Steel HPM38 QT48-50 vs HPM38 QT50-52
Steel · HPM38 temper comparison
HPM38 QT48-50 and HPM38 QT50-52 are two conditions of the same steel grade, HPM38: QT48-50 (hardened & tempered 48–50 HRC) versus QT50-52 (hardened & tempered 50–52 HRC). The chemistry is identical, so every difference below comes from the condition. HPM38 QT50-52 is the stronger of the two: yield strength 1,520 MPa (220 ksi) against 1,400 MPa (203 ksi) for HPM38 QT48-50, about 9% more; tensile strength follows at 1,780 MPa (258 ksi) vs 1,650 MPa (239 ksi). In exchange, HPM38 QT48-50 is the more ductile: elongation 6% versus 5% for HPM38 QT50-52, and HPM38 QT50-52 is harder (545 HV vs 510 HV). HPM38 QT48-50 runs hotter in service (200°C vs 180°C continuous). On the shop floor, HPM38 QT48-50 welds better (25 vs 15 out of 100).
HPM38 QT48-50Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
HPM38 QT50-52Choose it when strength drives the design.
HPM38 QT48-50 vs HPM38 QT50-52: 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
Compressive Strength
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 205 GPa29.7 Msi · Shear Modulus 79 GPa11.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 45% · Hardness, Brinell 215 HB
Physical
Density and transition temperatures.
Same in both: Density 7.8 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,420°C2,588 °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 20 W/m·K11.6 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.8 µm/m·K6 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 2.9 % IACS · Electrical Resistivity 6×10⁻⁷ Ω·m23.6 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Same in both: Galvanic Potential (seawater, vs SCE) -0.35 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Polishability
Same in both: Formability (cold) 25 / 100 · Castability 20 / 100 · Brazeability / Solderability 30 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 52 MJ/kg22,356 BTU/lb · Embodied Carbon (primary production) 3.6 kg CO₂/kg · Embodied Water 90 L/kg10.8 gal/lb · Typical Recycled Content 40%
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.
HPM38 QT48-50 vs HPM38 QT50-52 — frequently asked
Is HPM38 QT50-52 stronger than HPM38 QT48-50?
Yes. HPM38 QT50-52 has a typical yield strength of 1,520 MPa (220 ksi) against 1,400 MPa (203 ksi) for HPM38 QT48-50 — about 9% more. Tensile strength is 1,780 MPa (258 ksi) vs 1,650 MPa (239 ksi).
Which condition does FabDigit quote by default, QT48-50 or QT50-52?
ANN is the default HPM38 condition in the FabDigit quote flow (neither QT48-50 nor QT50-52). 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 welds better, HPM38 QT48-50 or HPM38 QT50-52?
HPM38 QT48-50. Its weldability rates poor (25/100) against poor (15/100) for HPM38 QT50-52.
Ready to make it?
Upload a CAD file and FabDigit prices the part in HPM38 QT48-50 and HPM38 QT50-52 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.