Stainless Steel SUS431 QT-38HRC vs SUS431-QT800
Stainless Steel · SUS431 temper comparison
SUS431 QT-38HRC and SUS431-QT800 are two conditions of the same stainless steel grade, SUS431: QT-38HRC (Q&T low-temper) versus QT800 (+QT800 / JIS heat-treated). The chemistry is identical, so every difference below comes from the condition. SUS431 QT-38HRC is the stronger of the two: yield strength 1,000 MPa (145 ksi) against 680 MPa (98.6 ksi) for SUS431-QT800, about 47% more; tensile strength follows at 1,250 MPa (181 ksi) vs 880 MPa (128 ksi). In exchange, SUS431-QT800 is the more ductile: elongation 16% versus 10% for SUS431 QT-38HRC, and SUS431 QT-38HRC is harder (353 HB vs 270 HB). SUS431-QT800 runs hotter in service (550°C vs 250°C continuous). On the shop floor, SUS431-QT800 machines more easily (fair vs poor).
SUS431 QT-38HRCChoose it when strength drives the design.
SUS431-QT800Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
SUS431 QT-38HRC vs SUS431-QT800: 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
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 77 GPa11.2 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 700 MPa102 ksi · Shear Strength 530 MPa76.9 ksi · Fracture Toughness (K_IC) 70 MPa·√m63.7 ksi·√in
Physical
Density and transition temperatures.
Same in both: Density 7.7 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F · Liquidus Temperature 1,510°C2,750 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 20 W/m·K11.6 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.3 µm/m·K5.7 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.4 % IACS · Electrical Resistivity 7.2×10⁻⁷ Ω·m28.3 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 %)
Same in both: Weldability 25 / 100 · Formability (cold) 25 / 100 · Brazeability / Solderability 40 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 53 MJ/kg22,786 BTU/lb · Embodied Carbon (primary production) 3.6 kg CO₂/kg · Embodied Water 130 L/kg15.6 gal/lb · Typical Recycled Content 60%
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.
SUS431 QT-38HRC vs SUS431-QT800 — frequently asked
Is SUS431 QT-38HRC stronger than SUS431-QT800?
Yes. SUS431 QT-38HRC has a typical yield strength of 1,000 MPa (145 ksi) against 680 MPa (98.6 ksi) for SUS431-QT800 — about 47% more. Tensile strength is 1,250 MPa (181 ksi) vs 880 MPa (128 ksi).
Which condition does FabDigit quote by default, QT-38HRC or QT800?
QT800 is the default SUS431 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, SUS431 QT-38HRC or SUS431-QT800?
SUS431-QT800. Its machinability rates fair (38/100) against poor (25/100) for SUS431 QT-38HRC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in SUS431 QT-38HRC and SUS431-QT800 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.