Stainless Steel X108CrMo17-QT56 vs X108CrMo17-QT58
Stainless Steel · X108CrMo17 temper comparison
X108CrMo17-QT56 and X108CrMo17-QT58 are two conditions of the same stainless steel grade, X108CrMo17: QT56 (hardened + tempered 200–300 °C, 55–57 HRC) versus QT58 (hardened + tempered 150–180 °C, 58–60 HRC). The chemistry is identical, so every difference below comes from the condition. X108CrMo17-QT58 is the stronger of the two: yield strength 1,900 MPa (276 ksi) against 1,750 MPa (254 ksi) for X108CrMo17-QT56, about 9% more; tensile strength follows at 1,970 MPa (286 ksi) vs 1,860 MPa (270 ksi). In exchange, X108CrMo17-QT56 is the more ductile: elongation 3% versus 2% for X108CrMo17-QT58, and X108CrMo17-QT58 is harder (690 HV vs 620 HV). X108CrMo17-QT56 runs hotter in service (280°C vs 180°C continuous).
X108CrMo17-QT56Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
X108CrMo17-QT58Choose it when strength drives the design.
X108CrMo17-QT56 vs X108CrMo17-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.
X108CrMo17-QT56X108CrMo17-QT58
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
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: Shear Modulus 78 GPa11.3 Msi · Bulk Modulus 166 GPa24.1 Msi · Poisson's Ratio 0.28 · Hardness, Brinell 235 HB · Hardness, Rockwell B 98 HRB
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 -70°C-94 °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) -0.25 V
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Polishability
Same in both: Brazeability / Solderability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 58 MJ/kg24,936 BTU/lb · Embodied Carbon (primary production) 5.4 kg CO₂/kg · Embodied Water 160 L/kg19.2 gal/lb · Typical Recycled Content 45%
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.
X108CrMo17-QT56 vs X108CrMo17-QT58 — frequently asked
Is X108CrMo17-QT58 stronger than X108CrMo17-QT56?
Yes. X108CrMo17-QT58 has a typical yield strength of 1,900 MPa (276 ksi) against 1,750 MPa (254 ksi) for X108CrMo17-QT56 — about 9% more. Tensile strength is 1,970 MPa (286 ksi) vs 1,860 MPa (270 ksi).
Which condition does FabDigit quote by default, QT56 or QT58?
A is the default X108CrMo17 condition in the FabDigit quote flow (neither QT56 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 welds better, X108CrMo17-QT56 or X108CrMo17-QT58?
X108CrMo17-QT56. Its weldability rates poor (15/100) against not recommended (8/100) for X108CrMo17-QT58.
Ready to make it?
Upload a CAD file and FabDigit prices the part in X108CrMo17-QT56 and X108CrMo17-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.