Steel A369 Grade FPB
ASTM A369 Grade FPB
A369 Grade FPB is a carbon-manganese forged and bored pipe grade under ASTM A369, available normalized, normalized-and-tempered or annealed.
Reference datasheet — A369 Grade FPB is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
Values for the N condition
A369 Grade FPB tempers and conditions
A369 Grade FPB is supplied in 4 conditions, soft to hard. N is the default FabDigit quotes; the values on this page are for it.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Solution annealed | Softest permitted condition — pick for maximum machinability and cold bending of the bored pipe, at the cost of lower strength margin. | 260 | 440 | 38 | 131 HB | — |
Isothermal annealed | Alternative anneal allowed by A369 giving very uniform ferrite-pearlite in heavy forged sections with minimal distortion. | 265 | 450 | 37 | 135 HB | 10 % IACS |
Normalized and tempered | Choose when heavy sections need residual-stress relief and slightly improved toughness/uniformity for thick-wall bored pipe. | 285 | 465 | 35 | 140 HB | 10 % IACS |
NDefault Normalized | Standard supply condition for FPB forged and bored pipe: uniform fine ferrite-pearlite, best combination of strength and toughness. | 295 | 480 | 34 | 147 HB | — |
What is A369 Grade FPB?
A369 Grade FPB is a carbon-manganese forged and bored pipe grade under ASTM A369, available normalized, normalized-and-tempered or annealed. It is specified where high-temperature piping needs greater allowable stress than FPA, offering 295 MPa yield, 480 MPa tensile, 34 % elongation and 147 HB (80 HRB) in forged pipe and header forms. Maximum service temperature is 425 °C and there is no corrosion resistance, so external coatings or insulation systems are required. Machinability is about 65 on the 1212 scale; drop to Grade FPA if weldability and low cost outrank strength. A369 Grade FPB has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,470°C (2,678 °F). A369 Grade FPB has a yield strength of 295 MPa (42.8 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 87% of steel grades. Elongation at break is 34% and the elastic modulus is 200 GPa (29 Msi).
What is A369 Grade FPB used for?
- High-pressure steam piping
- Boiler headers
- Power generation piping
Advantages
- Conducts heat well — 52 W/m·K (30 BTU/hr·ft·°F), better than 98% of steel grades
- Ductile — tolerates forming and impact — 34%, better than 97% of steel grades
- Easy to machine — 65/100, better than 93% of steel grades
- Readily welded — 88/100, better than 87% of steel grades
- Forms and bends easily — 70/100, better than 86% of steel grades
Limitations
- Low strength — 295 MPa (42.8 ksi), worse than 87% of steel grades
- Hard to polish — 45/100, worse than 84% of steel grades
A369 Grade FPB properties
Typical room-temperature values for A369 Grade FPB-N; bars are the position among steel grades.
Physical3
A369 Grade FPB has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,470°C (2,678 °F).
Mechanical16
A369 Grade FPB has a yield strength of 295 MPa (42.8 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 87% of steel grades. Elongation at break is 34% and the elastic modulus is 200 GPa (29 Msi).
Thermal6
A369 Grade FPB is rated for continuous service to 425°C (797 °F). It conducts heat at 52 W/m·K (30 BTU/hr·ft·°F), better than 98% of steel grades. Thermal expansion is 12 µm/m·K (6.67 µin/in·°F).
Electrical3
A369 Grade FPB conducts electricity at 10 % IACS, better than 83% of steel grades.
Chemical & Environmental3
Corrosion resistance is not recommended (12/100), worse than 53% of steel grades.
Sustainability4
Producing a kilogram of A369 Grade FPB takes about 25 MJ of energy and emits 2 kg of CO₂ — less than 82% of steel grades. Typical recycled content is 25%.
Manufacturability8
A369 Grade FPB's machinability is good (65/100, better than 93% of steel grades); weldability excellent (88/100); formability very good (70/100).
Common Calculations5
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the steel family
Yield strength against density for every steel grade FabDigit runs. A369 Grade FPB is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A369 Grade FPB
Is A369 Grade FPB easy to machine?
Machines readily with carbide or HSS at ~60–65 % of AISI 1212; gummy in the annealed state so use positive rake and good chip control for the bore.
Can A369 Grade FPB be welded?
Excellent weldability by SMAW/GTAW/SAW with E7018 or ER70S-2 fillers; preheat 100–150 °C for heavy walls and PWHT per ASME B31.1/B31.3 for thick sections.
Can A369 Grade FPB be formed, bent or molded?
Hot forging and hot bending are routine; cold bending is possible in the annealed condition, and forged pipe must be re-heat-treated after hot forming.
A369 Grade FPB chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| Cmax per ASTM A369 Grade FPB | ≤ 0.3 | 0.25 |
| Mn | 0.29 – 1.06 | 0.8 |
| P | ≤ 0.04 | 0.02 |
| S | ≤ 0.04 | 0.02 |
| Siminimum only | ≥ 0.1 | 0.25 |
| Fe | balance |
What surface finishes work on A369 Grade FPB?
No anodizing; protect with shop primer, epoxy or zinc coatings, or aluminize/phosphate for high-temperature and outdoor service.
Surface treatments FabDigit runs on steel parts — pick them in the quote configurator or call them out on the drawing. Each links to its datasheet in the surface-finish library (thickness, specs, call-out, material verdicts).
Organic Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel A369 Grade FPB in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- A369 FPB
How much does A369 Grade FPB cost?
A369 Grade FPB is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
A369 Grade FPB — frequently asked
What is A369 Grade FPB used for?
A369 Grade FPB is typically used for high-pressure steam piping, boiler headers and power generation piping. In short: stronger than A369 FPA; weldable high-temperature pipe; common C-Mn header grade.
What is the yield strength of A369 Grade FPB?
A369 Grade FPB has a typical yield strength of 295 MPa (42.8 ksi) and a tensile strength of 480 MPa (69.6 ksi) — weaker than 87% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A369 Grade FPB easy to machine?
Reasonably — machinability is rated good (65/100, better than 93% of steel grades). Machines readily with carbide or HSS at ~60–65 % of AISI 1212; gummy in the annealed state so use positive rake and good chip control for the bore.
Can A369 Grade FPB be welded?
Yes — weldability is rated excellent (88/100). Excellent weldability by SMAW/GTAW/SAW with E7018 or ER70S-2 fillers; preheat 100–150 °C for heavy walls and PWHT per ASME B31.1/B31.3 for thick sections.
What surface finishes work on A369 Grade FPB?
No anodizing; protect with shop primer, epoxy or zinc coatings, or aluminize/phosphate for high-temperature and outdoor service.
Can A369 Grade FPB be formed, bent or molded?
Hot forging and hot bending are routine; cold bending is possible in the annealed condition, and forged pipe must be re-heat-treated after hot forming.
What is the maximum service temperature of A369 Grade FPB?
A369 Grade FPB is rated for continuous use to about 425°C (797 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A369 Grade FPB-N and A369 Grade FPB-A?
N is the default condition — standard supply condition for FPB forged and bored pipe: uniform fine ferrite-pearlite, best combination of strength and toughness. A: softest permitted condition — pick for maximum machinability and cold bending of the bored pipe, at the cost of lower strength margin. Yield strength is 295 MPa in N versus 260 MPa in A.
How much does A369 Grade FPB cost?
A369 Grade FPB is a standard-cost steel ($$), cheaper than about 71% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- ASTM A369/A369M — Carbon and Ferritic Alloy Steel Forged and Bored Pipe for High-Temperature Service — ASTM International (2018)
- ASME BPVC Section II Part D — Materials Properties — ASME (2023)
- ASME B31.3 Process Piping / B31.1 Power Piping — ASME (2022)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- Machinery's Handbook, 31st ed. — Industrial Press (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.