Introduction of cleaning method for surface of stainless steel elbow

　　In order to clean the surface of stainless steel elbows, it is very important to remove discoloration and restore corrosion resistance. Now there are many back treatments and means.

　　Chemical and mechanical methods for distinguishing cleaning methods of stainless steel elbows:

　　The cleaning methods of ANSI B16.9 Seamless Pipe Fitting Butt Weld Stainless Steel Elbow are as follows:

　　Sandblasting, shot peening with glass or ceramic particles, annihilation, scrubbing and polishing.

　　Although all methods can produce weld seams, none of the mechanical back treatments can provide corrosive properties suitable for harsh applications.

　　Chemical methods are used to remove oxides and other contaminants on the surface of stainless steel elbows, while mechanical methods may erase contaminants caused by previously removed materials, polished materials or annihilated materials. All kinds of pollution, especially foreign iron particles, may be the source of corrosion, especially in humid environment.

　　Therefore, mechanical cleaning of welded stainless steel elbow surface should be carried out under dry conditions. After pickling, in order to remove all pollutants and pickling residues, it is very important to wash properly with water.

　　The final flushing should be carried out by softening water to avoid calcium stains and pollutants embedded in the increasing oxide layer, which is essential for the establishment of passivation layer.

　　So iron dissolves quickly in pickling solution and electrolyte, which enriches chromium on the surface and makes it more inert. Therefore, pickling and electropolishing are the only chemical methods that can restore the corrosion resistance of stainless steel at welds and other surface damages. These surface damages occur before welding.