ERW Pipe Dimensions

Material and Application Fine-Tune the Interaction: Ensuring Practical Performance

The third layer of interaction is: Pipe material (mild steel for ERW, medium-carbon for HFW) and application requirements fine-tune the nominal diameter-ID relationship-ensuring ID aligns with real-world needs. While nominal diameter fixes OD and schedule sets wall thickness, material strength lets us adjust how much wall thickness is needed for a given pressure-ultimately influencing ID.

Mild Steel ERW Pipes: Ductility Lets Us Optimize ID for Flow

Mild steel's lower tensile strength (335–450 MPa) means ERW pipes need slightly thicker walls than HFW pipes to achieve the same pressure rating-but we offset this by focusing on lower schedules (SCH 20–40) to keep IDs large. For example:

To achieve 4 MPa pressure, our NPS 2 ERW pipe (mild steel) uses SCH 40 (wall thickness 3.91mm, ID 52.48mm).

A hypothetical HFW pipe (medium-carbon steel, 450–650 MPa) could use SCH 20 (wall thickness 3.18mm, ID 53.94mm) for the same pressure-but ERW's focus on flow means we prioritize SCH 40 to balance strength and ID.

This fine-tuning was key for a 2024 Henan residential project: we supplied NPS 2 SCH 40 ERW pipes (ID 52.48mm) that delivered enough water flow for 5,000 households while meeting the 4 MPa municipal pressure standard.

Medium-Carbon HFW Pipes: Strength Lets Us Minimize ID Reduction

Medium-carbon steel's higher tensile strength lets HFW pipes use thinner walls than mild steel for the same pressure-reducing how much ID is sacrificed. For example:

To achieve 8 MPa pressure, our NPS 4 HFW pipe (medium-carbon steel) uses SCH 60 (wall thickness 7.11mm, ID 99.98mm).

A mild steel ERW pipe would need SCH 80 (wall thickness 8.56mm, ID 97.18mm) for the same pressure-losing more ID.

For the 2024 Southeast Asian offshore project, this meant we could supply NPS 8 HFW pipes (SCH 60, ID 198.88mm) that met the 10 MPa pressure requirement while maintaining enough ID to transport 150 m³/h of crude oil-something ERW pipes would struggle to do without increasing NPS (and cost).