ASTM A106 Seamless Carbon Steel Pipe for High Temperature

ASTM A106 / ASME SA106 steel pipes are seamless carbon steel pipes for high-temperature applications (up to 750 degrees Fahrenheit). These pipes are widely used in industries such as oil and gas, petrochemicals, power generation, and shipbuilding (e.g., refineries, downstream units, ships, boilers, and towers). A106 steel pipes are particularly suitable for conveying fluids at high temperatures or high pressures (or both).

Overview of Seamless Carbon Steel Pipe

Seamless carbon steel pipes are seamless pipes manufactured through piercing and hot rolling/cold drawing processes, primarily using carbon steel as the raw material. Compared to welded pipes, seamless pipes offer higher strength and pressure resistance, making them suitable for high-temperature, high-pressure, and corrosive environments. ASTM A106 is the most common standard for high-temperature applications.

ASTM A106 Standard Overview

The ASTM A106 standard (equivalent to ASME SA106) covers nominal size NPS 1/8" to 48" steel pipe.

Seamless carbon steel pipe temperature range is up to 750°F (approximately 400°C) (in continuously operating piping systems).

Key characteristics include:

1. Manufacturing Method

Hot-rolled or cold-drawn.

2. Length Supply

Single random length (17–24 ft) or double random length (36–44 ft).

3. Wall Thickness Grades

Schedule 10 to Schedule 160 (even down to XXS).

Small diameter (≤ NPS 1.5) seamless carbon steel pipes can be manufactured using cold-drawing or hot-rolling processes, while large diameter (≥ NPS 2) seamless carbon steel pipes are mostly manufactured using hot-rolling processes.

Manufacturing Process

1. Steelmaking Process

Electric furnace or converter steelmaking is primarily used, with precise control over the amount of each element added. Combined with ladle refining, harmful gases and impurities are removed from the molten steel to obtain high-purity steel with accurate composition.

2. Rolling Process

After the molten steel is cast into billets, it is heated and pierced, then rolled in multiple passes. Strict control of rolling temperature, speed, and deformation ensures finer grains and a more uniform microstructure, resulting in high dimensional accuracy and excellent overall performance of the pipe.

3. Heat Treatment Operation

Depending on the grade and application, normalizing and tempering are used. Normalizing refines the grains and improves the microstructure; tempering eliminates internal stress and adjusts hardness. Both work synergistically to improve the high-temperature mechanical properties of the steel pipe.

ASTM A106 Seamless Carbon Steel Pipe: Material Grade

In terms of material grade, A106 seamless carbon steel pipes are divided into three grades: A, B, and C. Among them:

1. ASTM A106 Gr.A

Grade A has relatively lower strength requirements, with a maximum carbon content of 0.25%;

2. ASTM A106 Gr.B

Grade B is widely used, offering a good balance of overall performance, with a maximum carbon content of 0.30%;

3. ASTM A106 Gr.C

Grade C has higher standards in terms of strength and toughness, with a maximum carbon content of 0.35%, enabling it to withstand more demanding high-temperature and high-pressure environments.

ASTM A106 Seamless Carbon Steel Pipe: Chemical Composition

ASTM A106 Seamless Carbon Steel Pipe: Mechanical Property

ASTM A106 Seamless Carbon Steel Pipe: Dimensions and Tolerancing

1. Outer Diameter Tolerance

±0.4 mm to ±4.8 mm (depending on size range)

2. Wall Thickness Tolerance

Not less than 12.5% of the nominal wall thickness

3. Weight Tolerance

Not exceeding +10% or -3.5%

These dimensional accuracy requirements ensure that seamless carbon steel pipes provide good sealing and safety during pressure system installation.

ASTM A106 Seamless Carbon Steel Pipe: Inspection and Testing Requirements

ASTM A106 Seamless Carbon Steel Pipe: Application Scenarios

1. Power Plant Boilers

From main steam pipelines to feedwater pipelines, seamless carbon steel pipes, with their high temperature and high pressure resistance, ensure the stable production and delivery of high-temperature steam in power plant boilers, maintaining a smooth power generation process.

2. Petrochemical Industry

In petroleum refining and chemical production, seamless carbon steel pipes are the core material for pipeline systems used to transport high-temperature, high-pressure oil, gas, and chemical raw materials, and must withstand complex chemical corrosion and physical impact.

3. Industrial Thermal Systems

ASTM A106 seamless carbon steel pipes are used in factories to transport high-temperature steam and hot water, providing a continuous source of heat for industrial production processes.

FAQ

1. What Is The Difference Between ASTM A106 And ASTM A53?

Although both are carbon steel pipe standards, their applications differ:

A106: Suitable for high-temperature, high-pressure fluid transportation (such as boilers and heat exchangers).

A53: Primarily used for low-temperature or ambient-temperature water, gas, and air transportation systems.

2. Are ASTM A106 Equivalent to European Standards Such As EN 10216-2 And DIN 17175? 

Yes, the approximate correspondences are as follows:

EN 10216-2 P235GH / P265GH ≈ ASTM A106 Grade B

DIN 17175 ST35.8 / ST45.8 ≈ ASTM A106 Grade A / B

These standards are all used for the production of high-temperature carbon steel seamless pipes, but the testing requirements and chemical limits differ slightly.

3. What Are Common Alternative Materials for ASTM A106 Seamless Carbon Steel Pipes?

Common alternatives under different standard systems include:

API 5L Gr.B / X42

EN 10216-2 P265GH / 20MnNb6

GB 5310 20G

JIS G3456 STPT410 When selecting alternative high temperature piping materials, a comprehensive evaluation should be conducted based on the operating temperature, pressure rating, and international certification requirements.

Conclusion

ASTM A106 seamless carbon steel pipe, with its excellent high-temperature resistance, weldability, and structural stability, is an irreplaceable standard material in the field of high-temperature fluid transportation. Whether in power plants, petrochemical plants, or marine systems, A106 pipe can provide long-term, stable safety assurance. Choosing products that meet ASTM/ASME certification requirements can effectively extend the life of piping systems and reduce operating and maintenance costs.

Read more: What Is The Heat-resistant Temperature of Carbon Steel Pipe? Or What Is The Low-temperature Use Range of Carbon Steel Pipe?