Do stainless steel pipe fittings and elbows really not rust

The name stainless steel pipe fittings is a relatively broad collective term, which can be further divided into industrial grade stainless steel and sanitary grade stainless steel pipe fittings. Other derivatives include stainless steel elbows, stainless steel tees, stainless steel tees, stainless steel reducers, and eccentric reducers; Because of the effect of nickel element, it is collectively referred to as "stainless steel" pipe fittings by everyone

Industrial grade pipe fittings are generally used in industry, and the surface does not require special treatment. Sanitary grade stainless steel pipes are mainly used in production equipment and assembly line factories for beverages, food, beer, biotechnology, etc. Therefore, both the surface and inner wall must be strictly treated to meet national standards. The main requirements are for the surface smoothness, oil prohibition, and passivation layer of stainless steel fittings;

Firstly, it is the surface smoothness, also known as mirror finish. Polishing treatment is applied to the inner and outer surfaces of the steel pipe to create a bright surface, mainly to prevent fluid substances from flowing inside the pipe from forming hanging walls, which can easily contaminate and cause blockage inside the pipe over time;

Next is the passivation layer. After polishing, the steel pipe needs to be immersed in a passivation pool, and the surface of the steel pipe is oxidized to form a passivation layer using acidic passivation solution, ultimately achieving the corrosion resistance effect of the steel pipe;

The final step is oil prohibition. After passivation is completed, oil prohibition cleaning must be carried out, and the oil stains on the surface of the steel pipe must be removed. After completing all the previous steps, it is necessary to use a grease analyzer for inspection. The purpose is to prevent oil pollution from the pipe wall itself from contaminating the fluid substances inside the pipe, truly meeting the requirements of food grade;

So whether stainless steel fittings rust is not only related to the need to add nickel elements during production and manufacturing, but also to the details of the production process, so it is also known as "sanitary grade fittings".