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Straight seam welded pipe antirust maintenance and inspection methods

Views: 0     Author: Site Editor     Publish Time: 2023-06-06      Origin: Site

The production process of straight seam welded pipe is simple, the production efficiency is high, the cost is low, and the development is rapid. The strength of the spiral welded pipe is generally higher than that of the straight seam welded pipe, and the welded pipe with a larger diameter can be produced with a narrower billet, and welded pipes with different diameters can be produced with the same width billet. But compared with the straight seam pipe of the same length, the weld length is increased by 30~100%, and the production speed is lower. Therefore, most of the welded pipes with smaller diameters adopt straight seam welding, and most of the large diameter welded pipes adopt spiral welding.

Longitudinal welded pipe rust removal and maintenance method: The maintenance of straight seam welded pipe equipment has become a headache. Longitudinal welded pipe equipment plays an important role in life and work. Generally, the surface of straight seam welded pipe fittings is required to reach the near-white level (Sa2.5). All scale, rust, and other dirt are removed, and the depth of the anchor pattern reaches 40-100 μm, which fully meets the adhesion requirements between the anti-corrosion layer and the steel pipe, and the spray (throwing) rust removal process can be achieved with low operating costs and stable reliability. Near white level (Sa2.5 technical conditions. When rust occurs on the longitudinal welded pipe, it should be treated according to the appropriate rust removal method and method to ensure the quality and performance of the longitudinal welded pipe. It can be used in different industries and fields, and it is a good choice for the construction industry. important contributions and roles.

Spraying (throwing) abrasives for straight seam welded pipes: To achieve the ideal rust removal effect, the abrasive should be selected according to the hardness of the appearance of the straight seam welded pipe equipment, the original rust level, the required surface roughness, and the type of coating. For single-layer Epoxy, two-layer or three-layer polyethylene coating, and the mixed abrasive of steel grit and steel shot can easily achieve the ideal rust removal effect. Steel shot has the effect of strengthening the steel surface, while steel grit has the effect of etching the steel surface. The mixed abrasive of steel grit and steel shot (usually the hardness of steel shot is 4050HRC and the hardness of steel grit is 5060HRC can be used on various steel surfaces, even if it is used on C-level and D-level corroded steel surfaces, the rust removal effect is also very good.

Derusting speed of straight seam welded pipe: that is, the total kinetic energy E applied to the steel pipe by abrasives per unit time and the kinetic energy E1 of single abrasive particles. The de-rusting speed of steel pipes depends on the type of abrasive and the displacement of the abrasive. Therefore, the abrasive with a lower loss rate should generally be selected, which is conducive to improving the cleaning speed and prolonging the life of the blade.

The particle size and ratio of abrasives for straight seam welded pipes: To obtain better uniform cleanliness and roughness distribution, the particle size and ratio design of abrasives are very important. If the roughness is too large, the anti-corrosion layer will become thinner at the peak of the anchor pattern; at the same time, because the anchor pattern is too deep, the anti-corrosion layer will easily form bubbles during the anti-corrosion process, which will seriously affect the performance of the anti-corrosion layer. It cannot rely solely on the high-strength impact of large-grained abrasives. If the roughness is too small, the adhesion and impact resistance of the anti-corrosion layer will decrease. For severe internal pitting. It is also necessary to grind away the corrosion products by small particles to achieve the cleaning effect. At the same time, a reasonable proportion design can not only slow down the wear of the abrasive on the pipe and nozzle (blade) but also greatly improve the utilization rate of the abrasive. Usually, the particle size of steel shot is 0.81.3mm, and the particle size of steel grit is 0.41.0mm, of which 0.51.0mm is the main component. The ratio of sand to shot is generally 58. It should be noted that in actual operation, it is difficult to achieve the ideal ratio of steel grit and steel shot in the abrasive because the broken rate of hard and brittle steel grit is higher than that of steel shot. For this reason, the mixed abrasives should be sampled and tested from time to time during operation, and new abrasives should be added to the de-rusting machine according to the particle size distribution, and the amount of steel grit should be the main one in the new abrasives mixed in.

Various detection methods for straight seam welded pipes: At present, the most widely used method is to use magnetic powder to detect straight seam welded pipes. Generally, magnetic testing can only detect defects on the surface of welded pipes, and many problems cannot be well reflected, and are usually judged based on experience. Then the purpose is to use waves and rays together. This kind of detection can detect the defects of the welded pipe sensitively, but there are also defects in this detection method and the material, shape, and size of the welded pipe cannot be judged. The current detection methods are all physical detection methods, which can not only reduce the damage to the material, but also accurately reflect the defects of the material, and obtain better information. However, everything has two sides, and this kind of detection method is not completely reliable. It is still necessary to tell the answer based on the customer's own experience in the long-term use and purchase process. It also reminds everyone to choose longitudinal welded pipes with a good reputation and good reputation in the procurement process, which can also reduce losses.


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