Steel A369 FP1
ASTM A369 FP1
A369 FP1 is a forged and bored ferritic C-0.5Mo alloy steel pipe for high-temperature service, matching seamless A335 P1 and equivalent to 16Mo3 / 1.5415.
Reference datasheet — A369 FP1 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 ANN condition
A369 FP1 tempers and conditions
A369 FP1 is supplied in 4 conditions, soft to hard. ANN 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 |
|---|---|---|---|---|---|---|
ANNDefault Annealed | Standard stocked condition for forged-and-bored FP1 pipe: softest, most machinable, best for cold bending and subsequent welding. | 270 | 460 | 34 | 140 HB | — |
Stress relieved | Supplementary supply condition for heavy bored sections where residual stress from forging/boring or field welding must be reduced without a full re-austenitization. | 295 | 490 | 30 | 155 HB | 8.2 % IACS |
Normalized and Tempered | Code-preferred condition for high-temperature pressure piping: balanced strength, good toughness and dimensionally stable microstructure for creep service. | 300 | 480 | 32 | 150 HB | — |
Normalized | Choose when finer ferrite-pearlite grain and slightly higher strength/toughness are wanted; usually followed by tempering for pressure service. | 310 | 500 | 30 | 158 HB | — |
What is A369 FP1?
A369 FP1 is a forged and bored ferritic C-0.5Mo alloy steel pipe for high-temperature service, matching seamless A335 P1 and equivalent to 16Mo3 / 1.5415. It is used for heavy-wall steam piping and forged fittings where seamless pipe is not available in the required size, and is supplied annealed, normalized, normalized and tempered, or stress relieved. The default condition gives 270 MPa yield, 460 MPa tensile, 34 % elongation, about 140 HB and service to 470 °C, with machinability 60, weldability 72 and formability 70. It has no oxidation or corrosion protection and needs Mo-bearing filler with PWHT; above 470 °C step up to 1.25Cr-0.5Mo A369 FP11. A369 FP1 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 FP1 has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 91% of steel grades. Elongation at break is 34% and the elastic modulus is 210 GPa (30.5 Msi).
What is A369 FP1 used for?
- High-temperature steam piping
- Header pipe fittings
- Superheater and reheater connecting piping
- Main steam and feedwater headers
- Refinery hot-oil transfer lines
- Forged pipe spools for power plants
- Thick-wall bored elbows and tees
Advantages
- Ductile — tolerates forming and impact — 34%, better than 97% of steel grades
- High service temperature — 470°C (878 °F), better than 87% of steel grades
- Forms and bends easily — 70/100, better than 86% of steel grades
- Readily welded — 72/100, better than 75% of steel grades
Limitations
- Low strength — 270 MPa (39.2 ksi), worse than 91% of steel grades
A369 FP1 properties
Typical room-temperature values for A369 FP1-ANN; bars are the position among steel grades.
Physical3
A369 FP1 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).
Mechanical15
A369 FP1 has a yield strength of 270 MPa (39.2 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 91% of steel grades. Elongation at break is 34% and the elastic modulus is 210 GPa (30.5 Msi).
Thermal6
A369 FP1 is rated for continuous service to 470°C (878 °F). It conducts heat at 44 W/m·K (25.4 BTU/hr·ft·°F), better than 57% of steel grades. Thermal expansion is 12.2 µm/m·K (6.78 µin/in·°F).
Electrical2
A369 FP1 has an electrical resistivity of 2.1×10⁻⁷ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (13/100), better than 66% of steel grades.
Sustainability4
Producing a kilogram of A369 FP1 takes about 30 MJ of energy and emits 2.3 kg of CO₂ — more than 56% of steel grades. Typical recycled content is 30%.
Manufacturability7
A369 FP1's machinability is good (60/100, better than 83% of steel grades); weldability very good (72/100); 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 FP1 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A369 FP1
Is A369 FP1 easy to machine?
Machines like annealed 4130-class low-alloy steel at ~60 % of AISI 1212; use rigid setups and positive-rake carbide for boring long heavy-wall sections, and expect slightly gummy chips in the fully annealed state.
Can A369 FP1 be welded?
Readily welded with matching Mo-bearing consumables (E7018-A1, ER80S-D2); preheat 120–200 °C on heavy wall and apply 650–720 °C PWHT per ASME B31.1 to restore toughness and control hardness.
Can A369 FP1 be formed, bent or molded?
Hot forge/bend at 950–1200 °C and re-heat-treat afterwards; cold bending is possible with generous radii but work-hardens and needs stress relief.
A369 FP1 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 |
|---|---|---|
| C16Mo3 range 0.12–0.20 | 0.1 – 0.2 | 0.16 |
| Si | 0.1 – 0.5 | 0.3 |
| Mn | 0.3 – 0.8 | 0.6 |
| P | ≤ 0.05 | 0.02 |
| S | ≤ 0.05 | 0.01 |
| Mothe C-0.5Mo creep-strengthening addition | 0.44 – 0.65 | 0.5 |
| Fe | balance |
What surface finishes work on A369 FP1?
No anodizing; protect with alkyd/epoxy or high-temperature aluminium paint, aluminizing or thermal-spray coating, and expect mill scale removal by pickling or blasting before painting.
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 FP1 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- ASTM
- A335 P1
- Similar grades
- 16Mo31.5415
How much does A369 FP1 cost?
A369 FP1 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 FP1 — frequently asked
What is A369 FP1 used for?
A369 FP1 is typically used for high-temperature steam piping, header pipe fittings, superheater and reheater connecting piping, main steam and feedwater headers, refinery hot-oil transfer lines and forged pipe spools for power plants. In short: entry-level Mo creep pipe; 470 °C service limit; most weldable A369 grade.
What is the yield strength of A369 FP1?
A369 FP1 has a typical yield strength of 270 MPa (39.2 ksi) and a tensile strength of 460 MPa (66.7 ksi) — weaker than 91% of steel grades. Strength varies by condition: see the 4 listed tempers.
Is A369 FP1 easy to machine?
Reasonably — machinability is rated good (60/100, better than 83% of steel grades). Machines like annealed 4130-class low-alloy steel at ~60 % of AISI 1212; use rigid setups and positive-rake carbide for boring long heavy-wall sections, and expect slightly gummy chips in the fully annealed state.
Can A369 FP1 be welded?
Yes — weldability is rated very good (72/100). Readily welded with matching Mo-bearing consumables (E7018-A1, ER80S-D2); preheat 120–200 °C on heavy wall and apply 650–720 °C PWHT per ASME B31.1 to restore toughness and control hardness.
What surface finishes work on A369 FP1?
No anodizing; protect with alkyd/epoxy or high-temperature aluminium paint, aluminizing or thermal-spray coating, and expect mill scale removal by pickling or blasting before painting.
Can A369 FP1 be formed, bent or molded?
Hot forge/bend at 950–1200 °C and re-heat-treat afterwards; cold bending is possible with generous radii but work-hardens and needs stress relief.
What is the maximum service temperature of A369 FP1?
A369 FP1 is rated for continuous use to about 470°C (878 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
What is the difference between A369 FP1-ANN and A369 FP1-N?
ANN is the default condition — standard stocked condition for forged-and-bored FP1 pipe: softest, most machinable, best for cold bending and subsequent welding. N: choose when finer ferrite-pearlite grain and slightly higher strength/toughness are wanted; usually followed by tempering for pressure service. Yield strength is 270 MPa in ANN versus 310 MPa in N.
How much does A369 FP1 cost?
A369 FP1 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)
- ASTM A335/A335M — Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service (Grade P1) — ASTM International (2022)
- EN 10216-2 — Seamless steel tubes for pressure purposes (16Mo3, 1.5415) — CEN (2020)
- ASME BPVC Section II Part D — Allowable stresses and physical properties — ASME (2023)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- 16Mo3 / 1.5415 pressure-vessel and boiler tube steel datasheets — various European tube producers (2022)
- API RP 941 — Steels for Hydrogen Service (graphitization guidance for C-0.5Mo) — API (2016)
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.