The advantage of high-frequency Longitudinal Welded Pipe ( commonly abbreviated as HFW steel pipe), some people also all it as ERW steel pipe is that it has heat treatment after welding, can eliminate the welding line and the residual stress in the heat affected zone, refine the grain and strengthen the mechanical properties. Making full use of and expanding this advantage, pipe manufacturer (such as Prime Steel Pipe) can improve product quality and develop new products. Such as Baosteel HFW610 unit, Zhejiang CNOOC Jinzhou oil steel pipe HFW630 unit, Wuhan Iron and Steel Wuhan Jiangbei HFW660 unit, Bohai equipment Dagang oilfield new century HFW245 unit and PetroChina Baoji oil steel pipe SEW unit develops high quality oil special tube, marine pipeline, oil casing and slurry Pipeline and so on all illustrate the trend.
For the HFW unit, the larger diameter will even more be limited by the weight of the strip material and the wall thickness. The storage equipment is limited by the spiral jackets. Therefore, foreign manufacturers use the 600 series units to implement 'roll to roll', such as Japan. In addition, the speed of HFW unit line is higher (16m/min) than others, and the speed of submerged arc welding is generally 3m/min, they do not match each other. The idea of HFW to SAW (submerged arc welding) extended greater is difficult.
Currently, the technical innovation category of HFW unit is limited to use in petroleum special pipe and cold bend steel products. In addition, it should also be used to the automotive, home appliances, chemicals, boilers, machinery and other industries in the direction of precision, as well as in the construction, textile, agriculture and other general pipe application.
