With the rapid development of the domestic energy industry, the application of stainless steel pipes is also increasing rapidly. In the process of anti-corrosion construction of oil and gas pipelines, there are 304 stainless steel capillaries, which are relatively high-precision pipes. The surface treatment of stainless steel pipes is one of the key factors that determine the service life of pipeline anti-corrosion, and it is also an important prerequisite for the firm combination of the anti-corrosion layer and the stainless steel pipe. In addition to the type of coating, coating quality and construction environment, the life of the anti-corrosion layer depends on the quality of the surface treatment of the stainless steel pipe, which accounts for about half of the life. Therefore, it is necessary to strictly follow the requirements of the anti-corrosion layer specification for the surface of stainless steel pipes and continuously optimize the surface treatment process of stainless steel pipes.
At present, the common surface treatment methods of stainless steel pipes are mainly cleaning, rust removal, pickling, etc. These methods are introduced below.
Cleaning
Using solvents and emulsions to clean the surface of stainless steel can remove oil, grease, dust, lubricants and similar organic matter, but this method cannot remove rust, scale, welding flux, etc. on the surface of stainless steel, so it is only an auxiliary means in anti-corrosion production.
Tool rust removal
Generally, tools such as wire brushes are used to polish the surface of stainless steel, which can remove loose or raised scale, rust, welding slag, etc. Manual tool rust removal can reach Sa2 level, and power tool rust removal can reach Sa3 level. If the surface of stainless steel is firmly attached to the scale of iron oxide, the tool rust removal effect is not ideal and cannot reach the anchor pattern depth required by anti-corrosion construction.
Pickling
There are usually two methods for pickling: chemical and electrolytic. Stainless steel pipeline anti-corrosion only uses chemical pickling, which can remove scale, rust, and old coating. Sometimes this method can also be used as a re-treatment after sandblasting rust removal. Although chemical cleaning can make the surface reach a certain degree of cleanliness and roughness, its anchor pattern is shallow and easy to pollute the environment.
Shot blasting
Shot blasting is a method of blasting rust removal. A high-power motor drives the blasting blade to rotate at high speed, so that abrasives such as steel sand, steel shot, wire segments, and minerals are blasted on the surface of the steel pipe under the action of centrifugal force. It can not only remove rust, oxides and dirt, but also achieve the required uniform roughness under the violent impact and friction of the abrasive.
After blasting rust removal, it can not only expand the physical adsorption effect on the surface of the stainless steel pipe, but also enhance the mechanical adhesion between the anti-corrosion layer and the pipe surface. Therefore, shot blasting rust removal is an ideal rust removal method for pipeline corrosion protection. Generally speaking, shot blasting rust removal is mainly used for the inner surface treatment of the pipe, and shot blasting rust removal is mainly used for the outer surface treatment of the pipe. Several issues should be paid attention to when using shot blasting rust removal.
Post time: Jul-31-2024