Alloy Steel Pipes
ASTM A335 Grade P91 seamless steel pipe is a 9Cr-1Mo-V-Nb martensitic alloy steel pipe designed for high-temperature and high-pressure service in fossil fuel power plants, petrochemical facilities and industrial process systems. It offers outstanding creep strength, oxidation resistance and long-term stability at elevated temperatures.
Product Overview
ASTM A335 Grade P91 seamless steel pipe is a 9Cr-1Mo-V-Nb martensitic alloy steel pipe designed for high-temperature and high-pressure service in fossil fuel power plants, petrochemical facilities and industrial process systems. It offers outstanding creep strength, oxidation resistance and long-term stability at elevated temperatures.
Hongcheng manufactures A335 P91 seamless pipes in accordance with ASTM A335 / ASME SA335. All pipes are supplied in the normalized and tempered condition unless otherwise specified, ensuring reliable performance in demanding high-temperature applications.
Material & Heat Treatment
A335 Grade P91 is a modified 9Cr-1Mo alloy steel containing controlled additions of vanadium, niobium and nitrogen to improve creep rupture strength and long-term thermal stability.
Heat treatment includes:
• Normalizing: 1040–1080°C
• Tempering: 730–780°C
This heat treatment develops a tempered martensitic microstructure suitable for long-term service at temperatures up to approximately 620°C.
Manufacturing Process
Steel Billet → Heating → Rotary Piercing → Hot Rolling → Sizing → Normalizing & Tempering → Inspection → Marking → Packing
Technical Parameters
|
Parameter |
Value |
|
Grade |
ASTM A335 P91 |
|
Type |
Seamless |
|
Outside Diameter |
1/2"–48" (Custom Available) |
|
Wall Thickness |
SCH 40 / SCH 80 / SCH 160 / XXS |
|
Length |
Random Length or Fixed Length |
|
Heat Treatment |
Normalized & Tempered |
|
Ends |
Plain End / Beveled End |
|
Surface |
Black Finish / Anti-rust Oil |
Inspection & Testing
Every A335 P91 seamless steel pipe is inspected throughout production to ensure compliance with ASTM A335 requirements.
Available inspections include:
*EN 10204 Type 3.1 Material Test Certificate is available for each production batch.
Applications
• Main steam pipelines
• Hot reheat piping
• Cold reheat piping
• Superheater outlet piping
• Power plant headers
• Supercritical and ultra-supercritical power units
• High-temperature pressure piping systems
• Petrochemical process plants
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Projects of Alloy Steel Pipes
Power Plant Projects
Products: P91 Pipes · P92 Pipes · Pipe Fittings · Pipe Spools
FAQs
Does P91 require post-weld heat treatment (PWHT)?
Yes. P91 welding normally requires preheating, controlled interpass temperature and post-weld heat treatment (PWHT) in accordance with the applicable welding procedure and project specifications.
Can P91 replace P22?
P91 may replace P22 in certain applications due to its higher creep strength, but engineering evaluation is required to verify wall thickness, stress levels and welding procedures.
Can customized dimensions be supplied?
Yes. Custom outside diameter, wall thickness, length, end preparation and inspection requirements are available.
What inspection documents are available?
EN 10204 Type 3.1 Material Test Certificates and project-specific inspection reports are available upon request.
Wuliyao Industrial Zone, Yanshan County, Cangzhou City, Hebei Province, China.
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