Anti-corrosion techniques and solutions for pipe flange fittings

Pipe flanges are commonly used connecting pipe fittings in pipeline construction, but there are many differences in the service life of flanges of different materials. In the use of flange pipe fittings, one thing is very important, that is, the corrosion resistance of flanges. How to prevent corrosion during the use of pipe flanges?

Cleaning flanges:

Cleaning flanges is the first step to protect them from rust. First, use warm water and soap or detergent to clean the surface of the flange to ensure that the surface is clean and free of impurities such as grease, dirt and water stains. After cleaning, use a clean towel or dryer to thoroughly dry the surface of the flange.

Coating flanges:
1. Use paint: After cleaning the surface of the flange, you can use spray paint or roller to paint the flange. You can choose to apply a layer of waterproof and anti-corrosion primer, and then apply a layer of paint. Wait for more than 24 hours after painting before reusing.

2. Use wax: Apply transparent waxing oil on the surface to increase the surface brightness and gloss. At the same time, it can prevent the flange from rusting due to water, dirt and oxidation.

Use corrosion inhibitors:
Corrosion inhibitors can provide an additional protective layer for the surface, inhibiting the oxidation and corrosion process on the flange surface, helping to prevent the formation of rust. Usually a non-corrosive oil or similar is applied to the seal.

There are several main anti-corrosion solutions for pipe flanges:

1. Use anti-corrosion coatings
Coatings are hard films that can be sprayed directly on the substrate. Generally, they are epoxy or polyurethane coatings. Flanges have many corners and edges, and due to the effect of edge thinning, it is difficult for traditional coatings to effectively cover the edges. Thickening the coating can solve the problem of edge protection, but if it blocks the fasteners at the same time. It will not be removable during future maintenance. In addition, operating the bolts will damage the coating and must be reapplied after maintenance.

2. Mechanical solution
Mainly use protective covers and clamps to seal the gap between the flange and the flange surface. Rubber seals are usually provided on stainless steel and plastic materials. This protection method has low flexibility. It is necessary to accommodate covers and clamps that are fully suitable for flanges of various sizes.

3. Tape or semi-solid anti-rust tape solution
Tapes packaged in rolls (such as petrolatum tapes, wax, elastic polymer tapes) are wound on the surface of the substrate for protection. Since semi-solid polymers have excellent waterproof properties. Therefore, this protection method can provide reliable corrosion protection.

However, the shape of the flange is complex, and this material is not only time-consuming but also difficult to apply. When the bolts need to be removed, the material is relatively soft and easy to cut. However, it is difficult to reseal and restore the original protection after removal, and re-application is required.

4. Hot melt plastic solution.
Hot melt plastic is essentially a waxy hot melt polymer heated at high temperature. It is sprayed on the surface of the substrate by professional hot melt equipment. The advantage of this protection method is that it can be dissolved again. It can be reused and save costs. However, this method also requires thermal power operations, professional equipment and construction services. It can be reused, but it is difficult to open or seal during inspection.

5. Polymer sealing bag solution
The sealing bag can completely wrap the flange. Its composition consists of low-permeability polymers, corrosion inhibitor vapor, and desiccant. It is easy to install, but the two ends of the bag are only sealed with tape. It does not use continuous and efficient mechanical bonding. There is a large area of steam space inside the bag, which is easy to accumulate a lot of moisture. The corrosion inhibitor will also be consumed for a period of time.

The above is some knowledge about the anti-corrosion of flange pipe fittings. I hope these contents can help you better master the knowledge of flange anti-corrosion. Of course, if the flange parts are facing some corrosive environments, it is better to use flanges made of anti-corrosion materials such as stainless steel flanges, so as to effectively extend the service life of the flange.

Read more: Pipe flange production process