What are the reasons for flange rusting and failure of rust prevention? What should be noted for flange rust prevention?

#Flange# A flange is an important component that connects various pipes and valves, usually connected at the pipe end. It is commonly used in machinery and is made through machining processes as follows:

Cutting → Heat treatment → Forging → Rough turning → Finishing turning → Thread turning → Drilling → Reaming → Deburring → Coating with anti-rust paint → Storage.

Regarding the anti-rust methods for flanges, most manufacturers mainly use coating anti-rust oil, galvanizing, and other anti-corrosion measures. This article will focus on some related issues regarding flange anti-rust:

01

Common issues to pay attention to during the anti-rust process of flanges include the following points:

① The grease and dirt on the flange connection surface and gaps are difficult to remove, and the quality of rust removal is hard to meet the requirements for coating anti-rust, so when applying anti-rust oil to the flange connections, it is easy to lead to poor anti-rust effects.

② The flange will go through multiple machining processes before anti-rust treatment. If the flange surface adheres to dust containing other metal elements or foreign metal particles before anti-rust, it will also increase the risk of rusting, leading to anti-rust failure.

③ If the flange has not undergone deep cleaning and drying before anti-rust, the residues on the surface may cause the anti-rust layer formed by the anti-rust oil to wrap around the metal surface, leading to internal oxidation corrosion, which can also indirectly cause the anti-rust oil to fail.

④ The anti-rust oil used for the flange may not meet the anti-rust requirements for all surfaces of the flange. For example, the connection of the flange has higher requirements for anti-rust oil than smooth surfaces, so when selecting anti-rust oil, products that have been verified for corrosion resistance should be chosen.

⑤ If the flange is in polluted air (such as containing a large amount of sulfides), combined with moisture in the environment, it can form corrosive chemicals like sulfuric acid, which can damage the original protective film on the flange surface and make it easily oxidized.

⑥ After applying anti-rust oil to the flange, if the cleanliness and dryness of the surface are not guaranteed, and it is packaged for storage or transportation, it can lead to damage to the anti-rust layer and anti-rust failure.

⑦ If there are rust issues on the flange before anti-rust treatment, and rust removal is not carried out in time.

⑧ The packaging method chosen for the flange is ordinary PE bags or films, without considering the requirements of storage and transportation conditions, resulting in poor anti-rust effects.

⑨ The humidity of the flange packaging is not controlled, leading to excessive humidity and unstable anti-rust.

⑩ If the packaging materials used for anti-rust oil or anti-rust agents are incompatible.

02

To address the above issues in the flange anti-rust process, effective anti-rust can be carried out according to the following points:

① Before anti-rust, thoroughly clean the oil stains, other metal dust, and dirty moisture on the flange surface. It is recommended to use VCI-600E biodegradable environmentally friendly cleaning agent to clean the flange, then rinse, dry, and cool.

② Choose anti-rust oil or anti-rust agents that have been tested for flange anti-rust for surface anti-rust treatment, and pay attention to the operational specifications for coating or the temperature and duration requirements for immersion.

③ Regularly check the various usage standards of the anti-rust oil or anti-rust agents used to avoid anti-rust parameters not meeting standards.

④ Choose packaging materials that are highly compatible with anti-rust oil or anti-rust agents, as well as packaging materials with low permeability; it is recommended to use VCI-2000 vapor-phase anti-rust film or anti-rust bags with low permeability.

⑤ For anti-rust, consider the entire process of storage, transportation, and use of the flange, and adopt suitable anti-rust methods for the entire process.

⑥ The anti-rust environment should be strictly controlled, such as ensuring that the temperature and humidity of the environment meet standards; operators should maintain cleanliness.

The above are 10 points to pay attention to during the flange anti-rust process, as well as some suggestions on how to effectively carry out flange anti-rust. Specific implementation methods can be adopted based on actual issues. If more detailed methods and techniques for flange anti-rust are needed, feel free to send a private message or comment for discussion!