Steel 15B41 QT-33-39HRC vs 15B41 QT-40-45HRC
Steel · 15B41 temper comparison
15B41 QT-33-39HRC and 15B41 QT-40-45HRC are two conditions of the same steel grade, 15B41: QT-33-39HRC versus QT-40-45HRC. The chemistry is identical, so every difference below comes from the condition. 15B41 QT-40-45HRC is the stronger of the two: yield strength 1,250 MPa (181 ksi) against 1,030 MPa (149 ksi) for 15B41 QT-33-39HRC, about 21% more; tensile strength follows at 1,400 MPa (203 ksi) vs 1,160 MPa (168 ksi). In exchange, 15B41 QT-33-39HRC is the more ductile: elongation 13% versus 10% for 15B41 QT-40-45HRC, and 15B41 QT-40-45HRC is harder (390 HB vs 336 HB). 15B41 QT-33-39HRC runs hotter in service (300°C vs 260°C continuous). On the shop floor, 15B41 QT-33-39HRC machines more easily (fair vs poor).
15B41 QT-33-39HRCChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
15B41 QT-40-45HRCChoose it when strength drives the design.
15B41 QT-33-39HRC vs 15B41 QT-40-45HRC: 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.
15B41 QT-33-39HRC15B41 QT-40-45HRC
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, Brinell
Hardness, Rockwell C
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 1,080 MPa157 ksi
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 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) 11.7 µm/m·K6.5 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 8.6 % IACS · Electrical Resistivity 2×10⁻⁷ Ω·m7.87 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 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 %)
Formability (cold)
Same in both: Weldability 25 / 100 · Brazeability / Solderability 45 / 100 · Polishability 60 / 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 45 L/kg5.4 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.
15B41 QT-33-39HRC vs 15B41 QT-40-45HRC — frequently asked
Is 15B41 QT-40-45HRC stronger than 15B41 QT-33-39HRC?
Yes. 15B41 QT-40-45HRC has a typical yield strength of 1,250 MPa (181 ksi) against 1,030 MPa (149 ksi) for 15B41 QT-33-39HRC — about 21% more. Tensile strength is 1,400 MPa (203 ksi) vs 1,160 MPa (168 ksi).
Which condition does FabDigit quote by default, QT-33-39HRC or QT-40-45HRC?
QT-33-39HRC is the default 15B41 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, 15B41 QT-33-39HRC or 15B41 QT-40-45HRC?
15B41 QT-33-39HRC. Its machinability rates fair (40/100) against poor (30/100) for 15B41 QT-40-45HRC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 15B41 QT-33-39HRC and 15B41 QT-40-45HRC 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.