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Steel A266 vs A369 Grade FPB

Steel · grade comparison

Steel A266 and A369 Grade FPB are both steel grades. A266 is the stronger of the two: tensile strength 550 MPa (79.8 ksi) against 480 MPa (69.6 ksi) for A369 Grade FPB, about 15% more. In exchange, A369 Grade FPB is the more ductile: elongation 34% versus 26% for A266, and A266 is harder (160 HB vs 147 HB). On the shop floor, A266 sits in a lower cost tier (budget, $) than A369 Grade FPB (standard, $$).

A266Choose it when strength drives the design, or when cost is the deciding factor.

A369 Grade FPBChoose it when the part is bent, formed or impact-loaded.

A266 vs A369 Grade FPB: properties

A266A369 Grade FPB

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Tensile Strength (Ultimate)

550 MPa79.8 ksi
480 MPa69.6 ksi

Yield Strength (0.2% offset)

290 MPa42.1 ksi
295 MPa42.8 ksi

Elongation at Break

26%
34%

Reduction in Area

48%
55%

Shear Strength

345 MPa50 ksi
300 MPa43.5 ksi

Fatigue Strength (Endurance Limit)

235 MPa34.1 ksi
215 MPa31.2 ksi

Fracture Toughness (K_IC)

120 MPa·√m109 ksi·√in
90 MPa·√m81.9 ksi·√in

Charpy V-Notch Impact (RT)

80 J59 ft·lbf
65 J47.9 ft·lbf

Hardness, Brinell

160 HB
147 HB

Hardness, Rockwell B

84 HRB
80 HRB

Hardness, Vickers

168 HV
150 HV

Same in both: Elastic (Young's) Modulus 200 GPa29 Msi · Shear Modulus 79 GPa11.5 Msi · Bulk Modulus 160 GPa23.2 Msi · Poisson's Ratio 0.29 · Compressive Strength 290 MPa42.1 ksi

Physical

Density and transition temperatures.

Melting Point (Solidus)

1,425°C2,597 °F
1,470°C2,678 °F

Liquidus Temperature

1,510°C2,750 °F
1,515°C2,759 °F

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

51 W/m·K29.5 BTU/hr·ft·°F
52 W/m·K30 BTU/hr·ft·°F

Thermal Expansion (CTE, 20–100 °C)

11.9 µm/m·K6.6 µin/in·°F
12 µm/m·K6.7 µin/in·°F

Latent Heat of Fusion

247 J/g106 BTU/lb
270 J/g116 BTU/lb

Same in both: Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Max Service Temperature (continuous) 425°C797 °F · Min Service Temperature -29°C-20 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Conductivity 10 % IACS · Electrical Resistivity 1.7×10⁻⁷ Ω·m6.69 µΩ·in

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Galvanic Potential (seawater, vs SCE)

-0.62 V
-0.61 V

Corrosion Resistance

10 / 100
12 / 100

Manufacturability

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

Machinability

62 / 100
65 / 100

Machinability Rating (AISI 1212 = 100 %)

60%
62%

Formability (cold)

65 / 100
70 / 100

Brazeability / Solderability

60 / 100
70 / 100

Castability

—
55 / 100

Same in both: Weldability 88 / 100 · Polishability 45 / 100

Sustainability

Primary-production footprint per kilogram.

Typical Recycled Content

28%
25%

Same in both: Embodied Energy (primary production) 25 MJ/kg10,748 BTU/lb · Embodied Carbon (primary production) 2 kg CO₂/kg · Embodied Water 45 L/kg5.4 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

70 kN·m/kg
61 kN·m/kg

Modulus of Resilience

210 kJ/m³
218 kJ/m³

Thermal Diffusivity

13.8 mm²/s
14.1 mm²/s

Thermal Shock Resistance Index

12
10

Same in both: Specific Stiffness (E / density) 25.5 MN·m/kg

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 scaleA266A369 Grade FPB

Manufacturing and finishing

CapabilityA266A369 Grade FPB
Default condition——
Relative cost$ Budget$$ Standard
Min. machined wall——
Best machined surface——

Both take the same 9 finishes: Copper Plating, Electroless Nickel (EN), Epoxy Coating, Gold Plating, Hard Chrome Plating, Manganese Phosphate, Plasma Spray, Silver Plating, Zinc Phosphate.

A266 vs A369 Grade FPB — frequently asked

Is A266 stronger than A369 Grade FPB?

Yes. A266 has a typical tensile strength of 550 MPa (79.8 ksi) against 480 MPa (69.6 ksi) for A369 Grade FPB — about 15% more.

Which is cheaper, A266 or A369 Grade FPB?

A266 is the lower-cost material: it sits in the budget tier ($) while A369 Grade FPB is standard ($$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

When should I choose A266 over A369 Grade FPB?

Pick A266 when strength drives the design, or when cost is the deciding factor. Pick A369 Grade FPB when the part is bent, formed or impact-loaded.

Ready to make it?

Upload a CAD file and FabDigit prices the part in A266 and A369 Grade FPB 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.