Particle size and ratio of cut wire shot and cast steel grit

　　In order to obtain a better uniform distribution of cleanliness and roughness, it is very important to design the particle size and proportion of shot blasting machine cast steel grit. Too large roughness is easy to cause the anti-corrosion coating thinning at the peak of anchor lines; at the same time, because the anchor lines are too deep, the anti-corrosion coating is easy to form bubbles in the anti-corrosion process, which seriously affects the performance of the anti-corrosion coating.

　　If the roughness is too small, the adhesion and impact resistance of the coating will be reduced. For serious internal pitting, it is not only necessary to rely on the high-strength impact of large particles of cut wire shot and cast steel grit, but also to rely on the small particles of cut wire shot and cast steel grit to grind away the corrosion products to achieve the cleaning effect. At the same time, the reasonable proportion design can not only slow down the wear of cut wire shot and cast steel grit on the pipeline and the blade of shot blasting machine, but also greatly improve the utilization rate of steel shot and cast steel grit. Generally, the particle size of cut wire shot is ss-280 (0.80mm) - ss-460 (1.4m), and the particle size of cast steel grit is G50 (0.4mm) - G18 (1.2mm).

　　It should be noted that in practice, the ideal proportion of cut wire shot and cast steel grit in abrasive is difficult to achieve, because the hard and fragile cast steel grit has higher crushing rate than cut wire shot. Therefore, in the operation, the mixed Abrasives should be sampled and tested continuously. According to the particle size distribution, the new cut wire shot and cast steel grit should be added into the shot blasting machine, and the new hot cast steel grit should be more than the cut wire shot.