Steel S690Q QT-100-150 vs S690Q-SR
Steel · S690Q temper comparison
S690Q QT-100-150 and S690Q-SR are two conditions of the same steel grade, S690Q: QT-100-150 (Q&T, plate thickness 100–150 mm) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. Both yield at about 690 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (Q&T, plate thickness 100–150 mm versus stress relieved). S690Q-SR is harder — 24 HRC against 22 HRC for S690Q QT-100-150 — which matters for wear surfaces and threads. On the shop floor, S690Q-SR welds better (68 vs 58 out of 100).
S690Q-SRChoose it when surface hardness matters, or when it will be welded.
S690Q QT-100-150 vs S690Q-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)
Charpy V-Notch Impact (RT)
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 165 GPa23.9 Msi · Poisson's Ratio 0.3
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 1,500°C2,732 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 40 W/m·K23.1 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 250 J/g107 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7.5 % IACS · Electrical Resistivity 2.3×10⁻⁷ Ω·m9.06 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 14 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Weldability
Formability (cold)
Same in both: Machinability 42 / 100 · Machinability Rating (AISI 1212 = 100 %) 50% · Brazeability / Solderability 40 / 100 · Polishability 50 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 29 MJ/kg12,468 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.
S690Q QT-100-150 vs S690Q-SR — frequently asked
What is the difference between S690Q QT-100-150 and S690Q-SR?
S690Q QT-100-150 and S690Q-SR are two conditions of the same steel grade, S690Q: QT-100-150 (Q&T, plate thickness 100–150 mm) versus SR (stress relieved). The chemistry is identical, so every difference below comes from the condition. Both yield at about 690 MPa — the mechanical properties are the same, and the difference is in how the stock is processed and what it is certified to (Q&T, plate thickness 100–150 mm versus stress relieved).
Which condition does FabDigit quote by default, QT-100-150 or SR?
Q is the default S690Q condition in the FabDigit quote flow (neither QT-100-150 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 welds better, S690Q QT-100-150 or S690Q-SR?
S690Q-SR. Its weldability rates good (68/100) against good (58/100) for S690Q QT-100-150.
Ready to make it?
Upload a CAD file and FabDigit prices the part in S690Q QT-100-150 and S690Q-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.