Steel HP9-4-30-ANN vs HP9-4-30-QT540
Steel · HP9-4-30 temper comparison
HP9-4-30-ANN and HP9-4-30-QT540 are two conditions of the same steel grade, HP9-4-30: ANN (annealed) versus QT540 (Q&T, austenitize 830–860 °C, oil quench, −73 °C refrigerate, double…). The chemistry is identical, so every difference below comes from the condition. HP9-4-30-QT540 is the stronger of the two: yield strength 1,400 MPa (203 ksi) against 790 MPa (115 ksi) for HP9-4-30-ANN, about 77% more; tensile strength follows at 1,655 MPa (240 ksi) vs 1,000 MPa (145 ksi). In exchange, HP9-4-30-ANN is the more ductile: elongation 18% versus 13% for HP9-4-30-QT540, and HP9-4-30-QT540 is harder (461 HB vs 295 HB). On the shop floor, HP9-4-30-ANN machines more easily (fair vs poor) and HP9-4-30-ANN welds better (good vs fair).
HP9-4-30-ANNChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
HP9-4-30-QT540Choose it when strength drives the design.
HP9-4-30-ANN vs HP9-4-30-QT540: 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
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.3 · Compressive Strength 1,450 MPa210 ksi · Shear Strength 995 MPa144 ksi · Fatigue Strength (Endurance Limit) 760 MPa110 ksi · Fracture Toughness (K_IC) 100 MPa·√m91 ksi·√in · Hardness, Vickers 490 HV
Physical
Density and transition temperatures.
Same in both: Density 7.84 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.
Same in both: Thermal Conductivity 24 W/m·K13.9 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.5 µm/m·K6.4 µin/in·°F · Latent Heat of Fusion 260 J/g112 BTU/lb · Max Service Temperature (continuous) 400°C752 °F · Min Service Temperature -73°C-99 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 3.8 % IACS · Electrical Resistivity 4.5×10⁻⁷ Ω·m17.7 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 20 / 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: Castability 30 / 100 · Brazeability / Solderability 35 / 100 · Polishability 70 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 45 MJ/kg19,347 BTU/lb · Embodied Carbon (primary production) 3.4 kg CO₂/kg · Embodied Water 85 L/kg10.2 gal/lb · Typical Recycled Content 15%
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.
HP9-4-30-ANN vs HP9-4-30-QT540 — frequently asked
Is HP9-4-30-QT540 stronger than HP9-4-30-ANN?
Yes. HP9-4-30-QT540 has a typical yield strength of 1,400 MPa (203 ksi) against 790 MPa (115 ksi) for HP9-4-30-ANN — about 77% more. Tensile strength is 1,655 MPa (240 ksi) vs 1,000 MPa (145 ksi).
Which condition does FabDigit quote by default, ANN or QT540?
QT540 is the default HP9-4-30 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, HP9-4-30-ANN or HP9-4-30-QT540?
HP9-4-30-ANN. Its machinability rates fair (40/100) against poor (25/100) for HP9-4-30-QT540; for welding the order is HP9-4-30-ANN first (good, 55/100) then HP9-4-30-QT540 (fair, 45/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in HP9-4-30-ANN and HP9-4-30-QT540 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.