EFW Steel Pipe DN70

What Makes SAW, ERW, and EFW Different?

The fundamental difference between the three processes lies in the welding energy source and fusion mode-this is the "gene" that distinguishes their performance. Walking through Huayang's 150,000-square-meter workshop, the distinct operation modes of the three production lines vividly interpret these differences.

ERW: Resistance Heat Fusion Without Filler

To understand erw pipe meaning, the core is "electric resistance heat". ERW, or electric resistance welded steel pipe, uses continuous hot-rolled steel strips as raw materials. After uncoiling, leveling, and edge trimming, the steel strip is formed into a pipe blank by a forming machine, with edges closely fitted. When high-frequency or low-frequency current passes through the contact surface, intense resistance heat is generated, heating the edges to a molten or semi-molten state, and then the squeeze roller applies instant pressure to complete the welding-no filler wire or flux is needed throughout the process.

Huayang's ERW production line is divided into two categories: 3 low-frequency lines (50-60Hz) for municipal water supply and drainage pipes, and 2 high-frequency lines corresponding to hfw steel pipe. Here, hfw meaning refers to high-frequency ERW (300-500kHz), which achieves rapid heating at 1000℃/s, with a welding time of only 0.5-1 second and a heat-affected zone (HAZ) as narrow as 0.5-1mm. This feature makes HFW pipes particularly suitable for low-temperature environments.