As a leading mill-backed seamless ASTM A335 P11 alloy steel pipe manufacturer, we supply ferritic alloy-steel tubing engineered specifically for high-temperature service. Containing nominally 1.25% Chromium and 0.5% Molybdenum, P11 tubes provide excellent creep resistance, oxidation resistance, and elevated-temperature strength up to 593°C (1100°F).
Designed for severe industrial environments, these tubes meet the rigorous demands of power generation, petrochemical processing, and high-pressure steam systems where standard carbon steels lose strength and scale rapidly.
Standard Specification: ASTM A335 / ASME SA335 P11
Production Method: Seamless (Hot finished or cold drawn)
Size Range: Outer Diameter (OD) 1/8" to 24" (10.3mm - 610mm); Wall Thickness (WT) Sch 40 to XXS / up to 100mm
Condition: Fully heat-treated (Normalized and tempered, or quenched and tempered)
Technical Specifications
Chemical Composition (%)
|
Element |
Content (%) |
|
Carbon (C) |
0.05 - 0.15 |
|
Manganese (Mn) |
0.30 - 0.60 |
|
Phosphorus (P), max |
0.025 |
|
Sulfur (S), max |
0.025 |
|
Silicon (Si) |
0.50 - 1.00 |
|
Chromium (Cr) |
1.00 - 1.50 |
|
Molybdenum (Mo) |
0.44 - 0.65 |
Mechanical Properties
|
Tensile Strength, min |
415 MPa (60,000 psi) |
|
Yield Strength, min |
205 MPa (30,000 psi) |
|
Elongation in 2 in. (50 mm), min |
30% (longitudinal) / 20% (transverse) |
|
Hardness, max (Brinell) |
220 HBW |
Material & Manufacturing
Consistent performance from an ASTM A335 P11 alloy steel tube supplier relies on strict metallurgical control and thermal processing precision:
Steelmaking & Refining: Produced via Electric Arc Furnace (EAF) followed by Ladle Furnace (LF) and Vacuum Degassing (VD) to minimize non-metallic inclusions and precisely control residual trace elements.
Piercing & Rolling: Rotary piercing and mandrel mill rolling ensure uniform wall thickness and concentricity, which are critical for high-pressure containment.
Heat Treatment: All P11 tubes undergo controlled thermal processing-normalized at >= 900°C followed by subcritical tempering at >= 650°C-to achieve a stable ferrite-pearlite microstructure, relieve residual stress, and optimize mechanical properties prior to fabrication.
Quality Inspection & Testing
Compliance with ASME Section I and VIII requires rigorous verification before factory dispatch. Every production lot undergoes:
Destructive Testing: Tension test, flattening test, hardness test, and transverse guided-bend test per ASTM A335.
Non-Destructive Examination (NDE): 100% Ultrasonic Testing (UT) or Hydrostatic Testing per ASTM A530 requirements.
Dimensional Verification: Laser-based OD, wall thickness, and straightness verification.
Traceability: Positive Material Identification (PMI) and permanent die-stamping on each tube body, linking directly to the heat number and EN 10204 3.1 Mill Test Certificate (MTC).
Typical Applications
As vital components in critical infrastructure, these ASME SA335 P11 boiler tubes are deployed in systems handling high-pressure steam and hydrocarbons:
Power Generation: Superheater headers, reheater loops, and main steam piping in subcritical and supercritical fossil-fuel boilers.
Petrochemical & Refining: Cracker furnace tubes, catalytic reforming units, and high-temperature hydrocarbon transfer lines.
Process Piping: Industrial steam distribution networks operating continuously above 400°C.
Customization & Supply Capability
Length Options:
Single random length (SRL), double random length (DRL), or cut-to-length exact dimensions (up to 12 meters).
Ends Configuration:
Plain ends, square cut, bevelled ends per ANSI B16.25, or threaded configurations.
Surface Protection:
External anti-rust oil coating, black varnish, or heavy-duty plastic caps on both ends.
Production Capacity:
3,000 metric tons monthly across seamless hot-rolling lines. Standard mill lead time: 30-45 days; dedicated inventory maintained for urgent stock replenishment.
Frequently Asked Questions
Q: What is the difference between ASTM A335 P11 and P22 alloy steel tubes?
A: P11 contains nominally 1.25% Cr and 0.5% Mo, suitable for operating temperatures up to 593°C. P22 contains 2.25% Cr and 1.0% Mo, offering higher creep strength and oxidation resistance for more demanding high-temperature/pressure regimes (exceeding 600°C).
Q: Does P11 require preheating and post-weld heat treatment (PWHT)?
A: Yes. Due to its alloy content and hardenability, P11 typically requires a preheat temperature of 150°C to 205°C during field welding, followed by mandatory PWHT (tempering) to relieve residual fabrication stresses and prevent brittle cracking.
Q: Are EN 10204 3.1 Mill Test Certificates (MTCs) provided with each shipment?
A: Yes. Each order ships with a comprehensive EN 10204 3.1 MTC detailing ladle analysis, product analysis, mechanical test results, heat treatment temperature logs, and NDT compliance.
Q: Can you accommodate Third-Party Inspection (TPI)?
A: Yes. We regularly work with major inspection agencies designated by clients, including SGS, Bureau Veritas (BV), TÜV, and Lloyd's Register.
Q: What is the standard export packaging method?
A: Tubes are bundled with high-strength steel strips, wrapped in heavy-duty waterproof woven plastic, and secured inside wooden crates or containerized with robust dunnage to prevent transit damage.
Q: Do you maintain buffer stock for urgent plant maintenance?
A: Yes. We maintain a rolling inventory of standard sizes (e.g., 3-inch to 12-inch, schedules 40 through XXS) ready for quick dispatch to support emergency plant turnarounds and outages.
Request a Quote
To receive an accurate commercial and technical quotation from our engineering team within 24 hours, please submit the following parameters:
1.Outer Diameter (OD) and Wall Thickness (WT) or Schedule
2.Exact Specification (ASTM A335 P11)
3.Total Quantity (Meters, Tons, or Pieces)
4.Required Length (Random or Exact Cut-to-Size)
5.Destination Port and Any Specific Third-Party Inspection (TPI) Requirements
[ Submit RFQ / Contact Our Technical Sales Team ]
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