How to paint seamless steel tubes?

In the cognition of most users, the seamless steel tube will be slowly oxidized by the air with the passage of time, and eventually rust and become scrap iron. Most of our common seamless steel tubes are painted with a layer of bright paint. The purpose of painting is to isolate the steel pipe from direct contact with the air, making the process of rusting more slowly. In many industrial steel pipes, For the anti-corrosion and anti-rust projects, it is better to do a good job. This is to pay attention to the process of painting the steel pipe. So what is the process of painting the seamless steel tube?

1. Electric rotating wire brush to remove rust

First clean the residual oil on the surface of the pipeline, then use a hammer or wire brush or waste grinding wheel to remove serious thick rust and welding slag, and then use a scraper, emery cloth, coarse rag to remove oxide scale, iron rust and other If there is any greasy dirt, use detergent to clean it. The included angle, back angle, dead angle of horizontal block and other parts are polished with a wire brush in both directions for multiple times, and the surface is clean and free of contamination after cleaning.The rust removal grade should meet the ST2.5 standard. There is no visible grease and dirt on the surface of the coated object, and there is no oxide scale, rust and paint coating that is not firmly attached; the surface should meet the relative humidity of the atmospheric environment greater than 85%, and the metal surface temperature should not be lower than the dew point temperature of 3 °C.

2. Paint coating

Before painting, the treated surface should be cleaned to remove dust and sundries, and the painting can be done only after passing the inspection and filling in the hidden construction signature. Before using the anti-corrosion coating, a second spot check should be done, and the coating can be done only after passing the test.

When using the paint, it should be stirred evenly, and the proportion of the two-component paint should be strictly followed by the instructions, and cannot be changed arbitrarily.

When using diluent, its type and dosage should comply with the manufacturer's standard regulations. When preparing paint, it must be filtered with fine copper wire mesh, and the viscosity should be measured before use.

The construction temperature and humidity shall be in accordance with the requirements of the manual. In case of rain, fog and strong wind, outdoor construction shall not be carried out.

Manual painting: It should be done from top to bottom, from left to right, first inside and then outside, first obliquely then straight, first difficult and then easy, in a criss-cross manner.

3. Construction requirements

After the first paint film of the coating is dry, the next coating can be applied. When painting, the layers should be crisscrossed and brushed evenly, and each layer should be reciprocated. All coatings must not be missed, the surface of the coating should be smooth and flat, with the same color, no pinholes, bubbles, sagging, peeling, powder paint, damage, etc.
The thickness of each layer and the total dry film thickness should fully meet the technical indicators of the coating.

The interval between each coating should not exceed an hour. It is best to make the second coating when the first coating is not dry, and the cured coating should be polished with emery cloth before brushing the next coating.

Before the construction of each process is concealed, it must be inspected and accepted by Party A's quality inspector, so that the surface is clean, free of paint, dust, and each paint film should be tested by a paint film thickness gauge to see whether the dry film thickness meets the design requirements.

Construction should strictly control the thickness of each coating, the thickness should meet the design requirements. For the dead corners and difficult-to-brush parts on the external components, apply a small brush first, and brush first to avoid the phenomenon of missing coating and brushing. The rust removal of small components should be thorough, and spray painting can be used during anti-corrosion to ensure the integrity of the paint film.