Stainless Steel N690 QT-56-58HRC vs N690-SR
Stainless Steel · N690 temper comparison
N690 QT-56-58HRC and N690-SR are two conditions of the same stainless steel grade, N690: QT-56-58HRC (hardened & tempered to 56–58 HRC) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. N690 QT-56-58HRC is the stronger of the two: yield strength 1,700 MPa (247 ksi) against 480 MPa (69.6 ksi) for N690-SR, about 3.5 times as much; tensile strength follows at 1,950 MPa (283 ksi) vs 800 MPa (116 ksi). In exchange, N690-SR is the more ductile: elongation 13% versus 2% for N690 QT-56-58HRC, and N690 QT-56-58HRC is harder (640 HV vs 250 HV). N690-SR runs hotter in service (400°C vs 250°C continuous). On the shop floor, N690-SR machines more easily (fair vs not recommended).
N690 QT-56-58HRCChoose it when strength drives the design.
N690-SRChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
N690 QT-56-58HRC vs N690-SR: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all stainless 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 stainless 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)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 215 GPa31.2 Msi · Shear Modulus 82 GPa11.9 Msi · Bulk Modulus 165 GPa23.9 Msi · Poisson's Ratio 0.28
Physical
Density and transition temperatures.
Same in both: Density 7.75 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,380°C2,516 °F · Liquidus Temperature 1,450°C2,642 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 16 W/m·K9.2 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.4 µm/m·K5.8 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -70°C-94 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.7 % IACS · Electrical Resistivity 6.5×10⁻⁷ Ω·m25.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.25 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Weldability 12 / 100 · Brazeability / Solderability 45 / 100 · Polishability 85 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 55 MJ/kg23,646 BTU/lb · Embodied Carbon (primary production) 4.5 kg CO₂/kg · Embodied Water 120 L/kg14.4 gal/lb · Typical Recycled Content 45%
Strength versus weight
Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
N690 QT-56-58HRC vs N690-SR — frequently asked
Is N690 QT-56-58HRC stronger than N690-SR?
Yes. N690 QT-56-58HRC has a typical yield strength of 1,700 MPa (247 ksi) against 480 MPa (69.6 ksi) for N690-SR — about 3.5 times as much. Tensile strength is 1,950 MPa (283 ksi) vs 800 MPa (116 ksi).
Which condition does FabDigit quote by default, QT-56-58HRC or SR?
Annealed is the default N690 condition in the FabDigit quote flow (neither QT-56-58HRC nor SR). 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, N690 QT-56-58HRC or N690-SR?
N690-SR. Its machinability rates fair (37/100) against not recommended (8/100) for N690 QT-56-58HRC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in N690 QT-56-58HRC and N690-SR 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.