2. Medium diameter welded pipe production unit

The mid-diameter welded pipe unit (8-26in) was the first to use the counter-roll forming method, but since the emergence of the row forming method in the 70s of the 20th century, the row roll forming method has become the mainstream of the medium-diameter welded pipe unit. After the 90s, except for the 5 sets of 12in units newly built by Taiwan Geng'an Company in China, and the 2 sets of 8-in units provided by Japan for the United States and Europe using the FF forming method, the rest almost without exception used the row roll forming method.
There are three main processes for the row roll forming method of the medium-diameter welded pipe unit: full row roll forming method, half row roll forming method and straight flange row roll forming method. Its manufacturers mainly include DMS in France, VAI in Austria and SMS-Demag in Germany, and the five new ERW units in the world in the past five years are manufactured by these three companies. The main varieties produced by these units are line pipes, structural pipes and casings.