ASTM A335 P5 Seamless Alloy Steel Pipe | ASME SA335 P5
ASTM A335 P5 is a seamless 5Cr-0.5Mo ferritic alloy steel pipe designed for high-temperature service. It is widely used in refinery heaters, petrochemical process piping, power plants and other elevated-temperature pressure piping systems.
We manufacture and supply ASTM A335 P5 / ASME SA335 P5 seamless alloy steel pipes in hot-finished and cold-finished conditions, with customized sizes, heat treatment, nondestructive examination, PMI and EN 10204 3.1 material certification.
ASTM A335 P5 Pipe Specification
| Item | ASTM A335 P5 |
|---|---|
| Standard | ASTM A335/A335M / ASME SA-335 |
| Grade | P5 |
| UNS | K41545 |
| Material Type | Ferritic Cr-Mo Alloy Steel |
| Nominal Alloy | 5Cr-0.5Mo |
| Manufacturing | Seamless |
| Condition | Hot-Finished / Cold-Finished |
| Cr Content | 4.00–6.00% |
| Mo Content | 0.45–0.65% |
| Tensile Strength | ≥415 MPa |
| Yield Strength | ≥205 MPa |
| Heat Treatment | Annealed / Isothermal Annealed / Normalized & Tempered |
| Minimum Tempering Temperature | 675°C / 1250°F |
| Certification | EN 10204 3.1 / 3.2 when specified |
What Is ASTM A335 P5?
ASTM A335/A335M covers seamless ferritic alloy-steel pipe intended for high-temperature service.
Grade P5 contains approximately 4–6% chromium and 0.45–0.65% molybdenum, and is therefore commonly described as a 5Cr-0.5Mo alloy steel.
Chromium contributes to oxidation and high-temperature corrosion resistance, while molybdenum improves elevated-temperature strength and mechanical stability.
P5 is commonly selected for piping systems where conventional carbon steel does not provide sufficient performance at elevated temperatures.
ASTM A335 covers seamless pipe only. Welded pipe should not be certified as ASTM A335 P5.
ASTM A335 P5 Chemical Composition
| Element | P5 Requirement |
|---|---|
| Carbon (C) | 0.15% max |
| Manganese (Mn) | 0.30–0.60% |
| Phosphorus (P) | 0.025% max |
| Sulfur (S) | 0.025% max |
| Silicon (Si) | 0.50% max |
| Chromium (Cr) | 4.00–6.00% |
| Molybdenum (Mo) | 0.45–0.65% |
P5 should not be treated as stainless steel. Its chromium content is substantially lower than conventional stainless grades, and corrosion suitability must be evaluated according to the actual process medium and operating temperature.
ASTM A335 P5 Mechanical Properties
| Property | Minimum Requirement |
|---|---|
| Tensile Strength | 415 MPa |
| Yield Strength | 205 MPa |
| Elongation | According to ASTM A335 requirements |
Room-temperature tensile properties should not be used directly to determine allowable pressure at elevated temperature.
For pressure piping, the applicable ASME design code and allowable stress values must be used.
Heat Treatment of A335 P5 Pipe
ASTM A335 P5 seamless pipe may be supplied in the following heat-treated conditions:
- Full annealed
- Isothermal annealed
- Normalized and tempered
For P5 pipe supplied in the normalized and tempered condition, the minimum tempering temperature is 675°C / 1250°F.
Correct heat treatment is important for achieving:
- Required mechanical properties
- Stable hardness
- Consistent microstructure
- Elevated-temperature performance
- Reliable welding and fabrication characteristics
The final heat-treatment condition should be stated on the material certificate.
Typical Supply Range
| Parameter | Typical Supply |
|---|---|
| Outside Diameter | 21–509 mm |
| Wall Thickness | 2.1–20 mm or customized |
| Schedules | SCH 40 / 80 / 120 / 160 / STD / XS |
| Length | 6 m / 9–12 m / Fixed Length |
| Ends | Plain / Beveled / Threaded when applicable |
| Surface | Black / Shot Blasted / Temporary Protective Coating |
| Packing | Bundles / Wooden Cases / Project Packing |
These dimensions represent our typical commercial supply range, not the dimensional limits of ASTM A335.
Special OD, heavy-wall and fixed-length P5 pipes can be evaluated according to project requirements.
Why Use 5Cr-0.5Mo P5 Pipe?
The higher chromium level distinguishes P5 from lower-chromium Cr-Mo grades.
Important characteristics include:
- Good elevated-temperature strength
- Improved oxidation resistance compared with lower-alloy steels
- Improved performance in certain high-temperature refinery environments
- Established use in refinery heater and process piping
- Good mechanical stability at elevated temperature
- Suitable for fusion welding with qualified procedures
- Available in heavy-wall seamless construction
Final material selection should consider temperature, pressure, process chemistry, allowable stress, corrosion mechanism and applicable piping code.
Applications of ASTM A335 P5 Pipe
Refinery & Petrochemical
P5 seamless pipes are commonly used for:
- Refinery heater piping
- High-temperature process lines
- Hydrocarbon transfer piping
- Crude and vacuum units
- Process headers
- Hot-oil systems
- Petrochemical process lines
Power & Industrial Systems
Other applications include:
- Steam and high-temperature piping
- Boiler-related piping
- Thermal processing systems
- Pressure equipment connections
- Headers and manifolds
- High-temperature industrial process systems
Material selection for sulfur-containing refinery environments should be based on the actual temperature, sulfur activity, hydrogen conditions and corrosion study, rather than alloy grade alone.
Inspection, Hydrostatic Test & NDE
ASTM A335 requires material and mechanical verification together with hydrostatic testing and applicable nondestructive examination.
Typical inspection documentation can include:
- EN 10204 3.1 Material Test Certificate
- Chemical analysis
- Mechanical test report
- Heat-treatment record
- Hydrostatic test report
- Nondestructive examination report
- Dimensional inspection
- Visual inspection
- PMI report
- Hardness testing
- Third-party inspection
Additional UT, eddy-current, magnetic-flux-leakage, metallographic examination or project-specific testing can be supplied when required by the purchase specification.
Full traceability is maintained through the heat number, grade, dimensions and production identification.
ASTM A335 P5 vs ASTM A213 T5
P5 and T5 use the same 5Cr-0.5Mo / UNS K41545 alloy system, but they are different products manufactured to different ASTM standards.
| Item | ASTM A335 P5 | ASTM A213 T5 |
|---|---|---|
| Product | Pipe | Tube |
| UNS | K41545 | K41545 |
| Alloy | 5Cr-0.5Mo | 5Cr-0.5Mo |
| Main Application | Process & pressure piping | Boiler / superheater / heat exchanger |
| Dimension Basis | NPS / Schedule / OD × WT | OD × Wall Thickness |
| Manufacturing | Seamless | Seamless |
| Typical Ends | Plain / Beveled | Plain |
P5 and T5 should not be used as interchangeable product descriptions.
ASTM A335 P5 is ordered as pipe for high-temperature piping service, while ASTM A213 T5 is ordered as boiler, superheater or heat-exchanger tube.
ASTM A335 P5 vs ASME SA335 P5
ASTM A335 P5 is the ASTM material specification, while ASME SA-335 P5 is the corresponding material specification used within the ASME Boiler and Pressure Vessel Code framework.
Both identify P5 seamless Cr-Mo alloy steel pipe, but the required standard designation, edition and ASME Code requirements should be clearly stated when ordering material for code construction.
Frequently Asked Questions
What is ASTM A335 P5 pipe?
ASTM A335 P5 is a seamless ferritic alloy-steel pipe containing approximately 5% chromium and 0.5% molybdenum. It is primarily used for high-temperature refinery, petrochemical, power and industrial piping.
Is ASTM A335 P5 seamless or welded?
ASTM A335 P5 is seamless pipe. ASTM A335 does not cover welded P5 pipe.
What does 5Cr-0.5Mo mean?
P5 contains 4.00–6.00% chromium and 0.45–0.65% molybdenum, which is commonly described commercially as a 5Cr-0.5Mo alloy.
What is the difference between P5 and T5?
P5 is ASTM A335 pipe for high-temperature piping systems, while T5 is ASTM A213 tube for boilers, superheaters and heat exchangers. Both use UNS K41545 chemistry but have different product standards and applications.
What heat treatment is required for ASTM A335 P5?
P5 may be supplied fully annealed, isothermally annealed, or normalized and tempered. When normalized and tempered, the minimum tempering temperature is 675°C / 1250°F.
Related Cr-Mo Alloy Steel Products
- ASTM A213 T5 Alloy Steel Tube – 5Cr-0.5Mo boiler, superheater and heat-exchanger tube.
- ASTM A335 P9 Seamless Pipe – 9Cr-1Mo alloy steel pipe for high-temperature service.
- ASTM A335 P11 Seamless Pipe – 1.25Cr-0.5Mo high-temperature alloy steel pipe.
- ASTM A335 P22 Seamless Pipe – 2.25Cr-1Mo seamless alloy steel pipe.
- ASTM A335 P91 Seamless Pipe – Modified 9Cr-1Mo-V-Nb pipe for advanced high-temperature service.
- ASTM A234 WP5 Pipe Fittings – 5Cr-0.5Mo elbows, tees and reducers.
- ASTM A182 F5 Flanges – Forged 5Cr-0.5Mo flanges for high-temperature piping.
ASTM A335 P5 Seamless Pipe Manufacturer Supplier
We supply ASTM A335 / ASME SA-335 P5 seamless 5Cr-0.5Mo alloy steel pipe for international refinery, petrochemical and high-temperature piping projects.
Custom dimensions, fixed lengths, heat treatment, PMI, NDE, third-party inspection and complete material documentation can be supplied according to project specifications.
For quotation, please provide the NPS or OD, schedule or wall thickness, length, quantity, heat-treatment condition and inspection requirements.
