astm a252 erw hfw carbon steel pipe
astm a252 erw hfw carbon steel pipe, Differences between ERW Steel Pipe and HFW Steel PipeThe high frequency welding (HFW) is mainly used in ordinary or thin wall steel pipe. It includes contact welding and induction welding. Direct current welding is generally used for small caliber steel tubes. In general, HFW is one of ERW production methods, it adopts the high frequency welding process. So, ERW steel pipe includes HFW steel pipe.