Steel E370 +C vs E370 +QT
Steel · E370 temper comparison
E370 +C and E370 +QT are two conditions of the same steel grade, E370: +C (cold drawn) versus +QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. E370 +QT is the stronger of the two: tensile strength 850 MPa (123 ksi) against 800 MPa (116 ksi) for E370 +C, about 6% more. E370 +QT is the more ductile: elongation 14% versus 7% for E370 +C, and E370 +QT is harder (250 HB vs 235 HB). On the shop floor, E370 +C machines more easily (good vs fair).
E370 +CChoose it when the part is machined in volume.
E370 +QTChoose it when strength drives the design, or when the part is bent, formed or impact-loaded.
E370 +C vs E370 +QT: 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)
Elongation at Break
Reduction in Area
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Yield Strength (0.2% offset) 620 MPa89.9 ksi · Compressive Strength 400 MPa58 ksi · Shear Strength 430 MPa62.4 ksi · Fracture Toughness (K_IC) 50 MPa·√m45.5 ksi·√in · Hardness, Rockwell B 95 HRB · Hardness, Vickers 220 HV
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 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 48 W/m·K27.7 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.8 µm/m·K6.6 µin/in·°F · Latent Heat of Fusion 250 J/g107 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 9 % IACS · Electrical Resistivity 1.9×10⁻⁷ Ω·m7.48 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 V · Corrosion Resistance 10 / 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 55 / 100 · Polishability 50 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Carbon (primary production) 2.1 kg CO₂/kg · Embodied Water 45 L/kg5.4 gal/lb · Typical Recycled Content 30%
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.
E370 +C vs E370 +QT — frequently asked
Is E370 +QT stronger than E370 +C?
Yes. E370 +QT has a typical tensile strength of 850 MPa (123 ksi) against 800 MPa (116 ksi) for E370 +C — about 6% more.
Which condition does FabDigit quote by default, +C or +QT?
+AR is the default E370 condition in the FabDigit quote flow (neither +C nor +QT). 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, E370 +C or E370 +QT?
E370 +C. Its machinability rates good (58/100) against fair (44/100) for E370 +QT; for welding the order is E370 +C first (poor, 30/100) then E370 +QT (poor, 25/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in E370 +C and E370 +QT 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.