# Flange# Flange is an important part of the pipe and valve, usually connected to the pipe end. Often used in machinery, to take machining, processing technology is as follows:

Cutting → heat treatment → forging → rough turning → finish turning → thread turning → drilling → reaming → fitter deburring → coating and antirust → warehousing.
Regarding the anti-rust method of flange, most manufacturers mainly adopt anti-corrosion measures such as coating anti-rust oil and galvanizing. Then this article will focus on some related issues about flange rust:

01
Flange rust in the process of common need to pay attention to the following issues:
The flange connection surface and the gap between the grease and dirt is difficult to remove, and the quality of rust removal is difficult to meet the requirements of anti-rust coating, so in the flange connection for anti-rust oil coating, it is easy to lead to poor anti-rust effect.

② The flange will go through multiple machining processes before rust prevention. If before rust prevention, if the flange surface is attached with dust or heterogeneous metal particles containing other metal elements, it will also increase the risk of rust and lead to rust prevention failure.

Before the flange is rust-proof, without deep cleaning and drying, the surface residue may be coated with anti-rust oil to form an anti-rust layer wrapped in the metal surface, resulting in internal oxidation corrosion, but also indirectly lead to anti-rust oil failure.

④ The anti-rust oil used in the flange is not suitable for the anti-rust requirements of each surface of the flange. For example, the requirements for anti-rust oil at the connection of the flange are higher than those for the smooth surface. When selecting anti-rust oil, products that have been verified by corrosion should be selected.

⑤ Flange in polluted air (such as containing a large amount of sulfide), coupled with the water vapor in the environment, the formation of chemicals such as sulfuric acid and other easy to corrode metals, which will cause the original protective film on the surface of the flange to be destroyed and easily oxidized by clothing.

⑥ After the flange is coated with anti-rust oil, if the cleanliness and dryness of the surface are not guaranteed, the packaging shall be carried out for storage or transportation and delivery. As a result, the anti-rust layer is damaged by the packaging and the anti-rust fails.

⑦ If the flange has rust problem before rust prevention, the rust removal treatment is not carried out in time.

⑧ The packaging method selected for the flange is ordinary PE bag or film, which does not take into account the requirements of storage and transportation conditions, and the anti-rust effect is not good.

⑨ The packaging humidity of the flange is not controlled, resulting in excessive humidity and unstable rust prevention.

The anti-rust oil or anti-rust agent is not compatible with the packaging materials used.

02
In view of the above problems in the process of flange rust prevention, effective rust prevention can be carried out in accordance with the following points:
① Before rust, the oil, other metal dust and dirty water on the surface of the flange should be thoroughly cleaned. recommend, the flange should be cleaned with VCI-600E degradable environmental protection cleaning agent, and then rinsed, dried and cooled.

② The anti-rust oil or anti-rust agent tested for flange anti-rust shall be selected for surface anti-rust treatment, and attention shall be paid to the operation specification of coating or the temperature and duration requirements of immersion;

③ To regularly test the use of anti-rust oil or anti-rust agent standards, to avoid the anti-rust parameters do not meet the standards;

④ Choose packaging materials with high compatibility with anti-rust oil or anti-rust agent, and packaging materials with low water permeability; recommend use VCI-2000 gas phase anti-rust film or anti-rust bag with low water permeability;

⑤ For rust prevention, it is necessary to take into account the anti-rust requirements and cycle of the entire process such as storage, transportation, and use of flanges, and adopt anti-rust methods suitable for the entire process

The rust-proof environment should be strictly controlled, such as environmental temperature and humidity to meet the standards; operators should do a good job of cleaning, etc.