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ASTM A335 P91 Pipe

ASTM A335 P91 Pipe – High-Strength Alloy Steel Solution for High-Temperature Applications

The ASTM A335 P91 Pipe is a high-grade, seamless ferritic alloy steel pipe recognized for its exceptional strength and high-temperature resilience, specifically tailored for industries that demand durability and performance under extreme conditions. Composed of 9% chromium and 1% molybdenum, with trace elements like vanadium, this pipe offers enhanced creep strength, wear resistance, and oxidation protection, making it an ideal choice for power plants, chemical processing units, and oil and gas services.

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ASTM A335 P91 Pipe

Crafted through a precise heat treatment process involving normalization at 1050°C and tempering at 760°C, the P91 pipe delivers a minimum tensile strength of 585 MPa and a yield strength of 415 MPa. These mechanical attributes are complemented by the alloy’s corrosion resistance, which enables it to endure operational temperatures up to 650°C without compromising structural integrity. The added elements of vanadium, nitrogen, and columbium contribute significantly to the pipe’s durability, ensuring stability and longevity in high-temperature, cyclic environments.

ASTM A335 P91 is versatile and supports various applications, from boilers and reheat lines to heaters and gas processing systems. Its superior creep strength allows a reduced wall thickness, effectively minimizing hanger loads and welding time. This unique characteristic positions it as a cost-effective, efficient solution for infrastructure in power generation facilities and other high-temperature industries. Additionally, it’s ideal for seamless fittings, valves, and flanges, all critical in ensuring safe and efficient fluid and gas transmission.

Available in sizes from ½” to 24” and schedules ranging from SCH 40 to SCH XXS, Kwality Steelage Pvt. Ltd. provides the ASTM A335 P91 pipe in custom lengths, finishes, and ends, including beveled and plain ends. For enhanced durability, the pipe is available with various external coatings, including varnishing, 3LPE, and FBE, ensuring adaptability across different industrial requirements.

Manufactured in strict accordance with ASTM A335 and ASME SA335 standards, P91 pipes come with precise dimensional tolerances for both inside and outside diameters, ensuring accuracy in high-stress applications. Dimensional tolerances vary based on size, ranging up to ±0.79mm for pipes with diameters over 8 inches, which meet the demands for tight tolerance control in modern industrial environments.

The distinctive blend of chromium and molybdenum in ASTM A335 P91 Pipe enhances oxidation resistance and temperature strength, ideal for power plants and petrochemical installations. The addition of minor alloying elements like vanadium and nitrogen further bolsters the alloy’s structural properties, preventing embrittlement, reducing oxidation, and increasing resistance to wear and tear. Molybdenum, in particular, contributes to the high temperature creep strength, making it a highly reliable option in demanding, cyclic applications.

Kwality Steelage Pvt. Ltd. offers ASTM A335 P91 Seamless Alloy Steel Pipes that cater to a broad array of industries globally, including oil and gas, power generation, and chemical processing. With in-depth quality checks, certifications, and third-party inspection reports, Kwality Steelage ensures each ASTM A335 P91 pipe meets stringent international standards for safe and optimal performance.

Specification Chart for ASTM A335 P91 Alloy Steel Pipes for High-Temperature Services

Specification Details
Size Range 1/8 to 24 inch NB
Schedule Thickness Range SCH 20, SCH 40, SCH 80, SCH 160, XS, XXS, All Schedules
Applications Power Plants, Oil Refineries, Petrochemical Industries, Chemical Industries, Boilers, Gas Processing, Fluid and Gas Transmission
Pipe Type Seamless
Pipe & Tube Form Round, Square, Rectangular, Hydraulic Pipes
Manufacturing Process Hot-Finished or Cold Drawn, Heat Treated (Normalizing, Quenching and Tempering)
Material Composition Alloy Steel with 9% Chromium, 1% Molybdenum, and optional Vanadium
End Type Plain, Beveled, Threaded
Length Options Single, Double Random, Custom Lengths (up to 12 meters)
End Protection Plastic Caps
Outside Coating Anti-Corrosion Oil, Black Painting

Dimensional Tolerances for ASTM A335 P91 Pipes

Tolerance Type Outside Diameter (OD) Wall Thickness (WT)
Size Tolerance +1% / -1% of specified OD +12.5% / -10% of specified WT

Size and Weight Chart for ASTM A335 P91 Seamless Alloy Steel Pipes

Outside Diameter (mm) Wall Thickness (mm) Nominal Size (in.) Schedule Weight (Kg/m)
13.72 1.65 1/4 SCH 10S 0.50
21.34 3.73 1/2 SCH 80 1.65
42.16 6.35 1-1/4 SCH 160 5.69
88.90 11.13 3 SCH 160 21.67
168.28 18.26 6 SCH 160 68.59

Note: Additional sizes and weights are available upon request.

Mechanical Properties of ASTM A335 P91 Pipes

Grade Yield Strength (Min) Tensile Strength (Min) Elongation (%)
P91 415 MPa 585 MPa 20-30

Chemical Composition of ASTM A335 P91 Pipes

Element Maximum % Composition
Carbon (C) 0.08-0.12%
Manganese (Mn) 0.30-0.60%
Phosphorus (P) 0.020%
Sulfur (S) 0.010%
Silicon (Si) 0.20-0.50%
Chromium (Cr) 8.00-9.50%
Molybdenum (Mo) 0.85-1.05%
Vanadium (V) 0.18-0.25%

Price Range (per Metric Ton)

Pipe Type Price Range (USD)
ASTM A335 P91 Seamless Pipes $1,200 – $2,500

Welding and Heat Treatment for ASTM A335 P91 Pipes

Welding ASTM A335 P91 pipes requires precise temperature control to maintain mechanical properties and prevent cracking. Preheating to 200°C is recommended, and Post-Weld Heat Treatment (PWHT) is essential for pipes over 13 mm in thickness to relieve residual stresses and ensure structural stability. PWHT typically involves heating between 730°C and 800°C to provide optimal durability in high-stress applications.

Differences Between ASTM A335 P91 and P22 Pipes

Feature P91 P22
Carbon Content 0.08-0.12% 0.05-0.15%
Chromium Content 8.00-9.50% 1.90-2.60%
Yield Strength (Min) 415 MPa 205 MPa
Applications High-Temperature, High Pressure Moderate Temperature, Moderate Pressure

Contact Kwality Steelage Pvt. Ltd. today to get a quote on ASTM A335 P91 pipes tailored for your high-temperature applications! We offer international shipping and custom specifications to meet your needs.