CRA Clad Pipe and Lined Pipe

CRA clad and lined pipes are engineered solutions developed for use in highly corrosive oil and gas environments, where standard carbon steel pipelines cannot withstand aggressive media such as CO₂, H₂S, or chlorides.

These pipes are considered a new-generation material in modern pipeline systems, combining two different metals through advanced bonding or cladding processes to achieve both mechanical strength and corrosion resistance.

Composition and Structure

CRA Clad Pipe consists of two main components:
Base Material: A conventional carbon steel or low alloy steel pipe, also called backing steel.
CRA Layer: A corrosion-resistant alloy layer metallurgically bonded to the internal (and sometimes external) surface of the steel pipe.

Clad and lined pipes are specialized types of pipes designed to enhance corrosion resistance and improve performance in various applications.

Together, these materials create a dual-layer system that offers the structural integrity of carbon steel and the corrosion resistance of high-performance alloys—making CRA clad and lined pipes ideal for offshore pipelines, sour gas fields, and subsea flowlines where long-term durability is essential.

Clad Pipes:

Definition: Clad pipes are made by bonding a layer of corrosion-resistant material (such as stainless steel) to a carbon steel pipe. This combination provides the strength of carbon steel with the corrosion resistance of the outer layer.
Applications: Commonly used in industries like oil and gas, chemical processing, and power generation, where exposure to corrosive environments is a concern.

Lined Pipes:

Definition: Lined pipes have a protective lining (often made of materials like PTFE, rubber, or other polymers) applied to the inner surface of the pipe. This lining acts as a barrier against corrosive substances.
Applications: Frequently used in applications involving the transport of aggressive chemicals, slurries, or other materials that could damage the pipe’s interior.

Material Selection and Standard Specification

Base materials of the CRA clad steel pipes include seamless or welded line pipes of API, ASTM, etc.

The CRA cladding or lining material covers an extensive range of stainless steels and nonferrous alloys. SS 304, SS 316, SS 317, Duplex, Alloy 254 SMO 904, Incoloy alloy 825, Inconel alloy 625, Hastelloy C-276, Inconel alloy 59, Alloy 31, AL6NX, Alloy 20, Monel alloy 400, Titanium, Zirconium, and some copper alloys.

Generally, CRA-clad pipes shall be manufactured in accordance with API 5LD. The base material (steel pipe) conforms to API 5L, ASTM A106, ASTM A333, ASTM A335, etc. The cladding material shall conform to ASTM A240, A263, A264, A265, B898, B424, B443, B619, B622, B675, B265, B551.

Advantages

• Excellent corrosion resistance in harsh environments, including high temperature, high pressure, and corrosive fluids.
• Combines the strength and durability of carbon steel with the corrosion resistance of CRA materials.
• Cost-effective for large-diameter heavy pipelines, as the thin CRA layer provides enhanced properties while minimizing expenses.

Applications

Clad pipes are widely used in oil and gas production, subsea pipelines, refineries, chemical processing plants, and power generation facilities, where exposure to CO₂, H₂S, chlorides, and other corrosive media poses a significant risk to standard carbon steel pipelines.

They are particularly suitable for:

• Offshore and subsea flowlines transporting corrosive fluids.
• Sour service pipelines containing H₂S or acidic components.
• Refinery and petrochemical piping systems require enhanced corrosion resistance.
• High-pressure and high-temperature service environments (HPHT).

By combining strength, cost efficiency, and corrosion protection, CRA clad pipes deliver reliable performance and extended service life in aggressive operational conditions.