Hot Products
China Suppliers Factory Pre-Galvanized Steel Pipe - Round, Square, Rectangular Tubing for Economical Solutions
Detailed Description of Pre-Galvanized Steel Pipe
Pre-galvanized pipe, sometimes referred to as mill-galvanized or in-line galvanized pipe, utilizes a different method for zinc protection. Different from post-galvanizing (hot-dip galvanizing), pre-galvanizing uses a steel strip that has been galvanized when the strips are made into pipes in a continuous process. The steel strip is galvanized and rolled into a tube using rollers. The edges of the tube are joined together with high-frequency induction welding. After welding is done, the exterior weld seam received a coating of zinc-rich invective spray to restore corrosion resistance. This is very fast and makes very smooth and uniform pipe, making it visually pleasing for many different applications.
Key Parameters for Pre-Galvanized Steel Pipe
| Parameter | Details |
|---|---|
| Manufacturing Process | ERW process using pre-galvanized steel coils |
| Base Material Standard | ASTM A653EN 10346 |
| Pipe Standard | EN 10219BS 4568JIS G3444 |
| Steel Grade | Q195Q235S235DX51D |
| Size Range (OD) | 21.3mm – 165mm (½" – 6") |
| Wall Thickness (WT) | 0.8mm – 5.0mm |
| Zinc Coating | Typically Z80 to Z275 (80–275 g/m²) |
| Surface Finish | Bright, smooth, uniform |
| Pipe Ends | Plain End |
Frequently Asked Questions
Q
What is the difference between pre-galvanized and hot-dip galvanized steel pipe?
Pre-galvanized pipe is made from steel strips that are galvanized before being formed into pipes using the ERW process, resulting in a smooth and uniform surface finish. Hot-dip galvanized pipe, by contrast, is dipped into molten zinc after the pipe is already formed, producing a thicker but less uniform zinc coating. Pre-galvanized pipe is ideal for applications where aesthetics and consistency matter.
Q
What zinc coating thickness is available for pre-galvanized steel pipe?
Pre-galvanized steel pipe typically offers zinc coating classes ranging from Z80 to Z275, corresponding to 80–275 grams of zinc per square meter (g/m²). The appropriate coating class depends on the corrosion exposure level required for the intended application.
Q
What standards does pre-galvanized steel pipe comply with?
Pre-galvanized steel pipe can be manufactured in compliance with several international standards. The base material commonly meets ASTM A653 or EN 10346, while the finished pipe may conform to EN 10219, BS 4568, or JIS G3444, depending on the project requirements and destination market.
Q
What size range is available for pre-galvanized steel pipe?
Pre-galvanized steel pipe is available in outer diameters (OD) ranging from 21.3mm to 165mm (equivalent to ½" to 6"), with wall thicknesses from 0.8mm to 5.0mm. This wide range makes it suitable for a variety of structural and mechanical applications.
Q
How is the weld seam of pre-galvanized pipe protected against corrosion?
During the ERW manufacturing process, the weld seam on the exterior of the pipe loses its zinc coating due to the heat of welding. To restore corrosion resistance, a zinc-rich spray coating is applied to the exterior weld seam immediately after welding. This ensures continuous corrosion protection along the entire length of the pipe.
Q
What are the typical applications of pre-galvanized steel pipe?
Pre-galvanized steel pipe is widely used in applications where a clean, smooth, and visually appealing surface is important. Common uses include fencing and railing systems, greenhouse structures, electrical conduit, furniture frameworks, and general structural fabrication. Its uniform surface finish makes it especially popular in visible or decorative installations.