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Pre-Galvanized Steel Pipe and Tubing - Round, Square, Rectangular | China Suppliers & Factory
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 A653, EN 10346 |
| Pipe Standard | EN 10219, BS 4568, JIS G3444 |
| Steel Grade | Q195, Q235, S235, DX51D |
| Size Range (OD) | 21.3mm – 165mm (1/2" – 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
Q1
What is the difference between pre-galvanized and hot-dip galvanized steel pipe?
Pre-galvanized pipe is made from steel strip that is galvanized before being formed into a pipe, resulting in a smooth and uniform zinc coating. Hot-dip galvanized pipe, on the other hand, is dipped into molten zinc after the pipe is formed, typically producing a thicker but less uniform coating. Pre-galvanized pipe offers a better surface finish, while hot-dip galvanized pipe generally provides stronger corrosion protection in harsh environments.
Q2
What welding method is used to manufacture pre-galvanized steel pipe?
Pre-galvanized steel pipe is manufactured using the ERW (Electric Resistance Welding) process, specifically high-frequency induction welding. This method joins the edges of the formed steel strip together efficiently and precisely, producing a strong, consistent weld seam along the pipe length.
Q3
What zinc coating levels are available for pre-galvanized steel pipe?
Pre-galvanized steel pipe is typically available with zinc coating levels ranging from Z80 to Z275, which corresponds to 80 to 275 grams of zinc per square meter (g/m²). Higher zinc coating levels offer greater corrosion resistance and are recommended for more demanding or outdoor applications.
Q4
What standards does pre-galvanized steel pipe comply with?
Pre-galvanized steel pipe can comply with multiple international standards. The base material (steel coil) typically meets ASTM A653 or EN 10346, while the finished pipe can be manufactured to EN 10219, BS 4568, or JIS G3444 depending on the application and regional requirements.
Q5
What are the common applications of pre-galvanized steel pipe?
Due to its smooth, bright, and uniform surface finish, pre-galvanized steel pipe is widely used in applications where aesthetics matter, including furniture frameworks, greenhouse structures, electrical conduit systems, scaffolding, fencing, and general construction. It is also popular in HVAC systems and light structural applications.
Q6
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 (approximately 1/2" to 6"), with wall thicknesses from 0.8mm to 5.0mm. This wide size range allows it to be used across a variety of structural and mechanical applications.