Anti-corrosion steel pipe refers to steel pipes that have been processed by anti-corrosion technology, which can effectively prevent or slow down the corrosion phenomenon caused by chemical or electrochemical reactions during transportation and use. Anti-corrosion steel pipe base materials include spiral pipes, straight seam pipes(such as LSAW pipe and ERW pipe), seamless pipes, etc. Widely used in pipeline engineering fields such as long-distance water transmission, petroleum, chemical industry, natural gas, thermal power, sewage treatment, water source, bridge, steel structure, marine water transportation piling, etc.
The rust removal grades of anti-corrosion pipe surface treatment are summarized as follows:
For the construction process of epoxy, vinyl, phenolic and other coatings commonly used for steel pipes, the surface of steel pipes is generally required to reach near-white grade (Sa2.5). Practice has proved that almost all the compound skin, rust and other dirt can be removed by using this level of rust removal, and the anchor pattern can reach 40~100μm, which fully meets the adhesion requirements between the layer and the steel pipe. The spray (throwing) jet derusting process can reach the technical conditions of near white level (Sa2.5) with low operating cost and stable quality.
In order to achieve the ideal derusting effect, the abrasive should be selected according to the hardness of the steel pipe surface, the degree of original rust, the required surface roughness, and the type of coating. For single-layer epoxy, two-layer or three-layer polyethylene coating, it is easy to achieve ideal rust removal effect by using the mixed abrasive of steel grit and steel shot. Steel shot has the effect of steel surface, while steel grit has the effect of etching steel surface
In order to obtain a better uniform cleanliness and roughness distribution, the particle size and proportion design of abrasives are very important. If the roughness is too large, the layer will become thinner at the peak of the anchor pattern; at the same time, because the anchor pattern is too deep, the layer will easily form bubbles during the process, which will seriously affect the performance of the layer.
If the roughness is too small, the layer adhesion and impact strength will decrease. For severe internal pitting, the cleaning effect cannot be achieved only by the impact of large-grained abrasives, but also by grinding away the corrosion products with small particles. At the same time, a reasonable ratio design can not only slow down the wear of abrasives on pipes and nozzles (blades), but also improve the utilization rate of abrasives. Usually, the particle size of steel shot is 0.8~1.3mm, and the particle size of steel grit is 0.4~1.0mm, of which 0.5~1.0mm is the main component. The ratio of sand to shot is generally 5~8.
The rust removal grades of anti-corrosion pipe surface treatment are summarized as follows:
For the construction process of epoxy, vinyl, phenolic and other coatings commonly used for steel pipes, the surface of steel pipes is generally required to reach near-white grade (Sa2.5). Practice has proved that almost all the compound skin, rust and other dirt can be removed by using this level of rust removal, and the anchor pattern can reach 40~100μm, which fully meets the adhesion requirements between the layer and the steel pipe. The spray (throwing) jet derusting process can reach the technical conditions of near white level (Sa2.5) with low operating cost and stable quality.
In order to achieve the ideal derusting effect, the abrasive should be selected according to the hardness of the steel pipe surface, the degree of original rust, the required surface roughness, and the type of coating. For single-layer epoxy, two-layer or three-layer polyethylene coating, it is easy to achieve ideal rust removal effect by using the mixed abrasive of steel grit and steel shot. Steel shot has the effect of steel surface, while steel grit has the effect of etching steel surface
In order to obtain a better uniform cleanliness and roughness distribution, the particle size and proportion design of abrasives are very important. If the roughness is too large, the layer will become thinner at the peak of the anchor pattern; at the same time, because the anchor pattern is too deep, the layer will easily form bubbles during the process, which will seriously affect the performance of the layer.
If the roughness is too small, the layer adhesion and impact strength will decrease. For severe internal pitting, the cleaning effect cannot be achieved only by the impact of large-grained abrasives, but also by grinding away the corrosion products with small particles. At the same time, a reasonable ratio design can not only slow down the wear of abrasives on pipes and nozzles (blades), but also improve the utilization rate of abrasives. Usually, the particle size of steel shot is 0.8~1.3mm, and the particle size of steel grit is 0.4~1.0mm, of which 0.5~1.0mm is the main component. The ratio of sand to shot is generally 5~8.
