Steel 9Cr18Mo-A vs 9Cr18Mo QT48-52
Steel · 9Cr18Mo temper comparison
9Cr18Mo-A and 9Cr18Mo QT48-52 are two conditions of the same steel grade, 9Cr18Mo: A (solution annealed) versus QT48-52 (Q&T 48–52 HRC). The chemistry is identical, so every difference below comes from the condition. 9Cr18Mo QT48-52 is the stronger of the two: yield strength 1,550 MPa (225 ksi) against 450 MPa (65.3 ksi) for 9Cr18Mo-A, about 3.4 times as much; tensile strength follows at 1,700 MPa (247 ksi) vs 760 MPa (110 ksi). In exchange, 9Cr18Mo-A is the more ductile: elongation 14% versus 3% for 9Cr18Mo QT48-52, and 9Cr18Mo QT48-52 is harder (50 HRC vs 25 HRC). 9Cr18Mo QT48-52 runs hotter in service (480°C vs 425°C continuous). On the shop floor, 9Cr18Mo-A machines more easily (fair vs not recommended).
9Cr18Mo-AChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
9Cr18Mo QT48-52Choose it when strength drives the design, or when the part sees heat.
9Cr18Mo-A vs 9Cr18Mo QT48-52: 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
Reduction in Area
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 200 GPa29 Msi · Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.28 · Compressive Strength 2,250 MPa326 ksi
Physical
Density and transition temperatures.
Same in both: Density 7.7 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,370°C2,498 °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 24.2 W/m·K14 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.2 µm/m·K5.7 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -50°C-58 °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) -0.3 V
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 12 / 100 · Castability 35 / 100 · Brazeability / Solderability 40 / 100 · Polishability 78 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 55 MJ/kg23,646 BTU/lb · Embodied Carbon (primary production) 4.5 kg CO₂/kg · Embodied Water 90 L/kg10.8 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.
9Cr18Mo-A vs 9Cr18Mo QT48-52 — frequently asked
Is 9Cr18Mo QT48-52 stronger than 9Cr18Mo-A?
Yes. 9Cr18Mo QT48-52 has a typical yield strength of 1,550 MPa (225 ksi) against 450 MPa (65.3 ksi) for 9Cr18Mo-A — about 3.4 times as much. Tensile strength is 1,700 MPa (247 ksi) vs 760 MPa (110 ksi).
Which condition does FabDigit quote by default, A or QT48-52?
QT58-60 is the default 9Cr18Mo condition in the FabDigit quote flow (neither A nor QT48-52). 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 is easier to machine, 9Cr18Mo-A or 9Cr18Mo QT48-52?
9Cr18Mo-A. Its machinability rates fair (35/100) against not recommended (12/100) for 9Cr18Mo QT48-52.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 9Cr18Mo-A and 9Cr18Mo QT48-52 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.