Steel 4335V (Modified 4340)-QT180 vs 4335V (Modified 4340)-QT200
Steel · 4335V (Modified 4340) temper comparison
4335V (Modified 4340)-QT180 and 4335V (Modified 4340)-QT200 are two conditions of the same steel grade, 4335V (Modified 4340): QT180 (Q&T 1240 MPa) versus QT200 (Q&T 1380 MPa). The chemistry is identical, so every difference below comes from the condition. 4335V (Modified 4340)-QT200 is the stronger of the two: yield strength 1,240 MPa (180 ksi) against 1,140 MPa (165 ksi) for 4335V (Modified 4340)-QT180, about 9% more; tensile strength follows at 1,380 MPa (200 ksi) vs 1,240 MPa (180 ksi). In exchange, 4335V (Modified 4340)-QT180 is the more ductile: elongation 15% versus 13% for 4335V (Modified 4340)-QT200, and 4335V (Modified 4340)-QT200 is harder (401 HB vs 375 HB). 4335V (Modified 4340)-QT180 runs hotter in service (400°C vs 340°C continuous).
4335V (Modified 4340)-QT180Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
4335V (Modified 4340)-QT200Choose it when strength drives the design.
4335V (Modified 4340)-QT180 vs 4335V (Modified 4340)-QT200: propertiesHow to read these bars
- One bar per material. A full bar is the highest value among all 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 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.
4335V (Modified 4340)-QT1804335V (Modified 4340)-QT200
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, Brinell
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 0.29
Physical
Density and transition temperatures.
Same in both: Density 7.83 g/cm³0.28 lb/in³ · Melting Point (Solidus) 1,416°C2,581 °F · Liquidus Temperature 1,490°C2,714 °F
Thermal
How each material carries heat and how hot it can run.
Max Service Temperature (continuous)
Same in both: Thermal Conductivity 42 W/m·K24.3 BTU/hr·ft·°F · Specific Heat Capacity 475 J/kg·K0.11 BTU/lb·°F · Thermal Expansion (CTE, 20–100 °C) 12.3 µm/m·K6.8 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -73°C-99 °F
Electrical
Conductivity and insulation.
Same in both: Electrical Conductivity 8 % IACS · Electrical Resistivity 2.2×10⁻⁷ Ω·m8.66 µΩ·in
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Same in both: Galvanic Potential (seawater, vs SCE) -0.6 V · Corrosion Resistance 12 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Same in both: Weldability 22 / 100 · Formability (cold) 10 / 100 · Brazeability / Solderability 35 / 100 · Polishability 78 / 100
Sustainability
Primary-production footprint per kilogram.
Same in both: Embodied Energy (primary production) 34 MJ/kg14,617 BTU/lb · Embodied Carbon (primary production) 2.6 kg CO₂/kg · Embodied Water 60 L/kg7.2 gal/lb · Typical Recycled Content 25%
Strength versus weight
Yield strength against density for every steel grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.
4335V (Modified 4340)-QT180 vs 4335V (Modified 4340)-QT200 — frequently asked
Is 4335V (Modified 4340)-QT200 stronger than 4335V (Modified 4340)-QT180?
Yes. 4335V (Modified 4340)-QT200 has a typical yield strength of 1,240 MPa (180 ksi) against 1,140 MPa (165 ksi) for 4335V (Modified 4340)-QT180 — about 9% more. Tensile strength is 1,380 MPa (200 ksi) vs 1,240 MPa (180 ksi).
Which condition does FabDigit quote by default, QT180 or QT200?
QT220 is the default 4335V (Modified 4340) condition in the FabDigit quote flow (neither QT180 nor QT200). 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, 4335V (Modified 4340)-QT180 or 4335V (Modified 4340)-QT200?
4335V (Modified 4340)-QT180, by a small margin. Both rate poor for machinability — 32/100 against 27/100 for 4335V (Modified 4340)-QT200.
Ready to make it?
Upload a CAD file and FabDigit prices the part in 4335V (Modified 4340)-QT180 and 4335V (Modified 4340)-QT200 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.