Seamless carbon steel pipe Sch 40

What is seamless carbon steel pipe?

Seamless carbon steel pipe is a weldless steel pipe made of carbon steel as raw material, through hot rolling, cold rolling or cold drawing process after perforating steel ingot or solid tube billet. Compared with welded steel pipe, it has a more beautiful appearance and excellent strength and pressure resistance. This kind of steel pipe is widely used in industrial fields such as petroleum, chemical industry, and natural gas.

Seamless Carbon Steel Pipe Sch 40 Specification:

Seamless Carbon Steel Pipe Sch 40 (Schedule 40) is a seamless steel pipe specification that meets the American standard. Its pipe wall thickness is Sch40 (corresponding to the standard wall thickness series), which represents the standard wall thickness under a specific pressure level and is often used in occasions with higher pressure and temperature.

Definition and standard of Sch 40:

Meaning of wall thickness grade:
Sch 40 is the wall thickness series defined in the ANSI/ASME B36.10 standard. The larger the value, the thicker the wall thickness (such as Sch 80 is thicker than Sch 40).
Calculation basis: Based on design pressure, material allowable stress and safety factor, non-fixed value.

Applicable standards:
ASTM A106: Seamless carbon steel pipe for high temperature (A106 Gr.B is most commonly used).
ASTM A53: General seamless/welded carbon steel pipe (A53 Gr.B and A106 Gr.B have similar performance).
API 5L: Pipe for oil and gas transportation (such as PSL1 Gr.B).

Performance characteristics of seamless carbon steel pipe Sch 40:

1. Pressure bearing capacity: Working pressure is usually ≤10MPa, with high strength, able to withstand high pressure and mechanical load.
2. Material selection: Commonly used A106 Gr.B (C≤0.3%, Mn 0.29-1.06%).
3. Temperature range: -29℃~450℃ (A106 Gr.B recommended upper limit).
4. Corrosion resistance: Carbon steel is easy to rust and needs to be galvanized/coated for humid environments.
5. Processing method: hot rolling (large diameter) or cold drawing (small diameter and high precision).

Application areas of seamless carbon steel pipe Sch 40:

This specification of steel pipe is often used in fields such as petroleum, chemical industry, and shipbuilding that need to transport fluids or withstand high pressure, such as transporting oil, natural gas and other media.

1. Petrochemical industry
Low-pressure oil/gas pipeline (non-acidic environment).
Heat exchanger support pipe.

2. Building water supply and drainage
Fire sprinkler system (needs to be galvanized).
Air conditioning refrigerant pipeline (SCH 40 has sufficient pressure bearing capacity).

3. Machinery manufacturing
Structural support frame (such as equipment base).

4. Power industry
Low-pressure steam pipeline (temperature ≤350℃).

Special application areas:

1. Food and pharmaceutical industry
Availability: Only non-contact auxiliary pipelines (such as cooling water).
Restrictions: 316L stainless steel is required for direct contact with the medium.

2. Shipbuilding and marine engineering
Applicable parts: low-pressure water pipes and ventilation pipes in cabins.
Anti-corrosion requirements: must be hot-dip galvanized + epoxy coating, salt spray test ≥500 hours.

3. Mining and tunneling
Application: drainage pipes, ventilation pipes.
Selection: SCH 40 galvanized pipe (better resistance to ore wear than welded pipes).

FAQ:

1. Can Sch 40 be used for high-pressure steam pipes?

It needs to be calculated based on temperature and pressure, usually ≥4MPa; SCH 80 or alloy steel is recommended for steam.

2. How to distinguish between Sch 40 seamless cold-drawn pipes and hot-rolled pipes?
Cold-drawn pipes: bright surface, high dimensional accuracy (such as ±0.1mm).
Hot-rolled pipes: with oxide scale, large wall thickness tolerance (such as ±10%).

3. What is the difference between Sch 40 and Sch 40s?
SCH 40:
Follow ANSI/ASME B36.10, suitable for carbon steel and alloy steel pipes.
Common materials: ASTM A106 Gr.B (seamless), A53 Gr.B (seamless/welded pipe).

SCH 40S:
Complies with ANSI/ASME B36.19, specially designed for stainless steel pipes.

Common materials: ASTM A312 TP304/316 (seamless), A358 (welded).

Read more: Schedule 80 Carbon Steel Pipe