation 18% versus 6% for S7 Nitrided, and S7 Nitrided is harder (55 HRC vs 15 HRC). On the shop floor, S7 Annealed machines more easily (fair vs not recommended) and S7 Annealed welds better (poor vs not recommended).
S7 AnnealedChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
S7 NitridedChoose it when strength drives the design.
S7 Annealed vs S7 Nitrided: 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.
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, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 207 GPa30 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Hardness, Brinell 200 HB · Hardness, Rockwell B 94 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.83 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.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.6 µm/m·K7 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
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: Brazeability / Solderability 40 / 100 · Polishability 75 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 36 MJ/kg15,477 BTU/lb · Embodied Carbon (primary production) 2.7 kg CO₂/kg · Embodied Water 65 L/kg7.8 gal/lb · Typical Recycled Content 40%
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.
S7 Annealed vs S7 Nitrided — frequently asked
Is S7 Nitrided stronger than S7 Annealed?
Yes. S7 Nitrided has a typical yield strength of 1,600 MPa (232 ksi) against 530 MPa (76.9 ksi) for S7 Annealed — about 3.0 times as much. Tensile strength is 1,950 MPa (283 ksi) vs 830 MPa (120 ksi).
Which condition does FabDigit quote by default, Annealed or Nitrided?
Annealed is the default S7 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, S7 Annealed or S7 Nitrided?
S7 Annealed. Its machinability rates fair (50/100) against not recommended (5/100) for S7 Nitrided; for welding the order is S7 Annealed first (poor, 30/100) then S7 Nitrided (not recommended, 5/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in S7 Annealed and S7 Nitrided 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.