Performance comparison of stainless steel pipes with welds and polished welded pipes in industrial stainless steel welded pipes

At present, stainless steel industrial welded pipes are used more and more widely in the stainless steel application market at home and abroad. Among them, due to differences in surface treatment processes, stainless steel industrial welded pipes are mainly divided into two types: pickled welded pipes with welds and polished welded pipes. Let’s introduce their respective principles, advantages and disadvantages.
Pickled stainless steel welded pipes with welds are made by automatic welding. The process is single-sided welding and double-sided forming, forming a uniform and smooth weld. Because pickled stainless steel welded pipes are processed from first-grade stainless steel plates, the surface of the welded pipe is consistent with the surface of the original flat plate. Polished welded pipes are welded and formed using a manual welding process, and then polished to remove the weld seam and surface passivation layer of the welded pipe, so the surface brightness of the stainless steel pipe is higher.
Let’s take a look at the advantages and disadvantages of stainless steel pickled welded pipes and polished welded pipes.
First of all, the wall thickness of pickled stainless steel welded pipes with welds is relatively uniform and has strong pressure-bearing performance. Manual polishing of polished welded pipes will make the wall thickness of the original pipe thinner, especially in the weld area. The thinner the wall thickness of the weld area, the lower its pressure-bearing performance.
Secondly, pickling stainless steel welded pipes with welds can ensure the complete performance of austenitic stainless steel. Most stainless steel welded pipes are made of austenitic stainless steel as raw material, such as 201, 202, 304 and 316 stainless steel, because the austenitic structure is non-magnetic or weakly magnetic. The polishing treatment of polished welded pipes will cause small changes in the chemical composition, making austenitic stainless steel more obviously magnetic.
Pickled stainless steel welded pipes with welds have stronger corrosion resistance. Because the passivation layer produced by the original pickling has been removed from polished stainless steel welded pipes, polished stainless steel welded pipes are prone to rust in normal environments, and their corrosion resistance will be weakened.
The quality stability of pickled stainless steel welded pipes with welds is higher. The reason for polished welded pipes is that most of the raw materials are secondary materials or even recycled materials. In order to cover up the defects on the surface of these materials, they will be polished; even in order to reduce the material cost, scrap plates will be used, so the quality stability of polished welded pipes cannot be guaranteed. , very prone to problems.
Pickled stainless steel welded pipes with welds are more practical. Because the stainless steel welded pipes mainly used in industrial welded pipes have mechanical properties, corrosion resistance, etc., and the requirements for the surface brightness of the welded pipes are not very high, of course, decorative welded pipes and sanitary grade welded pipes must be excluded, so many industrial welded pipes are There is no need to use polished stainless steel welded pipes with high cost and unstable performance.