Stainless Steel 40Kh13-A vs 40Kh13-QT400
Stainless Steel · 40Kh13 temper comparison
40Kh13-A and 40Kh13-QT400 are two conditions of the same stainless steel grade, 40Kh13: A (solution annealed) versus QT400 (Q&T 400–500 °C). The chemistry is identical, so every difference below comes from the condition. 40Kh13-QT400 is the stronger of the two: yield strength 1,250 MPa (181 ksi) against 420 MPa (60.9 ksi) for 40Kh13-A, about 198% more; tensile strength follows at 1,500 MPa (218 ksi) vs 700 MPa (102 ksi). In exchange, 40Kh13-A is the more ductile: elongation 20% versus 8% for 40Kh13-QT400, and 40Kh13-QT400 is harder (435 HB vs 200 HB). 40Kh13-A runs hotter in service (550°C vs 400°C continuous). On the shop floor, 40Kh13-A machines more easily (fair vs poor).
40Kh13-AChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.
40Kh13-QT400Choose it when strength drives the design.
40Kh13-A vs 40Kh13-QT400: 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
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
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 · Compressive Strength 720 MPa104 ksi · Shear Strength 430 MPa62.4 ksi · Hardness, Rockwell B 94 HRB
Physical
Density and transition temperatures.
Same in both: Density 7.68 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,425°C2,597 °F · Liquidus Temperature 1,500°C2,732 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 28.5 W/m·K16.5 BTU/hr·ft·°F · Specific Heat Capacity 460 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 10.4 µm/m·K5.8 µin/in·°F · Latent Heat of Fusion 270 J/g116 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
Machinability Rating (AISI 1212 = 100 %)
Polishability
Same in both: Weldability 25 / 100 · Formability (cold) 40 / 100 · Castability 40 / 100 · Brazeability / Solderability 45 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 53 MJ/kg22,786 BTU/lb · Embodied Carbon (primary production) 4.5 kg CO₂/kg · Embodied Water 130 L/kg15.6 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.
40Kh13-A vs 40Kh13-QT400 — frequently asked
Is 40Kh13-QT400 stronger than 40Kh13-A?
Yes. 40Kh13-QT400 has a typical yield strength of 1,250 MPa (181 ksi) against 420 MPa (60.9 ksi) for 40Kh13-A — about 198% more. Tensile strength is 1,500 MPa (218 ksi) vs 700 MPa (102 ksi).
Which condition does FabDigit quote by default, A or QT400?
A is the default 40Kh13 condition in the FabDigit quote flow. 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, 40Kh13-A or 40Kh13-QT400?
40Kh13-A. Its machinability rates fair (45/100) against poor (18/100) for 40Kh13-QT400.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 40Kh13-A and 40Kh13-QT400 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.