Spiral stainless steel welded pipe production features are:
(1) the strip of the same width can be used to produce pipes of various external diameters;
(2) the flatness of the pipe is good, the size is more accurate, and the internal and external spiral welding seam increases the rigidity of the pipe body, so there is no need for sizing and straightening process after welding;
(3) easy to realize mechanization, automation and continuous production;
(4) compared with other equipment of similar size, it is smaller in size, occupies less land and investment, and builds faster;
(5) compared with the straight welded pipe of the same size, the welding seam on the unit length of the pipe is longer, so the productivity is lower.
The spiral welded stainless steel pipe production process the spiral welded steel pipe raw material has the strip and the plate, the thickness above USES the plate in 19mm.In order to ensure continuous feeding of front and rear coils for butt welding, looper devices and flying welding trolleys can be used for butt welding connection. The whole material preparation operation from uncoiling to butt welding can be completed in the process of moving along the track on the flying welding trolley.When the end of the current coil steel is bitten by the back clamp of the welding machine, the trolley will pull forward at the same speed as the forming pre-welding machine. After the butt welding, release the clamp and the trolley will return to the original position by itself.Sheet metal shall be welded into slats outside the operation line before being sent to the operation line for butt welding by flying welding trolley.
Automatic submerged arc welding is used for all welding, which is carried out on the surface of the inner body of the pipe. After forming and pre-welding in the places which are not fully welded, the welding is conducted on the surface of the outer body of the pipe, and then the spiral welding is carried out internally and externally.Before the plate belt enters the forming machine, the edge of the plate must be pre-bent with a certain curvature according to the pipe diameter, wall thickness and forming Angle, so that the deformation curvature of the rear part of the forming is consistent with that of the middle part, to prevent the emergence of "bamboo joint" defects in the weld area.After pre-bending, it enters the screw forming machine (see screw forming) and pre-welding.In order to improve the productivity, more than one forming a pre - welding line and multiple internal and external welding line.This can not only improve the quality of the weld, but also greatly increase the output.In general, shielded gas arc welding or high frequency resistance welding with relatively fast welding speed is adopted for pre-welding, and full-length welding is adopted. This welding adopts multi-pole automatic submerged arc welding.
The main development direction of spiral stainless steel welded pipe production is as follows:
(1) production of large-diameter thick-walled pipes to improve pressure resistance;
(2) design and production of new structure of steel pipe, such as double spiral welded pipe, that is, the thickness of the wall is half of the strip welded into a double layer of pipe, not only the strength of the same thickness of the single layer of pipe is higher, and does not appear brittle damage;
(3) to develop new types of steel, improve the level of smelting technology, widely adopt the controlled rolling and post-rolling waste heat treatment process, in order to continuously improve the strength and toughness of the pipe body and welding performance;
(4) vigorously develop coated tubes, such as coating the inner wall with anticorrosive coating, can not only extend the service life, but also improve the smoothness of the inner wall, reduce fluid friction resistance, reduce wax deposition and dirt, reduce pigging times, reduce maintenance costs.