SA-335/SA-335M P11 Seamless ferritic alloy seamless steel pipe for high temperature use

SA-335/SA-335M P11 Seamless ferritic alloy seamless steel pipe for high temperature use

A335P11 alloy tube is a high-temperature seamless ferritic alloy steel specified in the American standard SA-335/SA-335M., Due to its excellent high-temperature strength, good oxidation resistance, and corrosion resistance, it has been widely used in fields such as power, petrochemical, chemical, aerospace, etc. This article will provide a detailed introduction to the use, material content, and production methods of A335P11 alloy pipes, helping readers better understand this high-quality pipe material.

2、 Material content

The main chemical composition of A335P11 alloy tube has been carefully formulated to meet the stringent requirements of high temperature and high pressure environments. Its key components include:

Carbon (C): with a content between 0.05% and 0.15%, as the basic element of steel, the balanced content of carbon ensures the strength and toughness of the alloy tube.

Chromium (Cr): with a content between 1.0% and 1.5%, the addition of chromium can form a dense Cr ₂ O3 oxide film, effectively preventing oxidation and corrosion of alloy tubes at high temperatures.

Molybdenum (Mo): With a content between 0.44% and 0.65%, molybdenum significantly improves the creep resistance of the alloy tube, enabling it to work stably for a long time at high temperatures.

In addition, A335P11 alloy tube also contains appropriate amounts of auxiliary elements such as silicon (Si) and manganese (Mn), with silicon content not exceeding 0.50% and manganese content between 0.30% and 0.60%. Under the combined action of these elements, the oxidation resistance, wear resistance, and mechanical properties of the alloy tube are further enhanced. At the same time, the content of impurity elements phosphorus (P) and sulfur (S) is strictly controlled, not exceeding 0.025% and 0.025% respectively, to ensure the purity and high-temperature performance of the material.

3、 Purpose:

A335P11 alloy tube plays an important role in multiple industrial fields due to its excellent performance:

power industry:

In thermal power plants, A335P11 alloy pipes are commonly used to manufacture high-temperature and high-pressure components such as boiler pipes, superheaters, and reheaters, which can withstand steam impacts up to 560 ℃/15MPa.

In nuclear power plants, A335P11 alloy tubes are also used in critical areas such as cooling systems, demonstrating excellent radiation resistance and high-temperature stability.

Petrochemical industry:

A335P11 alloy pipes are widely used in high-temperature and high-pressure environments such as cracking furnaces, hydrogenation reactors, and ethylene engineering ultra-high pressure steam pipelines in the petrochemical industry. Their corrosion resistance and high-temperature strength have been fully verified.

Aerospace:

In the aerospace field, A335P11 alloy tubes are used to manufacture key structural components such as aircraft engine parts, and their lightweight and high-strength characteristics provide strong support for the performance improvement of aircraft.

Other fields:

In addition, A335P11 alloy pipes are also used in various fields such as high-pressure hydraulic systems, heat exchangers, and burners, and their wide range of applications reflects their excellent comprehensive performance.

4、 Production mode

The production process of A335P11 alloy pipes strictly follows relevant standards and specifications to ensure the quality and performance of the products. Its main production methods include:

Smelting and refining:

Advanced electric arc furnaces or LF refining furnaces are used for melting, and the chemical composition is adjusted by adding alloy elements and deoxidizers to ensure the purity and uniformity of the alloy tube.

During the melting process, VD vacuum degassing and other processes are also used to further reduce the content of gas inclusions and impurities.

Forming processing:

Hot rolling process: The melted steel billet is sent to the hot rolling mill for perforation, rolling, and sizing steps to form alloy tubes of the required specifications. Hot rolled pipes have advantages such as high dimensional accuracy and good surface quality.

Cold drawing process: For alloy tubes that require higher dimensional accuracy and surface quality, cold drawing process can be used for processing. During the cold drawing process, multiple drawing and annealing treatments are carried out to ensure the dimensional accuracy and mechanical properties of the alloy tube.

Heat treatment strengthening:

Heat treatment is an important step in the production process of A335P11 alloy tubes. By dual treatment of normalizing and tempering, internal stress is eliminated, and the strength and toughness of the alloy tube are improved. Meanwhile, heat treatment can also improve the processing and welding performance of alloy pipes.

Testing and acceptance:

During the production process, strict chemical composition analysis, mechanical property testing, non-destructive testing, and other inspections and tests are conducted on A335P11 alloy pipes to ensure compliance with relevant standards and engineering requirements.

The final product also needs to undergo ultrasonic testing, eddy current testing and other testing methods to ensure the reliable quality of each alloy tube.

ASTM A335 P11 alloy seamless steel pipe manufacturer

1. A335 P11 is an American standard seamless ferritic alloy steel pipe for high temperature applications.
2. The manufacturer requires ferrite to be a interstitial solid solution of carbon dissolved in α – Fe, commonly represented by the symbol F. Having a body centered cubic lattice, its carbon solubility is very low, only able to dissolve 0.0008% of carbon at room temperature, and the maximum carbon solubility at 727 ℃ is 0.02%.
3. The manufacturer requires smooth ferrite grain boundaries and rare twinning or slip lines within the crystal. The color is light green, shiny, and darkens after deep corrosion. Ferrite in steel exists in the form of flakes, blocks, needles, and networks.
4. Pure ferrite structure has good plasticity and toughness, but low strength and hardness; Cold work hardening is slow and can withstand a large reduction rate of drawing, but the tensile strength of the finished steel wire is difficult to exceed 1200MPa. Due to the low carbon content of ferrite, its properties are similar to pure iron, with good plasticity and toughness, and elongation δ=45% to 50%. Low strength and hardness, σb≈250MPa， And HBS=80.

A335 P11 Seamless Alloy Steel Pipe Specification Table

A335 P11 Chemical composition: C：0.05~0.15 Si：0.50~1.00 Mn：0.30~0.60 P≤0.025 S≤0.025 Cr：1.00~1.50 Mo：0.44~0.65
Mechanical properties of A335 P11 high-pressure boiler tube: tensile strength ≥ 415Map, yield strength ≥ 205Mpa, elongation at break ≥ 30%,
Delivery status of A335 P11 pipe fittings: fully annealed or isothermal annealed, normalized tempered.
A335 P11 pipe fittings with pipe specifications and sizes of 60.3-765 * 2-120, commonly used diameters of 60.3, 73, 88.9, 114.3, 168.3, 219.1, 273.1, 323.9, 355.6, 406.4, 457.2, 508, 559, 610, 660, 711, 762. Other sizes can also be customized according to customer requirements.