The inner coating will fall off the corrosion resistance of steel pipe, steel production need to strictly control the quality problems. Inner coating is mainly small diameter steel pipe water, oil, em...
The inner coating will fall off the corrosion resistance of steel pipe, steel production need to strictly control the quality problems. Inner coating is mainly small diameter steel pipe water, oil, embroidery, graphite, etc. are not clean, the anchor pattern of the density can not meet the requirements, the coating is not enough adhesion caused. The main forms are:
1, Drum package Drum package is not completely dry because the inner coating case, the tube in the sunlight exposure was wrapped in the coating under the heat of the water after the rapid expansion of the volume, so that the formation of inner coating muster.
2, Vertical loss The emergence of the longitudinal along the tube body is mainly uncoated fluorescent tube in the open when the rain poured into the accumulation of accumulated in the bottom of the tube rust is more serious, rust 4 structural steel pipe at the same time, more serious corrosion of the site Rust is not complete, it formed along the vertical tube body delamination.
3, Ring drum package Inner drum bag mainly in the tube sand blowing sand blowing compressed air in the water, soot blowing straight nozzle forward, steel pipe in the rotation, forming a ring of water marks, so that the inner coating also formed a muster ring.
4, Start the end of shedding The inner coating falls off basically at the beginning of the inner coating, because there is a fan at the end of the coating to the tube blowing, dry the end of the tube of water, but also prevent moisture in the air into the end of the coating steel pipe. The bulging occurs only at the beginning of the coating, not on the end of the pipe.
The prevention of fall off measures are: 1, The environmental control within the coating, when the ambient humidity ≥ 90%, or tube temperature below 3 below the dew point, should not be produced. 2, Outside the coating must be poured into the tube after the cooling water to clean, to ensure that the inner surface of the pipe before drying. 3, Inside the tube before drying with a dehumidifier device, to prevent the impact of moisture to the inner coating quality. 4, Shot blasting to clear the nozzle to clear the time to prevent the nozzle clogging, while ensuring the depth of the anchor pattern, but also have a certain density in order to increase the adhesion of the coating. 5, The speed of anti-corrosion can not be too fast, the carbon steel pipe between the process must have a certain time interval, so that the tube has a natural air-drying process.