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Steel AR400 vs En40B

Steel · grade comparison

Steel AR400 and En40B are both steel grades. AR400 is the stronger of the two: yield strength 1,050 MPa (152 ksi) against 745 MPa (108 ksi) for En40B, about 41% more; tensile strength follows at 1,250 MPa (181 ksi) vs 930 MPa (135 ksi). In exchange, En40B is the more ductile: elongation 15% versus 11% for AR400, and AR400 is harder (400 HB vs 277 HB). En40B runs hotter in service (500°C vs 250°C continuous) and AR400 conducts heat better (42 W/m·K vs 34 W/m·K). On the shop floor, En40B machines more easily (fair vs poor), AR400 welds better (good vs poor), and En40B sits in a lower cost tier (budget, $) than AR400 (premium, $$$).

AR400Choose it when strength drives the design, or when it will be welded.

En40BChoose it when the part is bent, formed or impact-loaded, or when the part sees heat.

AR400 vs En40B: properties

AR400En40B

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

205 GPa29.7 Msi
210 GPa30.5 Msi

Tensile Strength (Ultimate)

1,250 MPa181 ksi
930 MPa135 ksi

Yield Strength (0.2% offset)

1,050 MPa152 ksi
745 MPa108 ksi

Elongation at Break

11%
15%

Reduction in Area

40%
50%

Compressive Strength

1,100 MPa160 ksi
750 MPa109 ksi

Shear Strength

780 MPa113 ksi
560 MPa81.2 ksi

Fatigue Strength (Endurance Limit)

520 MPa75.4 ksi
440 MPa63.8 ksi

Fracture Toughness (K_IC)

70 MPa·√m63.7 ksi·√in
80 MPa·√m72.8 ksi·√in

Charpy V-Notch Impact (RT)

30 J22.1 ft·lbf
45 J33.2 ft·lbf

Hardness, Brinell

400 HB
277 HB

Hardness, Rockwell C

43 HRC
29 HRC

Hardness, Vickers

420 HV
290 HV

Same in both: Shear Modulus 80 GPa11.6 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29

Physical

Density and transition temperatures.

Density

7.85 g/cm³0.28 lb/in³
7.8 g/cm³0.28 lb/in³

Liquidus Temperature

1,500°C2,732 °F
1,480°C2,696 °F

Same in both: Melting Point (Solidus) 1,420°C2,588 °F

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

42 W/m·K24.3 BTU/hr·ft·°F
34 W/m·K19.6 BTU/hr·ft·°F

Specific Heat Capacity

470 J/kg·K0.11 BTU/lb·°F
460 J/kg·K0.11 BTU/lb·°F

Max Service Temperature (continuous)

250°C482 °F
500°C932 °F

Min Service Temperature

-20°C-4 °F
-40°C-40 °F

Same in both: Thermal Expansion (CTE, 20–100 °C) 12 µm/m·K6.7 µin/in·°F · Latent Heat of Fusion 250 J/g107 BTU/lb

Electrical

Conductivity and insulation.

Electrical Conductivity

8 % IACS
6.6 % IACS

Electrical Resistivity

2.2×10⁻⁷ Ω·m8.66 µΩ·in
2.6×10⁻⁷ Ω·m10.2 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

12 / 100
15 / 100

Galvanic Potential (seawater, vs SCE)

—
-0.6 V

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

22 / 100
45 / 100

Machinability Rating (AISI 1212 = 100 %)

20%
50%

Weldability

55 / 100
20 / 100

Formability (cold)

25 / 100
20 / 100

Brazeability / Solderability

20 / 100
40 / 100

Polishability

55 / 100
65 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

28 MJ/kg12,038 BTU/lb
31 MJ/kg13,328 BTU/lb

Embodied Carbon (primary production)

2.3 kg CO₂/kg
2.2 kg CO₂/kg

Embodied Water

45 L/kg5.4 gal/lb
60 L/kg7.2 gal/lb

Same in both: Typical Recycled Content 25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

159 kN·m/kg
119 kN·m/kg

Specific Stiffness (E / density)

26.1 MN·m/kg
26.9 MN·m/kg

Modulus of Resilience

2,689 kJ/m³
1,321 kJ/m³

Thermal Diffusivity

11.4 mm²/s
9.5 mm²/s

Thermal Shock Resistance Index

21
13

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.

2005001,0002,0007.588.5Density (g/cm³)Yield strength (MPa) — log scaleAR400En40B

Manufacturing and finishing

CapabilityAR400En40B
CNC machiningYes—
Sheet metalYes—
Default conditionQ&T—
Relative cost$$$ Premium$ Budget
Min. machined wall0.8 mm—
Best machined surfaceRa 1.6 µm—
AlCrNYes—
AlTiNYes—
Black OxideYes—
CVD Al2O3Yes—
CVD TiCNYes—
CVD TiNYes—
CerakoteYes—
Chrome PlatingYes—
CrNYes—
DLCYes—
E-CoatingYes—
HVOF CoatingYes—
Hot-Dip GalvanizingYes—
MoS2Yes—
Multilayer CVDYes—
Nickel PlatingYes—
PTFE CoatingYes—
PaintingYes—

They share 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

AR400 vs En40B — frequently asked

Is AR400 stronger than En40B?

Yes. AR400 has a typical yield strength of 1,050 MPa (152 ksi) against 745 MPa (108 ksi) for En40B — about 41% more. Tensile strength is 1,250 MPa (181 ksi) vs 930 MPa (135 ksi).

Which is cheaper, AR400 or En40B?

En40B 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 En40B?

En40B. Its machinability rates fair (45/100) against poor (22/100) for AR400; for welding the order is AR400 first (good, 55/100) then En40B (poor, 20/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in AR400 and En40B 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.