Steel 6120-A vs 6120 QT-25
Steel · 6120 temper comparison
6120-A and 6120 QT-25 are two conditions of the same steel grade, 6120: A (solution annealed) versus QT-25 (Q&T 22–28 HRC). The chemistry is identical, so every difference below comes from the condition. 6120 QT-25 is the stronger of the two: yield strength 650 MPa (94.3 ksi) against 370 MPa (53.7 ksi) for 6120-A, about 76% more; tensile strength follows at 830 MPa (120 ksi) vs 570 MPa (82.7 ksi). In exchange, 6120-A is the more ductile: elongation 29% versus 20% for 6120 QT-25, and 6120 QT-25 is harder (255 HB vs 163 HB).
6120-AChoose it when the part is bent, formed or impact-loaded.
6120 QT-25Choose it when strength drives the design.
6120-A vs 6120 QT-25: 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
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
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 58% · Shear Strength 400 MPa58 ksi · Hardness, Rockwell B 84 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °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 44 W/m·K25.4 BTU/hr·ft·°F · Specific Heat Capacity 475 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 -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7.5 % IACS · Electrical Resistivity 2.3×10⁻⁷ Ω·m9.06 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 Rating (AISI 1212 = 100 %)
Same in both: Machinability 52 / 100 · Weldability 55 / 100 · Formability (cold) 58 / 100 · Brazeability / Solderability 65 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 30 MJ/kg12,898 BTU/lb · Embodied Carbon (primary production) 2.2 kg CO₂/kg · Embodied Water 60 L/kg7.2 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.
6120-A vs 6120 QT-25 — frequently asked
Is 6120 QT-25 stronger than 6120-A?
Yes. 6120 QT-25 has a typical yield strength of 650 MPa (94.3 ksi) against 370 MPa (53.7 ksi) for 6120-A — about 76% more. Tensile strength is 830 MPa (120 ksi) vs 570 MPa (82.7 ksi).
Which condition does FabDigit quote by default, A or QT-25?
A is the default 6120 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.
When should I choose 6120-A over 6120 QT-25?
Pick 6120-A when the part is bent, formed or impact-loaded. Pick 6120 QT-25 when strength drives the design.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 6120-A and 6120 QT-25 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.