Argon arc welding of high pressure stainless steel pipe

1.1 The production of small external aligning fixtures is the same as the parent material) to ensure the quality of the counterparts. The pressure of the dry medium is high, and the pipe diameter is small, which brings great difficulties to the aligning work. How to make efficient external aligning fixtures to ensure the reproduction between the counterparts and the amount of misaligned edges. , Crossing straight with the pipeline. The barrier of the counterpart does not meet the specifications. If the wide gap is small, it will cause impermeable welding and reduce the carrying capacity of the pipeline. Hidden dangers to the Anyu production floor, and also caused by the ultra-high sinking of the weld bead and the concentration of thermal shadow stress, which is detrimental to the normal operation of the pipeline: if the barrier is large, it is easy to cause overfilling and lead to defects such as internal collapse and local stress concentration. As a result, the wrong side of the pipeline that affects the normal operation of the pipeline is not in compliance with the specification, which causes the local change of the medium channel, and the long-term erosion of the dry high-pressure medium can easily cause stress flattening and reduce the useful life of the pipeline. The pipe leveling and straightness does not conform to the specification, and the kinetic energy of the long-hub tooth of the pipeline is caused by the change of the direction of the T high pressure medium to reduce the strength of the pipe and reduce the service life of the pipeline. 12 Make suitable ground clamps and arc pilot plates (the same material as the base material) Because the pipeline material is stainless, it is necessary to make a suitable ground wire clamp to prevent the virtual connection of the ground wire from injuring the oxidation particles on the surface of the pipeline, causing the surface to damage the pen, and it is easy to be selected as the pipeline pitting. The ground wire is Yi Haocheng of carbon steel. Pipeline carburization destroys the metal structure and reduces the pressure bearing capacity of the pipeline.

It is necessary to have a pilot arc board. The pilot arc board can reduce the occurrence of "tungsten inclusion" defects in the welding seam, and it can also stabilize the arc. If there is no chlorine introduction board, the presence of dry tungsten elements , To change the metallographic structure of the weld, thereby reducing the performance of the welding machine, leaving hidden dangers in the operation of the pipe

1.3 The element chromium in the stainless copper material of the oxide film on the slope surface of the cleaning pipe mouth and the oxygen in the air are extremely easy to form chromium oxide, covering the surface. This layer of oxide film can help the material resist corrosion, but it is very unfavorable for obtaining good, high-quality welds. During the welding process, it is extremely difficult to melt due to dry oxidation, which destroys the continuity of the molten pool and makes the welding seam poorly formed. In addition, the oxygen in the chromium hydride is separated under the action of high temperature, and penetrates into the molten pool to make the weld easy to produce pores. Therefore, when welding, 20 martingales inside and outside the nozzle must be cleaned, and the oil stains must be cleaned, and the oxide waist and oil stains on the bevel surface must also be cleaned. The treated nozzle must be reprocessed after four hours after it is placed. Anti-oxidation regeneration