Steel C15E +AR vs C15E +QT
Steel · C15E temper comparison
C15E +AR and C15E +QT are two conditions of the same steel grade, C15E: +AR (hot rolled) versus +QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. C15E +QT is the stronger of the two: yield strength 420 MPa (60.9 ksi) against 230 MPa (33.4 ksi) for C15E +AR, about 83% more; tensile strength follows at 650 MPa (94.3 ksi) vs 380 MPa (55.1 ksi). In exchange, C15E +AR is the more ductile: elongation 28% versus 17% for C15E +QT, and C15E +QT is harder (195 HB vs 111 HB). On the shop floor, C15E +AR welds better (95 vs 85 out of 100).
C15E +ARChoose it when the part is bent, formed or impact-loaded, or when it will be welded.
C15E +QTChoose it when strength drives the design.
C15E +AR vs C15E +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)
Yield Strength (0.2% offset)
Elongation at Break
Shear Strength
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
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 · Reduction in Area 50% · Compressive Strength 325 MPa47.1 ksi · Fracture Toughness (K_IC) 110 MPa·√m100 ksi·√in · Hardness, Vickers 127 HV
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,460°C2,660 °F · Liquidus Temperature 1,520°C2,768 °F
Thermal
How each material carries heat and how hot it can run.
Same in both: Thermal Conductivity 51 W/m·K29.5 BTU/hr·ft·°F · Specific Heat Capacity 480 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.9 µm/m·K6.6 µin/in·°F · Latent Heat of Fusion 247 J/g106 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 10.8 % IACS · Electrical Resistivity 1.6×10⁻⁷ Ω·m6.3 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.65 V · Corrosion Resistance 10 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Weldability
Formability (cold)
Same in both: Machinability Rating (AISI 1212 = 100 %) 55% · Brazeability / Solderability 85 / 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) 1.9 kg CO₂/kg · Embodied Water 40 L/kg4.8 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.
C15E +AR vs C15E +QT — frequently asked
Is C15E +QT stronger than C15E +AR?
Yes. C15E +QT has a typical yield strength of 420 MPa (60.9 ksi) against 230 MPa (33.4 ksi) for C15E +AR — about 83% more. Tensile strength is 650 MPa (94.3 ksi) vs 380 MPa (55.1 ksi).
Which condition does FabDigit quote by default, +AR or +QT?
+N is the default C15E condition in the FabDigit quote flow (neither +AR 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, C15E +AR or C15E +QT?
C15E +QT, by a small margin. Both rate fair for machinability — 45/100 against 40/100 for C15E +AR; for welding the order is C15E +AR first (excellent, 95/100) then C15E +QT (excellent, 85/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in C15E +AR and C15E +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.