Manufacturing method for X80 pipeline steel spiral welded pipe

The invention belongs to the field of mechanical equipment manufacturing and particularly relates to a manufacturing method for a spiral submerged arc welded pipe. A manufacturing method for an X80 pipeline steel spiral welded pipe includes the following technological steps that uncoiling and flattening of an X80 pipeline steel plate coil are conducted; edge milling is conducted; pre-bending is conducted; forming is conducted; pre-welding is conducted; internal welding is conducted; external welding is conducted; pipe end expanding is conducted; and product inspection is conducted. Brand new design is conducted on a welding groove type, and therefore energy of a welding line of an inner weld bead and energy of a welding line of an outer weld bead are distributed again, the energy of the welding line of the outer weld bead is improved, and the energy of the welding line of the inner weld bead is reduced. The grain size in a critical coarse-grain area in a heat-affected area can be obviously reduced due to the reduction of the energy of the welding line of the inner weld bead, scattering of distribution of chain-shaped M-A components is facilitated, meanwhile, the size of the M-A components can be reduced, and therefore the toughness of the welding heat-affected area is obviously improved. In addition, although the filling amount of the outer weld bead is increased to some extent, a double-wire tandem sequence is changed into a three-wire tandem sequence for welding, the welding speed can be ensured, and the production efficiency cannot be reduced.