Standards for Large Diameter Seamless Pipe

Large diameter seamless pipes generally refer to seamless steel pipes with an outer diameter ≥ 219 mm (8"). They are characterized by strong pressure resistance, minimal welding, and high reliability, and are widely used in oil, gas, chemical, and power industries.

As an important industrial material, large diameter seamless steel pipes are often used in high-temperature, high-pressure, corrosive media, and complex working conditions. Therefore, several strict technical standards have been established internationally to ensure their quality, safety, and reliability. The following is a detailed introduction to the main international standards.

ISO Large Diameter Seamless Pipes

1. ISO 3183 Pipe

"Steel Pipeline Systems for Oil and Gas Industry"

This standard is the core international standard for steel pipes used in oil and gas pipelines and is applicable to large diameter seamless pipes. The latest version is ISO 3183:2019. Its main technical contents include:

- Specifying two product specification levels, PSL1 and PSL2;

- Detailed specifications for chemical composition, mechanical properties, dimensional tolerances, etc.;

- Strict requirements for non-destructive testing;

- Includes special requirements for resistance to hydrogen-induced cracking (HIC) and sulfide stress cracking (SSC).

2. ISO 11960 Pipe

"Specification for Casing and Tubing for the Oil and Gas Industry"

Applicable to large diameter seamless casing for oil and gas wells. The latest version is ISO 11960:2020. Key features:

- Classified into 9 groups according to steel grade: H, J, K, N, C, L, P, Q, R;

- Specifies thread processing and connection performance requirements;

- Includes special performance requirements under high temperature and high pressure environments;

- Clearly specifies the impact toughness of the pipe body.

API Large Diameter Seamless Pipe

1. API SPEC 5L Pipe

"Specification for Pipeline Steel Pipe"

This is the most widely used pipeline pipe standard globally. The latest version is API SPEC 5L 46 (2018). Key contents:

- Products are divided into two levels: PSL1 and PSL2;

- Steel grades range from A25 to X120, totaling 20 grades;

- Specifications for Charpy V-notch Impact Test:

- Specific requirements for welding procedure qualification:

- Supplementary requirements for alternative energy pipelines:

2. API SPEC 5CT Pipe

"Specification for Casing and Tubing"

Applicable to large diameter seamless casing for oil and gas wells. The latest version is API SPEC 5CT 9 (2018):

- Includes 11 steel grades from H40 to Q125:

- Specifies performance requirements for special threaded connections:

- Strict limits on tube body hardness:

- Includes special requirements for crush resistance:

ASTM Large Diameter Seamless Pipe

1. ASTM A106/A106M Pipe

"Seamless Carbon Steel Pipes for High-Temperature Services"

Applicable to large diameter seamless tubes for high-temperature services. The latest version is ASTM A106/A106M-19:

- Divided into three grades: A, B, and C:

- Specifies minimum tensile strength at high temperatures:

- Clear limits on carbon equivalent:

- Includes normalizing requirements.

2. ASTM A333/A333M Pipe

"Seamless and Welded Steel Pipes for Low Temperatures"

Applicable to large diameter seamless tubes for low-temperature environments. The latest version is ASTM A333/A333M-18:

- Includes 6 grades (1, 3, 6, 7, 8, 9, 10);

- Specifies low-temperature impact test requirements;

- Minimum service temperature down to -195°C;

- Specific requirements for heat treatment processes.

3. ASTM A335/A335M Pipe

"Seamless Ferritic Alloy Steel Tubes for High Temperatures"

Applicable to large diameter alloy seamless tubes for high-temperature and high-pressure environments. The latest version is ASTM A335/A335M-19:

- Includes 11 grades from P5 to P92;

- Specifies the range of alloy element content;

- Strict requirements for microstructure;

- Includes hardness testing requirements.

EN Large Diameter Seamless Pipes

1. EN 10216-2 Pipe

"Seamless Steel Pipes for Pressure Applications"

- Part 2: Non-alloy and alloy steel tubes specifying high-temperature properties

- Applicable to large diameter seamless tubes for high-temperature applications. Main contents:

- Includes 8 steel grades from P195 to P460;

- Specifies creep rupture strength requirements;

- Strict limitations on non-metallic inclusions;

- Includes special inspection requirements.

2. EN 10210-1 Pipe

"Hot-Formed Structural Hollow Profiles of Non-Alloy And Fine Grained Steels"

Applicable to large diameter seamless tubes for structural applications. Main characteristics:

- Includes 5 steel grades from S235 to S460;

- Specifies impact energy requirements;

- Detailed specifications for dimensional tolerances;

- Includes weldability requirements.

Other Important International Standards

1. JIS G3454 Pipe

"Carbon Steel Pipes for High-Pressure Applications"

Japanese Industrial Standard, applicable to large diameter seamless tubes for high-pressure applications:

- Includes 4 grades from STPT370 to STPT480;

- Specifies the requirements for hydrostatic testing;

- Strict requirements for surface quality.

2. GOST 8732-78 Pipe

"Seamless Hot-Rolled Steel Pipe"

Russian national standard, applicable to general-purpose large diameter seamless pipes:

- Includes 5 steel grades from 10 to 20;

- Specifies the requirements for flaring tests;

- Special provisions for bending tests.

Comparison of Common Standards for Large Diameter Seamless Pipes

International Standard Development Trends

1. High Performance

New standards continuously increase strength and toughness requirements, such as the addition of the X120 steel grade in API 5L.

2. Environmental Adaptability

Increased requirements for special operating conditions such as acidic and low-temperature environments.

3. Stricter Testing

Continuously improving non-destructive testing standards, such as adding TOFD testing requirements.

4. Full Life Cycle Management

Standards are beginning to cover the entire lifecycle requirements of steel pipe design, manufacturing, installation, and operation.

5. Digitalization Trend

Some new standards are beginning to require the provision of digital product data.

Recommendations for Standard Selection of Large Diameter Seamless Pipes

FAQ

1. What is The Difference Between Large Diameter Seamless Pipes and Seam Pipes?

Seamless pipes are made by piercing a single piece of steel billet, without welds, resulting in high strength and a higher price.

Seam pipes are made by rolling and welding steel plates, resulting in welds, slightly lower strength, and a more affordable price.

2. What are The Applications of Large Diameter Seamless Pipes?

Oil and gas transportation; oil and gas well completion and drilling; high-temperature steam pipelines in thermal power plants; chemical pressure equipment; large scale structural engineering.

3. What is The Size Range of Large Diameter Seamless Pipes?

Common outer diameter range: 219mm–1220mm; Wall thickness: 6mm–60mm (can be extended according to standards).

Summary

With technological advancements and industrial development, international standards for large diameter seamless steel pipes will continue to be updated and improved. It is recommended that relevant companies closely monitor standard developments and adjust their production processes and quality control systems accordingly.