The steel plate is first pressed into a U shape in the forming die, and then pressed into an O shape, and then the inner and outer submerged arc welding is performed. After welding, the diameter is generally expanded at the end of the full length, which is called the UOE welded pipe, and the one tha

Annealing of steel pipesHeating the steel pipe to a certain temperature and holding it for a while, and then enabling it to cool slowly, is called annealing. Annealing of steel pipe is a heat treatment method in which the steel pipe is maintained at a temperature at which phase change or partial pha

1. Hot spinning methodIt fixes the flat blank or pre-formed blank to the rotating mandrel, uses the rotating wheel to apply pressure to the blank, and the rotating wheel simultaneously feeds in the axial direction. After one or more processing, numerous thin-walled hollow rotating systems are obtain

The steel pipe blank is corroded too badly, and a thick iron oxide layer appears on the surface. Because the elements in the steel matrix are not necessarily uniform, some places are rusted deeply, and some places are rusted shallowly, and unevenness appears after pickling. Large uneven pits, such a