Steel A369 Grade FPA vs A369 Grade FPB
Steel · grade comparison
Steel A369 Grade FPA and A369 Grade FPB are both steel grades. A369 Grade FPB is the stronger of the two: yield strength 295 MPa (42.8 ksi) against 250 MPa (36.3 ksi) for A369 Grade FPA, about 18% more; tensile strength follows at 480 MPa (69.6 ksi) vs 415 MPa (60.2 ksi). A369 Grade FPB is harder — 147 HB against 120 HB for A369 Grade FPA — which matters for wear surfaces and threads.
A369 Grade FPBChoose it when strength drives the design, or when surface hardness matters.
A369 Grade FPA vs A369 Grade FPB: 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.
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 B
Hardness, Vickers
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
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 Expansion (CTE, 20–100 °C)
Same in both: Thermal Conductivity 52 W/m·K30 BTU/hr·ft·°F · Specific Heat Capacity 470 J/kg·K0.11 BTU/lb·°F · Latent Heat of Fusion 270 J/g116 BTU/lb · 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)
Same in both: Corrosion Resistance 12 / 100
Manufacturability
FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.
Machinability Rating (AISI 1212 = 100 %)
Weldability
Formability (cold)
Polishability
Same in both: Machinability 65 / 100 · Castability 55 / 100 · Brazeability / Solderability 70 / 100
Sustainability
Primary-production footprint per kilogram.
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 · Typical Recycled Content 25%
Common Calculations
Ratios derived from the values above.
Specific Strength (UTS / density)
Modulus of Resilience
Thermal Shock Resistance Index
Same in both: Specific Stiffness (E / density) 25.5 MN·m/kg · Thermal Diffusivity 14.1 mm²/s
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 | A369 Grade FPA | A369 Grade FPB |
|---|---|---|
| Default condition | — | — |
| Relative cost | $$ Standard | $$ 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.
A369 Grade FPA vs A369 Grade FPB — frequently asked
Is A369 Grade FPB stronger than A369 Grade FPA?
Yes. A369 Grade FPB has a typical yield strength of 295 MPa (42.8 ksi) against 250 MPa (36.3 ksi) for A369 Grade FPA — about 18% more. Tensile strength is 480 MPa (69.6 ksi) vs 415 MPa (60.2 ksi).
Which is cheaper, A369 Grade FPA or A369 Grade FPB?
Both sit in the same relative cost tier ($$, standard); the part price will be decided by machining time, tolerance and quantity rather than by the material.
When should I choose A369 Grade FPA over A369 Grade FPB?
Pick A369 Grade FPB when strength drives the design, or when surface hardness matters.
Ready to make it?
Upload a CAD file and FabDigit prices the part in A369 Grade FPA 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.