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Weld Quality Analysis of Welded Pipe Equipment
Release time:
2021-02-20 10:24
In our daily production, there are often weld quality accidents.Welded pipe equipmentThe weld quality accident has been analyzed in the following aspects for your reference only.
Long lap welding refers to the dislocation bonding formed after the two sides of the tube blank are stacked together. In terms of length, lap welding is divided into long and short, generally several meters or even longer. In terms of dislocation, there is a slight dislocation of a few tenths of a millimeter, which is equal to the complete dislocation of the wall thickness. The main factors causing the through-length lap welding are as follows:
(1) Axial stringing of the squeezing roller is unstable due to the positioning of the squeezing roller and the squeezing roller shaft, and during assembly. Other factors such as the open amount formed by the incomplete matching of other zero parts will cause the squeezing roller to move axially and swing radially. At this time, the hole pattern of the squeezing roller will not match and cause lap welding.
(2) The bearing is damaged. After the bearing is damaged, the normal position of the squeezing roller will be destroyed. Take the two-roller squeezing roller device as an example, the upper and lower sets of bearings are generally installed in the squeezing roller. When one set is damaged, the squeezing roller loses control, and the weld seam will be high and cause lap welding. In the production movement, we can observe the swing of the squeezing roller. When the upper bearing is damaged, the swing amplitude of the roller is larger. When the lower bearing is damaged, the swing amplitude of the roller is smaller. The damage degree of the bearing also has a certain relationship. After the bearing of the guide roller is damaged, not only the weld direction of the tube blank cannot be well controlled. Moreover, the guide ring may also cause pressure damage to the edge of the tube blank, causing the height of the weld to change, and a lap welding accident will occur if it is slightly inappropriate.
(3) The bending of the extrusion roller shaft is still taken as an example of a two-roller extrusion roller device. There are two reasons for the bending of the extrusion roller shaft: one is the external bending of the long-term upper jacking wire under insufficient pressure, and the other is the internal bending of the upper jacking wire under excessive pressure. When checking, release the jacking device and place the elevation of the steel ruler on the end surface of the roller. In order to check the inclination angle between the end face of the other roller and the steel ruler, when the shaft is bent, the scratch is caused by the roller that does not bend the shaft.
(4) the extrusion force of this case of lap welded pipe, generally occurs in the production of thin-walled pipe. Because in the production of thin-walled tubes, the steel degree of the tube blank is poor. Once the extrusion pressure is too large, the blank width of the tube can not be accepted after producing too much margin in the pass, and it moves to other spaces to cause lap welding. Therefore, the pass designer should select the appropriate pass radius and roller seam allowance according to different pipe wall thicknesses, and pay attention to appropriately adjust the extrusion amount. Of course, as long as we strictly control the quality of the roller, this lap welding phenomenon can be overcome.
Welded pipe equipment
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