The Surface Treatment of the Steel Pipe

With the sustainable development of the economy, the country strives to develop the energy industry. And the oil and gas pipeline of long distance is an important way to ensure the3 energy. During the corrosion prevention of the oil and gas pipelines, the surface treatment of the steel pipe is a key factor that depends on the service life of the pipelines. Statistics show that except for coating types, coating quality as well as the construction environment, the surface treatment of the steel pipe also has influence on the service like of the steel pipe. Thus, it is necessary to improve the surface treatment of the steel pipe, especially the steel pipes that are used in important country's engineer such as API steel pipe for oil transport and welded steel pipe for machinery construction.

1. Cleaning
Clean the surface of the steel pipe with resolvent and milk to erase oil, dirt, lube as well as similar organics. However, the rust, oxide skin on the surface of the steel pipe cannot be erased with cleaning, so it is just a supplementary method in aczoiling production.

2. Rust Removal with Tools
To polish the surface of the steel pipe such as API steel pipe and welded steel pipes with tools that are mainly steel brushes to remove the loose oxide skin, rust and welding spatter.

3. Acid Pickling
There are two ways to carry out acid pickling treatment: chemistry and electrolysis. As for pipeline anticorrosion, the chemistry acid pickling is an ideal way to erase oxide skin, steel rust as well as old coating. Sometimes, it is also needed to be used as the reprocessing after sand blast anticorrosion. Although the chemistry acid pickling can make the surface of the steel pipe reach certain cleanliness and roughness to some degree, it has shallow anchor pattern and is easy to do harm to the environment.

4. Compressed-air Blast Cleaning
The compressed-air blast cleaning is to use electrical machine with high power to drive the revolving of the injecting blade to make steel grit, iron wire, mineral materials and other grinding materials carry out injecting treatment of the surface of the steel pipe. This method can not only erase the rust, oxide materials and dirt completely, but also reach uniform roughness under the function of strong impact and friction.

Removing rust through injecting can expand the physical absorption of the surface of the steel pipe, and strengthen the mechanical adhesion function between erosion resistant coating and the surface of the pipes. The welded steel pipe and black steel pipe are also available. Thus, the compressed-air blast cleaning is an ideal rust removing method. However, it is necessary to mention some problem in the middle of rust erasing. In order to reach the ideal rest cleaning effect, the grinding material should be chosen according to the hardness of the surface of the steel pipe such as API steel pipe and welded steel pipe, original rusting level, surface roughness as well as the coating types. And the speed of the rust removal relies on the style and discharge capacity of the grinding material. It is general to choose grinding material with lower attrition rate, which is beneficial to improving cleaning speed and the service life of the long blade.