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

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

Secondly due to the presence of hydrogen. For example, the flux is not dried enough, the preheating temperature is insufficient preheating before welding is not carried out, and the interlayer temperature of multi-layer welding is not enough.

There are also metallurgical factors of spiral welded steel pipes. During the welding process, low melting point impurities enter, such as copper and copper alloys. The main source of copper is copper plated on the surface of the welding wire to prevent corrosion of the welding wire. These copper shavings enter the flux from the inner hole of the contact tip and contact the welding pool during the welding process, causing transverse cracks.

Then one is: the welding process of spiral submerged arc welded steel pipe is unreasonable. For example, the weld forming coefficient is too small, the preheating temperature is not enough or no preheating before welding, the welding line energy is too large, the heat treatment after welding is improper, the holding time is too short, etc.

If there is welding slag during spiral seam submerged arc welding of steel pipes, use argon arc welding, or wait for the stainless steel welded pipe to cool down and then hit it with a hammer and it will fall off. These two methods are relatively simple, but they may not be clean. Welding slag is relatively easy to clean, but splashed slag is difficult to clean. If you can use electric grinding to clean welding slag, use electric grinding. Otherwise, it will be difficult to clean off welding slag.

As for some defects that occur when cutting spiral welded steel pipes, we can also remove them, but if we want to remove these defects, we must find a reasonable method. 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 use more troublesome. Another way to clean welding slag from welded pipes is to use a file. Using a file can also clean the welding slag very cleanly. Another simpler and more labor-saving method is to take a saw blade or half heel, reach into the pipe, hold the pipe in your left hand, and the saw blade in your right hand, and pull it clockwise or counterclockwise. This allows the welding slag in the welded pipe to be cleaned very cleanly without wasting too much time, making it simple and convenient.