High-frequency Welded Steel Pipe Surface Treatment
In the oil (gas) pipeline anti-corrosion construction process, the surface treatment of high-frequency welded steel pipe is one of the key factors to determine the useful life of the pipeline. It is the premise that the erosion resistant coating can be firmly bonded to the steel pipe. According to the research institutions, the life of the erosion resistant coating depends on the coating type, coating quality, construction environment and other factors. The surface treatment of steel pipe accounted for about 50% on the life of the erosion resistant coating.
1. Pickling
Generally, we use chemical and electrolytic two methods for pickling treatment. Pipeline corrosion only uses chemical pickling, which can remove the oxide, rust and the old coating. And sometimes it can be used as a re-treatment after derusting by sandblast. Although using chemical to clean the surface can achieve a certain degree of cleanliness and roughness, but the anchor is shallow, and it easy to cause pollution to the environment.
2. Cleaning
Using solvents and emulsions to clean the surface of steel to achieve the removal of oil, grease, dust, lubricants and similar things, but it can not remove the rust, oxide, welding, etc. on steel surface, so it only can be an auxiliary means in anti-corrosion production.
3. Abrasive blasting
Abrasive blasting is through high-power motor rotating to drive jet vane to rotate on high speed to make steel sand, steel balls, wire segments, minerals and other abrasives doing spray treatment on the surface of the steel pipe in the centrifugal force. This method not only can completely remove the rust, oxides and dirt, but the steel pipe under the action of the abrasive impact and friction also can achieve the required uniform roughness.
4. Toolrust-removal
We mainly use steel wire brush and other tools to polish the steel surface, which can remove loose or tilt oxide, rust, welding slag and so on. Manual tool derusting can reach Sa2 level, power tools derusting can reach Sa3 level. If the steel surface attached to a solid iron oxide skin, the effect of toolrust-removal is not ideal, and can not up to the depth of the anchor required by anti-corrosion construction.
1. Pickling
Generally, we use chemical and electrolytic two methods for pickling treatment. Pipeline corrosion only uses chemical pickling, which can remove the oxide, rust and the old coating. And sometimes it can be used as a re-treatment after derusting by sandblast. Although using chemical to clean the surface can achieve a certain degree of cleanliness and roughness, but the anchor is shallow, and it easy to cause pollution to the environment.
2. Cleaning
Using solvents and emulsions to clean the surface of steel to achieve the removal of oil, grease, dust, lubricants and similar things, but it can not remove the rust, oxide, welding, etc. on steel surface, so it only can be an auxiliary means in anti-corrosion production.
3. Abrasive blasting
Abrasive blasting is through high-power motor rotating to drive jet vane to rotate on high speed to make steel sand, steel balls, wire segments, minerals and other abrasives doing spray treatment on the surface of the steel pipe in the centrifugal force. This method not only can completely remove the rust, oxides and dirt, but the steel pipe under the action of the abrasive impact and friction also can achieve the required uniform roughness.
4. Toolrust-removal
We mainly use steel wire brush and other tools to polish the steel surface, which can remove loose or tilt oxide, rust, welding slag and so on. Manual tool derusting can reach Sa2 level, power tools derusting can reach Sa3 level. If the steel surface attached to a solid iron oxide skin, the effect of toolrust-removal is not ideal, and can not up to the depth of the anchor required by anti-corrosion construction.
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