ASTM A691 GR 91

A691 GR 91, Alloy Steel Pipes, High-Temperature Applications, Corrosion-Resistant Pipes, Pressure Vessel-Grade Pipes, EFW Steel Pipes

Kwality Steelage Pvt. Ltd., a globally acclaimed manufacturer, supplier, and exporter based in Mumbai, India, offers top-quality ASTM A691 GR 91 Alloy Steel Pipes. These pipes are specially engineered to endure extreme temperatures and high-pressure conditions, making them the preferred choice for critical applications in industries such as power generation, oil refineries, petrochemicals, and chemical processing. Fabricated using pressure vessel-grade plates and the Electric Fusion Welding (EFW) process, these pipes deliver outstanding mechanical strength, durability, and corrosion resistance.

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ASTM A691 GR 91

ASTM A691 GR 91 pipes are available in nominal bore (NB) sizes ranging from 1/2 inch to 36 inches, with wall thicknesses of up to 75 mm. They are offered in various schedules, including SCH 40, SCH 80, SCH 120, and SCH XXS, catering to diverse industrial requirements. These pipes exhibit a tensile strength of 585–760 MPa and a minimum yield strength of 415 MPa, ensuring reliable performance under demanding conditions.

The material composition of ASTM A691 GR 91 pipes features 9% chromium and 1% molybdenum, which significantly enhance their resistance to creep, oxidation, and thermal stress. Additionally, trace elements like vanadium, niobium, and nitrogen improve mechanical properties, making these pipes ideal for applications requiring superior strength and durability. These pipes are extensively used in power plants, pressure vessels, and high-temperature fluid transportation systems.

Dimensional precision is achieved with tolerances of ±1% for outside diameter and +12.5%/-10% for wall thickness, ensuring compatibility with international standards. End options such as plain, beveled, and threaded ends are available, along with surface treatments like black painting, galvanization, and anti-corrosion coatings. Custom lengths of up to 12 meters can be supplied to meet specific project requirements.

Kwality Steelage Pvt. Ltd. ensures stringent quality assurance through advanced testing techniques, including ultrasonic, radiographic, and hydrostatic examinations. With a strong commitment to quality and timely delivery, the company supplies ASTM A691 GR 91 Alloy Steel Pipes to global markets, including the Middle East, Europe, and Asia. Contact us today to explore our range of high-performance pipes and elevate your industrial projects.

Specification Chart for ASTM A691 GR 91 Alloy Steel Pipes

Specification Details
Size Range 1/2 to 36 inch NB
Wall Thickness Range SCH 20, SCH 40, SCH 80, SCH 120, SCH 160, XXS
Applications Power Plants, Petrochemicals, Oil Refineries, High-Temperature Fluid Transport
Pipe Type Electric Fusion Welded (EFW)
Pipe Form Round, Square, Rectangular, Hydraulic Pipes
Manufacturing Process Heat-Treated (Normalized, Quenched, Tempered), EFW with Pressure Vessel Grade Plates
Material Composition Alloy Steel with 9% Chromium, 1% Molybdenum, Vanadium, Niobium, and Nitrogen
End Type Plain, Beveled, Threaded
Length Options Single Random, Double Random, Custom Lengths (up to 12 meters)
Surface Coating Anti-Corrosion Coating, Black Painting, Galvanized

Dimensional Tolerances for ASTM A691 GR 91 Pipes

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

Mechanical Properties of ASTM A691 GR 91 Pipes

Grade Yield Strength (Min) Tensile Strength (Min) Elongation (%)
91 415 MPa 585–760 MPa 18%

Chemical Composition of ASTM A691 GR 91 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%
Nitrogen (N) 0.030-0.070%
Niobium (Nb) 0.06-0.10%

Price Range (per Metric Ton)

Pipe Type Price Range (USD)
ASTM A691 GR 91 Alloy Steel Pipes $1,000 – $2,200

Welding and Heat Treatment for ASTM A691 GR 91 Pipes

Welding and heat treatment are critical for ASTM A691 GR 91 pipes to achieve the desired mechanical properties. These pipes undergo stress-relieving at 1100-1250°F (590-675°C) and can be normalized at up to 1900°F (1040°C). Quenching and tempering processes are used as required to enhance strength and durability. Post-weld heat treatment (PWHT) is recommended for thicknesses above 12 mm to minimize residual stresses and improve weld integrity.

Differences Between ASTM A691 GR 9 CR and GR 91 Pipes

Feature GR 9 CR GR 91
Chromium Content 8.00-10.00% 8.00-9.50%
Molybdenum Content 0.90-1.10% 0.85-1.05%
Vanadium Content Not Present 0.18-0.25%
Applications High-Temperature, High Pressure Extreme-Temperature, Creep Resistance

Choose Kwality Steelage Pvt. Ltd. for premium ASTM A691 GR 91 Alloy Steel Pipes. Designed for extreme applications, our pipes deliver unmatched quality and durability. Contact us now for custom solutions and global delivery!