Steel A335 P11
ASTM A335 P11 · EN 10CrMo5-5
A335 P11 is a seamless 1.25Cr-0.5Mo low-alloy ferritic heat-resistant pipe for power boiler main steam and reheat lines, headers, and refinery high-temperature process piping.
Values for the HR condition
A335 P11 tempers and conditions
A335 P11 is supplied in 5 conditions, soft to hard. HR is the default FabDigit quotes; the values on this page are for it.
Compare all 5 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
full anneal or isothermal anneal (A335 heat-treated condition) | Softest code-compliant condition; choose for maximum bendability, cold expansion and lowest hardness for sour/NACE service. | 275 | 465 | 33 | 140 HB | — |
Normalized and tempered | Default stocked condition for boiler and high-temperature piping: balanced strength, toughness and creep performance with hardness kept under ~163 HB. | 310 | 485 | 30 | 155 HB | — |
HRDefault Hot rolled | Mill hot-finished condition before final heat treatment — used only for redraw/forming stock, since A335 requires final heat treatment for code service. | 340 | 520 | 26 | 170 HB | — |
austenitized ~900–950 °C, air cooled (no temper) | Uniform fine ferrite-bainite with higher strength than annealed; usually followed by tempering, and rarely shipped untempered for code piping. | 350 | 530 | 27 | 170 HB | — |
Quenched and tempered | Used for heavy-wall forgings/pipe or bolting-type parts where higher room-temperature strength is needed; check code allowables, since creep strength is set by chemistry not by quenching. | 470 | 620 | 22 | 16 HRC | — |
What is A335 P11?
A335 P11 is a seamless 1.25Cr-0.5Mo low-alloy ferritic heat-resistant pipe for power boiler main steam and reheat lines, headers, and refinery high-temperature process piping. Chromium and molybdenum raise creep strength and resistance to high-temperature oxidation and hydrogen attack, allowing sustained pressure service at roughly 550-580 °C; delivered annealed or normalized and tempered at 340 MPa yield, 520 MPa tensile, 26 % elongation and 170 HB (87 HRB), with 480 °C listed as maximum service temperature. Room-temperature strength is modest, preheat and PWHT are mandatory, and graphitization and temper embrittlement limit very long hot service; A335 P22 is the next step up. A335 P11 has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,450°C (2,642 °F). A335 P11 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 76% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi).
What is A335 P11 used for?
- Main steam and reheat piping
- Boiler superheater and economizer headers
- Refinery hydroprocessing pipework
- Hydrocracker transfer lines
- High-temperature process manifolds
- Pipe elbows and fittings
- Heat exchanger nozzles
Advantages
- Tough — resists crack growth — 140 MPa·√m (127.4 ksi·√in), better than 94% of steel grades
- High service temperature — 480°C (896 °F), better than 88% of steel grades
- Ductile — tolerates forming and impact — 26%, better than 82% of steel grades
Limitations
- Low strength — 340 MPa (49.3 ksi), worse than 76% of steel grades
A335 P11 properties
Typical room-temperature values for A335 P11-HR; bars are the position among steel grades.
Physical3
A335 P11 has a density of 7.8 g/cm³ (0.282 lb/in³), lighter than 87% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical16
A335 P11 has a yield strength of 340 MPa (49.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 76% of steel grades. Elongation at break is 26% and the elastic modulus is 205 GPa (29.7 Msi).
Thermal6
A335 P11 is rated for continuous service to 480°C (896 °F). It conducts heat at 38 W/m·K (22 BTU/hr·ft·°F), worse than 69% of steel grades. Thermal expansion is 12.3 µm/m·K (6.83 µin/in·°F).
Electrical3
A335 P11 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (16/100), better than 79% of steel grades.
Sustainability4
Producing a kilogram of A335 P11 takes about 32 MJ of energy and emits 2.3 kg of CO₂ — more than 70% of steel grades. Typical recycled content is 25%.
Manufacturability7
A335 P11's machinability is fair (50/100, worse than 53% of steel grades); weldability good (60/100); formability fair (50/100).
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. A335 P11 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A335 P11
Is A335 P11 easy to machine?
Machines like normalized 4130-class low-alloy steel at ~60 % of 1212 — use rigid setups, carbide tooling, moderate speeds and flood coolant; keep hardness ≤163 HB for easy threading and bevelling.
Can A335 P11 be welded?
Readily welded with matching 1.25Cr-0.5Mo filler (E8018-B2 / ER80S-B2), preheat 150–200 °C, interpass control and PWHT 700–750 °C to restore toughness and avoid hydrogen cracking.
Can A335 P11 be formed, bent or molded?
Hot bend 900–1000 °C or cold bend with generous radii followed by re-normalizing/tempering; cold-formed pipe bends normally require post-form heat treatment per ASME B31.1.
Manufacturability
The process limits FabDigit applies to A335 P11. Every A335 P11 part is priced by an engineer; design inside these and the quote comes back without a redesign loop.
CNC machining
| Machinability | Fair50 / 100 |
|---|---|
| ISO material group | P.2 |
| Cutting speed (rough / finish) | 180 / 210 m/min |
| Minimum wall | 0.8 mm |
| Minimum internal radius | 1 mm |
| Drill depth limit | 5× diameter |
| Best surface (machined / polished) | Ra 1.6 / — |
| Hardenable after machining | No |
Sheet metal
| Formability | Fair50 / 100 |
|---|---|
| Weldability | Better60 / 100 |
A335 P11 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 |
|---|---|---|
| C | 0.05 – 0.15 | 0.12 |
| Si | 0.5 – 1 | 0.7 |
| Mn | 0.3 – 0.6 | 0.45 |
| P | ≤ 0.03 | |
| S | ≤ 0.03 | |
| Cr | 1 – 1.5 | 1.25 |
| Mo | 0.44 – 0.65 | 0.55 |
| Fe | balance |
What surface finishes work on A335 P11?
No anodizing; protect with high-temperature aluminium/silicone paint, phosphate or aluminizing, and remove mill scale by pickling or blasting before insulation to limit CUI.
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).
Plating
CVD Coating
Black / Phosphate
Thermal Spray
Equivalent designations
Standards and trade names that resolve to Steel A335 P11 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 10CrMo5-5
How much does A335 P11 cost?
A335 P11 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.
A335 P11 — frequently asked
What is A335 P11 used for?
A335 P11 is typically used for main steam and reheat piping, boiler superheater and economizer headers, refinery hydroprocessing pipework, hydrocracker transfer lines, high-temperature process manifolds and pipe elbows and fittings. In short: low-alloy chrome-moly pipe.
What is the yield strength of A335 P11?
A335 P11 has a typical yield strength of 340 MPa (49.3 ksi) and a tensile strength of 520 MPa (75.4 ksi) — weaker than 76% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A335 P11 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Machines like normalized 4130-class low-alloy steel at ~60 % of 1212 — use rigid setups, carbide tooling, moderate speeds and flood coolant; keep hardness ≤163 HB for easy threading and bevelling.
Can A335 P11 be welded?
Yes — weldability is rated good (60/100). Readily welded with matching 1.25Cr-0.5Mo filler (E8018-B2 / ER80S-B2), preheat 150–200 °C, interpass control and PWHT 700–750 °C to restore toughness and avoid hydrogen cracking.
What surface finishes work on A335 P11?
No anodizing; protect with high-temperature aluminium/silicone paint, phosphate or aluminizing, and remove mill scale by pickling or blasting before insulation to limit CUI.
Can A335 P11 be formed, bent or molded?
Hot bend 900–1000 °C or cold bend with generous radii followed by re-normalizing/tempering; cold-formed pipe bends normally require post-form heat treatment per ASME B31.1.
What is the maximum service temperature of A335 P11?
A335 P11 is rated for continuous use to about 480°C (896 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does A335 P11 cost?
A335 P11 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.
Can FabDigit make parts in A335 P11?
Yes — A335 P11 is available for CNC machining and sheet metal; every part is priced by an engineer rather than instantly. Upload a STEP file to get a price and a DFM check.
Sources
- ASTM A335/A335M — Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service — ASTM International (2023)
- ASME BPVC Section II Part D — Properties (Metric) — ASME (2023)
- GB 5310 — (15CrMoG) — SAC (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- ASM Handbook Vol.19 — Fatigue and Fracture — ASM International (1996)
- API RP 941 — Steels for Hydrogen Service at Elevated Temperatures — 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.