ASTM A691
Basic Info
The ASTM A691 standard specifies the standard specifications for high-temperature and high-pressure welded alloy steel pipes, which are commonly used in petroleum, natural gas transmission pipelines, and other industrial applications. This standard covers the chemical composition, mechanical properties, and dimensional requirements of pipes to ensure that products have good weldability and durability in high temperature and high pressure environments.
Characteristics
High-Pressure Service: ASTM A691 steel pipes are specifically designed for use in high-pressure applications. They can withstand elevated pressures, making them suitable for transporting fluids and gases under demanding conditions.
Electric-Fusion-Welded: ASTM A691 pipes are manufactured using the electric fusion welding process. This method ensures strong and durable welds, enhancing the structural integrity of the pipes and allowing them to withstand the stresses encountered during operation.
Suitable for Moderate Temperatures: ASTM A691 steel pipes are intended for use at moderate temperatures. While not suitable for extreme temperature environments, they are designed to perform reliably within a specified temperature range, providing an efficient and cost-effective solution for various industrial applications.
Wide Range of Grades: ASTM A691 encompasses pipes made from various grades of carbon and alloy steel. These grades are categorized based on their minimum yield strength, tensile strength, and chemical composition, allowing for the selection of the appropriate grade based on the intended application and service conditions.
ASTM A691 Data Sheet
Steel Grade
Dimensions and Tolerances
Equivalent Steel Grades
Chemical Composition
Mechanical Properties
Fabrication and Welding
ASTM A691 vs. ASTM A53:
Steel Grade
1 1/4 CR: Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at High Temperatures
2 1/4 CR: Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at Moderate Temperatures
3 1/2 CR: Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at Elevated Temperatures
5 CR: Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at Elevated Temperatures
9 CR: Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at Elevated Temperatures
1 1/4 CR: Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at High Temperatures
2 1/4 CR: Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at Moderate Temperatures
3 1/2 CR: Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at Elevated Temperatures
5 CR: Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at Elevated Temperatures
9 CR: Carbon and Alloy Steel Pipe, Electric-Fusion-Welded for High-Pressure Service at Elevated Temperatures
Dimensions and Tolerances
Round
- Outer Diameter (OD): 6″ to 144″ (150mm to 3658mm)
- Wall Thickness (WT): 0.109″ to 4″ (2.8mm to 101.6mm)
Square
- Width: 4″ to 144″ (100mm to 3658mm)
- Height: 4″ to 144″ (100mm to 3658mm)
- Wall Thickness (WT): 0.109″ to 4″ (2.8mm to 101.6mm)
Rectangular
- Width: 6″ to 144″ (150mm to 3658mm)
- Height: 4″ to 144″ (100mm to 3658mm)
- Wall Thickness (WT): 0.109″ to 4″ (2.8mm to 101.6mm)
Equivalent Steel Grades
United States
- Equivalent Grades: A537/A537M, A671/A671M
- Standard: ASTM A691/A691M
China
- Equivalent Grades: Q345R, Q235R
- Standard: GB/T 5310, GB/T 3091
India
- Equivalent Grades: SA537/SA537M, IS 3589
- Standard: IS 1978, IS 1239
Japan
- Equivalent Grades: SPV490, SG295
- Standard: JIS G3115, JIS G3116
Chemical Composition
Carbon (C)
Composition (%): 0.18 max
Manganese (Mn)
Composition (%): 0.90-1.40
Phosphorus (P)
Composition (%): 0.025 max
Sulfur (S)
Composition (%): 0.025 max
Silicon (Si)
Composition (%): 0.15-0.40
Nickel (Ni)
Composition (%): 0.45 max
Chromium (Cr)
Composition (%): 0.25 max
Molybdenum (Mo)
Composition (%): 0.10 max
Mechanical Properties
Tensile Strength, min, ksi (MPa)
- Minimum Requirement: 60 (415) to 95 (655)
Yield Strength, min, ksi (MPa)
- Minimum Requirement: 32 (220) to 60 (415)
Elongation in 2 inches (50 mm), min, %
- Minimum Requirement: 21
Elongation in 8 inches (200 mm), min, %
- Minimum Requirement: 17
Charpy V-notch Impact Test
- Minimum Requirement: As per ASTM A691 specification
Hardness
- Minimum Requirement: As per ASTM A691 specification
Hydrostatic Test
- Minimum Requirement: As per ASTM A691 specification
Flattening Test
- Minimum Requirement: As per ASTM A691 specification
Bend Test
- Minimum Requirement: As per ASTM A691 specification
Fabrication and Welding
Weldability
- Fabrication and Welding Consideration: ASTM A691 steel pipes exhibit good weldability, allowing for easy fabrication and assembly.
Machinability
- Fabrication and Welding Consideration: Machining of ASTM A691 steel pipes is feasible but may require proper tooling and techniques.
Formability
- Fabrication and Welding Consideration: ASTM A691 steel pipes can be formed using standard techniques, such as bending and rolling.
Hot Working
- Fabrication and Welding Consideration: ASTM A691 steel pipes are typically not subjected to hot working processes due to their manufacturing method.
Cold Working
- Fabrication and Welding Consideration: Cold working processes such as cold bending and cold forming can be applied to ASTM A691 steel pipes.
Heat Treatment
- Fabrication and Welding Consideration: ASTM A691 steel pipes are generally not subjected to heat treatment after welding.
Annealing
- Fabrication and Welding Consideration: Annealing may not be required for ASTM A691 steel pipes, but stress relieving may be beneficial.
Hardening
- Fabrication and Welding Consideration: ASTM A691 steel pipes are not typically subjected to hardening processes.
Stress Relieving
- Fabrication and Welding Consideration: Stress relieving may be performed after welding to reduce residual stresses and improve dimensional stability.
Cutting
- Fabrication and Welding Consideration: ASTM A691 steel pipes can be cut using standard cutting tools such as saws or torches.
Bending
- Fabrication and Welding Consideration: ASTM A691 steel pipes can be bent using cold bending methods, but caution must be exercised to prevent damage.
Punching
- Fabrication and Welding Consideration: Punching holes in ASTM A691 steel pipes can be done using standard punching equipment.
Drilling
- Fabrication and Welding Consideration: Drilling holes in ASTM A691 steel pipes can be done using standard drilling equipment.
Sawing
- Fabrication and Welding Consideration: ASTM A691 steel pipes can be sawed using band saws or other appropriate cutting equipment.
Welding Processes
- Fabrication and Welding Consideration: ASTM A691 steel pipes are suitable for various welding processes, including SMAW, SAW, and GTAW.
Preheating
- Fabrication and Welding Consideration: Preheating may be required for certain grades and wall thicknesses of ASTM A691 steel pipes, as specified in welding procedures.
Interpass Temperature
- Fabrication and Welding Consideration: Interpass temperature control may be necessary during welding to prevent excessive heat input.
Post-weld Heat Treatment (PWHT)
- Fabrication and Welding Consideration: Post-weld heat treatment may be required for certain grades and wall thicknesses of ASTM A691 steel pipes, as specified in welding procedures.
Precautions
- Fabrication and Welding Consideration: Proper fit-up, alignment, and welding techniques should be followed to ensure quality welds and minimize defects.
ASTM A691 vs. ASTM A53:
Material Type
- ASTM A691: Electric-Fusion-Welded (EFW) Steel Pipe
- ASTM A53: Seamless and Welded Carbon Steel Pipe
Application
- ASTM A691: Used for high-pressure and high-temperature applications in power plants, refineries, and petrochemical plants.
- ASTM A53: Used for general-purpose applications in plumbing, HVAC, fire sprinkler systems, and structural components.
Dimensional Tolerances
- ASTM A691:
- Outer Diameter: +/- 1% of specified OD
- Wall Thickness: +/- 12.5% of specified WT
- Length: +6 inches, -0 inches
2. ASTM A53:
- Seamless: Outer Diameter: +/- 1% of specified OD
- Wall Thickness: +/- 12.5% of specified WT
- Welded: Outer Diameter: +/- 1%, Wall Thickness: +/- 12.5% of specified WT
Manufacturing Standards
- ASTM A691:
- Manufactured according to ASTM A691/A691M standard, which covers electric-fusion-welded steel pipe for high-pressure service at moderate temperatures.
- Dimensional specifications include ASME B36.10M for pipe dimensions and ASME B36.19M for pipe sizes and wall thicknesses.
2. ASTM A53:
- Manufactured according to ASTM A53/A53M standard, which covers seamless and welded black and hot-dipped galvanized steel pipe.
- Dimensional specifications include ASME B36.10M for pipe dimensions and ASME B36.19M for pipe sizes and wall thicknesses.
Pressure and Temperature Rating
- ASTM A691: Suitable for high-pressure service at moderate temperatures, typically up to 750°F (399°C).
- ASTM A53: Suitable for general-purpose applications with lower pressure and temperature requirements.
Weldability
- ASTM A691: Weldable using conventional welding methods such as shielded metal arc welding (SMAW), gas tungsten arc welding (GTAW), and gas metal arc welding (GMAW).
- ASTM A53: Weldable using common welding techniques, including oxy-acetylene welding, shielded metal arc welding (SMAW), and gas tungsten arc welding (GTAW).
