ASME SA335 P9 Boiler Steel Tube / Alloy Steel Pipe for Petrochemical Industry

Yuhong Group is one of the earliest groups to export Chrome Moly Pipe in China, with approximately 20 years of experience in alloy steel pipe and tube supply. Products are manufactured according to ASME SA335 / ASTM A335 P1, P11, P12, P22, P5, P9, P91, P92 and ASME SA213 / ASTM A213 T1, T11, T12, T22, T5, T9, T91, T92. Alloy steel pipe and tube are widely used in petrochemical, oil refinery, power plant, and related high-temperature industries.

A335 / SA335 P9 is a seamless ferritic alloy-steel pipe used for high-temperature applications. These pipes are versatile and can be used to transmit water, oil and natural gas. Chrome moly alloy P9 contains chromium and molybdenum. Chromium improves high-temperature (540–750°C) strength, increases oxidation resistance, and raises tensile, yield, and hardness at room temperatures. Molybdenum increases strength, elastic limit, resistance to wear, impact qualities, and hardenability; it increases resistance to softening, restrains grain growth, and makes chromium steel less susceptible to embrittlement. Molybdenum is also the most effective additive for increasing high-temperature creep strength and creep resistance; it enhances the corrosion resistance of steel and inhibits pitting.

The following standards and practices apply to ASTM A335 / ASME SA335 P9 alloy steel pipe:

• ASTM A335 / A335M – Standard Specification for Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service

• ASME SA335 / SA335M – ASME-adopted material specification for seamless ferritic alloy-steel pipe for high-temperature service

• ASTM A990 / A990M – Standard specification for common requirements for stainless and alloy steel pipe

• ASTM A92 – Hardness test methods for steel materials

• E213 – Instructions and practice for ultrasonic testing of steel pipe and tube

• E309 – Eddy-Current Examination methods for steel pipe products

• E381 – Inspection methods for steel bars, beams, profiles, billets and forgings

• E527 – Numbering metals and alloys practices

• E570 – Instructions for flux leakage examination of ferromagnetic steel pipe products

The pipe shall be heat treated in accordance with the requirements of ASTM A335 / ASME SA335. The selection of heat treatment type shall be at the manufacturer's option unless otherwise specified in the purchase order. P9 pipe is typically supplied in the fully annealed, isothermally annealed, or normalized and tempered condition.

ASTM A335 / ASME SA335 P9 alloy steel pipe is used in high-temperature and high-pressure services across multiple industries:

• Refineries: Crude distillation units, hydrotreaters, heavy vacuum gas oil (HVGO) conveyance, high-temperature process piping

• Petrochemical Plants: High-temperature process lines, reformer outlet piping, fired heater tubes

• Power Generation: Boiler tubes, superheater tubes, reheater tubes, steam piping

• Oil and Gas: High-pressure gas and liquid transmission, oil field services

• Fertilizer Plants: Process piping and heat exchanger tubing

• Heat Exchangers: Shell and tube heat exchanger tubing, finned tube bundles

The P9 grade is suitable for operating temperatures up to 650°C (1200°F) and is commonly used in refinery and petrochemical services where high-temperature strength and oxidation resistance are required.

Yuhong Group supplies alloy steel pipe and tube in the following grades per ASTM A335 / ASME SA335 and ASTM A213 / ASME SA213:

• P1 / T1 – 0.5Mo

• P11 / T11 – 1.25Cr-0.5Mo

• P12 / T12 – 1Cr-0.5Mo

• P22 / T22 – 2.25Cr-1Mo

• P5 / T5 – 5Cr-0.5Mo

• P9 / T9 – 9Cr-1Mo

• P91 / T91 – 9Cr-1Mo-V

• P92 / T92 – 9Cr-1Mo-V-W

All pipes undergo rigorous inspection and testing in accordance with ASTM A335 / ASME SA335 and supplementary requirements:

• Hydrostatic Test – Performed per specification requirements

• Non-Destructive Examination (NDE) – Ultrasonic Testing (UT), Magnetic Particle Testing (MT), Hardness Testing (HT), Eddy Current Testing (ET), Positive Material Identification (PMI)

• Mechanical Testing – Tensile test, flattening test, hardness test

• Dimensional Inspection – Verification of OD, wall thickness, and length tolerances per ASTM A530

• Material Traceability – Full traceability with mill test certificates per EN 10204 Type 3.1

Each shipment is supplied with complete documentation including:

• Mill Test Certificates (EN 10204 Type 3.1)

• Heat treatment records

• NDT reports (UT, MT, ET as applicable)

• Hydrostatic test reports

• Dimensional inspection reports