What is P23 material
Feb 06, 2026
A335 P23 is a chromium-molybdenum alloy steel pipe under the ASTM A335 standard, with a chemical composition of 1.25Cr-0.5Mo-V-Nb-N (UNS K11547). Compared to the traditional P22 material, P23 significantly improves high-temperature strength and oxidation resistance by adding microalloying elements such as vanadium (V), niobium (Nb), and nitrogen (N).
Its typical mechanical properties are: room temperature tensile strength ≥510MPa, yield strength ≥400MPa, and excellent creep rupture strength even at 600℃. This material conforms to international standards such as ASME SA-335 and EN 10216-2, and has passed the PED 2014/68/EU Pressure Equipment Directive certification, making it suitable for harsh environments with an operating temperature range of -10℃ to 625℃.
GNEE Group is a leading steel pipe supplier in China, providing pipe consulting and processing services. Free 1–2 meter samples shipped, freight collect – if you order within 30 days, sample cost is deducted.
ASTM A335 P23 Seamless pipe Chemical Composition
| C, % | Mn, % | P, % | S, % | Si, % | Cr, % | Mo, % | V, % | Nb, % | B,% | N, % | Al, % | W, % |
| 0.04-0.10 | 0.1-0.6 | 0.03 max | 0.01 max | 0.5 max | 1.9-2.6 | 0.05-0.30 | 0.20-0.30 | 0.02-0.08 | 0.0005-0.006 | 0.03 max | 0.03 max | 1.45-1.75 |
Check ASTM A335 P23 Material Composition and ASTM A335 Gr P23 Composition list is given above in the table
ASTM A335 P23 boiler tube Properties
| Tensile Strength, MPa | Yield Strength, MPa | Elongation, % |
| 510 min | 400 min | 20 min |
Alloy Steel P23 Pipe Outside Diameter
| ASTM A450 | Hot rolled | Outside Diameter, mm | Tolerance, mm |
| OD≤101.6 | +0.4/-0.8 | ||
| 101.6＜OD≤190.5 | +0.4/-1.2 | ||
| 190.5＜OD≤228.6 | +0.4/-1.6 | ||
| Cold Drawn | Outside Diameter, mm | Tolerance, mm | |
| OD＜25.4 | ±0.10 | ||
| 25.4≤OD≤38.1 | ±0.15 | ||
| 38.1＜OD＜50.8 | ±0.20 | ||
| 50.8≤OD＜63.5 | ±0.25 | ||
| 63.5≤OD＜76.2 | ±0.30 | ||
| 76.2≤OD≤101.6 | ±0.38 | ||
| 101.6＜OD≤190.5 | +0.38/-0.64 | ||
| 190.5＜OD≤228.6 | +0.38/-1.14 | ||
| ASTM A530 & ASTM A335 | NPS | Outside Diameter, inch | Tolerance, mm |
| 1/8≤OD≤1-1/2 | ±0.40 | ||
| 1-1/2＜OD≤4 | ±0.79 | ||
| 4＜OD≤8 | +1.59/-0.79 | ||
| 8＜OD≤12 | +2.38/-0.79 | ||
| OD>12 | ±1% |
ASTM A335 Gr P23 Pipe Wall Thickness
| ASTM A450 | Hot rolled | Outside Diameter, mm | Tolerance, % |
| OD≤101.6, WT≤2.4 | +40/-0 | ||
| OD≤101.6, 2.4＜WT≤3.8 | +35/-0 | ||
| OD≤101.6, 3.8＜WT≤4.6 | +33/-0 | ||
| OD≤101.6, WT>4.6 | +28/-0 | ||
| OD>101.6, 2.4＜WT≤3.8 | +35/-0 | ||
| OD>101.6, 3.8＜WT≤4.6 | +33/-0 | ||
| OD>101.6, WT>4.6 | +28/-0 | ||
| Cold Drawn | Outside Diameter, mm | Tolerance, % | |
| OD≤38.1 | +20/-0 | ||
| OD>38.1 | +22/-0 | ||
| ASTM A530 | NPS | Outside Diameter, inch | Tolerance, % |
| 1/8≤OD≤2-1/2 | +20.0/-12.5 | ||
| 3≤OD≤18, WT/OD≤5% | +22.5/-12.5 | ||
| 3≤OD≤18, WT/OD>5% | +15.0/-12.5 | ||
| OD≥20, WT/OD≤5% | +22.5/-12.5 | ||
| OD≥20, WT/OD>5% | +15.0/-12.5 |
A335 P23 Seamless Pipe Advantages:
High Temperature and High Pressure Resistance:
A335P23 alloy steel pipe is specifically designed for high temperature and high pressure environments, capable of withstanding extreme working conditions, and suitable for high temperature and high pressure pipeline systems in power plants, etc.
Good Mechanical Properties:
This steel pipe has high tensile strength and yield strength, maintaining stable mechanical properties at high temperatures, ensuring the safety and reliability of the pipeline system.
Excellent Corrosion Resistance:
A335P23 alloy steel pipe has a certain resistance to various corrosive media, and can be used for a long time in harsh industrial environments without severe corrosion.
Good Weldability:
This steel pipe is easy to weld, facilitating on-site installation and maintenance, reducing construction difficulty and costs.
Wide Range of Applications:
A335P23 alloy steel pipe is suitable for various applications requiring high temperature and high pressure resistance, such as power plants, nuclear power plants, petrochemical plants, etc. In power plants, it is commonly used to connect boiler heating surfaces and other equipment, ensuring efficient steam and hot water transmission.
Environmental Protection and Sustainability:
A335P23 alloy steel pipe is 100% recyclable, aligning with national strategies for environmental protection, energy conservation, and resource saving. With increasing global emphasis on environmental protection and sustainable development, this advantage makes A335P23 alloy steel pipe more competitive in the market.
A335 P23 Seamless pipe Application Scenarios
1. Supercritical Power Plant Boilers: Used as main steam pipelines and reheater connection pipes, capable of withstanding operating parameters of 31MPa/605℃.
Case studies show that the supplied P23 pipelines operated continuously for 80,000 hours in a 1000MW unit without creep damage.
2. Petroleum Cracking Units: Used for inlet and outlet pipelines of hydrogenation reactors, with resistance to hydrogen sulfide stress corrosion superior to 316L stainless steel. A certain refining project used 45mm thick P23 steel pipes with a design life of 20 years.
3. Nuclear Power Auxiliary Systems: Used as feedwater heater pipelines in AP1000 units, certified by NACE MR0175 acid environment standards.
4. High-Temperature Chemical Piping: Suitable for conversion furnace piping systems in ammonia synthesis, methanol, and other units, resistant to corrosion from H₂+CO mixed gases.
A335 P23 Boiler tube factory
