316 stainless steel welded tube surface deposits of deposits containing other metal elements of dust or heterogeneous metal particles in the humid air, the condensate between the attachment and stainless steel, the two connected into a micro-cell, triggering the electrochemical reaction, protective film damaged, called electrochemical corrosion. Organic stainless steel tube surface adhesion of organic juice (such as vegetables, noodles soup, sputum, etc.), in the case of water oxygen, organic acids, organic acids for a long time on the metal surface corrosion. Stainless steel pipe surface adhesion contains acid, alkali, salt substances (such as the renovation of the wall of alkali water, lime splashing), causing local corrosion. In polluted air (such as a large amount of sulfide, carbon dioxide, nitrogen oxides in the atmosphere), the case of condensate, the formation of sulfuric acid, nitric acid, acetic acid point, causing chemical corrosion.
The above situation is caused by the destruction of stainless steel pipe surface protective film caused corrosion. Therefore, to ensure that 316 stainless steel welded tube is not corroded, the following recommendations for large-diameter stainless steel welded pipe:
The surface of the stainless steel pipe must always be cleaned and scrubbed to remove attachments and eliminate the external factors that cause the modification. In some coastal areas to use 316 stainless steel pipe, 316 stainless steel pipe to resist seawater corrosion. After cleaning up the rusty parts, keep them dry and clean, and the passivation layer will continue to be formed after a period of time.
Chemical approach: stainless steel pipe with acid pickling cream or spray to help repair the rust site de novo from the formation of chromium oxide film from scratch rehabilitation of corrosion-resistant ability, after pickling, in order to remove all pollutants and acid residues, with water for the appropriate flushing is very important. After all treatment with polishing equipment from scratch polishing, polishing wax can be closed. On the part of the slight rust can also be used 1: 1 gasoline, oil mixture with a clean rag to wipe the rust can be.
Mechanical methods: sand blasting, shot peening with glass or ceramic particles, buried, brushing and polishing. Mechanically there may be wipe out of previously cleared information, polishing information or buried information pollution. All kinds of pollution, especially foreign iron particles, may have become the source of corrosion, especially in humid environments. Therefore, the mechanical finishing the best appearance should be carried out in the boring conditions of the order. The use of mechanical method can only organize their appearance, can not change their own anti-corrosion data. Therefore, stainless steel oval tube advocated in the mechanical finishing with polishing equipment from scratch polishing, polishing wax closed.
