ASTM A106 vs. A53 Seamless Pipe

Seamless steel pipe is a seamless, round steel tube that offers excellent compressive strength, high corrosion resistance, and a high temperature resistance. Depending on the production and quality inspection standards, the standards for seamless pipe vary. Common standards for seamless pipe include ASTM A106 and ASTM A53. While A106 and A53 share some similarities, there are also some significant differences. The following provides a detailed introduction:

ASTM A106

ASTM A106 is a standard specification for hot-rolled seamless steel pipe. The ASTM A106 standard covers seamless carbon steel pipe for high-temperature service. It is suitable for high-temperature and high-pressure environments, such as those encountered in the petroleum, chemical, and power industries. This pipe has the following characteristics:

1. High-Temperature Strength

ASTM A106 pipe exhibits high strength and toughness at high temperatures, capable of withstanding the demands of high-pressure and high-temperature environments.

2. Excellent Corrosion Resistance

ASTM A106 pipe is made of carbon steel and other alloys, offering excellent corrosion resistance and the ability to withstand a wide range of chemical substances.

ASTM A53

ASTM A53 is a standard specification for cold-drawn seamless steel pipe. The ASTM A53 specification covers seamless and welded pipe types, carbon steel, and black steel materials. Surface finishes include natural, black, hot-dip galvanized, and galvanized steel pipe. Diameters range from NPS 1⁄8 to NPS 26 (10.3mm to 660mm), with nominal wall thicknesses. This pipe is suitable for low-temperature, low-pressure environments, such as heating, air conditioning, and water supply. This specification offers the following characteristics:

1. Excellent Low-Temperature Toughness

ASTM A53 pipe exhibits excellent toughness and impact resistance at low temperatures, making it suitable for use in low-temperature environments.

2. Excellent Corrosion Resistance

ASTM A53 pipe is made from carbon steel and other alloys, offering excellent corrosion resistance and the ability to withstand attack from a variety of chemicals.

Types and Grades

1. ASTM A53 E/F/S Type Steel Pipe

ASTM A53 has two grades: Grade A and Grade B.

ASTM A53 Type F, furnace butt-welded continuous pipe. Grade A only.

ASTM A53 Type E, electric resistance welded, post-weld weld heat treatment temperature not less than 540°C.

ASTM A53 Type S, extruded seamless steel pipe. Grades A and B.

Note: Grade B electric resistance welded seamless steel pipe should be heat treated at a minimum temperature of 1000°F (540°C) after welding to eliminate the presence of untempered martensite, or treated in such a manner that no untempered martensite remains.

If different grades of raw steel are continuously cast, the resulting transition material should be determined. Manufacturers should use a process to remove the transition material that reliably distinguishes the grades.

If ASTM A53 Grade B is used in ERW (electric resistance welded) pipe, the weld should be heat treated at a minimum temperature of 1000°F [540°C]. This will not leave untempered martensite.

If ASTM A53 B pipe is cold expanded, the expansion should not exceed 1.5% of the required outside diameter.

(Type F is not used for flanging. If Type S or E is used for coiling or cold bending, ASTM A106 Grade A pipe is recommended. Although the use of ASTM A106 Grade B is not prohibited, Type E of ASTM A53 pipe can be supplied with either non-cold expanded or cold expanded steel, depending on the manufacturer's facility.)

2. ASTM A106 Grades A/B/C

For ASTM A106 steel pipe, only seamless, cold-rolled, and hot-rolled processes are used. Cold-drawn Grades A, B, and C are available.

Grade A: Maximum carbon 0.25%, Mn 0.27-0.93%. Minimum tensile strength 48,000 Psi (330 MPa), yield strength 30,000 Psi (205 MPa).

Grade B: Maximum C value less than 0.30%, Mn 0.29-1.06%. Minimum tensile strength 60,000 Psi (415 MPa), yield strength 35,000 Psi (240 MPa).

Grade C: Maximum C 0.35%, Mn 0.29-1.06%. Minimum tensile strength 70,000 Psi (485 MPa), yield strength 40,000 Psi (275 MPa).

Size Range

1. American Standard A53: 50-600 [DN]

When cold expansion of steel pipe occurs, the expansion should not exceed 1.5% of the specified outside diameter of the pipe.

2. American Society for Testing and Materials ASTM A106: 6-1200 [Normal]. 

Weight: The weight of any length of pipe must not exceed 10% of the specified weight and must not be less than 3.5% of the specified weight.

Thickness: The minimum wall thickness at any point must not exceed the specified nominal wall thickness by more than 12.5%.

A106 generally offers a wider range of wall thicknesses and diameters to accommodate more complex engineering requirements.

Chemical Properties

ASTM A53 and ASTM A106 have fundamental differences in their chemical composition requirements.

The primary differences between the two lie in the manganese, phosphorus, and sulfur content. ASTM A53, by comparison, contains relatively higher levels of all three.

Mechanical Properties

ASTM A53 pipe is designed for mechanical and pressure applications, with a minimum yield strength of 30,000 psi and a minimum tensile strength of 48,000 psi.

In comparison, ASTM A106 pipe offers higher strength, with a minimum yield strength of 35,000 psi and a minimum tensile strength of 60,000 psi.

Delivery Condition and Applications

ASTM A53 pipe is typically delivered in the hot-rolled or cold-finished condition and is suitable for low-pressure fluid transport (e.g., water and gas) and general structural applications. Welded pipe requires weld heat treatment for stress relief.

ASTM A106 is primarily used in high-temperature and high-pressure applications (such as steam piping and boiler systems). It requires seamless steel pipe to undergo normalizing heat treatment or controlled rolling to ensure stability and creep resistance at high temperatures.

A53 is designed for general use, while A106 is designed for high-temperature environments and has more stringent manufacturing and heat treatment requirements.

Summary

When choosing ASTM seamless pipe, you need to consider the specific application and requirements. For general low-pressure applications, A53 seamless pipe is an economical choice; for piping systems operating in high-temperature and high-pressure environments, A106B seamless pipe is more suitable. When purchasing seamless pipe, you should also pay attention to the standard and quality of the pipe material to ensure that the material meets the requirements to enhance the safety and reliability of the piping system.