Low-Pressure Carbon Steel Pipes

Low-pressure carbon steel pipes generally refer to carbon steel pipes with a design pressure ≤1.6MPa.

The materials are mainly ordinary carbon steel and high-quality low-carbon steel, suitable for normal temperature, normal pressure, and weakly corrosive or non-corrosive environments:

1. Q235B:

The most widely used, suitable for media such as tap water, fire water, compressed air, low-pressure steam, and gas at normal temperature (above -20℃). It is mainly used in municipal water supply and drainage, building fire protection, and general process pipelines in factories.

2. Q235C/Q235D:

Suitable for low-temperature environments. Grade C can be used outdoors above 0℃, while Grade D can be used in low-pressure outdoor pipe networks in extremely cold regions down to -20℃, offering better resistance to low-temperature brittle fracture.

3. 10# Steel / 20# Steel:

Purer material with superior toughness and weldability, suitable for low-pressure applications requiring clean water, softened water, low-pressure oil, and inert gases, and also commonly used in heat return water and low-pressure pipelines in light industry and chemical industries.

4. ASTM A53 Gr.B, API 5L Gr.B:

Commonly used American standard materials for overseas export projects, suitable for general environments such as low-pressure water supply and drainage, low-pressure oil and gas transmission, and municipal engineering.

5. Q195/Q215:

Lower cost, used only for non-pressure pipelines such as drainage, ventilation sleeves, and structural pipes with no or low pressure.

Common Specifications:

Low-pressure carbon steel pipes are classified into welded steel pipes (mainstream) and seamless steel pipes according to their manufacturing process.

Specifications are expressed as nominal diameter DN / outer diameter Φ:

Welded low-pressure carbon steel pipe (GB/T 3091)

Nominal diameter: DN15, DN20, DN25, DN32, DN40, DN50, DN65, DN80, DN100, DN125, DN150, DN200～DN2000

Outer diameter: 21.3mm～2020mm

Wall thickness: 2.0mm～14mm (standard 2.5~6mm)

Standard length: Mainly 6 meters, 8 meters / 12 meters can be customized.

Low-pressure seamless carbon steel pipe (GB/T 8163 20#)

Outer diameter: Φ18mm, Φ25mm, Φ32mm, Φ42mm, Φ48mm, Φ57mm～Φ426mm

Wall thickness: 2.5mm～8mm

Fixed length: 6 meters～12 meters.

Selection and Cooperation Recommendations

Material Selection: 20#/Q235B for fluid transportation, Q355B/low alloy steel for high-pressure applications, Q235D for low-temperature environments.

Process Selection: Seamless pipes for critical high-pressure components, spiral welded pipes for large-diameter low-pressure pipelines, and straight seam welded pipes for small and medium-diameter structural applications.

Key Cooperation Points: Prioritize manufacturers with API/CE certification, annual production capacity of over 500,000 tons, and extensive overseas project experience.

Cost Optimization: Bulk purchases can enjoy a 10-15% discount, combined with customized services to reduce secondary processing costs.