Stainless Steel 7Cr17MoV QT50-52 vs 7Cr17MoV QT57-59
Stainless Steel · 7Cr17MoV temper comparison
7Cr17MoV QT50-52 and 7Cr17MoV QT57-59 are two conditions of the same stainless steel grade, 7Cr17MoV: QT50-52 (Q&T 50–52 HRC) versus QT57-59 (Q&T + Cryo 57–59 HRC). The chemistry is identical, so every difference below comes from the condition. 7Cr17MoV QT57-59 is the stronger of the two: yield strength 1,780 MPa (258 ksi) against 1,500 MPa (218 ksi) for 7Cr17MoV QT50-52, about 19% more; tensile strength follows at 2,050 MPa (297 ksi) vs 1,700 MPa (247 ksi). In exchange, 7Cr17MoV QT50-52 is the more ductile: elongation 7% versus 2.5% for 7Cr17MoV QT57-59, and 7Cr17MoV QT57-59 is harder (58 HRC vs 51 HRC). 7Cr17MoV QT50-52 runs hotter in service (450°C vs 350°C continuous).
7Cr17MoV QT50-52Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
7Cr17MoV QT57-59Choose it when strength drives the design.
7Cr17MoV QT50-52 vs 7Cr17MoV QT57-59: 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.
7Cr17MoV QT50-527Cr17MoV QT57-59
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 2,100 MPa305 ksi
Physical
Density and transition temperatures.
Same in both: Density 7.75 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 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) 10.2 µm/m·K5.7 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -60°C-76 °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
Same in both: Machinability Rating (AISI 1212 = 100 %) 8% · Weldability 15 / 100 · Formability (cold) 5 / 100 · Brazeability / Solderability 40 / 100 · Polishability 82 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 48 MJ/kg20,636 BTU/lb · Embodied Carbon (primary production) 3.2 kg CO₂/kg · Embodied Water 130 L/kg15.6 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.
7Cr17MoV QT50-52 vs 7Cr17MoV QT57-59 — frequently asked
Is 7Cr17MoV QT57-59 stronger than 7Cr17MoV QT50-52?
Yes. 7Cr17MoV QT57-59 has a typical yield strength of 1,780 MPa (258 ksi) against 1,500 MPa (218 ksi) for 7Cr17MoV QT50-52 — about 19% more. Tensile strength is 2,050 MPa (297 ksi) vs 1,700 MPa (247 ksi).
Which condition does FabDigit quote by default, QT50-52 or QT57-59?
QT55-57 is the default 7Cr17MoV condition in the FabDigit quote flow (neither QT50-52 nor QT57-59). 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, 7Cr17MoV QT50-52 or 7Cr17MoV QT57-59?
7Cr17MoV QT50-52, by a small margin. Both rate not recommended for machinability — 12/100 against 5/100 for 7Cr17MoV QT57-59.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 7Cr17MoV QT50-52 and 7Cr17MoV QT57-59 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.