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Steel A203 vs AR400

Steel · grade comparison

Steel A203 and AR400 are both steel grades. AR400 is the stronger of the two: yield strength 1,050 MPa (152 ksi) against 325 MPa (47.1 ksi) for A203, about 3.2 times as much; tensile strength follows at 1,250 MPa (181 ksi) vs 535 MPa (77.6 ksi). In exchange, A203 is the more ductile: elongation 25% versus 11% for AR400, and AR400 is harder (400 HB vs 156 HB). A203 runs hotter in service (370°C vs 250°C continuous) and AR400 conducts heat better (42 W/m·K vs 35 W/m·K). On the shop floor, A203 machines more easily (fair vs poor) and A203 sits in a lower cost tier (standard, $$) than AR400 (premium, $$$).

A203Choose it when the part is bent, formed or impact-loaded, or when the part sees heat.

AR400Choose it when strength drives the design.

A203 vs AR400: properties

A203AR400

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

204 GPa29.6 Msi
205 GPa29.7 Msi

Shear Modulus

79 GPa11.5 Msi
80 GPa11.6 Msi

Tensile Strength (Ultimate)

535 MPa77.6 ksi
1,250 MPa181 ksi

Yield Strength (0.2% offset)

325 MPa47.1 ksi
1,050 MPa152 ksi

Elongation at Break

25%
11%

Reduction in Area

58%
40%

Compressive Strength

325 MPa47.1 ksi
1,100 MPa160 ksi

Shear Strength

365 MPa52.9 ksi
780 MPa113 ksi

Fatigue Strength (Endurance Limit)

245 MPa35.5 ksi
520 MPa75.4 ksi

Fracture Toughness (K_IC)

155 MPa·√m141 ksi·√in
70 MPa·√m63.7 ksi·√in

Charpy V-Notch Impact (RT)

145 J107 ft·lbf
30 J22.1 ft·lbf

Hardness, Brinell

156 HB
400 HB

Hardness, Rockwell B

82 HRB
—

Hardness, Vickers

164 HV
420 HV

Hardness, Rockwell C

—
43 HRC

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

Physical

Density and transition temperatures.

Density

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

Melting Point (Solidus)

1,415°C2,579 °F
1,420°C2,588 °F

Liquidus Temperature

1,490°C2,714 °F
1,500°C2,732 °F

Thermal

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

Thermal Conductivity

35 W/m·K20.2 BTU/hr·ft·°F
42 W/m·K24.3 BTU/hr·ft·°F

Specific Heat Capacity

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

Thermal Expansion (CTE, 20–100 °C)

11.2 µm/m·K6.2 µin/in·°F
12 µm/m·K6.7 µin/in·°F

Latent Heat of Fusion

270 J/g116 BTU/lb
250 J/g107 BTU/lb

Max Service Temperature (continuous)

370°C698 °F
250°C482 °F

Min Service Temperature

-101°C-150 °F
-20°C-4 °F

Electrical

Conductivity and insulation.

Electrical Conductivity

7.5 % IACS
8 % IACS

Electrical Resistivity

2.4×10⁻⁷ Ω·m9.45 µΩ·in
2.2×10⁻⁷ Ω·m8.66 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.58 V
—

Corrosion Resistance

16 / 100
12 / 100

Manufacturability

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

Machinability

52 / 100
22 / 100

Machinability Rating (AISI 1212 = 100 %)

54%
20%

Weldability

63 / 100
55 / 100

Formability (cold)

58 / 100
25 / 100

Brazeability / Solderability

58 / 100
20 / 100

Same in both: Polishability 55 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

36 MJ/kg15,477 BTU/lb
28 MJ/kg12,038 BTU/lb

Embodied Carbon (primary production)

2.7 kg CO₂/kg
2.3 kg CO₂/kg

Embodied Water

70 L/kg8.4 gal/lb
45 L/kg5.4 gal/lb

Typical Recycled Content

28%
25%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

68 kN·m/kg
159 kN·m/kg

Specific Stiffness (E / density)

25.9 MN·m/kg
26.1 MN·m/kg

Modulus of Resilience

259 kJ/m³
2,689 kJ/m³

Thermal Diffusivity

9.6 mm²/s
11.4 mm²/s

Thermal Shock Resistance Index

8
21

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 scaleAR400A203

Manufacturing and finishing

CapabilityA203AR400
CNC machining—Yes
Sheet metal—Yes
Default condition—Q&T
Relative cost$$ Standard$$$ Premium
Min. machined wall—0.8 mm
Best machined surface—Ra 1.6 µm
AlCrN—Yes
AlTiN—Yes
Black Oxide—Yes
CVD Al2O3—Yes
CVD TiCN—Yes
CVD TiN—Yes
Cerakote—Yes
Chrome Plating—Yes
CrN—Yes
DLC—Yes
E-Coating—Yes
HVOF Coating—Yes
Hot-Dip Galvanizing—Yes
MoS2—Yes
Multilayer CVD—Yes
Nickel Plating—Yes
PTFE Coating—Yes
Painting—Yes

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

A203 vs AR400 — frequently asked

Is AR400 stronger than A203?

Yes. AR400 has a typical yield strength of 1,050 MPa (152 ksi) against 325 MPa (47.1 ksi) for A203 — about 3.2 times as much. Tensile strength is 1,250 MPa (181 ksi) vs 535 MPa (77.6 ksi).

Which is cheaper, A203 or AR400?

A203 is the lower-cost material: it sits in the standard 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, A203 or AR400?

A203. Its machinability rates fair (52/100) against poor (22/100) for AR400; for welding the order is A203 first (good, 63/100) then AR400 (good, 55/100).

Ready to make it?

Upload a CAD file and FabDigit prices the part in A203 and AR400 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.