ERW steel pipe

ERW STEEL PIPES Usage: Used for low pressure liquid delivery, such as water, gas, and oil. Process: ERW (Electric Resistance Welded) HFI (High Frequency Induction) EFW(ELECTRIC FUSION WELDED TUBE) HFW(High-Frequency Welding) Quality Standard: ERW HFI , EFW,: GB/T3091 Welded steel pipe for low pressure liquid delivery GB/T9711 Petroleum and natural gas industries--Steel pipe for pipelines IS: 3589 Steel tubes for water and sewage IS : 1978-1982? Steel tubes for use in