Shandong Seamless Steel Tube Factory teaches you four kinds of seamless steel pipe surface treatment methods

Shandong Seamless Steel Tube Plant teaches you four types of seamless steel pipe surface treatment methods. In the process of anti-corrosion construction of oil (gas) pipelines, the surface treatment of seamless steel pipes is one of the key factors that determine the service life of pipelines. It is a coating and steel pipe. The premise of a firm combination. After verification by the research institute, the life of the anti-corrosion coating depends on the coating type, coating quality and construction environment. The effect of the surface treatment of the steel pipe on the life of the anti-corrosion coating accounts for approximately 50%. Therefore, the anticorrosion layer should be strictly followed. The requirements of the surface of the steel pipe are continuously explored and summarized, and the steel pipe surface treatment method is continuously improved. 1. Cleaning Uses solvents and emulsions to clean the surface of steel to remove oil, grease, dust, lubricants, and similar organics. However, it cannot remove rust, oxide scale, and welding flux on the steel surface. Therefore, it is only used as an anticorrosive product. Aids. 2. Tool rust removal The main use of wire brushes and other tools to sand the steel surface, can remove loose or tilt of the scale, rust, welding slag and so on. Hand tool derusting can reach Sa2 grade, and the derusting of power tool can reach Sa3 grade. If the steel sheet surface is attached with solid iron oxide scale, the tool derusting effect is not ideal, and the depth of the anchoring pattern can not reach the requirements of anti-corrosion construction. 3. General use for pickling Chemical and electrolysis methods are used for pickling treatment. Pipeline anti-corrosion uses only chemical pickling, which can remove scale, rust, and old coatings. It can be used as a re-treatment after sand blasting. Although chemical cleaning can make the surface reach a certain degree of cleanliness and roughness, its anchorage is light and it is easy to cause pollution to the environment. Shandong Seamless Steel Tube Factory provides it. 4, spray (throw) shot rust spray (throw) shot rust is driven by high-power motor spray (throw) shot blade rotation at high speed, so that steel sand, steel shot, wire segment, minerals and other abrasives under the action of centrifugal force The sprayed (throw) shot treatment on the surface of the steel pipe can not only completely remove the rust, oxides and dirt, but also can achieve the required uniform roughness under the action of the abrasive impact and friction force of the abrasive. After spraying (throwing) shot rust removal, not only can the physical adsorption of the pipe surface be enlarged, but also the mechanical adhesion of the anti-corrosion layer to the pipe surface can be enhanced. Therefore, spraying (throwing) shot rust removal is the ideal rust removal method for pipeline anti-corrosion. In general, shot peening (sand) rust removal is mainly used for inner surface treatment of pipes. Shot peening (sand) rust removal is mainly used for outer surface treatment of pipes. There are several issues that need to be taken into account when using spray (throw) shot rust removal. 4.1 Rust-removing grades For the construction process of anti-corrosion coatings such as epoxy, vinyl, and phenolic, which are commonly used for steel pipes, the surface of the steel pipe is generally required to reach a level of nearly white (Sa2.5). Practice has proved that this kind of derusting grade can remove almost all scales, rust, and other contaminants. The depth of the anchoring pattern can reach 40~100μm, fully satisfying the adhesion requirements of the anticorrosive layer and the steel pipe, and spraying (throwing) the shot The rust process can achieve near-white (Sa2.5) technical conditions with lower operating costs and stable and reliable quality. 4.2 Spray (throw) shot abrasive In order to achieve the desired rust removal effect, the abrasive should be selected based on the hardness of the surface of the steel pipe, the degree of original rust, the required surface roughness, the type of coating, etc., for a single layer of epoxy, two or three layers. Polyethylene coating, the use of mixed abrasive steel grit and steel pellets more easily achieve the desired effect of rust. Steel shots have the effect of strengthening the steel surface, while steel sand has the effect of etching the steel surface. Mixed abrasives of steel grit and steel shots (usually steel shots with a hardness of 40-50 HRC, steel grit with a hardness of 50-60 HRC can be used on various steel surfaces, even on grade C and D grade corroded steel surfaces Rust removal effect is also very good. 4.3 Abrasive particle size and ratio In order to obtain a better uniform cleanliness and roughness distribution, the abrasive particle size and proportioning design is very important. If the roughness is too large, the anti-corrosion coating may become thinner at the peak of the anchorage pattern. At the same time, due to the deeper anchorage pattern, the anti-corrosion coating may easily form bubbles during the anti-corrosion process, which will seriously affect the performance of the anti-corrosion coating. If the roughness is too small, the adhesion of the coating and the impact strength will be reduced. For severe internal pitting, high-strength impact cannot only be achieved by large-grained abrasives, but also by small particles to remove corrosion products to achieve the cleaning effect. At the same time, a reasonable proportioning design can not only reduce abrasive wear on pipes and nozzles (blades). , And the utilization of abrasives can also be greatly improved. In general, the particle diameter of the steel shot is 0.8-1.3 mm, and the diameter of the steel grit is 0.4-1.0 mm, of which the main component is 0.5-1.0 mm. Sand pills are generally 5-8. It should be noted that in practice, the ideal ratio of steel grit and steel shots in abrasives is difficult to achieve due to the fact that hard and brittle grit has a higher breakage rate than steel shots. Therefore, in the operation, the abrasive should be continuously sampled and tested. According to the particle size distribution, new abrasives should be added to the derusting machine. In addition, the number of steel sands should be the major one in the new abrasives. This information is made up of Shandong. Seamless pipe factory provided. 4.4 Rust removal rate The derusting speed of the steel pipe depends on the type of abrasive and the displacement of the abrasive, ie the total kinetic energy E applied by the abrasive to the steel pipe per unit of time and the kinetic energy E1 of the single-particle abrasive. In the formula: m - abrasive spray (throwing); V - abrasive speed; M1—mass of single particle abrasive. m. The size is related to the abrasive crushing rate. The crushing rate directly affects the cost of surface treatment operations and the cost of rust removal equipment. When the equipment is fixed, m is a constant, y is a constant, so E is also a constant, but due to abrasive crushing, m1 changes, therefore, generally should choose the abrasive with a lower loss rate, which will help improve the cleaning speed and long The life of the blade. 4.5 Cleaning and preheating Before spraying (throwing) shot processing, cleaning method is used to remove the grease and scale on the surface of the steel pipe. The furnace is preheated to 40-60°C with a heating furnace to keep the surface of the steel pipe dry. In spray (throw) shot processing, since the surface of the steel tube does not contain grease and other dirt, the effect of rust removal can be enhanced, and the dried steel tube surface is also conducive to the separation of steel shot, steel sand and rust and scale, so that after the rust removal The steel surface is cleaner. 5 Conclusion In production emphasis on the importance of surface treatment, strict control of the process parameters of rust removal, in actual construction, the peel strength of steel pipe coating greatly exceeds the standard requirements, to ensure the quality of the coating, in the same equipment On the basis of it, the level of technology is greatly increased and production costs are reduced. Shandong seamless steel pipe plant Liaocheng Wanlihong Steel Pipe Factory is a professional manufacturer of seamless steel pipe, high quality and low price, spot supply of Shandong Seamless Steel Tube Factory Wanlihong Steel Pipe welcomes friends from all walks of life come to order negotiations, the hotline: 0635-2110045 2110345.