Welded steel pipe is formed by rolling plate and welding the seam. There are ERW, LSAW and SSAW production processes. And we mainly supply HFW (High frequency welding) of ERW pipe. ERW steel pipe is cost-effective pipe with precise dimension and light weight. It is mainly used to convey fluid at low and medium pressures ambient, such as water line (cold & hot), firefighting pipeline, HVAC line, etc.