The production process of straight seam welded pipes is simple, with high production efficiency, low cost and rapid development. The strength of spiral welded pipes is generally higher than that of straight seam welded pipes. Narrower billets can be used to produce welded pipes with larger diameters, and billets of the same width can also be used to produce welded pipes with different diameters. However, compared with straight seam pipes of the same length, the weld length increases by 30~100%, and the production speed is lower. Therefore, smaller diameter welded pipes are mostly straight seam welded, while large diameter welded pipes are mostly spiral welded.

First, rust removal and maintenance methods for straight seam welded pipes:
However, the maintenance of straight seam welded pipe equipment has become a headache. Straight seam welded pipe equipment plays a major role in life and work. Generally, the surface of straight seam welded pipe fittings is required to reach near white grade (Sa2.5. Practice has proved that the construction process of epoxy, ethylene, phenolic, and other anti-corrosion coatings is commonly used in straight seam welded pipe fittings. This rust removal grade can almost remove all scales, rust, and other dirt, and the anchor pattern depth reaches 40~100μm to fully meet the adhesion requirements of the anti-corrosion layer and the steel pipe, while the spray (casting) rust removal process can achieve near white grade (Sa2.5 technical conditions with low operating costs and stable and reliable. When rust occurs on straight seam welded pipes, they should be treated by the rust removal methods and methods to ensure the safety and performance of straight seam welded pipes, and can be used in different industries and fields, making important contributions and roles for the construction industry.

Second, spray (casting) abrasives for straight seam welded pipes:
To achieve the ideal rust removal effect, it should be based on According to the hardness of the surface of the straight seam welded pipe equipment, the original rust level, the required surface roughness, the type of coating, etc., the abrasive selected. For single-layer epoxy, two-layer, or three-layer polyethylene coating, 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 for various steel surfaces, even on the surface of steel with C and D grade rust, the rust removal effect is also very good.

Third, the rust removal speed of the straight seam welded pipe:
That is, the total kinetic energy E of the abrasive applied to the steel pipe per unit time and the kinetic energy E1 of the single particle abrasive. The rust removal speed of the steel pipe depends on the type of abrasive and the displacement of the abrasive. In the formula: m is the spray (throw) amount of the abrasive; V abrasive running speed; m1 single particle abrasive. The size of m is related to the abrasive breakage rate, and the size of the breakage rate directly affects the interest of the surface treatment operation and the cost of the rust removal equipment. When the equipment is fixed, m is a constant, y is a constant, so E is also a constant, but due to the abrasive breakage, m1 changes. Therefore, generally, abrasives with a lower loss rate should be selected, which is conducive to improving the cleaning speed and extending the life of the blades.

Fourth, the particle size and ratio of the abrasive of the straight seam welded pipe:
To obtain better uniform cleanliness and roughness distribution, the particle size and ratio design of the abrasive are very important. Too much roughness can easily cause the anti-corrosion layer to become thinner at the peak of the anchor pattern; at the same time, because the anchor pattern is too deep, the anti-corrosion layer is prone to form bubbles during the anti-corrosion process, which seriously affects the performance of the anti-corrosion layer. It cannot rely solely on the high-intensity impact of large-particle abrasives, and the roughness is too high. Too small a roughness will cause the adhesion and impact resistance of the anti-corrosion layer to decrease. For severe internal pitting. It is also necessary to rely on small particles to grind off the corrosion products to achieve the cleaning effect. At the same time, a reasonable ratio design can not only slow down the wear of abrasives on pipes and nozzles (blades) but also greatly improve the utilization rate of abrasives. Usually, the particle size of steel shot is 0.81.3mm and the particle size of steel sand is 0.41.0mm, of which 0.51.0mm is the main component. The sand-shot ratio is generally 58. It should be noted that in actual operation, the ideal ratio of steel sand and steel shot in the abrasive is difficult to achieve because the hard and brittle steel sand has a higher crushing rate than steel shot. For this reason, the mixed abrasive should be sampled and tested from time to time during operation. According to the particle size distribution, new abrasives should be added to the rust remover, and the amount of steel sand should account for the majority of the new abrasives added.

Fifth, various detection methods for straight seam welded pipes:
Currently, the most widely used is to use magnetic powder to detect straight seam welded pipes. Magnetic detection can generally only detect defects on the surface of welded pipes, and many problems cannot be well reflected, and are usually judged based on experience. So the purpose is to use waves and rays together. Such detection can sensitively detect defects in welded pipes, but such detection methods also have defects, and cannot judge the material, shape, size, etc. of welded pipes.

The current detection methods are all physical detection methods, which can not only reduce damage to the material but also accurately reflect material defects and obtain information better. However, everything has two sides, and such detection methods are not reliable. It is still necessary to tell the answer to the customer based on his own experience in the long-term use and purchase process. It also reminds everyone to choose straight seam welded pipes with a good reputation and good reputation during the purchase process, which can also reduce losses.