Steel 4037 QT-32-36HRC vs 4037 QT-40-45HRC
Steel · 4037 temper comparison
4037 QT-32-36HRC and 4037 QT-40-45HRC are two conditions of the same steel grade, 4037: QT-32-36HRC versus QT-40-45HRC. The chemistry is identical, so every difference below comes from the condition. 4037 QT-40-45HRC is the stronger of the two: yield strength 1,240 MPa (180 ksi) against 965 MPa (140 ksi) for 4037 QT-32-36HRC, about 28% more; tensile strength follows at 1,380 MPa (200 ksi) vs 1,080 MPa (157 ksi). In exchange, 4037 QT-32-36HRC is the more ductile: elongation 15% versus 12% for 4037 QT-40-45HRC, and 4037 QT-40-45HRC is harder (390 HB vs 320 HB). 4037 QT-32-36HRC runs hotter in service (400°C vs 250°C continuous). On the shop floor, 4037 QT-32-36HRC machines more easily (fair vs poor).
4037 QT-32-36HRCChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
4037 QT-40-45HRCChoose it when strength drives the design.
4037 QT-32-36HRC vs 4037 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.
4037 QT-32-36HRC4037 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
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 870 MPa126 ksi · Shear Strength 580 MPa84.1 ksi
Physical
Density and transition temperatures.
Same in both: Density 7.85 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,416°C2,581 °F · Liquidus Temperature 1,495°C2,723 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 42 W/m·K24.3 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 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 12 / 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 50 / 100 · Brazeability / Solderability 60 / 100 · Polishability 62 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 31 MJ/kg13,328 BTU/lb · Embodied Carbon (primary production) 2.2 kg CO₂/kg · Embodied Water 60 L/kg7.2 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.
4037 QT-32-36HRC vs 4037 QT-40-45HRC — frequently asked
Is 4037 QT-40-45HRC stronger than 4037 QT-32-36HRC?
Yes. 4037 QT-40-45HRC has a typical yield strength of 1,240 MPa (180 ksi) against 965 MPa (140 ksi) for 4037 QT-32-36HRC — about 28% more. Tensile strength is 1,380 MPa (200 ksi) vs 1,080 MPa (157 ksi).
Which condition does FabDigit quote by default, QT-32-36HRC or QT-40-45HRC?
QT-28-32HRC is the default 4037 condition in the FabDigit quote flow (neither QT-32-36HRC nor QT-40-45HRC). 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, 4037 QT-32-36HRC or 4037 QT-40-45HRC?
4037 QT-32-36HRC. Its machinability rates fair (45/100) against poor (33/100) for 4037 QT-40-45HRC.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4037 QT-32-36HRC and 4037 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.