ERW Steel Pipe Weld Quality Accident Analysis

There was a slight dislocation dislocation in terms of tenths of a millimeter, and equal thickness completely misplaced. Since the pressing roller and the pressing roller positioning instability and in the assembly, with the other parts is not close to zero and so the amount of waste formed by factors will appear axial movement of the pressing roller and the radial wobble, then squeeze rollers will not fit hole caused by lap welding. After the bearing is damaged, it will disrupt the normal position squeeze rollers. Two roller to squeeze roller device, for example, generally have a built-in squeeze roll up and down two sets of bearings, when one set is damaged, squeeze rollers out of control, resulting in higher weld will take welding. In the production of movement, we can observe the swing squeeze rollers. When the upper end of the bearing is damaged, the roller swings larger, the lower end of the bearing is damaged, the roller swings on smaller, it also has some bearing the extent of damage to the relationship. After the guide roller bearing damage, not only unable to control the direction of the weld tube, and the tube guide ring edge may also be caused by pressure loss, so that the weld height varies, lap welding accident occurs slightly inappropriate . Two roller still squeeze roller device, for example, squeeze rollers bend there are two reasons: First, the lack of long-term pressure on the top wire of the outer curved; Second, within the top wire bending pressure is too large. Inspection, release the top tight unit facade steel ruler can be placed in the end face of the rollers to check the tilt angle end and steel ruler to another roller. When the shaft bent, scratched by not bending roller shaft caused. Take the pipe this situation, generally occurs in the production of thin-walled tube. Because the production of thin-walled tubes, steel tube degree of poor, crowded once the pressure is too large, the width of the tube in the hole produced a much margin can not be accepted after, and to take other space motion caused by welding . So pass the designer to select the appropriate hole radius and roll seam allowance depending on the erw steel pipe wall thickness, and pay attention to appropriately adjust the amount of compression. Of course, as long as we strictly control the quality of the rolls, which take welding phenomenon can be overcome. After closing hole worn, it can not effectively control the normal operation of the tube so that the tube back and forth in the hole, and the guide ring gap breakdown occurs, the tube during operation, the edge guide will be the pressure ring gap sink, take the pipe to form a generation. Pipe welding cycle ride is the same length, regularity, relatively easy to determine. With the rupture general guide ring rotation, it can be found traces of indentation. Mainly refers to the closing hole on the bottom of the roll diameter parts appear stepped, as well as the upper portion of the vertical roll pass the emergence of a stepped opening hole. After sliding into the site when the boss hole swing pass tube occurs within, so that the tube will produce indentation marks the edge of the formation lap welding. Momentary slide and slide, lap welding will be smaller, and vice versa lap welding on some long. The best way to take this pipe to eliminate, is to pay attention to reasonable normal production is adjusted so that hole wear uniform, stepped to avoid, once discovered hole arc irregular shapes, timely replacement to eradicate lap welding production. Sometimes the arc on the pass, when for some reason the other metallic foreign body adhesion, the surface pressure will make the collapsible tube scars, when such foreign objects blocking the tube location is at the edge of the running track, it will cause a short periodic equidistant lap welding. Under normal circumstances, this phenomenon is rarely happen.