In some specific projects where there is corrosive environment such as salty water, chemical pollutions and acid soil, the anti-corrosion treatment will be significant in such projects. The corrosive environment could be divided into Underground Corrosion, Atmospheric Corrosion, Fresh Water Corrosion, Marine Corrosion and Localized Corrosion.
According to peoples’ and experts’ analysis and experiments, in undisturbed soil, the corrosion for the sheet piles is slight, but taking the calculation purpose into consideration, the maximum corrosion rate is 0.012mm per year per side.
In the experiments taken in Japan, where people installed the sheet piles at 10 corrosive natural soil, the maximum corrosion rate is 0.015mm per year per side after collecting them 10 years later.
Thickness will affect the sheet piles and tubular pipe pile performance in those projects, and would probably cause safety accidents in such projects. Thus anti-corrosion treatment for the sheet piles and tubular pipe piles are very important.
The most traditional methods for anti-corrosion are painting and galvanizing. However, galvanization equipment has given limitations on the length and at the same time, galvanization will cost too much and even a higher coat than the piles themselves. Painting has become the most popular method to face the corrosion problem.
For a whole coating process, pre-treatment for the pile surfaces and painting process control have the equal importance.
Pre-treatment means shotblasting. Shotblasting will help eliminate the oxides on the sheet pile and tubular pipe pile surface, and will provide a profile thickness on the pile surface. People normally require the blasted pile surface to reach the Level SA2.5. The profile thickness shall meet the painting requirement which will help increase the adhesion performance between the pile surface and paints.
The piles shall be painted within 4 hours after shotblasting. Before painting, the dirt or any contaminations shall be removed. The environment temperature, relative humidity and dew point shall be measured and calculated before starting the process.
Shunli is dedicated to provide his clients with one-stop surface including sheet piles and tubular pipe pile coating. Now the mill is equipped with 3 shotblasting machines and 8 heating rooms, which made the coating process much easier in whatever season it is.