Steel Q890Q-QT vs Q890Q-SR
Steel · Q890Q temper comparison
Q890Q-QT and Q890Q-SR are two conditions of the same steel grade, Q890Q: QT (quenched and tempered) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. Both yield at about 950 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (quenched and tempered versus stress relieved). Q890Q-QT is harder — 34 HRC against 32 HRC for Q890Q-SR — which matters for wear surfaces and threads.
Q890Q-QTChoose it when surface hardness matters.
Q890Q-QT vs Q890Q-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.
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)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 81 GPa11.7 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.3 · Charpy V-Notch Impact (RT) 65 J47.9 ft·lbf
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °F · Liquidus Temperature 1,500°C2,732 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 35 W/m·K20.2 BTU/hr·ft·°F · 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 270 J/g116 BTU/lb · Max Service Temperature (continuous) 350°C662 °F · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7 % IACS · Electrical Resistivity 2.5×10⁻⁷ Ω·m9.84 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 12 / 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: Castability 0 / 100 · Brazeability / Solderability 30 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 31 MJ/kg13,328 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.
Q890Q-QT vs Q890Q-SR — frequently asked
What is the difference between Q890Q-QT and Q890Q-SR?
Q890Q-QT and Q890Q-SR are two conditions of the same steel grade, Q890Q: QT (quenched and tempered) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. Both yield at about 950 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (quenched and tempered versus stress relieved).
Which condition does FabDigit quote by default, QT or SR?
QT is the default Q890Q 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 Q890Q-QT over Q890Q-SR?
Pick Q890Q-QT when surface hardness matters.
Ready to make it?
Upload a CAD file and FabDigit prices the part in Q890Q-QT and Q890Q-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.