Steel 15B37 QT32-38 vs 15B37 QT38-44
Steel · 15B37 temper comparison
15B37 QT32-38 and 15B37 QT38-44 are two conditions of the same steel grade, 15B37: QT32-38 (Q&T 32–38 HRC) versus QT38-44 (Q&T 38–44 HRC). The chemistry is identical, so every difference below comes from the condition. 15B37 QT38-44 is the stronger of the two: yield strength 1,200 MPa (174 ksi) against 980 MPa (142 ksi) for 15B37 QT32-38, about 22% more; tensile strength follows at 1,350 MPa (196 ksi) vs 1,100 MPa (160 ksi). In exchange, 15B37 QT32-38 is the more ductile: elongation 14% versus 11% for 15B37 QT38-44, and 15B37 QT38-44 is harder (388 HB vs 331 HB). 15B37 QT32-38 runs hotter in service (300°C vs 250°C continuous). On the shop floor, 15B37 QT32-38 machines more easily (fair vs poor).
15B37 QT32-38Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
15B37 QT38-44Choose it when strength drives the design.
15B37 QT32-38 vs 15B37 QT38-44: 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, 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
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 1,495°C2,723 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 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 -30°C-22 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 8 % IACS · Electrical Resistivity 2.1×10⁻⁷ Ω·m8.27 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 %)
Same in both: Weldability 35 / 100 · Formability (cold) 45 / 100 · Brazeability / Solderability 55 / 100 · Polishability 55 / 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 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.
15B37 QT32-38 vs 15B37 QT38-44 — frequently asked
Is 15B37 QT38-44 stronger than 15B37 QT32-38?
Yes. 15B37 QT38-44 has a typical yield strength of 1,200 MPa (174 ksi) against 980 MPa (142 ksi) for 15B37 QT32-38 — about 22% more. Tensile strength is 1,350 MPa (196 ksi) vs 1,100 MPa (160 ksi).
Which condition does FabDigit quote by default, QT32-38 or QT38-44?
QT32-38 is the default 15B37 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, 15B37 QT32-38 or 15B37 QT38-44?
15B37 QT32-38. Its machinability rates fair (45/100) against poor (32/100) for 15B37 QT38-44.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 15B37 QT32-38 and 15B37 QT38-44 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.