Impact of pattern on the adhesion of pipe external epoxy coating

In the corrosion control of long-distance oil & gas pipeline, the surface preparation quality of pipe has an important impact on the adhesion of coating, while the pattern is one of the most important factors. Based on GB/T 5210－2006, the adhesion testing data for different patterns are obtained. By analyzing the data, the relationship between the pipe surface roughness, microcosmic unevenness gap, pattern depth and the coating's adhesion is acquired. Fitting the data, the curves and formulations between pattern and the adhesion are established. By analyzing the experiment result, the optimum pattern is determined, i.e., the surface roughness R_a is 4~6 μm, the pattern depth R_z remains at 30~45 μm.