Steel P355Q QT-100-150 vs P355Q QT-50-100
Steel · P355Q temper comparison
P355Q QT-100-150 and P355Q QT-50-100 are two conditions of the same steel grade, P355Q: QT-100-150 (QT) versus QT-50-100 (QT). The chemistry is identical, so every difference below comes from the condition. P355Q QT-50-100 is the stronger of the two: yield strength 380 MPa (55.1 ksi) against 355 MPa (51.5 ksi) for P355Q QT-100-150, about 7% more. P355Q QT-50-100 is harder — 177 HV against 168 HV for P355Q QT-100-150 — which matters for wear surfaces and threads.
P355Q QT-50-100Choose it when strength drives the design, or when surface hardness matters.
P355Q QT-100-150 vs P355Q QT-50-100: 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.
P355Q QT-100-150P355Q QT-50-100
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 B
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 1,510°C2,750 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 44 W/m·K25.4 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) 400°C752 °F · Min Service Temperature 0°C32 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 8.2 % IACS · Electrical Resistivity 2.1×10⁻⁷ Ω·m8.27 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.62 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 55 / 100 · Polishability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 26 MJ/kg11,178 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 35 L/kg4.2 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.
P355Q QT-100-150 vs P355Q QT-50-100 — frequently asked
Is P355Q QT-50-100 stronger than P355Q QT-100-150?
Yes. P355Q QT-50-100 has a typical yield strength of 380 MPa (55.1 ksi) against 355 MPa (51.5 ksi) for P355Q QT-100-150 — about 7% more. Tensile strength is 540 MPa (78.3 ksi) vs 520 MPa (75.4 ksi).
Which condition does FabDigit quote by default, QT-100-150 or QT-50-100?
QT is the default P355Q condition in the FabDigit quote flow (neither QT-100-150 nor QT-50-100). 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 P355Q QT-100-150 over P355Q QT-50-100?
Pick P355Q QT-50-100 when strength drives the design, or when surface hardness matters.
Ready to make it?
Upload a CAD file and FabDigit prices the part in P355Q QT-100-150 and P355Q QT-50-100 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.