Steel A335 P22
ASTM A335 P22 · EN 12CrMo9-10, 10CrMo9-10
A335 P22 is a 2.25Cr-1Mo ferritic alloy seamless pipe grade for main steam lines, superheater and reheater headers and hydrocracker piping.
Values for the HR condition
A335 P22 tempers and conditions
A335 P22 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 or isothermal anneal (ASTM A335 heat-treated condition) | Choose the full or isothermal annealed pipe when field bending and welding matter most: 140 HB and the best formability, at only 310 MPa yield and 490 MPa tensile. | 310 | 490 | 32 | 140 HB | — |
HRDefault Hot rolled | Intermediate hot rolled or hot extruded state only: ASTM A335 requires final delivery annealed or normalised and tempered, so use it for tube blanks and further processing. | 350 | 550 | 24 | 12 HRC | 7.8 % IACS |
Normalized and tempered | Specify normalizing at 900–950 °C plus tempering at not less than 677 °C for thick-wall main steam pipe and headers: 360 MPa yield, 580 °C service, best creep-toughness balance. | 360 | 550 | 26 | 160 HB | — |
austenitized ~900–950 °C, air cooled (no temper) | Use after austenitizing at 900–950 °C and air cooling to refine grain and reach 420 MPa yield; hardness climbs to 185 HB with high residual stress, so most piping is tempered afterwards. | 420 | 620 | 22 | 185 HB | — |
Quenched and tempered | Pick liquid quenching plus tempering at 675 °C or above for heavy forgings, valve bodies and hydrocracker shells; uniform tempered bainite gives 500 MPa yield but machinability drops to 44. | 500 | 660 | 22 | 19 HRC | — |
What is A335 P22?
A335 P22 is a 2.25Cr-1Mo ferritic alloy seamless pipe grade for main steam lines, superheater and reheater headers and hydrocracker piping. The Cr-Mo balance gives creep strength, oxidation resistance and resistance to high-temperature hydrogen attack (Nelson curves) at 450–580 °C at lower cost than stainless; normalized-and-tempered pipe runs 350 MPa yield, 550 MPa tensile, 24 % elongation and 165 HB. Ambient corrosion resistance is barely above carbon steel; welding needs 200–250 °C preheat and 700–760 °C post-weld heat treatment. Long service also risks temper embrittlement, graphitization and creep damage; P91 is the choice above 580 °C. A335 P22 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F). A335 P22 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 74% of steel grades. Elongation at break is 24% and the elastic modulus is 207 GPa (30 Msi).
What is A335 P22 used for?
- Main steam piping
- Superheater and reheater headers
- Boiler header stubs and tube connections
- Hydrocracker and hydrotreater piping
- Hot petrochemical process pipework
- Fired heater and reformer coils
- Machined pipe spools, adapters and flanged fittings
Advantages
- High service temperature — 550°C (1,022 °F), better than 95% of steel grades
A335 P22 properties
Typical room-temperature values for A335 P22-HR; bars are the position among steel grades.
Physical3
A335 P22 has a density of 7.85 g/cm³ (0.284 lb/in³), heavier than 56% of steel grades. It melts at 1,450°C (2,642 °F).
Mechanical17
A335 P22 has a yield strength of 350 MPa (50.8 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 74% of steel grades. Elongation at break is 24% and the elastic modulus is 207 GPa (30 Msi).
Thermal6
A335 P22 is rated for continuous service to 550°C (1,022 °F). It conducts heat at 37 W/m·K (21.4 BTU/hr·ft·°F), worse than 71% of steel grades. Thermal expansion is 12.4 µm/m·K (6.89 µin/in·°F).
Electrical3
A335 P22 conducts electricity at 7.8 % IACS, worse than 57% of steel grades.
Chemical & Environmental3
Corrosion resistance is poor (18/100), better than 83% of steel grades.
Sustainability4
Producing a kilogram of A335 P22 takes about 33 MJ of energy and emits 2.4 kg of CO₂ — more than 76% of steel grades. Typical recycled content is 30%.
Manufacturability7
A335 P22's machinability is fair (50/100, worse than 53% of steel grades); weldability fair (50/100); formability fair (48/100).
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 P22 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with A335 P22
Is A335 P22 easy to machine?
Annealed P22 cuts much like annealed 4140, about 55–60 % of AISI 1212; use coated carbide at moderate speed with a healthy feed, and watch for work hardening and built-up edge at depth.
Can A335 P22 be welded?
Weld by GTAW or SMAW with matching Cr-Mo consumables (ER90S-B3, E9015-B3); preheat 200–250 °C, hold interpass below 350 °C, and apply 700–760 °C post-weld hydrogen-release and stress-relief heat treatment to prevent hydrogen cracking and a hard, brittle HAZ.
Can A335 P22 be formed, bent or molded?
Prefer hot bending and forming at 900–1000 °C, then re-normalize and temper; cold bending requires large bend radii followed by a stress-relief cycle.
Manufacturability
The process limits FabDigit applies to A335 P22. Every A335 P22 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 | Fair48 / 100 |
|---|---|
| Weldability | Better50 / 100 |
A335 P22 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 | 0.11 |
| Mn | 0.3 – 0.6 | 0.45 |
| Si | ≤ 0.5 | 0.25 |
| P | ≤ 0.03 | 0.01 |
| S | ≤ 0.03 | 0.01 |
| Cr | 1.9 – 2.6 | 2.25 |
| Mo | 0.87 – 1.13 | 1 |
| Fe | balance |
What surface finishes work on A335 P22?
Not anodizable; shot blast and apply high-temperature heat-resistant coating, aluminizing or diffusion coating, or zinc plating for low-temperature duty, to control atmospheric and flue-gas side oxidation.
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 P22 in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- EN / DIN / Werkstoff-Nr.
- 12CrMo9-1010CrMo9-10
How much does A335 P22 cost?
A335 P22 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 P22 — frequently asked
What is A335 P22 used for?
A335 P22 is typically used for main steam piping, superheater and reheater headers, boiler header stubs and tube connections, hydrocracker and hydrotreater piping, hot petrochemical process pipework and fired heater and reformer coils. In short: workhorse boiler pipe.
What is the yield strength of A335 P22?
A335 P22 has a typical yield strength of 350 MPa (50.8 ksi) and a tensile strength of 550 MPa (79.8 ksi) — weaker than 74% of steel grades. Strength varies by condition: see the 5 listed tempers.
Is A335 P22 easy to machine?
Reasonably — machinability is rated fair (50/100, worse than 53% of steel grades). Annealed P22 cuts much like annealed 4140, about 55–60 % of AISI 1212; use coated carbide at moderate speed with a healthy feed, and watch for work hardening and built-up edge at depth.
Can A335 P22 be welded?
With care — weldability is rated fair (50/100). Weld by GTAW or SMAW with matching Cr-Mo consumables (ER90S-B3, E9015-B3); preheat 200–250 °C, hold interpass below 350 °C, and apply 700–760 °C post-weld hydrogen-release and stress-relief heat treatment to prevent hydrogen cracking and a hard, brittle HAZ.
What surface finishes work on A335 P22?
Not anodizable; shot blast and apply high-temperature heat-resistant coating, aluminizing or diffusion coating, or zinc plating for low-temperature duty, to control atmospheric and flue-gas side oxidation.
Can A335 P22 be formed, bent or molded?
Prefer hot bending and forming at 900–1000 °C, then re-normalize and temper; cold bending requires large bend radii followed by a stress-relief cycle.
What is the maximum service temperature of A335 P22?
A335 P22 is rated for continuous use to about 550°C (1,022 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does A335 P22 cost?
A335 P22 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 P22?
Yes — A335 P22 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 — Materials, Properties (Metric) — ASME (2023)
- GB/T 5310 (12Cr2MoG / 10CrMo910) — SAC (2017)
- ASM Handbook Vol.1 — Properties and Selection: Irons, Steels, and High-Performance Alloys — ASM International (1990)
- 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.