Steel 51B60-A vs 51B60 QT-40HRC
Steel · 51B60 temper comparison
51B60-A and 51B60 QT-40HRC are two conditions of the same steel grade, 51B60: A (solution annealed) versus QT-40HRC (Q&T 540 °C). The chemistry is identical, so every difference below comes from the condition. 51B60 QT-40HRC is the stronger of the two: yield strength 1,160 MPa (168 ksi) against 276 MPa (40 ksi) for 51B60-A, about 4.2 times as much; tensile strength follows at 1,310 MPa (190 ksi) vs 725 MPa (105 ksi). In exchange, 51B60-A is the more ductile: elongation 17% versus 12.5% for 51B60 QT-40HRC, and 51B60 QT-40HRC is harder (388 HB vs 197 HB). 51B60 QT-40HRC runs hotter in service (400°C vs 300°C continuous). On the shop floor, 51B60-A machines more easily (good vs poor) and 51B60-A welds better (poor vs not recommended).
51B60-AChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
51B60 QT-40HRCChoose it when strength drives the design, or when the part sees heat.
51B60-A vs 51B60 QT-40HRC: 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)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Vickers
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 · Compressive Strength 730 MPa106 ksi · Shear Strength 435 MPa63.1 ksi · Hardness, Rockwell B 92 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,415°C2,579 °F · Liquidus Temperature 1,480°C2,696 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 46 W/m·K26.6 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 7.8 % 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 10 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Same in both: Formability (cold) 45 / 100 · Castability 20 / 100 · Brazeability / Solderability 45 / 100 · Polishability 60 / 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 55 L/kg6.6 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.
51B60-A vs 51B60 QT-40HRC — frequently asked
Is 51B60 QT-40HRC stronger than 51B60-A?
Yes. 51B60 QT-40HRC has a typical yield strength of 1,160 MPa (168 ksi) against 276 MPa (40 ksi) for 51B60-A — about 4.2 times as much. Tensile strength is 1,310 MPa (190 ksi) vs 725 MPa (105 ksi).
Which condition does FabDigit quote by default, A or QT-40HRC?
A is the default 51B60 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, 51B60-A or 51B60 QT-40HRC?
51B60-A. Its machinability rates good (58/100) against poor (33/100) for 51B60 QT-40HRC; for welding the order is 51B60-A first (poor, 25/100) then 51B60 QT-40HRC (not recommended, 12/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in 51B60-A and 51B60 QT-40HRC 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.