Steel En18 QT28-32HRC vs En18 QT34-38HRC
Steel · En18 temper comparison
En18 QT28-32HRC and En18 QT34-38HRC are two conditions of the same steel grade, En18: QT28-32HRC (Q&T to 28–32 HRC) versus QT34-38HRC (Q&T to 34–38 HRC). The chemistry is identical, so every difference below comes from the condition. En18 QT34-38HRC is the stronger of the two: yield strength 930 MPa (135 ksi) against 740 MPa (107 ksi) for En18 QT28-32HRC, about 26% more; tensile strength follows at 1,150 MPa (167 ksi) vs 950 MPa (138 ksi). In exchange, En18 QT28-32HRC is the more ductile: elongation 15% versus 11% for En18 QT34-38HRC, and En18 QT34-38HRC is harder (340 HB vs 285 HB). En18 QT28-32HRC runs hotter in service (400°C vs 350°C continuous). On the shop floor, En18 QT28-32HRC machines more easily (48 vs 35 out of 100).
En18 QT28-32HRCChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
En18 QT34-38HRCChoose it when strength drives the design.
En18 QT28-32HRC vs En18 QT34-38HRC: 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.
En18 QT28-32HRCEn18 QT34-38HRC
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Reduction in Area
Compressive Strength
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 207 GPa30 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) 1,425°C2,597 °F · Liquidus Temperature 1,495°C2,723 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 475 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 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.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.62 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 %)
Weldability
Formability (cold)
Same in both: Brazeability / Solderability 55 / 100 · Polishability 65 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 33 MJ/kg14,187 BTU/lb · Embodied Carbon (primary production) 2.1 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 35%
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.
En18 QT28-32HRC vs En18 QT34-38HRC — frequently asked
Is En18 QT34-38HRC stronger than En18 QT28-32HRC?
Yes. En18 QT34-38HRC has a typical yield strength of 930 MPa (135 ksi) against 740 MPa (107 ksi) for En18 QT28-32HRC — about 26% more. Tensile strength is 1,150 MPa (167 ksi) vs 950 MPa (138 ksi).
Which condition does FabDigit quote by default, QT28-32HRC or QT34-38HRC?
T is the default En18 condition in the FabDigit quote flow (neither QT28-32HRC nor QT34-38HRC). 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, En18 QT28-32HRC or En18 QT34-38HRC?
En18 QT28-32HRC, by a small margin. Both rate fair for machinability — 48/100 against 35/100 for En18 QT34-38HRC; for welding the order is En18 QT28-32HRC first (poor, 33/100) then En18 QT34-38HRC (poor, 25/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in En18 QT28-32HRC and En18 QT34-38HRC 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.