Stainless Steel X65Cr14-QT45 vs X65Cr14-QT58
Stainless Steel · X65Cr14 temper comparison
X65Cr14-QT45 and X65Cr14-QT58 are two conditions of the same stainless steel grade, X65Cr14: QT45 (Q&T 44–48 HRC) versus QT58 (Q&T 57–59 HRC). The chemistry is identical, so every difference below comes from the condition. X65Cr14-QT58 is the stronger of the two: yield strength 1,750 MPa (254 ksi) against 1,250 MPa (181 ksi) for X65Cr14-QT45, about 40% more; tensile strength follows at 2,050 MPa (297 ksi) vs 1,500 MPa (218 ksi). In exchange, X65Cr14-QT45 is the more ductile: elongation 6% versus 1.5% for X65Cr14-QT58, and X65Cr14-QT58 is harder (660 HV vs 460 HV). X65Cr14-QT45 runs hotter in service (350°C vs 180°C continuous). On the shop floor, X65Cr14-QT45 machines more easily (poor vs not recommended).
X65Cr14-QT45Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
X65Cr14-QT58Choose it when strength drives the design.
X65Cr14-QT45 vs X65Cr14-QT58: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all stainless 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 stainless 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
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Vickers
Same in both: Elastic (Young's) Modulus 215 GPa31.2 Msi · Shear Modulus 83 GPa12 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.28 · Hardness, Brinell 235 HB · Hardness, Rockwell B 99 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.7 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 25 W/m·K14.4 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.5 µm/m·K5.8 µin/in·°F · Latent Heat of Fusion 260 J/g112 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) -0.3 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Polishability
Same in both: Machinability Rating (AISI 1212 = 100 %) 45% · Weldability 20 / 100 · Formability (cold) 35 / 100 · Castability 40 / 100 · Brazeability / Solderability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 52 MJ/kg22,356 BTU/lb · Embodied Carbon (primary production) 3.8 kg CO₂/kg · Embodied Water 150 L/kg18 gal/lb · Typical Recycled Content 55%
Strength versus weight
Yield strength against density for every stainless steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
X65Cr14-QT45 vs X65Cr14-QT58 — frequently asked
Is X65Cr14-QT58 stronger than X65Cr14-QT45?
Yes. X65Cr14-QT58 has a typical yield strength of 1,750 MPa (254 ksi) against 1,250 MPa (181 ksi) for X65Cr14-QT45 — about 40% more. Tensile strength is 2,050 MPa (297 ksi) vs 1,500 MPa (218 ksi).
Which condition does FabDigit quote by default, QT45 or QT58?
A is the default X65Cr14 condition in the FabDigit quote flow (neither QT45 nor QT58). 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, X65Cr14-QT45 or X65Cr14-QT58?
X65Cr14-QT45. Its machinability rates poor (18/100) against not recommended (5/100) for X65Cr14-QT58.
Ready to make it?
Upload a CAD file and FabDigit prices the part in X65Cr14-QT45 and X65Cr14-QT58 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.