Stainless Steel S42030 QT-425 vs S42030 QT-650
Stainless Steel · S42030 temper comparison
S42030 QT-425 and S42030 QT-650 are two conditions of the same stainless steel grade, S42030: QT-425 (hardened and tempered at 425 °C (800 °F) — embrittlement range, avoid…) versus QT-650 (hardened and tempered at 650 °C). The chemistry is identical, so every difference below comes from the condition. S42030 QT-425 is the stronger of the two: yield strength 1,330 MPa (193 ksi) against 690 MPa (100 ksi) for S42030 QT-650, about 93% more; tensile strength follows at 1,550 MPa (225 ksi) vs 900 MPa (131 ksi). In exchange, S42030 QT-650 is the more ductile: elongation 18% versus 10% for S42030 QT-425, and S42030 QT-425 is harder (445 HB vs 285 HB). S42030 QT-650 runs hotter in service (550°C vs 400°C continuous). On the shop floor, S42030 QT-650 machines more easily (33 vs 16 out of 100) and S42030 QT-650 welds better (poor vs not recommended).
S42030 QT-425Choose it when strength drives the design.
S42030 QT-650Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
S42030 QT-425 vs S42030 QT-650: 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)
Charpy V-Notch Impact (RT)
Hardness, Brinell
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 · Hardness, Rockwell B 95 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.75 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,450°C2,642 °F · Liquidus Temperature 1,510°C2,750 °F
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Max Service Temperature (continuous)
Same in both: Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.3 µm/m·K5.7 µin/in·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · Min Service Temperature -30°C-22 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
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 %)
Weldability
Formability (cold)
Same in both: Brazeability / Solderability 40 / 100 · Polishability 85 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 48 MJ/kg20,636 BTU/lb · Embodied Carbon (primary production) 4.3 kg CO₂/kg · Embodied Water 150 L/kg18 gal/lb · Typical Recycled Content 50%
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.
S42030 QT-425 vs S42030 QT-650 — frequently asked
Is S42030 QT-425 stronger than S42030 QT-650?
Yes. S42030 QT-425 has a typical yield strength of 1,330 MPa (193 ksi) against 690 MPa (100 ksi) for S42030 QT-650 — about 93% more. Tensile strength is 1,550 MPa (225 ksi) vs 900 MPa (131 ksi).
Which condition does FabDigit quote by default, QT-425 or QT-650?
A is the default S42030 condition in the FabDigit quote flow (neither QT-425 nor QT-650). 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, S42030 QT-425 or S42030 QT-650?
S42030 QT-650, by a small margin. Both rate poor for machinability — 33/100 against 16/100 for S42030 QT-425; for welding the order is S42030 QT-650 first (poor, 25/100) then S42030 QT-425 (not recommended, 10/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in S42030 QT-425 and S42030 QT-650 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.