Steel X11CrMo9-1 +I vs X11CrMo9-1 +QT
Steel · X11CrMo9-1 temper comparison
X11CrMo9-1 +I and X11CrMo9-1 +QT are two conditions of the same steel grade, X11CrMo9-1: +I (isothermally annealed) versus +QT (quenched and tempered). The chemistry is identical, so every difference below comes from the condition. X11CrMo9-1 +QT is the stronger of the two: yield strength 360 MPa (52.2 ksi) against 260 MPa (37.7 ksi) for X11CrMo9-1 +I, about 38% more; tensile strength follows at 570 MPa (82.7 ksi) vs 470 MPa (68.2 ksi). In exchange, X11CrMo9-1 +I is the more ductile: elongation 28% versus 22% for X11CrMo9-1 +QT, and X11CrMo9-1 +QT is harder (200 HB vs 160 HB). On the shop floor, X11CrMo9-1 +I machines more easily (good vs fair).
X11CrMo9-1 +IChoose it when the part is bent, formed or impact-loaded, or when the part is machined in volume.
X11CrMo9-1 +QTChoose it when strength drives the design.
X11CrMo9-1 +I vs X11CrMo9-1 +QT: 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
Fatigue Strength (Endurance Limit)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell B
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 213 GPa30.9 Msi · Shear Modulus 82 GPa11.9 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.3 · Compressive Strength 300 MPa43.5 ksi · Shear Strength 340 MPa49.3 ksi · Fracture Toughness (K_IC) 100 MPa·√m91 ksi·√in
Physical
Density and transition temperatures.
Same in both: Density 7.75 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.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 29 W/m·K16.8 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 11.3 µm/m·K6.3 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -30°C-22 °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).
Same in both: Galvanic Potential (seawater, vs SCE) -0.55 V · Corrosion Resistance 30 / 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 40 / 100 · Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 31 MJ/kg13,328 BTU/lb · Embodied Carbon (primary production) 2.4 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 25%
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.
X11CrMo9-1 +I vs X11CrMo9-1 +QT — frequently asked
Is X11CrMo9-1 +QT stronger than X11CrMo9-1 +I?
Yes. X11CrMo9-1 +QT has a typical yield strength of 360 MPa (52.2 ksi) against 260 MPa (37.7 ksi) for X11CrMo9-1 +I — about 38% more. Tensile strength is 570 MPa (82.7 ksi) vs 470 MPa (68.2 ksi).
Which condition does FabDigit quote by default, +I or +QT?
+NT is the default X11CrMo9-1 condition in the FabDigit quote flow (neither +I nor +QT). 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, X11CrMo9-1 +I or X11CrMo9-1 +QT?
X11CrMo9-1 +I. Its machinability rates good (55/100) against fair (40/100) for X11CrMo9-1 +QT.
Ready to make it?
Upload a CAD file and FabDigit prices the part in X11CrMo9-1 +I and X11CrMo9-1 +QT 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.