ASME SA335 P91 P92 Seamless Alloy Steel Pipe

ASME SA335 P91 and P92 seamless alloy steel pipes are ferritic alloy steel pipes manufactured according to ASME SA335 / ASTM A335 requirements for high-temperature service.

ASTM A335 covers seamless ferritic alloy-steel pipe for high-temperature service. P91 and P92 are Cr-Mo alloy steel grades designed for high-temperature pressure-service applications.

P91 contains approximately 8.00–9.50% chromium and 0.85–1.05% molybdenum, with controlled additions of vanadium, niobium and nitrogen.

P92 uses a different alloy design, with approximately 8.50–9.50% chromium, 1.50–2.00% tungsten and controlled boron, together with vanadium, niobium and nitrogen.

The different alloy compositions make P91 and P92 suitable for demanding high-temperature pressure systems where material selection is based on design temperature, pressure, allowable stress and applicable engineering codes.

The pipes are supplied in seamless construction and can be customized in outside diameter, wall thickness, length, end preparation, heat treatment and inspection according to project requirements.

Product Specifications

Chemical Composition

ASTM A335 P91 / P92 Chemical Composition

Mechanical Properties

P91 / P92 Mechanical Properties

Mechanical properties should be verified according to the applicable ASTM A335 / ASME SA335 edition and purchase order requirements.

Manufacturing Process

Manufacturing Process of P91 / P92 Seamless Pipe

Steelmaking → Billet Preparation → Heating → Piercing → Hot Rolling → Heat Treatment → Straightening → Cutting → NDE → Dimensional Inspection → Mechanical Testing → Final Inspection → Marking → Packing

The manufacturing process focuses on seamless pipe production, controlled heat treatment, dimensional accuracy and inspection traceability.

Heat treatment is an important part of P91/P92 production and is performed according to the applicable specification and project requirements.

Inspection & Testing

Quality Inspection

Each ASME SA335 P91/P92 pipe can be inspected according to ASTM A335 / ASME SA335 and the applicable purchase order.

Chemical Inspection

• Heat Chemistry Analysis
• Product Analysis, when required
• PMI, when specified

Mechanical Testing

• Tensile Test
• Yield Strength Test
• Elongation Test
• Hardness Test

Pipe Testing

• Hydrostatic Test
• Ultrasonic Testing
• Eddy Current Testing, where applicable
• Other NDE according to specification or purchase order

Dimensional Inspection

• Outside Diameter
• Wall Thickness
• Length
• Straightness
• End Preparation

Documentation

• Material Test Certificate
• Heat Number Traceability
• EN 10204 3.1 Certificate
• Inspection Report
• Dimensional Report
• NDE Report, when required

Applications

Power Plant

ASME SA335 P91/P92 seamless alloy steel pipes are used in high-temperature pressure systems, including:

• Main Steam Piping
• Hot Reheat Steam Piping
• High-Temperature Steam Piping
• Boiler Pressure Systems
• Superheater Systems
• Reheater Systems
• High-Pressure Bypass Systems

Boiler and HRSG

Typical applications include:

• Superheater Piping
• Reheater Piping
• High-Temperature Pressure Components
• HRSG High-Temperature Piping Systems

Petrochemical Industry

• High-Temperature Process Piping
• Steam Piping
• Furnace-Related Piping Systems
• High-Temperature Process Equipment

P91 vs P92

P91 and P92 are both ferritic alloy steel grades covered by ASTM A335 / ASME SA335, but they use different alloy systems.

P91 contains approximately 8.00–9.50% chromium and 0.85–1.05% molybdenum, together with controlled vanadium, niobium and nitrogen.

P92 contains approximately 8.50–9.50% chromium and 1.50–2.00% tungsten, with controlled additions of molybdenum, vanadium, niobium, nitrogen and boron.

Grade selection should be based on:

• Design Temperature
• Design Pressure
• Allowable Stress
• Pipe Size
• Wall Thickness Calculation
• Welding Procedure
• Heat Treatment Requirements
• Applicable Design Code
• Project Specifications

Customized P91 / P92 Alloy Steel Pipe

We can supply ASME SA335 P91/P92 seamless alloy steel pipes according to project requirements, including:

• Outside Diameter
• Wall Thickness
• Pipe Length
• End Preparation
• Heat Treatment
• NDE Requirements
• Hydrostatic Testing
• PMI Requirements
• MTC Requirements
• Third-Party Inspection
• Marking and Traceability
• Export Packaging

For power plant projects, pipe dimensions and inspection requirements can be coordinated according to project drawings, piping specifications and applicable design codes.

Surface & End Finish

Surface

Available surface conditions can include:

• Hot Finished
• Cold Finished
• Descaled
• Pickled, when specified

End Finish

• Plain Ends
• Beveled Ends
• Cut Ends
• Customized End Preparation

End preparation can be supplied according to the customer's piping and welding requirements.

Packaging

P91/P92 seamless alloy steel pipes are packed according to pipe dimensions, quantity and transportation requirements.

Typical export packaging includes:

• Steel Bundles
• Steel Strapping
• Steel Frame
• Wooden Cases
• Plywood Cases
• Plastic End Caps
• Waterproof Protection
• Heat Number Marking
• Product Identification Tags