Corrosion Treatment of 316 Stainless Steel Welded Pipe

316 stainless steel welded pipes are generally favored for their exceptional resistance to corrosion; however, corrosion may still manifest under specific conditions. The causes of corrosion can range from environmental factors to operating conditions and improper welding practices. This article outlines several common treatment methods for addressing the corrosion of 316 stainless steel welded pipes.

Manual Approach:

Regularly cleaning and scrubbing the surface of stainless steel pipes is essential to eliminate attachments and external factors that contribute to deterioration. In coastal areas where 316 stainless steel pipes are commonly used due to their resistance to seawater corrosion, it is crucial to keep the rusted areas dry and clean. The formation of a passivation layer will continue over time after cleaning the rusted areas.

Chemical Method:

Utilizing pickling paste or spray on stainless steel pipes aids in repairing rusted sections by forming a chromium oxide film, thereby restoring corrosion resistance. Proper flushing with water after pickling is essential to remove all pollutants and acid residues. Following the completion of all processing, mechanical polishing equipment can be employed to start polishing from scratch, and the use of polishing wax can provide sealing. For minor rust on parts, a 1:1 mixture of gasoline and engine oil, applied with a clean rag, can effectively remove the rust.

Mechanical Method:

Mechanical techniques such as sandblasting, shot peening with glass or ceramic particles, embedding, brushing, and polishing can be employed. These methods help erase previous imperfections, polish surfaces, or conceal contamination. Contaminants, especially foreign iron particles, pose a risk of corrosion, particularly in humid environments. Therefore, mechanical finishing should be carried out under specified conditions to ensure optimal appearance. While mechanical methods can enhance appearance, they do not alter the inherent corrosion resistance of the material. As a recommendation, stainless steel oval tubes should undergo polishing from scratch using polishing equipment during mechanical finishing and be sealed with polishing wax.

Timely implementation of repair measures is crucial in addressing corrosion in 316 stainless steel welded pipes. Prior to treatment, it is advisable to conduct a detailed corrosion analysis to determine the most appropriate treatment method.