Low Alloy Steel

Low Alloy steels
A/SA335 P11/P22/P5/P9/P91

Low Alloy Steel, commonly referred to as Chrome-Moly steel, is a ferritic alloy steel designed for high-temperature and high-pressure service. It is alloyed primarily with Chromium (Cr) and Molybdenum (Mo), resulting in enhanced mechanical strength, creep resistance, and heat resistance.

These materials are widely used in power generation, petrochemical plants, refineries, and oil field services, where fluids and gases are transported under extreme operating conditions. Materials supplied under ASTM A335 are suitable for bending, flanging, forming operations, and fusion welding.

Stainalloy supplies Low Alloy Steel piping components in accordance with internationally recognized ASTM and ASME standards, focusing on reliability and long-term performance in critical systems.

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Key Characteristics

Seamless ferritic alloy steel for high-temperature service
Enhanced tensile strength and creep resistance
Excellent heat resistance due to Molybdenum content
Increased hardness and strength through controlled Chromium levels
Favorable welding characteristics
Suitable for forming operations such as bending and flanging
Designed for long mechanical lifetime under severe conditions

Fast, Flexible, Global Delivery

Whether you need immediate delivery from stock or scheduled shipments for long-term projects, we deliver where and when you need it.

From urgent single shipments to complete packages, we tailor our delivery to your planning.

Prefer to handle logistics yourself? No problem. We offer flexible delivery terms, including Ex Works. Want us to take care of everything? We’ll arrange full-service transport, tracking, and documentation.

Get in touch to discuss the best delivery setup for your project.

Product Details

Applications – By Service and Function

Low Alloy Steel piping systems are used where mechanical stability must be maintained under thermal and pressure load.
Typical services include:
High-temperature steam lines
High-pressure process piping
Transport of hot gases and aggressive process fluids
Critical piping subject to creep and fatigue loading
Key functional roles:
Main steam and hot reheat systems
High-temperature headers and manifolds
Process and transfer lines in continuous operation

Applications – By Industry

Low Alloy Steel (Chrome-Moly) piping materials are widely applied in industries where systems operate under extremely high temperatures and pressures.

Applications include:

Power generation facilities, including high-temperature steam and reheat systems
Petrochemical plants requiring long mechanical lifetime and improved creep resistance
Refineries handling high-temperature and high-pressure process streams
Oil field services transporting hot fluids and gases under severe operating conditions

Standards and Specifications

Product	Standard	Common Grades	Notes
Pipes	ASTM A335 / ASME SA335	P5, P9, P11, P22, P91, P92	Seamless ferritic alloy steel for high-temperature service
Fittings	ASTM A234	Matching P-grades	Seamless and welded fittings
Flanges & Forgings	ASTM A182	Alloy steel grades	High integrity forged components

Stainalloy Capabilities

Stainalloy combines specialized stock availability with deep technical knowledge of Low Alloy Steel applications.

Capabilities include:

Supply of ASTM A335 seamless pipes from ½” up to and including 48”
Primary focus on grades P9 and P91
Materials sourced exclusively from reputable, top-tier mills
Supply of complete piping packages including pipes, fittings, and flanges
Strong understanding of grade selection for power, petrochemical, and refinery applications
Support for projects requiring long mechanical lifetime and improved creep resistance

This combination allows Stainalloy to support clients operating in demanding environments where material performance and delivery reliability are critical.

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