Steel C300-HR vs C300 Q&T
Steel · C300 temper comparison
C300-HR and C300 Q&T are two conditions of the same steel grade, C300: HR (hot rolled) versus Q&T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. C300 Q&T is the stronger of the two: yield strength 1,860 MPa (270 ksi) against 850 MPa (123 ksi) for C300-HR, about 119% more; tensile strength follows at 1,930 MPa (280 ksi) vs 1,050 MPa (152 ksi). In exchange, C300-HR is the more ductile: elongation 13% versus 8% for C300 Q&T, and C300 Q&T is harder (550 HB vs 310 HB). On the shop floor, C300-HR machines more easily (fair vs poor) and C300-HR welds better (very good vs good).
C300-HRChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
C300 Q&TChoose it when strength drives the design.
C300-HR vs C300 Q&T: 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.
Elastic (Young's) Modulus
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: Shear Modulus 71 GPa10.3 Msi · Bulk Modulus 158 GPa22.9 Msi · Poisson's Ratio 0.3
Physical
Density and transition temperatures.
Same in both: Density 8 g/cm³0.29 lb/in³ · Melting Point (Solidus) 1,413°C2,575 °F · Liquidus Temperature 1,440°C2,624 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Same in both: Specific Heat Capacity 452 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.1 µm/m·K5.6 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -196°C-321 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 22 / 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 42 / 100 · Brazeability / Solderability 50 / 100 · Polishability 78 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 105 MJ/kg45,142 BTU/lb · Embodied Carbon (primary production) 7 kg CO₂/kg · Embodied Water 200 L/kg24 gal/lb · Typical Recycled Content 20%
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.
C300-HR vs C300 Q&T — frequently asked
Is C300 Q&T stronger than C300-HR?
Yes. C300 Q&T has a typical yield strength of 1,860 MPa (270 ksi) against 850 MPa (123 ksi) for C300-HR — about 119% more. Tensile strength is 1,930 MPa (280 ksi) vs 1,050 MPa (152 ksi).
Which condition does FabDigit quote by default, HR or Q&T?
HR is the default C300 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.
Which is easier to machine, C300-HR or C300 Q&T?
C300-HR. Its machinability rates fair (42/100) against poor (22/100) for C300 Q&T; for welding the order is C300-HR first (very good, 80/100) then C300 Q&T (good, 68/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in C300-HR and C300 Q&T 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.