Xi'an Dongmeng Group Co., Ltd. is one of the most reliable manufacturers and suppliers of ASTM A335 P22 Pipe in China, also supports customized service. With abundant experience, we warmly welcome you to wholesale cheap products in stock here and get free sample from our factory. For price consultation, contact us.
2.25Cr-1Mo Chrome Moly Alloy Steel Pipe for High-Temperature Pressure Service
Xi'an Dongmeng Group Co., Ltd. supplies ASTM A335 P22 / ASME SA335 P22 seamless alloy steel pipe for power generation, refinery, petrochemical, boiler and high-temperature process piping projects.
P22 is a nominal 2.25Cr-1Mo chromium-molybdenum ferritic alloy steel. Compared with P11, its higher chromium and molybdenum content provides improved oxidation resistance and elevated-temperature performance, while its seamless construction makes it suitable for critical pressure piping systems.
Material selection should be based on the applicable design code, design pressure and temperature, fluid medium, allowable stress, welding requirements and project specification rather than on a generic maximum service temperature.
ASTM A335 P22 Quick Specification
ASTM A335 P22 Seamless Pipe is a 2.25Cr-1Mo chromium-molybdenum alloy steel pipe designed for elevated-temperature and pressure service in power plants, refineries, petrochemical systems and industrial process piping.
Dongmeng Group supplies ASTM A335 P22 seamless pipe with heat-number traceability, project-specific inspection, heavy-wall options and technical documentation for international high-temperature piping projects.
| Item | Specification |
| Standard | ASTM A335/A335M / ASME SA335 |
| Grade | P22 |
| UNS | K21590 |
| Material Family | 2.25Cr-1Mo Chrome Moly Steel |
| Manufacturing | Seamless |
| Production Route | Hot Finished or Cold Drawn |
| Heat Treatment | Full/Isothermal Annealed or Normalized & Tempered |
| Tensile Strength | 415 MPa min |
| Yield Strength | 205 MPa min |
| Common Sizes | NPS 1/2–24 in. supply range; larger/project sizes subject to availability |
| Wall | SCH 40 / 80 / 120 / 160 / XXS / Heavy Wall |
| Length | 6 m / 12 m / Random / Custom |
| Ends | Plain End / Beveled End |
| Testing | Hydrostatic + Applicable NDE + Mechanical Testing |
| Documentation | EN 10204 3.1; additional inspection documentation available |
| Applications | Power Plant · Refinery · Petrochemical · Steam & Process Piping |
What Is ASTM A335 P22 Pipe?
ASTM A335 P22 is a seamless ferritic alloy-steel pipe intended for elevated-temperature service.
The designation contains two important elements:
ASTM A335 identifies the product specification for seamless ferritic alloy-steel pipe.
P22 identifies the 2.25Cr-1Mo material grade.
P22 contains significantly more chromium and molybdenum than P11. Chromium contributes to resistance against high-temperature oxidation, while molybdenum supports strength and creep performance at elevated temperatures.
However, ASTM A335 is a material specification, not a complete piping design specification.
The final allowable pressure and temperature of a P22 piping system must be determined using the applicable design code, pipe dimensions, allowable stresses, joint details and project engineering requirements.
ASTM A335 P22 Chemical Composition
P22 corresponds to UNS K21590.
| Element | ASTM A335 P22 |
| Carbon, C | 0.05–0.15% |
| Manganese, Mn | 0.30–0.60% |
| Phosphorus, P | 0.025% max |
| Sulfur, S | 0.025% max |
| Silicon, Si | 0.50% max |
| Chromium, Cr | 1.90–2.60% |
| Molybdenum, Mo | 0.87–1.13% |
P22 is therefore commonly described as 2.25Cr-1Mo steel, although procurement should always be based on the actual ASTM chemical limits rather than the nominal alloy designation alone.
Mechanical Properties
Typical minimum room-temperature tensile requirements for ASTM A335 P22 include:
| Property | Requirement |
| Tensile Strength | ≥415 MPa / 60 ksi |
| Yield Strength | ≥205 MPa / 30 ksi |
| Elongation | According to ASTM A335 specimen and wall-thickness requirements |
Elongation should not be reduced to one universal percentage for every pipe size because the applicable requirement depends on specimen orientation and dimensions.
For engineering design at elevated temperature, room-temperature tensile values should not be substituted for allowable stress data from the governing design code.
Heat Treatment of A335 P22
Heat treatment is particularly important for Cr-Mo piping materials.
ASTM A335 P22 is not correctly described as being supplied only in the normalized-and-tempered condition.
Permitted finishing heat-treatment routes include:
Full Annealing
Isothermal Annealing
or
Normalizing and Tempering
When normalized and tempered, the minimum tempering temperature specified for P22 is 1250°F [675°C].
The actual delivery condition should therefore be stated on the purchase order and confirmed on the material documentation.
Why This Matters to Buyers
Heat treatment affects microstructure, hardness, fabrication behavior and high-temperature properties.
For critical projects, procurement teams should verify:
Heat-treatment condition
Furnace records where required
Heat number
Mechanical test results
Chemistry
NDE records
Hydrostatic test status
Material traceability
before accepting the material.
How ASTM A335 P22 Seamless Pipe Is Manufactured
A typical manufacturing route includes steelmaking, billet preparation, piercing, hot forming or cold drawing, heat treatment, straightening, dimensional finishing, testing and final inspection.
1. Raw Material Control
Heat chemistry and raw-material traceability are reviewed against the ordered P22 requirements.
2. Seamless Piercing
A solid billet is pierced to form a hollow shell without a longitudinal weld seam.
3. Hot Finishing or Cold Drawing
The pipe is processed to obtain the required outside diameter, wall thickness and dimensional accuracy.
4. Heat Treatment
The pipe receives an ASTM-compliant finishing heat treatment appropriate for P22.
5. Straightening and End Preparation
Pipe straightness, length and ends are prepared according to the purchase specification.
6. Mechanical Testing and NDE
Required mechanical tests, hydrostatic testing and nondestructive examination are performed according to the applicable standard and purchase order.
7. Final Documentation
Chemical analysis, mechanical results, heat treatment and required inspection records are reviewed before final certification and shipment.
Testing and Inspection Requirements
Testing should be one of the strongest sections of a professional P22 purchasing page.
ASTM A335 includes requirements covering mechanical testing, hydrostatic testing and nondestructive examination.
Depending on the applicable size and specification requirements, inspection may include:
Chemical Analysis
Verification of P22 chemistry and heat traceability.
Tensile Testing
Verification of minimum tensile and yield properties.
Flattening or Bend Testing
Applied according to applicable dimensional and specification requirements.
Hydrostatic Testing
Used to verify pipe integrity under the specified test conditions.
Nondestructive Examination
Pipe is examined using an applicable nondestructive examination practice under ASTM A335 requirements.
Project specifications may additionally request UT, Eddy Current, flux leakage or other inspection methods within the applicable standard framework.
Additional PMI, hardness testing, impact testing, dimensional inspection or third-party witness inspection can be specified where required by the project.
Do Not Confuse ASTM A335 Testing with Weld Inspection
ASTM A335 P22 is a seamless pipe.
Therefore, requirements such as longitudinal weld radiography used for EFW pipe should not be copied into an A335 P22 product specification.
For large-diameter welded 2.25Cr-1Mo pipe manufactured from plate, the purchaser may instead evaluate an ASTM A691 2-1/4Cr product, subject to design-code and project approval.
A335 P22 Pipe Sizes
ASTM A335 does not mean that every mill supplies every NPS and schedule.
Dongmeng Group's commercial supply program may include:
| NPS | Typical OD | SCH 40 | SCH 80 |
| 1/2 in. | 21.3 mm | 2.77 mm | 3.73 mm |
| 1 in. | 33.4 mm | 3.38 mm | 4.55 mm |
| 2 in. | 60.3 mm | 3.91 mm | 5.54 mm |
| 4 in. | 114.3 mm | 6.02 mm | 8.56 mm |
| 6 in. | 168.3 mm | 7.11 mm | 10.97 mm |
| 8 in. | 219.1 mm | 8.18 mm | 12.70 mm |
| 10 in. | 273.0 mm | 9.27 mm | 15.09 mm |
| 12 in. | 323.9 mm | 10.31 mm | 17.48 mm |
SCH 120, SCH 160, XXS and project-specific heavy-wall dimensions can be quoted according to mill capability and required quantity.
For procurement, always specify NPS/OD + wall thickness or schedule, rather than schedule alone.
ASTM A335 P11 vs P22 vs P91
These grades should not be selected simply by ranking them as "good, better, best."
| Item | P11 | P22 | P91 |
| Nominal Alloy | 1.25Cr-0.5Mo | 2.25Cr-1Mo | 9Cr-1Mo-V-Nb |
| Chromium | 1.00–1.50% | 1.90–2.60% | Approx. 8–9.5% |
| Molybdenum | 0.44–0.65% | 0.87–1.13% | Approx. 0.85–1.05% |
| Min. Tensile Strength | 415 MPa | 415 MPa | Higher than P11/P22 |
| Min. Yield Strength | 205 MPa | 205 MPa | Higher than P11/P22 |
| Welding Complexity | Moderate | Higher than P11 | Significantly more demanding |
| Typical Selection | Moderate Cr-Mo service | Higher-alloy Cr-Mo service | High-creep-strength critical piping |
When Is P22 Preferred Over P11?
P22 may be selected where the engineering design benefits from the higher Cr-Mo alloy content and its elevated-temperature performance.
This does not mean that every P11 system should be upgraded to P22.
Design allowable stresses, corrosion mechanisms, welding procedure, PWHT, thermal expansion, fittings, valves and existing system metallurgy must all be considered.
When Is P91 Preferred Over P22?
P91 offers much higher creep strength through its modified 9Cr-1Mo-V-Nb metallurgy, but fabrication and heat-treatment control are substantially more demanding.
Therefore, P91 should not be described simply as a superior replacement for P22.
The selection should follow the design code and project metallurgy specification.
ASTM A335 P22 vs ASTM A691 2-1/4Cr
These two specifications are often searched together but represent different pipe constructions.
| Item | ASTM A335 P22 | ASTM A691 2-1/4Cr |
| Construction | Seamless | EFW Welded |
| Material Family | 2.25Cr-1Mo | 2.25Cr-1Mo family |
| Longitudinal Seam | None | Yes |
| Typical Procurement | Seamless pressure piping | Large-diameter welded pressure piping |
| Starting Product | Billet | Pressure-vessel-quality plate |
A691 should not be marketed as an automatic replacement for A335 P22. Substitution requires engineering approval.
Matching P22 Piping Components
A complete P22 piping package may use corresponding Cr-Mo material families such as:
| Product | Common Material |
| Seamless Pipe | ASTM A335 P22 |
| Butt-Weld Fittings | ASTM A234 WP22 |
| Forged Flanges / Fittings | ASTM A182 F22 |
| Plate | ASTM A387 Grade 22 |
| EFW Welded Pipe | ASTM A691 2-1/4Cr |
The exact fitting or forging class, heat-treatment condition and pressure rating must be selected according to the applicable piping specification.
Welding Considerations for P22
P22 is weldable, but welding should be controlled by an approved Welding Procedure Specification rather than by a universal website temperature.
Common engineering considerations include:
Base-material identification
Low-hydrogen welding practice
Suitable Cr-Mo filler metal
Preheat and interpass temperature
Heat input
Hydrogen control
Post-weld heat treatment
Hardness control
NDE
Repair procedure
Matching filler-metal families may include B3-type consumables, subject to the governing welding specification and WPS/PQR.
Is PWHT Always Required?
It is not technically correct to state that ASTM A335 itself makes PWHT "absolutely required" for every fabricated P22 joint.
PWHT requirements for an installed piping weld are determined by factors including:
ASME B31.1 / B31.3 or another governing code
Material P-Number / Group
Wall thickness
Service condition
Welding procedure
Project specification
Applicable exemptions
The purchaser and fabricator should therefore use the approved WPS/PQR and governing construction code.
P22 Pipe Applications
ASTM A335 P22 is commonly specified for elevated-temperature pressure systems such as:
Main and auxiliary steam piping
Boiler piping
Superheater and reheater-related piping systems
Power-generation pressure piping
Refinery process piping
Petrochemical piping
High-temperature process lines
Hydrogen-containing refinery services where project metallurgy specifies 2.25Cr-1Mo
High-temperature headers and manifolds
Pressure equipment connecting piping
Suitability for a specific application must be confirmed by project engineering.
Does P22 Have a Maximum Service Temperature?
A fixed statement such as:
"P22 maximum service temperature = 595°C"
should not be used as a universal purchasing rule.
ASTM A335 defines material and manufacturing requirements; it does not by itself establish one universal maximum design temperature for every P22 piping installation.
Actual design limits depend on factors including:
Governing design code
Allowable stress at design temperature
Required service life
Creep exposure
Internal pressure
Wall thickness
Corrosion allowance
Fluid environment
Welding condition
Cyclic operation
For high-temperature projects, buyers should provide the design temperature and design pressure in the RFQ.
Material Traceability and Inspection Documents
For industrial P22 projects, Dongmeng Group can provide documentation according to the purchase order, including:
Heat number
Material Test Certificate
Chemical analysis
Mechanical properties
Heat-treatment condition
Hydrostatic test record
NDE information
Dimensional inspection
Product marking
Packing list
Certificate of origin where required
EN 10204 3.1 certification can be supplied according to the agreed order.
EN 10204 3.2 or third-party inspection should be confirmed at quotation stage because it requires additional inspection arrangements.
Third-party inspection may be arranged by purchaser-approved organizations where specified.
What Should Be Included in a P22 RFQ?
A professional request for quotation should contain more than:
"Need P22 pipe."
Provide:
| RFQ Item | Example |
| Material | ASTM A335 P22 |
| Standard Edition | Project-specified edition |
| ASME Requirement | SA335 P22 if applicable |
| Size | NPS 8 |
| Wall | SCH 160 |
| Length | 12 m |
| Quantity | 25 MT |
| End | BE |
| Heat Treatment | Per ASTM / project requirement |
| NDE | Standard + project supplementary requirements |
| Documentation | EN 10204 3.1 |
| PMI | Required / Not Required |
| Impact Test | If project-required |
| Design Code | ASME B31.1 / B31.3 |
| Design Temperature | Project value |
| Design Pressure | Project value |
| TPI | If required |
| Delivery Destination | Port / Country |
This information allows the supplier to review technical compliance before issuing a quotation.
Why Choose Dongmeng Group for P22 Pipe
Xi'an Dongmeng Group Co., Ltd. supports international Cr-Mo alloy steel piping procurement with attention to material specification, traceability, inspection and project documentation.
For ASTM A335 P22 orders, we can support:
Material Verification
Heat number, chemistry and MTC review.
Size & Heavy-Wall Supply
Standard schedules and project-specific heavy-wall requirements subject to mill capability.
Cutting & End Preparation
Fixed length, plain ends and beveled ends according to order requirements.
Inspection Support
Standard testing plus supplementary project inspection when specified.
Third-Party Inspection
SGS, BV, TÜV or other purchaser-approved inspection arrangements where required.
Export Packing
Bundle protection, end protection and seaworthy export packaging.
Our objective is to supply the correct material + dimension + heat treatment + inspection + documentation package, rather than simply quoting a pipe by nominal grade.
ASTM A335 P22 FAQ
1. Is ASTM A335 P22 seamless or welded?
ASTM A335 P22 is a seamless alloy-steel pipe. A longitudinally welded 2.25Cr-1Mo pipe belongs under a different product specification, such as ASTM A691 where applicable.
2. What is the nominal alloy composition of P22?
P22 is commonly called 2.25Cr-1Mo steel. ASTM limits chromium to 1.90–2.60% and molybdenum to 0.87–1.13%.
3. What is UNS K21590?
K21590 is the UNS designation associated with ASTM A335 P22.
4. Is P22 stronger than P11 at room temperature?
Under ASTM A335 minimum room-temperature tensile requirements, both P11 and P22 have minimum tensile strength of 415 MPa and minimum yield strength of 205 MPa. Their important differences lie in chemistry and elevated-temperature behavior rather than simply room-temperature minimum strength.
5. Is every P22 pipe normalized and tempered?
No. ASTM A335 permits P22 to be supplied full annealed, isothermal annealed, or normalized and tempered according to the specification requirements.
6. What is the minimum tempering temperature for normalized-and-tempered P22?
For the normalized-and-tempered route, the specified minimum tempering temperature is 1250°F [675°C].
7. Does P22 require hydrostatic testing?
ASTM A335 includes hydrostatic testing requirements, together with nondestructive examination requirements. Project-specific supplementary inspection should be stated in the purchase order.
8. Does P22 require PWHT after welding?
PWHT requirements for fabrication welds are determined by the governing construction code, wall thickness, service conditions, approved WPS/PQR and project specification. It should not be treated as one universal ASTM A335 rule.
9. Can P22 replace P11?
Not automatically. Any material substitution should be reviewed against allowable stresses, design temperature, welding procedure, matching components, corrosion mechanism and applicable design code.
10. What fittings are normally used with P22 pipe?
ASTM A234 WP22 butt-weld fittings and ASTM A182 F22 forged components belong to corresponding 2.25Cr-1Mo material families. Exact grades/classes must follow the piping specification.
11. Is A691 2-1/4Cr equivalent to A335 P22?
They belong to a related Cr-Mo material family but are different product specifications. A335 P22 is seamless; A691 2-1/4Cr is EFW welded pipe manufactured from plate. They should not be treated as automatically interchangeable.
12. What information is required for a quotation?
Please provide ASTM/ASME designation, NPS or OD, wall thickness/schedule, length, quantity, design conditions where relevant, required NDE, documentation, third-party inspection requirements and delivery destination.
Request an ASTM A335 P22 Pipe Quotation
For a technical and commercial quotation, send your:
ASTM A335 P22 / ASME SA335 P22
NPS / OD × Wall Thickness
Length
Quantity
Required Heat Treatment / Inspection
MTC / TPI Requirements
Delivery Destination
Xi'an Dongmeng Group Co., Ltd.
Phone / WhatsApp: +86 157 6921 4734
Email: office@dongmjd.com
Office: Room 4107, Runfeng Building, Sanqiao New Street, Weiyang District, Xi'an City, Shaanxi Province
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