Stainless Steel SUH4-A vs SUH4-QT
Stainless Steel · SUH4 temper comparison
SUH4-A and SUH4-QT are two conditions of the same stainless steel grade, SUH4: A (solution annealed) versus QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. SUH4-QT is the stronger of the two: yield strength 730 MPa (106 ksi) against 500 MPa (72.5 ksi) for SUH4-A, about 46% more; tensile strength follows at 950 MPa (138 ksi) vs 820 MPa (119 ksi). In exchange, SUH4-A is the more ductile: elongation 18% versus 12% for SUH4-QT, and SUH4-QT is harder (300 HB vs 270 HB). SUH4-QT runs hotter in service (800°C vs 600°C continuous).
SUH4-AChoose it when the part is bent, formed or impact-loaded.
SUH4-QTChoose it when strength drives the design, or when the part sees heat.
SUH4-A vs SUH4-QT: 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
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 215 GPa31.2 Msi · Shear Modulus 83 GPa12 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 760 MPa110 ksi · Shear Strength 570 MPa82.7 ksi · Fatigue Strength (Endurance Limit) 400 MPa58 ksi · Fracture Toughness (K_IC) 25 MPa·√m22.8 ksi·√in
Physical
Density and transition temperatures.
Same in both: Density 7.7 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,400°C2,552 °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 21 W/m·K12.1 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.8 µm/m·K6 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 2.2 % IACS · Electrical Resistivity 8×10⁻⁷ Ω·m31.5 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.3 V · Corrosion Resistance 48 / 100
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 20 / 100 · Brazeability / Solderability 40 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 55 MJ/kg23,646 BTU/lb · Embodied Carbon (primary production) 3.6 kg CO₂/kg · Embodied Water 80 L/kg9.6 gal/lb · Typical Recycled Content 40%
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.
SUH4-A vs SUH4-QT — frequently asked
Is SUH4-QT stronger than SUH4-A?
Yes. SUH4-QT has a typical yield strength of 730 MPa (106 ksi) against 500 MPa (72.5 ksi) for SUH4-A — about 46% more. Tensile strength is 950 MPa (138 ksi) vs 820 MPa (119 ksi).
Which condition does FabDigit quote by default, A or QT?
QT is the default SUH4 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, SUH4-A or SUH4-QT?
SUH4-A, by a small margin. Both rate poor for machinability — 28/100 against 22/100 for SUH4-QT.
Ready to make it?
Upload a CAD file and FabDigit prices the part in SUH4-A and SUH4-QT 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.