Fault welding machine is relatively more, and the cause of the failure is also more complex, the result is often caused by a variety of reasons, can be caused by several reasons or a result. Tube welding machine appeared scratches caused mainly by two parts, one guide means, and second extrusion welding mechanism.

Scratch-oriented parts generally occurs in both sides of the tube, if fitted with the guide sleeve guide restructuring irrational, two upper and lower surfaces of the tube will appear abrasive scratch, scratch that is characterized by relatively wounds big, strong continuity.

Mainly because of the height position of the guide sleeve is incorrect, or the upper and lower guide roller bearing is damaged, the tube can not be well controlled, so as to create friction with the guide sleeve after formation. In addition, when the guide roller is too large deviation from the center line of the rolling, the guide sleeve and the guide roller axis relative difference is too large, it can cause scratches on both sides of the tube.

Scratches caused by the squeeze roller, mainly in the bottom of the tube, there are a few reasons why: weld extruded structure has two roll, three-roll and four-roll type, as long as the combination of the hole do not match, then can easily cause scratches the surface of the tube, two roll-type structure is particularly prominent. Factors that do not fit and pass a lot, a two-roll structure as an example, such as bearing damage; roller axial movement; pass sample sizes; two roller height position is not the same; shaft bending and assembly of instability and so on.

Squeeze roll groove with the lower edge of the height shall be consistent with the rolling line, and the height of the guide rollers is determined by the tube wall thickness. If the height of the guide rolls down to a certain limit, the squeezing roll groove rounded edges will cause scratches on the bottom of the tube, especially after extrusion roll groove R rounded sharpened, scratch it more likely to occur. In particular, the structure of the two rollers squeeze roller means when there is insufficient pressure on the squeeze, with tension in the tube, the rollers will appear on the elevation, so prominent rounded grooved edge R, resulting in a lower portion of the erw steel pipe scratch. When the squeeze roll groove R rounded sharpened, it will increase the occurrence of scratch accident.