ASTM A234 WP91 Alloy Steel Tee
ASTM A234 WP91 Alloy Steel Tee is a 9Cr-1Mo-V alloy steel butt weld fitting manufactured in accordance with ASTM A234 / ASME SA234 and ASME B16.9 for high-temperature and high-pressure piping systems.
Tee
ASTM A234 WP91 Alloy Steel Tee is a 9Cr-1Mo-V alloy steel butt weld fitting manufactured in accordance with ASTM A234 / ASME SA234 and ASME B16.9 for high-temperature and high-pressure piping systems.
Product Overview
ASTM A234 WP91 Alloy Steel Tee is a 9Cr-1Mo-V alloy steel butt weld fitting manufactured in accordance with ASTM A234 / ASME SA234 and ASME B16.9 for high-temperature and high-pressure piping systems. Based on a 9Cr-1Mo-V alloy system, WP91 alloy steel tees provide excellent creep rupture strength, oxidation resistance and microstructural stability, making them suitable for ultra-supercritical (USC) power plant main steam, hot reheat piping and high-temperature refinery applications. WP91 is a widely adopted alloy steel grade for power generation and petrochemical industries, offering reliable performance in demanding high-temperature service conditions. Hongcheng supplies ASTM A234 WP91 alloy steel tees in normalized and tempered condition, with full material traceability, inspection documentation and project-specific technical support.
Material & Heat Treatment
ASTM A234 WP91 belongs to the same 9Cr-1Mo-V alloy system used for ASTM A335 P91 seamless pipe and ASTM A182 F91 forgings. These grades are commonly used together in high-temperature piping systems, while each product form is governed by its respective ASTM / ASME material specification.
Key alloying elements include: Chromium (Cr), Molybdenum (Mo), Vanadium (V), Niobium (Nb), Nitrogen (N), Manganese (Mn), Silicon (Si), Carbon (C).
Chromium provides oxidation resistance, molybdenum and vanadium enhance creep strength, while niobium and nitrogen improve microstructural stability under long-term high-temperature service.
Typical heat treatment includes:
• Normalizing: 1040–1080°C
• Tempering: 730–800°C
This produces a stable tempered martensitic microstructure suitable for long-term operation in USC main steam and hot reheat systems. Heat treatment parameters are controlled according to ASTM A234, ASME SA234, manufacturing procedures and customer project specifications.
Manufacturing Process
Steel Billet / Forging Stock → Heating → Hot Forming → Sizing & Calibration → Normalizing & Tempering → UT & MT Inspection → Beveling → Marking → Packing
Hongcheng applies strict manufacturing controls throughout forming, heat treatment and inspection processes to ensure dimensional accuracy, material integrity and consistent performance of every WP91 alloy steel tee.
Technical Parameters
|
Parameter |
Value |
|
Grade |
ASTM A234 WP91 |
|
Product Type |
Alloy Steel Butt Weld Tee (Equal / Reducing) |
|
Applicable Standards |
ASTM A234 / ASME SA234, ASME B16.9 |
|
Outside Diameter |
1/2"–48" (DN15–DN1200) |
|
Wall Thickness |
SCH 40, SCH 80, SCH 160, XXS and Custom |
|
Branch Size |
1/2"–48" (DN15–DN1200) |
|
Heat Treatment |
Normalized & Tempered |
|
Ends |
Beveled Ends (ASME B16.25) |
|
Surface |
Black Painted / Anti-rust Oil / Natural Finish |
|
Customization |
Custom Branch Sizes, Angles and Dimensions Available |
Inspection & Testing
Every ASTM A234 WP91 alloy steel tee is inspected throughout production to ensure compliance with ASTM A234, ASME SA234, dimensional requirements and customer specifications.
Available inspections and testing include:
EN 10204 Type 3.1 Material Test Certificates (MTC) are available for each production batch. Third-party inspection, additional non-destructive testing and project-specific documentation can be provided according to customer requirements.
Applications
ASTM A234 WP91 alloy steel tees are widely used in:
• Ultra-supercritical (USC) power plant main steam systems
• Hot reheat piping systems
• Boiler outlet headers and manifolds
• Refinery high-temperature process piping
• Hydrogen production facilities
• Petrochemical high-temperature reactors
• High-pressure, high-temperature industrial piping
WP91 alloy steel tees are selected for applications requiring high creep strength, oxidation resistance and long-term microstructural stability under elevated-temperature service conditions. For hydrogen service applications, material selection and heat treatment should be confirmed according to API 941 (Nelson Curves) and applicable project specifications.
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Projects of Tee
Power Plant Projects
Products: P91 Pipes · P92 Pipes · Pipe Fittings · Pipe Spools
FAQs
What is the difference between WP91 and WP92?
WP91 and WP92 are both 9Cr alloy steel grades used for high-temperature power plant service. WP92 contains tungsten (W) and optimized alloy additions, providing higher creep strength and allowing higher design stresses compared with WP91. WP91 offers better weldability, while WP92 is selected for the most demanding A-USC main steam and hot reheat applications.
What post-weld heat treatment is required for WP91?
PWHT may be required for WP91 piping systems depending on the applicable construction code, wall thickness, welding procedure and project requirements. WP91 welding requires qualified procedures, controlled preheating and appropriate post-weld heat treatment where specified.
What temperature is WP91 alloy steel tee suitable for?
WP91 is designed for elevated-temperature service and is widely used in USC power generation and other high-temperature applications. Actual allowable service conditions depend on the applicable design code, pressure, wall thickness, material condition and project specifications.
Can custom branch sizes and angles be supplied?
Yes. Hongcheng can manufacture custom WP91 alloy steel tees according to customer drawings and technical specifications.
What standards are supported?
Products can be manufactured according to ASTM A234, ASME SA234, ASME B16.9 and ASME B16.25.
Wuliyao Industrial Zone, Yanshan County, Cangzhou City, Hebei Province, China.
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