Used welded pipe machine often consider many key technologies when producing precision welded pipes, such as ① quality requirements for raw materials, ② welded pipe forming process, ③ formation and removal of weld burrs, ④ weld heat treatment, ⑤ non-destructive testing, ⑥ correct Equipment requirements for welded pipe unit. For this reason, we introduce the ⑤ non-destructive testing to be considered in the production of precision welded pipes.

Precision welded pipes are more accurate in geometric dimensions than general welded pipes. The welds and inner and outer surfaces are of good quality, and the wall thickness is uniform. It can be used in equipment components directly or with a small amount of processing. It is widely used in chemical, textile machinery, aviation, instrumentation, automotive and other sectors.

Various defects appear in the process of manufacturing precision welded pipes with used welded pipe machine, which can generally be found during flattening, flaring or hydraulic tests in production, but there are also some defects, especially internal defects, which are difficult to find and judge by visual inspection. But it may appear during use or during subsequent cold working. Therefore, it is very necessary to set up non-destructive testing on the production line to discover product defects in time. Considering the high production efficiency of used welded pipe machine, the production of low-quality welded pipes in batches can be avoided, and the quality of the finished products and the quality of the subsequent cold processing can also be guaranteed.

There are many methods for non-destructive testing of steel pipes. The commonly used methods for welding precision steel pipes are ultrasonic, eddy current or magnetic flux leakage testing. Eddy current testing is suitable for the detection of surface defects and defects close to the surface of metal materials; magnetic flux leakage testing is used for surface defects and internal defects of a certain depth. Ultrasonic flaw detection can find slender defects, incomplete penetration of the top of the weld, latent cracks and cracks extending in the heat-affected zone at the center of the weld can be correctly found and determined. Through non-destructive testing, the welded pipe welds are inspected for incomplete penetration, unmelted, slag inclusion, bubbles, shrinkage cracks, horizontal and vertical strips and delamination on the inner and outer surfaces.

Used welded pipe machine has two levels of non-destructive inspection of steel pipes. The first level is placed in the sizing section, that is, on-line inspection, which is used to monitor the quality of welds; the second level is non-destructive testing of finished steel pipes, requiring the entire pipe to be inspected. Testing to ensure product quality.