Selection Guide of Anticorrosion Paint for Seamless Steel Pipes

Materials and characteristics of seamless steel pipe

As one of the main materials for constructing various conveying equipment, seamless steel pipes usually exhibit corrosion resistance, strong load-bearing capacity, and high safety. Depending on the material, its characteristics vary:

1. Carbon structural steel

Carbon steel seamless pipes have weak corrosion resistance and are suitable for use in some environments that do not require strong anticorrosion requirements.

2. Alloy structural steel

Alloy seamless steel pipes have better corrosion resistance and can meet some special needs.

3. Stainless steel

The excellent corrosion resistance of stainless steel seamless pipes is its greatest feature and is widely used in construction, chemical industry, medical and other fields.

Commonly used anticorrosion paints for seamless steel pipes

1. Asphalt-based anticorrosion paint

Asphalt-based anticorrosion paint is a relatively traditional seamless steel pipe anticorrosion material. It has good acid and alkali resistance, corrosion resistance and insulation properties, and can effectively prevent corrosion on the surface of steel pipes and erosion by water.

However, the service life of asphalt-based anticorrosion paint is short, generally only about 5 to 7 years, and it is easy to lose and leak, and requires frequent maintenance.

2. Epoxy anticorrosive paint

Epoxy anticorrosive paint is a high-performance anticorrosive paint with excellent adhesion, hardness and chemical corrosion resistance. It is suitable for the use of seamless steel pipes in harsh environments such as humidity, acid and alkali.

Epoxy anticorrosive paint is mainly divided into three types: water-based epoxy, solvent-based epoxy and 100% cured epoxy. Its service life can reach more than 15 to 20 years.

3. Polyurethane anticorrosive paint

Polyurethane anticorrosive paint is a highly weather-resistant anticorrosive paint with corrosion resistance, chemical resistance and good UV resistance. It can effectively protect the surface of seamless steel pipes from various corrosive media such as sunlight, water vapor, acid and alkali.

In addition, polyurethane anticorrosive paint also has excellent wear resistance and good adhesion, and its service life can reach more than 15 to 20 years.

4. Inorganic zinc-rich anticorrosive paint

Inorganic zinc-rich anticorrosive paint is an anticorrosive paint that forms an inorganic ceramic film on the surface of the steel pipe. It has high hardness, high corrosion resistance and good high temperature resistance. It does not contain organic components and is harmless to the environment and human body.

The service life of inorganic zinc-rich anti-corrosion paint can be up to 30 years or more, which is the longest service life of seamless steel pipe anti-corrosion materials.

Paint types suitable for different seamless steel pipes

When choosing the appropriate paint type, it should be determined according to the specific requirements of the steel pipe. The following is the correspondence between common seamless steel pipes and paint types:

1. Carbon structural steel

Generally, asphalt paints are used, such as asphalt primer, asphalt paint, etc.

The advantages are low price and good anti-corrosion performance. The disadvantages are cracking and falling off after a few years, which need to be repaired in time.

2. Alloy structural steel:

Alloy structural steel can use epoxy or polyurethane paints, such as epoxy primer + epoxy intermediate paint, polyurethane primer + polyurethane intermediate paint, etc.

Both paints have good adhesion and anti-corrosion performance, moisture-proof, water-resistant, and oil-resistant, so they have a long service life.

3. Stainless steel

After surface treatment, two coating methods can be used. The primer is epoxy primer and the middle paint is epoxy middle paint, which can protect stainless steel.

Painting precautions

During the painting process, the following points should be noted:

1. Apply primer thinly

The primer layer should be controlled at about 25-30μm, and the middle paint and topcoat layers should also be slightly thinner to ensure adhesion and anti-corrosion performance.

2. The paint should be uniform

After each coating, the paint should be uniform without leaving any coating marks. Brushing, rolling, spraying and other methods can be used to achieve uniform coating.

3. Control the thickness of the paint layer

During coating, the paint should be applied evenly in layers, and each layer should ensure uniformity and good adhesion.

4. Prevent the end nose phenomenon

After the paint shrinks, it is easy to shrink horizontally and form the end nose phenomenon. Therefore, the paint film should ensure continuity and firm adhesion.

Summary

In short, the selection of the appropriate type of anti-corrosion paint should be determined in combination with the needs and material of the seamless steel pipe. At the same time, during the painting process, it is also necessary to apply the paint according to the requirements to maximize the anti-corrosion and corrosion resistance of the paint.