Seamless black steel pipe schedule 40

Schedule 40 seamless black steel pipe refers to seamless steel pipe manufactured according to ASME B36.10M standard with a wall thickness grade of SCH 40. "Black steel pipe" indicates that its surface is not galvanized, retaining the black oxide layer formed by hot rolling; "seamless" means that there are no welds in the steel pipe during the manufacturing process, resulting in higher pressure-bearing reliability.

Seamless black steel pipe

Seamless black steel pipe is made up of steel that has not being galvanized. Its name comes from the skin, dark-colored iron oxide coating on its surface. It is used in applications that does not requires galvanized steels.

Black steel pipe's strength makes it ideal for transporting water and gas in rural and urban areas and for conduits that protect electrical wiring and for delivering high pressure steam and air. The oil and petroleum industries use black steel pipe for moving large quantities of oil through remote areas. This is beneficial, since black steel pipe requires very little maintenance. Other uses for black steel pipes include gas distribution inside and outside homes, water wells and sewage systems. 

Chemical composition of schedule 40 steel pipe

Schedule 40 steel pipe refers to the nominal wall thickness, not the steel grade. Therefore, the chemical composition of different grades of Schedule 40 steel pipe may not be the same. However, Schedule 40 steel pipe is usually made of low-carbon steel, generally A53 steel. Its chemical composition may vary, especially between different grades and weld seams.

For reference, the chemical composition of S-type seamless welded A53 steel is typically as follows:

Carbon: 0.25% (maximum)

Manganese: 0.95% (maximum)

Phosphorus: 0.05% (maximum)

Sulfur: 0.045% (maximum)

Copper: 0.4% (maximum)

Nickel: 0.4% (maximum)

Chromium: 0.4% (maximum)

Molybdenum: 0.15% (maximum)

Vanadium: 0.08% (maximum)

This composition ensures that the steel pipe has mechanical properties suitable for a variety of applications, making Schedule 40 steel pipe an ideal choice for a wide range of industries.

Schedule 40 steel pipe grades

Schedule 40 steel pipe comes in several grades, each with unique properties and characteristics. Here are some of the most common grades:

1. ASTM A53 Grade B

Applications: Piping, construction, and industrial applications.

Yield Strength: 35,000 psi (minimum)

Tensile Strength: 60,000 psi (minimum)

2. ASTM A106 Grade B

Applications: High-temperature applications, such as steam and gas pipelines, refineries, and plants.

Yield Strength: 35,000 psi (minimum)

Tensile Strength: 60,000 psi (minimum)

3. API 5L Grade B

Applications: Oil and gas industry.

Yield Strength: 35,000 psi (minimum)

Tensile Strength: 60,000 psi (minimum)

4. ASTM A333 Grade 6

Applications: Low-temperature applications, such as liquefied natural gas (LNG) plants.

Yield strength: 35,000 psi (minimum)

Tensile strength: 60,000 psi (minimum)

Other grades of Schedule 40 steel pipe may be available depending on the specific application and requirements. Always refer to the manufacturer's specifications to determine the appropriate steel pipe grade for your application.

Features of seamless black steel pipe schedule 40

1. Material

Low-carbon steel (carbon content ≤ 0.25%, such as ASTM A53 Gr.B and Q235B).

2. Wall Thickness

SCH 40 offers a medium wall thickness, balancing pressure-bearing capacity and cost.

3. Surface Finish

Dark gray/black, retaining the natural oxide layer after rolling.

4. Dimensional Parameters

Outer diameter and wall thickness (WT) should be consulted according to specific standards (such as the ANSI B36.10 steel pipe size table). Different pipe diameters correspond to different wall thicknesses.

5. Applications

Primarily used for conveying fluids such as oil, gas, and water, meeting certain pressure-bearing and corrosion-resistant requirements.

Advantages of seamless black steel pipe schedule 40

1. Cost-Effectiveness

The price of SCH 40 wall thickness is 20%-30% lower than SCH 80 black steel pipe and 40% lower than galvanized pipe.

2. Easy to Process

Mild carbon steel has good ductility and is easy to cut and weld.

3. Reliable Strength

Meets most low-pressure fluid and structural requirements.

Seamless black steel pipe schedule 40 dimensions

Application of seamless black steel pipe schedule 40

1. Low and middle pressure fluid pipeline

2. Casing Pipe

3. Boiler Pipe

4. Petroleum and natural gas industry

5. Chemistry industry

6. Electric industry

Usage restrictions of seamless black steel pipe schedule 40

1. Direct Use Prohibited

Drinking water systems (sanitary conditions not qualified)

Acidic/alkaline media transportation

Coastal or high-humidity outdoor environments (unprotected, service life less than 3 years)

2. Corrosion Protection Options

Outdoor use: epoxy coal tar coating (extended service life to 10 years)

Underground installation: 3pe anti-corrosion coating

Read more: Black Steel Pipe Vs Carbon Steel Pipe or Seamless Steel Pipe Schedule 40