Steel 21CrMoV5-7 +AC vs 21CrMoV5-7 +QT
Steel · 21CrMoV5-7 temper comparison
21CrMoV5-7 +AC and 21CrMoV5-7 +QT are two conditions of the same steel grade, 21CrMoV5-7: +AC (spheroidize annealed) versus +QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. 21CrMoV5-7 +QT is the stronger of the two: yield strength 700 MPa (102 ksi) against 450 MPa (65.3 ksi) for 21CrMoV5-7 +AC, about 56% more; tensile strength follows at 830 MPa (120 ksi) vs 700 MPa (102 ksi). In exchange, 21CrMoV5-7 +AC is the more ductile: elongation 22% versus 18% for 21CrMoV5-7 +QT, and 21CrMoV5-7 +QT is harder (250 HB vs 215 HB). 21CrMoV5-7 +QT runs hotter in service (540°C vs 450°C continuous). On the shop floor, 21CrMoV5-7 +AC machines more easily (good vs fair) and 21CrMoV5-7 +AC welds better (45 vs 35 out of 100).
21CrMoV5-7 +ACChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
21CrMoV5-7 +QTChoose it when strength drives the design, or when the part sees heat.
21CrMoV5-7 +AC vs 21CrMoV5-7 +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
Reduction in Area
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 210 GPa30.5 Msi · Shear Modulus 81 GPa11.7 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 710 MPa103 ksi · Shear Strength 500 MPa72.5 ksi · Fracture Toughness (K_IC) 95 MPa·√m86.5 ksi·√in · Hardness, Rockwell C 25 HRC
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,450°C2,642 °F · Liquidus Temperature 1,500°C2,732 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 39 W/m·K22.5 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.2 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7.2 % IACS · Electrical Resistivity 2.4×10⁻⁷ Ω·m9.45 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 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 30 / 100 · Brazeability / Solderability 45 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 32 MJ/kg13,758 BTU/lb · Embodied Carbon (primary production) 2.3 kg CO₂/kg · Embodied Water 65 L/kg7.8 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.
21CrMoV5-7 +AC vs 21CrMoV5-7 +QT — frequently asked
Is 21CrMoV5-7 +QT stronger than 21CrMoV5-7 +AC?
Yes. 21CrMoV5-7 +QT has a typical yield strength of 700 MPa (102 ksi) against 450 MPa (65.3 ksi) for 21CrMoV5-7 +AC — about 56% more. Tensile strength is 830 MPa (120 ksi) vs 700 MPa (102 ksi).
Which condition does FabDigit quote by default, +AC or +QT?
+QT is the default 21CrMoV5-7 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, 21CrMoV5-7 +AC or 21CrMoV5-7 +QT?
21CrMoV5-7 +AC. Its machinability rates good (55/100) against fair (42/100) for 21CrMoV5-7 +QT; for welding the order is 21CrMoV5-7 +AC first (fair, 45/100) then 21CrMoV5-7 +QT (fair, 35/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 21CrMoV5-7 +AC and 21CrMoV5-7 +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.