What to do when there is rust on the surface of stainless steel seamless pipe that is difficult to wash off

Stainless steel seamless pipes are generally treated when leaving the factory, and there will be no rust on the surface. However, when they are used for a long time and in a harsh environment, some rust that is difficult to remove may appear. At this time, it is necessary to perform a "pickling" cleaning procedure on the stainless steel seamless pipe.

After the production of stainless steel seamless pipes, a procedure is generally carried out, that is, "pickling". Pickling can remove surface contamination stains for stainless steel pipes. Make the surface of stainless steel seamless pipes acid white after production.

The preparations to be done before pickling the surface of stainless steel seamless pipes include pickling and passivation. The welding coating, splashes, burrs, dirt, etc. on the surface of the pipe fittings must be cleaned. The surface of the stainless steel pipe should be wiped clean with gasoline or other organic solvents. If it is a large area of dirt, it can be cleaned with steam or 3~5% caustic soda (NaOH) solution, and then rinsed with clean water and dried. Note that the CL- concentration of the clean water used should not exceed 25mg/l.

What should I do if there is a little rust or other dirt on the surface of the stainless steel seamless pipe that is difficult to wash off? You can consider using the acid washing process to clean the slight rust on the surface of the stainless steel thick-walled pipe without damaging the oxide film on the surface of the stainless steel pipe or other substrates of the stainless steel pipe. The dirt on the surface of the stainless steel seamless pipe will also disappear, making the surface of the stainless steel pipe purified.

To avoid damaging the performance of the stainless steel seamless pipe when cleaning it with chemicals, you can use the passivation process to form a dense oxide film or oxygen adsorption layer on the surface of the stainless steel pipe to prevent the chemical and the metal substrate of the stainless steel pipe from developing a chemical reaction, thereby improving the corrosion resistance of the stainless steel pipe surface.