Views: 0 Author: Site Editor Publish Time: 2024-12-04 Origin: Site
(1) In the actual promotion process of the welding machine installation technology, the welding of the pipe + elbow, such as the wall thickness of the pipe exceeds 14mm, due to the heavy weight at the elbow, the horizontal support roller surface will be separated; Therefore, if the wall thickness exceeds 14mm during the welding process, the number of horizontal supports needs to be increased, the original horizontal supports are 2, and at least 1 more needs to be added.
When the diameter of the pipe is greater than 200mm, there will be a collision between the elbow and the welding machine during the welding process; Therefore, in the future installation process, the distance between the rotary positioner and the welding machine should be increased, and the distance after the increase should be at least 60mm.
(2) Slag inclusion occurs in the welding process.
Cause analysis: wrong side occurs when the group is matched; No levelness measurement was carried out during pipe installation; When welding thick-walled pipes, the grooves between the weld passes are too deep.
Solution: strictly control the amount of the wrong side of the pipe when the group is matched, and the amount of the wrong side is less than 2mm; The pipe must be measured horizontally before welding to ensure that the pipe is level; When welding thick wall pipe, it is necessary to adjust the bead distribution reasonably.
(3) Swing technology in the welding process. When welding thick-walled pipes (General pipe wall thickness ≥ 10mm), due to the Angle of the groove is 30°, resulting in the filling and covering of the surface will be too wide weld and weld; The tungsten electrode swing is too large in the welding process, there will be oxidation and slag inclusion phenomenon, so at this time should be reasonable weld bead distribution. Through the test, it can be seen that the swing width of the weld bead is ≤8mm, and the swing width is 6mm.
(4) The reason for the phenomenon of oxidation on the surface after welding: the purity of argon is not enough to meet the requirements of 99.99% purity of argon; The interlayer temperature is too high. The welding speed is fast, and the welding pool is not protected in time. The gas flow does not match the size of the tungsten nozzle; Parameters such as welding current and welding speed do not match.
Solution: to ensure that the purity of argon can reach 99.99% requirements; Strictly control the inter-layer temperature ≤ 150℃. The test shows that the tungsten nozzle should not be too small, and the general application is 7 # nozzle; When the nozzle cannot be welded during the welding of the thick wall pipe, the tungsten pole can be extended to 20mm, and the frontal argon flow rate can be increased to 15 ~ 20L/min. Appropriate reduction of welding speed, not too fast.
(5) The formation of pores in the welding process. Cause analysis: X-ray inspection showed that stomata mainly appeared in the interlayer. The main reasons include: the floor cleaning is not clean; The amount of wire feeding in each layer is too large, and the number of welding layers is less; The nozzle is used for a long time, the gas lens is damaged, and the argon gas protection effect is not ideal.
Solution: Clean up the floors; Control the wire feeding amount of each layer, increase the number of welding layers appropriately, and reduce the heat input; Often check the nozzle, gas lens, such as damage should be replaced in time; If a batch of materials are tested after welding, porosity problems often occur, and chemical analysis tests need to be carried out on the materials.
