Description
Product Description A335 P12 Seamless All0y Steel Pipe
ASTM A335 P12 seamless alloy steel pipe is a high-performance piping material widely used in various industrial applications, particularly in the petrochemical, chemical, and power generation industries. This grade of alloy steel pipe is known for its excellent mechanical properties and ability to withstand high-pressure and high-temperature environments. Manufactured in accordance with ASTM A335 specifications, these pipes offer enhanced durability, resistance to corrosion, and can be welded and formed with ease. The “P12” refers to a specific grade of steel within the ASTM A335 specification, known for its composition and mechanical properties. P12 alloy steel pipes are primarily used for the construction of boilers, superheaters, and heat exchangers, where they must endure high temperature and pressure conditions. The seamless nature of these pipes ensures that they are uniform in wall thickness, which provides better performance compared to welded pipes. The lack of a welded seam also reduces the risk of leakage or failure in critical applications.
ASTM A335 P12 Dimensions and Tolerances
- Nominal bore size: 1/8NB to 24NB
- Outer diameter: 19.05 mm to 114.3 mm
- Wall thickness: 2 mm to 14 mm
- Length: Up to 16,000 mm
NPS (in) | OD (in) | SCH 10 (WT/ID) | SCH 40 (WT/ID) | SCH 80 (WT/ID) | SCH 160 (WT/ID) | SCH XXS (WT/ID) |
1/8 | 0.405 | 0.049 / 0.307 | 0.068 / 0.269 | 0.095 / 0.215 | 0.123 / 0.159 | 0.215 / 0.215 |
1/4 | 0.540 | 0.065 / 0.410 | 0.088 / 0.364 | 0.119 / 0.302 | 0.157 / 0.226 | 0.302 / 0.302 |
1/2 | 0.840 | 0.083 / 0.674 | 0.109 / 0.622 | 0.147 / 0.546 | 0.187 / 0.466 | 0.294 / 0.294 |
3/4 | 1.050 | 0.083 / 0.884 | 0.113 / 0.824 | 0.154 / 0.742 | 0.218 / 0.614 | 0.308 / 0.434 |
1 | 1.315 | 0.109 / 1.097 | 0.133 / 1.049 | 0.179 / 0.957 | 0.250 / 0.815 | 0.358 / 0.599 |
1 1/4 | 1.660 | 0.109 / 1.442 | 0.140 / 1.380 | 0.191 / 1.278 | 0.250 / 1.160 | 0.382 / 0.896 |
1 1/2 | 1.900 | 0.109 / 1.682 | 0.145 / 1.610 | 0.200 / 1.500 | 0.281 / 1.338 | 0.400 / 1.100 |
2 | 2.375 | 0.109 / 2.157 | 0.154 / 2.067 | 0.218 / 1.939 | 0.344 / 1.687 | 0.436 / 1.503 |
3 | 3.500 | 0.120 / 3.260 | 0.216 / 3.068 | 0.300 / 2.900 | 0.438 / 2.624 | 0.600 / 2.300 |
4 | 4.500 | 0.120 / 4.260 | 0.237 / 4.026 | 0.337 / 3.826 | 0.531 / 3.438 | 0.674 / 3.152 |
6 | 6.625 | 0.134 / 6.357 | 0.280 / 6.065 | 0.432 / 5.761 | 0.719 / 5.187 | 0.864 / 4.897 |
8 | 8.625 | 0.148 / 8.329 | 0.322 / 7.981 | 0.500 / 7.625 | 0.906 / 6.813 | 1.125 / 6.375 |
10 | 10.750 | 0.165 / 10.420 | 0.365 / 10.020 | 0.500 / 9.750 | 1.250 / 8.250 | 1.406 / 7.938 |
12 | 12.750 | 0.180 / 12.390 | 0.375 / 12.000 | 0.500 / 11.750 | 1.406 / 9.938 | 1.562 / 9.625 |
ASTM A335 P12 Chemical Composition
Element | Composition (%) |
Carbon (C) | 0.05 - 0.15 |
Manganese (Mn) | 0.30 - 0.61 |
Silicon (Si) | 0.50 - 1.00 |
Phosphorus (P) | 0.025 max |
Sulfur (S) | 0.025 max |
Chromium (Cr) | 0.80 - 1.25 |
Molybdenum (Mo) | 0.44 - 0.65 |
ASTM A335 P12 Mechanical Properties
Property | Value |
Tensile Strength | 415 MPa (60,200 psi) min |
Yield Strength | 205 MPa (29,700 psi) min |
Elongation | 30% min |
Hardness (Brinell) | 163 HB max |
Hardness (Rockwell B) | 85 HRB max |
Impact Energy (Charpy V-Notch) | 27 J (20 ft-lbf) min at -20°C (-4°F) |
Manufacturing Process
- Steel Production: The raw steel is produced using electric arc furnaces (EAF) or other methods. This step ensures the proper chemical composition of the alloy.
- Billet Heating: The steel is heated to a high temperature (about 2300°F or 1260°C) in a furnace.
- Piercing: The billet is pierced using a rotary piercer, creating a hollow section that will eventually become the pipe.
- Extrusion or Pilgering: The hollow billet is then extruded or pilgered to elongate the tube and reduce its diameter.
- Stretching and Sizing: The pipe is stretched and sized to achieve the desired dimensions and wall thickness.
- Heat Treatment: The pipe is heat-treated to relieve stresses and improve its mechanical properties. This can involve normalizing, annealing, or quenching and tempering, depending on the desired results.
- Surface Treatment: The pipes undergo surface treatment processes such as pickling or shot blasting to remove oxides and scale.
- Inspection and Testing: Each batch of pipes undergoes stringent quality control procedures, including mechanical and chemical testing, to ensure compliance with ASTM A335 P12 standards.
- Packaging and Shipping: The final product is carefully inspected and packaged for shipping to ensure it reaches its destination in optimal condition.
Heat Treatment
- Normalizing: Heating the pipe to a temperature of 900-1000°C and allowing it to cool in air to refine the grain structure and enhance toughness.
- Annealing: Heating the pipe to a specific temperature and then cooling it slowly to soften the steel and increase ductility.
- Quenching and Tempering: A two-step process that involves heating the steel to a high temperature, quenching it to harden the material, and then tempering it to achieve the desired balance between hardness and toughness.
Applications
- Power Generation: P12 pipes are widely used in power plants for superheaters, reheaters, and boilers, where the pipes must withstand high pressure and temperature.
- Petrochemical and Chemical Industry: P12 steel pipes are used in the transportation of fluids and gases in chemical plants, especially in high-temperature and high-pressure environments.
- Heat Exchangers: The alloy steel’s resistance to scaling and corrosion makes it an excellent choice for heat exchanger tubes, where the pipes come into contact with hot fluids and gases.
- Fossil Fuel Power Plants: P12 pipes are ideal for use in systems such as steam generators and heat recovery steam generators, where high heat resistance and mechanical strength are crucial.
- Marine Applications: Due to their excellent resistance to corrosion, P12 pipes are also used in the marine industry for heat exchangers and high-pressure piping systems.
Advantages
- High-Temperature Resistance: P12 pipes can withstand temperatures up to 600°F (315°C) and are ideal for high-temperature applications.
- Corrosion Resistance: The chromium content in P12 steel provides good resistance to oxidation and corrosion in high-temperature environments.
- Creep Resistance: The presence of molybdenum in the alloy enhances its resistance to creep under high pressure and temperature.
- High Strength and Durability: P12 pipes exhibit excellent mechanical properties, including high tensile strength and yield strength, making them suitable for demanding industrial applications.
- Weldability: P12 steel is easily welded using most conventional methods, ensuring that it can be used in various piping configurations.
- Seamless Construction: The seamless construction of P12 pipes eliminates the risk of failure at welded joints, which is especially important in high-pressure and high-temperature environments.
Conclusion
ASTM A335 P12 seamless alloy steel pipe is a critical material for industries that require pipes to perform under extreme conditions. With its excellent mechanical properties, high-temperature and corrosion resistance, and versatile applications, it is a go-to material for power plants, chemical processing, and other high-pressure environments. Understanding the technical data, manufacturing processes, and applications of ASTM A335 P12 steel pipes is essential for selecting the right material for your project. Whether you’re working on a new
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