Steel A536 80-55-06-QT vs A536 80-55-06-SR
Steel · A536 80-55-06 temper comparison
A536 80-55-06-QT and A536 80-55-06-SR are two conditions of the same steel grade, A536 80-55-06: QT (quenched and tempered) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. A536 80-55-06-QT is the stronger of the two: yield strength 620 MPa (89.9 ksi) against 390 MPa (56.6 ksi) for A536 80-55-06-SR, about 59% more; tensile strength follows at 850 MPa (123 ksi) vs 565 MPa (81.9 ksi). In exchange, A536 80-55-06-SR is the more ductile: elongation 9% versus 3% for A536 80-55-06-QT, and A536 80-55-06-QT is harder (290 HB vs 190 HB). A536 80-55-06-QT runs hotter in service (400°C vs 350°C continuous) and A536 80-55-06-SR conducts heat better (35 W/m·K vs 31 W/m·K). On the shop floor, A536 80-55-06-SR machines more easily (very good vs fair) and A536 80-55-06-SR welds better (32 vs 18 out of 100).
A536 80-55-06-QTChoose it when strength drives the design, or when the part sees heat.
A536 80-55-06-SRChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
A536 80-55-06-QT vs A536 80-55-06-SR: 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.
A536 80-55-06-QTA536 80-55-06-SR
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Shear Modulus 65 GPa9.4 Msi · Bulk Modulus 135 GPa19.6 Msi · Poisson's Ratio 0.28
Physical
Density and transition temperatures.
Same in both: Density 7.1 g/cm³0.26 lb/in³ · Melting Point (Solidus) 1,150°C2,102 °F · Liquidus Temperature 1,170°C2,138 °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 µm/m·K6.7 µin/in·°F · Latent Heat of Fusion 220 J/g94.6 BTU/lb · Min Service Temperature -20°C-4 °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) -0.61 V
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: Castability 90 / 100 · Brazeability / Solderability 35 / 100 · Polishability 50 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 20 MJ/kg8,598 BTU/lb · Embodied Carbon (primary production) 1.9 kg CO₂/kg · Embodied Water 45 L/kg5.4 gal/lb · Typical Recycled Content 90%
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.
A536 80-55-06-QT vs A536 80-55-06-SR — frequently asked
Is A536 80-55-06-QT stronger than A536 80-55-06-SR?
Yes. A536 80-55-06-QT has a typical yield strength of 620 MPa (89.9 ksi) against 390 MPa (56.6 ksi) for A536 80-55-06-SR — about 59% more. Tensile strength is 850 MPa (123 ksi) vs 565 MPa (81.9 ksi).
Which condition does FabDigit quote by default, QT or SR?
AS-CAST is the default A536 80-55-06 condition in the FabDigit quote flow (neither QT 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, A536 80-55-06-QT or A536 80-55-06-SR?
A536 80-55-06-SR. Its machinability rates very good (72/100) against fair (45/100) for A536 80-55-06-QT; for welding the order is A536 80-55-06-SR first (poor, 32/100) then A536 80-55-06-QT (poor, 18/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in A536 80-55-06-QT and A536 80-55-06-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.