Pipeline anticorrosion detection of black steel seamless steel pipe

Posted by chase Liu on March 3rd, 2023

The materials used in the seamless black steel pipe have good corrosion resistance, but if the black steel seamless steel pipe is in a strong alkali or strong acid environment, corrosion will occur, and certain anti-corrosion measures need to be taken. After the anti-corrosion work is done, some procedures are needed to check whether the anti-corrosion work is qualified. The detection method is as follows

Coating inspection and acceptance

1. During and after surface coating construction, the painted workpiece should be protected to prevent flying dust and other sundries.

2. The treatment and inspection after painting should achieve consistent coating color, bright and bright color, no obvious defects such as wrinkled skin, blistering, sagging and missing coating.

For the measurement of coating film thickness, use a contact type paint film thickness gauge to measure the paint film thickness. The paint film thickness gauge generally measures the thickness of 3 points and takes the average value.

Quality Inspection

1. The quality inspection is carried out by sampling inspection according to the design regulations.

2. Visually inspect root by root. The surface of the covering layer should be uniform, flat and free of air bubbles, and there should be no defects in the covering layer such as wrinkles, bumps, and uneven blanking.

3. The thickness of the paint film is measured with a magnetic thickness gauge. Measure points every 1.5 meters on the circumference of the two ends and the middle of the single-section steel pipe. The thickness of the paint film should meet two 85%. That is, the thickness of 85% of the measuring points meets the design requirements, and the minimum value of the measuring points that cannot reach the thickness should not be lower than 85% of the design thickness;

4. Use a pinhole tester to check the pinholes. If pinholes are found, use a sandpaper grinder to polish and recoat;

5. If the paint film is not thick enough or has pinholes, it should be re-examined after repairing and curing. If it is unqualified, it should be repaired again until it is qualified;

6. Adhesion check. Use a hard knife to draw an angle of 60 cuts on the coating for random inspection. The coating should be cut through to the substrate, and the cut part should be pasted with tape. After tearing off the tape, carefully observe the scratch. The coating should not peel off . It is also possible to have a sample panel painted under the same conditions for inspection