Stainless Steel SUS440C-H vs SUS440C-QT450
Stainless Steel · SUS440C temper comparison
SUS440C-H and SUS440C-QT450 are two conditions of the same stainless steel grade, SUS440C: H (hardened) versus QT450 (hardened + tempered 425–480 °C). The chemistry is identical, so every difference below comes from the condition. SUS440C-H is the stronger of the two: yield strength 1,900 MPa (276 ksi) against 1,700 MPa (247 ksi) for SUS440C-QT450, about 12% more; tensile strength follows at 2,030 MPa (294 ksi) vs 1,830 MPa (265 ksi). In exchange, SUS440C-QT450 is the more ductile: elongation 3% versus 1% for SUS440C-H, and SUS440C-H is harder (620 HB vs 560 HB). SUS440C-QT450 runs hotter in service (400°C vs 150°C continuous).
SUS440C-HChoose it when strength drives the design.
SUS440C-QT450Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
SUS440C-H vs SUS440C-QT450: 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
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 166 GPa24.1 Msi · Poisson's Ratio 0.28 · Hardness, Rockwell B 99 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.68 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,370°C2,498 °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) 10.2 µm/m·K5.7 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -70°C-94 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
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 5 / 100 · Brazeability / Solderability 40 / 100 · Polishability 85 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 53 MJ/kg22,786 BTU/lb · Embodied Carbon (primary production) 5 kg CO₂/kg · Embodied Water 220 L/kg26.4 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.
SUS440C-H vs SUS440C-QT450 — frequently asked
Is SUS440C-H stronger than SUS440C-QT450?
Yes. SUS440C-H has a typical yield strength of 1,900 MPa (276 ksi) against 1,700 MPa (247 ksi) for SUS440C-QT450 — about 12% more. Tensile strength is 2,030 MPa (294 ksi) vs 1,830 MPa (265 ksi).
Which condition does FabDigit quote by default, H or QT450?
A is the default SUS440C condition in the FabDigit quote flow (neither H nor QT450). 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, SUS440C-H or SUS440C-QT450?
SUS440C-QT450, by a small margin. Both rate not recommended for machinability — 10/100 against 5/100 for SUS440C-H.
Ready to make it?
Upload a CAD file and FabDigit prices the part in SUS440C-H and SUS440C-QT450 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.