Steel 55SiMnVB-QT400 vs 55SiMnVB-QT460
Steel · 55SiMnVB temper comparison
55SiMnVB-QT400 and 55SiMnVB-QT460 are two conditions of the same steel grade, 55SiMnVB: QT400 (oil quenched 860 °C, tempered ~400 °C) versus QT460 (oil quenched 860 °C, tempered 460 °C). The chemistry is identical, so every difference below comes from the condition. 55SiMnVB-QT400 is the stronger of the two: yield strength 1,550 MPa (225 ksi) against 1,320 MPa (191 ksi) for 55SiMnVB-QT460, about 17% more; tensile strength follows at 1,750 MPa (254 ksi) vs 1,500 MPa (218 ksi). In exchange, 55SiMnVB-QT460 is the more ductile: elongation 8% versus 6% for 55SiMnVB-QT400, and 55SiMnVB-QT400 is harder (50 HRC vs 45 HRC). 55SiMnVB-QT460 runs hotter in service (250°C vs 230°C continuous).
55SiMnVB-QT400Choose it when strength drives the design.
55SiMnVB-QT460Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
55SiMnVB-QT400 vs 55SiMnVB-QT460: 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)
Charpy V-Notch Impact (RT)
Hardness, Rockwell C
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 206 GPa29.9 Msi · Shear Modulus 79 GPa11.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 1,350 MPa196 ksi · Hardness, Brinell 425 HB
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 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 40 W/m·K23.1 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 · Min Service Temperature -40°C-40 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 6.4 % IACS · Electrical Resistivity 2.7×10⁻⁷ Ω·m10.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 11 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Formability (cold)
Same in both: Weldability 20 / 100 · Brazeability / Solderability 35 / 100 · Polishability 60 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 27 MJ/kg11,608 BTU/lb · Embodied Carbon (primary production) 2.1 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.
55SiMnVB-QT400 vs 55SiMnVB-QT460 — frequently asked
Is 55SiMnVB-QT400 stronger than 55SiMnVB-QT460?
Yes. 55SiMnVB-QT400 has a typical yield strength of 1,550 MPa (225 ksi) against 1,320 MPa (191 ksi) for 55SiMnVB-QT460 — about 17% more. Tensile strength is 1,750 MPa (254 ksi) vs 1,500 MPa (218 ksi).
Which condition does FabDigit quote by default, QT400 or QT460?
QT460 is the default 55SiMnVB 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, 55SiMnVB-QT400 or 55SiMnVB-QT460?
55SiMnVB-QT460, by a small margin. Both rate poor for machinability — 25/100 against 18/100 for 55SiMnVB-QT400.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 55SiMnVB-QT400 and 55SiMnVB-QT460 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.