Explanation of the main reasons for the axial movement of the weldment when it rotates on the turning-roll

Welding turning-roll is mainly used for the assembly and welding of cylindrical weldments. 

Due to the manufacturing and installation errors of welding rollers and the irregular geometry of weldments,the weldments will move along its axial direction when rotating on the roller carrier,which will affect the welding quality and the normal welding process. 

The main reason that affects the axial movement of weldments is the parallelism between the axis of the roller and the axis of the weldment.The manufacturing and installation error of the welding roller carrier has been stipulated in the industry standards.The specific content of the error includes the tolerance of the span,support distance,diagonal length,height and deflection angle of the roller,and finally shows the spiral angle. 

In serious cases,the welding process will be interrupted,and even the weldment will fall off the pipe turning rolls.

Therefore,the axial movement of the cylinder is often inevitable.The spiral angle between the roller and the workpiece is the internal factor of the axial movement of the workpiece.

Detection of axial movement of weldment

The purpose of detecting the axial movement of the weldment is to detect the displacement of the weldment in the axial direction.In principle,it can be detected on the side of the weldment cylinder wall and on the end face of the weldment.The side detection method of cylinder wall can not be affected by the end face error of weldment. 

However,it is not easy to manufacture reliable sensor because of removing the vertical rotation component of cylinder wall,plus the influence of skid,surface roughness and dirt.

At present,the detection method of weldment end face is commonly used at present.This kind of detection is inevitably affected by the uneven vertical direction of the welding end face and its axis line.Therefore,it is required to process the tested end face of the weldment. 

However,for large weldments,the higher the accuracy required,the more difficult and expensive it will be.It is important to reduce the requirement of end face machining.For example,the process requires that the axial movement of the weldment is not greater than ± 2mm,but the roughness of the measured end surface of the weldment is greater than ± 2mm. 

Under this condition,whether the axial movement of the turning-roll weldment can be prevented is one of the important indexes to judge whether the anti channeling roller carrier is practical.