How to remove rust from carbon steel flange

Flange is a very important part of pipeline connection, it can usually affect the safety of the entire pipeline. After the flange is installed, regular cleaning and maintenance are usually required to prevent the flange from rusting and damage, resulting in leakage of the entire pipeline. Therefore, after installing the flange, it is also necessary to pay attention to the cleaning of the flange to avoid pipeline leakage accidents caused by rust damage of the flange.

Carbon steel flanges are widely used in industrial pipelines and building systems because of their low cost, mature processing technology and excellent mechanical properties. However, the corrosion resistance of carbon steel flange itself is not high, in the face of wet, corrosive environment, corrosion and rust will inevitably occur. The following will list the methods that can effectively remove the rust of carbon steel flange and prevent the rust of carbon steel flange:

1. Mechanical rust removal

Hand sanding: If the rust on the flange is only floating rust, you can use a wire brush or brush to remove the rust on the flange clearance and screw.
Sand blasting/shot blasting: Use a sand blasting machine or shot blasting machine to hit the surface of the flange with high hardness sand or steel pellets at high speed to peel off the rust layer and contaminants.
Mechanical cutting: Using a special rust remover or grinder to cut the surface of the flange to remove the rust layer, suitable for thick rust layer or local rust serious parts.

2. Chemical rust removal

Pickling: Use diluted sulfuric acid, hydrochloric acid or phosphoric acid to soak or brush the surface of the flange, through the acid reaction to dissolve the rust. During operation, the acid concentration and action time should be strictly controlled to prevent excessive corrosion of the substrate. After pickling, rinse with plenty of water, and neutralize the residual acid with alkaline solution, and finally dry and protective coating treatment.

3. Electrochemical rust removal
The carbon steel flange is used as the cathode, and the appropriate electrolyte (such as diluted acidic solution) is used to reduce the rust layer and fall off by direct current.

Method to prevent rust of carbon steel flange

1. The surface of the carbon steel flange is plated with a layer of metal that is not easy to rust, such as zinc, tin, chromium, nickel and so on. These metal surfaces can form a dense oxide film, so as to prevent iron products and water, air and other substances contact and rust.
2. The surface of the carbon steel flange is coated with anti-rust oil, but the anti-rust effect of this method is not ideal, there is a certain pollution and affects the appearance.
3. Brush paint protection or spray wax anti-rust: Spray wax is to spray a layer of wax protective film on the metal surface, so that the metal surface is isolated from moisture, so as to achieve the purpose of rust prevention. This method is simple to use, requires hot water cleaning when cleaning, and is a safe and environmentally friendly one-time rust prevention material.

Concludion

The rust removal of carbon steel flanges is not only to remove the surface rust layer, but more importantly, to provide a clean and uniform substrate surface for subsequent anti-corrosion coatings or other protective measures. By selecting the appropriate rust removal method and reasonable combination of mechanical, chemical or electrochemical methods, the rust removal effect can be achieved efficiently, thoroughly and with minimal damage to the substrate, so as to ensure the long-term stable operation of the flange in the conveying system.