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What are the factors that cause horizontal stripes in spiral seam submerged arc welded steel pipe

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First of all, it may be due to the stress of the spiral seam submerged arc welded steel pipe. That is, the residual stress and welding stress after the steel pipe is formed.

Secondly due to the presence of hydrogen. If the flux is not dried enough, the preheating temperature is insufficient or the preheating before welding is not carried out, and the interlayer temperature of multilayer welding is not enough.

There is also the metallurgical factor of the spiral welded steel pipe. During the welding process, impurities with low melting points enter, such as copper and copper alloys. The source of copper is mainly the copper plated on the surface of the welding wire to prevent the corrosion of the welding wire. These copper shavings enter the flux from the inner hole of the contact tip and contact the weld pool during the welding process to cause transverse cracks.

Then one is: the welding process of spiral seam submerged arc welded steel pipe is unreasonable. For example, the weld forming coefficient is too small, the preheating temperature is not enough, or pre-weld preheating is not carried out, the welding line energy is too large, the heat treatment after welding is improper, and the holding time is too short.

If there is welding slag when the spiral submerged arc welded steel pipe is connected, use argon arc welding, or hit the stainless steel welded pipe with a hammer after it cools down, and it will fall off. These two methods are relatively simple, but they may not be cleaned up. Welding slag is easier to clean, but the splashed slag is not easy to clean. If you can use an electric grinder to clean the welding slag, use an electric grinder, otherwise the welding slag is difficult to clean.

As for some defects that occur during the cutting of spiral welded steel pipes, we can also remove them, but we must find a reasonable method to remove these defects. Only the correct method can make up for the defects of welded pipes. Corresponding solutions can be found for these defects, but if the method is not found correctly, it will make it more troublesome to use. For welded pipes, there is another way to clean the welding slag, which is to use a file, which can also clean the welding slag very cleanly. Another simpler and less labor-saving method is to take a saw blade or a half-heel, stretch it into the pipe, hold the pipe in the left hand, and the saw blade in the right hand, and pull it clockwise or counterclockwise. In this way, the welding slag in the welded pipe can be cleaned very cleanly, and it will not waste too much time, which is simple and convenient.




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