Water Transmission X65M Q235B High Frequency Welded Pipe

Water Transmission X65M Q235B High Frequency Welded Pipe

Electric Resistance Welded (ERW) and High Frequency Induction (HFI) Welded Pipe, originally this type of pipe, which contains a solid phase butt weld, was produced using resistance heating to make the longitudinal weld (ERW). But most pipe mills now use high frequency induction heating (HFI) for better control and consistency. However, the product is still often referred to as ERW pipe, even though the weld may have been produced by the HFI process.

As a result of these early problems, ERW pipe was generally regarded as a second-grade pipe suitable only for low pressure applications. However, prompted by a shortage of seamless pipe and the lower cost of ERW pipe, suppliers and end users directed a major effort toward improving the pipe mill quality in the 1980s. In particular, accurate tracking of the weld line by the automatic ultrasonic inspection equipment was found to be crucial, since the weld line can rotate slightly as the pipe leaves the welding station. In addition, the standard of heat treatment of the weld line, which is necessary to ensure good toughness, was found to be important and some specifications call for local weld line heat treatment using induction coils followed by full body normalizing of the whole pipe in a furnace. As a result of these improvements, modern ERW/HFI pipe has much better performance than the traditional product and has been accepted by a number of operators for high pressure gas transmission.