There are many surface treatment methods for stainless steel flanges, and rust removal is the main surface treatment method. Stainless steel flanges are generally not easy to rust, but the presence of free iron on the surface will cause them to corrode.
Therefore, we must deal with these factors that easily cause stainless steel flanges to rust in a timely manner.
Stainless steel flanges can be immersed in hydrochloric acid, the principle of which is to reduce rust to iron. However, this method is more dangerous, because hydrochloric acid is a corrosive substance and harmful to the human body, so care must be taken not to contact the skin during operation.
The order requirements and inspection after the stainless steel flange is produced can detect and prevent free iron. ASTM standard A380 [3] specifies the rust test method for inspecting iron or steel particles on the surface of stainless steel. This method applies to the requirement that no iron is present. After the inspection, clean the surface with clean pure water or nitric acid until the dark blue color disappears. If the rust test solution cannot be cleaned, it is not recommended to produce human consumer products directly on the surface of the equipment process. The simple test is to expose in water for 12-24 hours to check whether there are rust spots, but the disadvantage of this test method is that it has poor sensitivity and takes a long time.
The rust on the surface of the stainless steel flange can be cleaned by chemical or electrochemical methods, which can be effectively removed.