Steel 40Cr Annealed vs 40Cr Q&T
Steel · 40Cr temper comparison
40Cr Annealed and 40Cr Q&T are two conditions of the same steel grade, 40Cr: Annealed versus Q&T (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. 40Cr Q&T is the stronger of the two: yield strength 830 MPa (120 ksi) against 400 MPa (58 ksi) for 40Cr Annealed, about 108% more; tensile strength follows at 1,020 MPa (148 ksi) vs 680 MPa (98.6 ksi). In exchange, 40Cr Annealed is the more ductile: elongation 22% versus 12% for 40Cr Q&T, and 40Cr Q&T is harder (300 HB vs 187 HB). On the shop floor, 40Cr Annealed machines more easily (good vs fair) and 40Cr Annealed welds better (50 vs 35 out of 100).
40Cr AnnealedChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
40Cr Q&TChoose it when strength drives the design.
40Cr Annealed vs 40Cr 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.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Hardness, Brinell
Hardness, Rockwell C
Same in both: Elastic (Young's) Modulus 211 GPa30.6 Msi · Shear Modulus 81 GPa11.7 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 430 MPa62.4 ksi · Charpy V-Notch Impact (RT) 55 J40.6 ft·lbf · Hardness, Rockwell B 94 HRB
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 1,495°C2,723 °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 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.5 µm/m·K6.9 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 8 % IACS · Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.61 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)
Polishability
Same in both: Brazeability / Solderability 55 / 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 60 L/kg7.2 gal/lb · Typical Recycled Content 35%
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.
40Cr Annealed vs 40Cr Q&T — frequently asked
Is 40Cr Q&T stronger than 40Cr Annealed?
Yes. 40Cr Q&T has a typical yield strength of 830 MPa (120 ksi) against 400 MPa (58 ksi) for 40Cr Annealed — about 108% more. Tensile strength is 1,020 MPa (148 ksi) vs 680 MPa (98.6 ksi).
Which condition does FabDigit quote by default, Annealed or Q&T?
HR is the default 40Cr condition in the FabDigit quote flow (neither Annealed nor Q&T). 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, 40Cr Annealed or 40Cr Q&T?
40Cr Annealed. Its machinability rates good (65/100) against fair (42/100) for 40Cr Q&T; for welding the order is 40Cr Annealed first (fair, 50/100) then 40Cr Q&T (fair, 35/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 40Cr Annealed and 40Cr 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.