Introduction
Engineers use ASTM A335 Grade P Alloy Steel Pipes for high-temperature and high-pressure services in power generation, petrochemical, and refinery applications. These seamless ferritic alloy-steel pipes offer exceptional strength and reliability under extreme conditions. As a leading manufacturer, supplier, and exporter of ASTM A335 Grade P pipes, we provide a comprehensive range of alloy-steel seamless pipes that meet the highest international standards.
We supply ASTM A335 Grade P Alloy Steel Pipes for boilers, heat exchangers, and steam lines that demand high strength, oxidation resistance, and long-term durability. Our company ensures consistent quality, on-time delivery, and competitive pricing—making us a trusted choice among global industries.
What is ASTM A335 Grade P?
The ASTM A335 standard defines the requirements for seamless ferritic alloy-steel pipes that industries use in high-temperature applications. The letter “P” denotes the grade classification, followed by numerals that represent the alloy composition—such as P1, P5, P9, P11, P22, and P91.
Each grade offers distinct mechanical and chemical properties tailored to various temperature and pressure requirements. Manufacturers often supply ASTM A335 pipes as ASME SA335 equivalents for power and energy applications. The seamless design enhances mechanical integrity, ensuring long service life under demanding thermal stress.
Chemical Composition of ASTM A335 Grade P Pipes
| Element | C (%) | Mn (%) | Si (%) | Cr (%) | Mo (%) | P (%) | S (%) |
|---|---|---|---|---|---|---|---|
| P1 | 0.15 max | 0.30-0.80 | 0.10-0.50 | 0.44-0.65 | 0.44-0.65 | 0.025 max | 0.025 max |
| P11 | 0.05-0.15 | 0.30-0.60 | 0.50-1.00 | 1.00-1.50 | 0.44-0.65 | 0.025 max | 0.025 max |
| P22 | 0.05-0.15 | 0.30-0.60 | 0.50-1.00 | 1.90-2.60 | 0.87-1.13 | 0.025 max | 0.025 max |
Chromium (Cr) and Molybdenum (Mo) are the primary strengthening elements that improve creep resistance and oxidation protection. Carbon (C) enhances hardness, while Silicon (Si) contributes to oxidation resistance at elevated temperatures.
Mechanical Properties
| Grade | Tensile Strength (MPa) | Yield Strength (MPa) | Elongation (%) | Hardness (BHN) |
|---|---|---|---|---|
| P1 | 415 | 205 | 30 | 143 max |
| P11 | 415 | 205 | 30 | 163 max |
| P22 | 415 | 205 | 30 | 179 max |
These properties ensure that ASTM A335 pipes maintain dimensional stability and mechanical strength even in cyclic thermal loading, making them ideal for high-pressure steam pipelines, superheaters, and reheaters.
Manufacturing Process
ASTM A335 Grade P Alloy Steel Pipes are produced using the seamless process, which involves:
- Billet Selection & Heating: High-quality alloy-steel billets are heated uniformly.
- Piercing & Rolling: Heated billets are pierced and rolled into hollow shells using rotary mills.
- Sizing & Stretch Reducing: Pipes are brought to precise diameters and wall thicknesses.
- Heat Treatment: Pipes are normalized, quenched, and tempered for improved mechanical properties.
- Testing & Inspection: Every pipe undergoes non-destructive testing, hydrostatic testing, and dimensional checks.
This meticulous manufacturing ensures superior quality, consistency, and compliance with ASTM A335 and ASME SA335 standards.
Available Grades under ASTM A335
- P1 / P2 – Low-alloy grades for moderate-temperature use.
- P5 / P9 – Chromium-rich grades for improved oxidation resistance.
- P11 / P22 – Commonly used in power plants and refineries.
- P91 / P92 – Advanced grades for ultra-supercritical boilers.
Each grade is available in various schedules (SCH 40, 80, 160) and lengths depending on project specifications.
Specifications and Sizes
Standard: ASTM A335 / ASME SA335
Type: Seamless Alloy Steel Pipe
Size Range: ½″ NB to 36″ NB
Wall Thickness: SCH 40 to SCH 160 / XXS
Length: Up to 12 meters or as required
Ends: Plain, Beveled, Threaded
Form: Round, Hydraulic, Boiler, Heat Exchanger
All pipes are produced and tested in accordance with international codes such as ASTM, ASME, DIN, EN, and ISO.
Testing & Quality Assurance
Quality is verified through rigorous in-house and third-party inspection programs, including:
- Hydrostatic Test – Checks for leakage and pressure integrity.
- Ultrasonic / Eddy Current Test – Detects internal surface flaws.
- Positive Material Identification (PMI) – Confirms chemical composition.
- Mechanical Testing – Tensile, Hardness, Flattening, and Flaring tests.
- Visual & Dimensional Inspection – Ensures compliance with drawings.
Pipes are supplied with complete documentation, including EN 10204 3.1 / 3.2 test certificates, ensuring traceability and reliability.
Applications & Industries Served
ASTM A335 Grade P Alloy Steel Pipes are essential components in:
- Power Plants: Superheater, reheater, and steam pipelines.
- Oil & Gas Refineries: Transport of steam, crude oil, and process fluids.
- Petrochemical Plants: Furnace tubes and catalytic reactors.
- Boiler and Heat Exchanger Systems: High-pressure applications.
- Chemical and Fertilizer Industries: Resistant to corrosive environments.
The combination of strength, heat resistance, and corrosion protection ensures dependable performance even in aggressive service conditions.
Advantages of ASTM A335 Grade P Alloy Steel Pipes
- Exceptional strength at elevated temperatures.
- Excellent corrosion and oxidation resistance.
- Dimensional accuracy due to precise seamless manufacturing.
- Long service life under high stress and thermal cycling.
- Customizable sizes and grades for different applications.
These advantages make ASTM A335 pipes the first choice for critical engineering projects worldwide.
Packaging, Supply & Export
Pipes are packaged to prevent mechanical damage and corrosion during transport:
- Bundled and wrapped in HDPE or jute cloth.
- Capped ends to protect against moisture and debris.
- Export-ready seaworthy packaging with wooden boxes or pallets.
We export ASTM A335 Grade P pipes to more than 40 countries, including the UAE, Saudi Arabia, Qatar, USA, UK, and South Africa. Global logistics partnerships ensure timely and safe delivery.
Why Choose Us
- Decades of experience as an ISO 9001-certified manufacturer and supplier.
- Advanced production facilities with state-of-the-art equipment.
- In-house laboratory testing for consistent quality assurance.
- Large inventory enabling immediate dispatch.
- Customer-centric approach ensuring technical support and on-time delivery.
Our commitment to quality, transparency, and service excellence has made us one of the most reliable names in the alloy-steel pipe industry.
To learn more about our commitment to quality and industry expertise, visit our About Us page. For inquiries, quotations, or project support, please reach out through our Contact Us page — our team will be glad to assist you.
Conclusion
ASTM A335 Grade P Alloy Steel Pipes offer unmatched strength, thermal stability, and corrosion resistance for critical industrial operations. As a trusted manufacturer, supplier, and exporter, we deliver high-quality seamless pipes that comply with international standards and performance expectations.
For detailed specifications, price quotes, or technical assistance, contact us today to source top-grade ASTM A335 Alloy Steel Pipes for your next project.
Frequently Asked Questions (FAQs)
1. What is ASTM A335 Grade P Alloy Steel Pipe?
ASTM A335 Grade P refers to a specification for seamless ferritic alloy steel pipes designed for high-temperature and high-pressure services. These pipes are commonly used in power plants, refineries, and petrochemical industries. The “P” denotes alloy grades like P1, P5, P11, P22, and P91, which differ based on their chromium and molybdenum content.
2. What are the main applications of ASTM A335 Grade P Pipes?
These pipes are used in:
- Steam pipelines and boiler tubes
- Heat exchangers and superheaters
- Power generation and petrochemical plants
- Oil and gas refineries
Their ability to withstand extreme temperatures and pressures makes them ideal for high-performance environments.
3. What is the difference between ASTM A335 and ASTM A213?
While both are alloy steel standards:
- ASTM A335 covers seamless pipes for high-temperature service.
- ASTM A213 covers seamless tubes used in boilers, superheaters, and heat exchangers.
The main difference lies in application and dimensions—A335 for piping systems, A213 for heat transfer components.
4. What grades are available under ASTM A335?
Common grades include:
P1, P2, P5, P9, P11, P22, P91, and P92.
Each grade offers unique chemical and mechanical properties suited for specific temperature ranges and service conditions. For example, P11 and P22 are most popular in boiler and steam line applications.
5. What tests are performed on ASTM A335 Alloy Steel Pipes?
To ensure quality and compliance, the following tests are conducted:
- Hydrostatic test
- Ultrasonic and eddy current test
- Tensile and hardness test
- Positive Material Identification (PMI)
- Flattening and flaring test
These tests verify strength, composition, and durability before dispatch.
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