Steel AR400 vs EN9
Steel · grade comparison
Steel AR400 and EN9 are both steel grades. AR400 is the stronger of the two: yield strength 1,050 MPa (152 ksi) against 340 MPa (49.3 ksi) for EN9, about 3.1 times as much; tensile strength follows at 1,250 MPa (181 ksi) vs 620 MPa (89.9 ksi). In exchange, EN9 is the more ductile: elongation 16% versus 11% for AR400, and AR400 is harder (400 HB vs 187 HB). EN9 runs hotter in service (350°C vs 250°C continuous) and EN9 conducts heat better (49 W/m·K vs 42 W/m·K). On the shop floor, EN9 machines more easily (fair vs poor), AR400 welds better (good vs fair), and EN9 sits in a lower cost tier (budget, $) than AR400 (premium, $$$).
AR400Choose it when strength drives the design, or when it will be welded.
EN9Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.
AR400 vs EN9: 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.
Mechanical
Strength, stiffness, ductility and hardness at room temperature.
Elastic (Young's) Modulus
Tensile Strength (Ultimate)
Yield Strength (0.2% offset)
Elongation at Break
Compressive Strength
Shear Strength
Fatigue Strength (Endurance Limit)
Fracture Toughness (K_IC)
Charpy V-Notch Impact (RT)
Hardness, Brinell
Hardness, Rockwell C
Hardness, Vickers
Hardness, Rockwell B
Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Reduction in Area 40%
Physical
Density and transition temperatures.
Melting Point (Solidus)
Liquidus Temperature
Same in both: Density 7.85 g/cm³0.28 lb/in³
Thermal
How each material carries heat and how hot it can run.
Thermal Conductivity
Specific Heat Capacity
Thermal Expansion (CTE, 20–100 °C)
Max Service Temperature (continuous)
Same in both: Latent Heat of Fusion 250 J/g107 BTU/lb · Min Service Temperature -20°C-4 °F
Electrical
Conductivity and insulation.
Electrical Conductivity
Electrical Resistivity
Chemical & Environmental
Corrosion and environmental resistance (0–100 scores).
Corrosion Resistance
Galvanic Potential (seawater, vs SCE)
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Brazeability / Solderability
Castability
Same in both: Polishability 55 / 100
Sustainability
Primary-production footprint per kilogram.
Embodied Energy (primary production)
Embodied Carbon (primary production)
Embodied Water
Typical Recycled Content
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Specific Stiffness (E / density)
Modulus of Resilience
Thermal Diffusivity
Thermal Shock Resistance Index
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.
Manufacturing and finishing
| Capability | AR400 | EN9 |
|---|---|---|
| Default condition | Q&T | HR |
| Relative cost | $$$ Premium | $ Budget |
| Min. machined wall | 0.8 mm | 0.8 mm |
| Best machined surface | Ra 1.6 µm | Ra 1.6 µm |
Both are offered for CNC machining and Sheet metal. Both take the same 38 finishes: AlCrN, AlTiN, Black Oxide, CVD Al2O3, CVD TiCN, CVD TiN, Cerakote, Chrome Plating, Copper Plating, CrN, DLC, E-Coating and 26 more.
AR400 vs EN9 — frequently asked
Is AR400 stronger than EN9?
Yes. AR400 has a typical yield strength of 1,050 MPa (152 ksi) against 340 MPa (49.3 ksi) for EN9 — about 3.1 times as much. Tensile strength is 1,250 MPa (181 ksi) vs 620 MPa (89.9 ksi).
Which is cheaper, AR400 or EN9?
EN9 is the lower-cost material: it sits in the budget tier ($) while AR400 is premium ($$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.
Which is easier to machine, AR400 or EN9?
EN9. Its machinability rates fair (50/100) against poor (22/100) for AR400; for welding the order is AR400 first (good, 55/100) then EN9 (fair, 35/100).
Ready to make it?
Upload a CAD file and FabDigit prices the part in AR400 and EN9 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.