Steel A517 Grade B-QT vs A517 Grade B QT-SR
Steel · A517 Grade B temper comparison
A517 Grade B-QT and A517 Grade B QT-SR are two conditions of the same steel grade, A517 Grade B: QT (quenched and tempered) versus QT-SR (Q&T + PWHT/stress relieved). The chemistry is identical, so every difference below comes from the condition. A517 Grade B-QT is the stronger of the two: yield strength 760 MPa (110 ksi) against 710 MPa (103 ksi) for A517 Grade B QT-SR, about 7% more; tensile strength follows at 860 MPa (125 ksi) vs 815 MPa (118 ksi). A517 Grade B-QT is harder — 255 HB against 240 HB for A517 Grade B QT-SR — which matters for wear surfaces and threads.
A517 Grade B-QTChoose it when strength drives the design, or when surface hardness matters.
A517 Grade B-QT vs A517 Grade B QT-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.
A517 Grade B-QTA517 Grade B QT-SR
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)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 205 GPa29.7 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29
Physical
Density and transition temperatures.
Same in both: Density 7.85 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 42 W/m·K24.3 BTU/hr·ft·°F · Specific Heat Capacity 470 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 270 J/g116 BTU/lb · Min Service Temperature -45°C-49 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Resistivity 2.4×10⁻⁷ Ω·m9.45 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 13 / 100
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: Brazeability / Solderability 35 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb · Embodied Carbon (primary production) 2.3 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 25%
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.
A517 Grade B-QT vs A517 Grade B QT-SR — frequently asked
Is A517 Grade B-QT stronger than A517 Grade B QT-SR?
Yes. A517 Grade B-QT has a typical yield strength of 760 MPa (110 ksi) against 710 MPa (103 ksi) for A517 Grade B QT-SR — about 7% more. Tensile strength is 860 MPa (125 ksi) vs 815 MPa (118 ksi).
Which condition does FabDigit quote by default, QT or QT-SR?
QT is the default A517 Grade B 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.
When should I choose A517 Grade B-QT over A517 Grade B QT-SR?
Pick A517 Grade B-QT when strength drives the design, or when surface hardness matters.
Ready to make it?
Upload a CAD file and FabDigit prices the part in A517 Grade B-QT and A517 Grade B QT-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.