Methods of prolonging the service life of welded pipes

Welded pipe, also known as welded pipe, is a steel pipe made of steel plate or strip steel after being crimped and welded, generally with a fixed length of 6 meters. Welded steel pipes have simple production process, high production efficiency, many varieties and specifications, and less equipment investment, but the general strength is lower than that of seamless steel pipes. The corrosion resistance and service life of welded pipes are long, but they also need to be used reasonably to maximize their service life.

The exposed metal surface will produce an electrochemical reaction or a chemical reaction, and it will be evenly corroded. The parts with weak corrosion resistance in the purification film on the surface of the welded pipe,Due to the self-excited reaction, a pitting reaction is formed, small holes are formed, and the oxygen ions are close to form a strong corrosive solution, which accelerates the rate of the corrosion reaction. In addition, the occurrence of intergranular corrosion inside the welded pipe leads to cracking, which will pulverize the purification film on the surface of the welded pipe.

Therefore, regular maintenance of the welded pipe surface is required to ensure its clean surface and prolong its service life. When washing the surface of the welded pipe, it is necessary to carefully avoid surface scratches; it is forbidden to use bleaching powder, washing liquid containing abrasives, grinding tools for steel balls, etc.; in order to remove excess washing liquid, rinse the surface with clean water after washing.

When there is dust on the surface of the welded pipe and it is easy to remove contaminants, it can be washed with weak ionic detergent, or with alcohol or organic solvent (ether, benzene).

If there are grease or lubricating oil contaminants on the surface of the welded pipe, after cleaning with a soft cloth, wash with neutral detergent, ammonia solution or special detergent.When bleach and various acids are attached to the surface of the welded pipe, rinse it with water immediately, then dip it with ammonia solution or neutral carbonic acid and aqueous solution, or wash it with neutral detergent or warm water.

When there is a rainbow pattern on the surface of the welded pipe (caused by excessive use of detergent or oil), it can be washed with warm water neutral detergent when washing.When there is rust caused by pollutants on the surface of the welded pipe, it can be washed with 10% nitric acid or abrasive detergent, or it can be washed with special cleaning chemicals.

Note: The seamless pipe must wear labor protection equipment before pickling. The working environment on site should also be checked in detail, mainly to check whether the sling of the steel pipe is in good condition;When pickling seamless pipes, pickling is mainly done with hydrochloric acid. Generally, the content of hydrochloric acid is 18% to 20%. The specification of seamless pipes is expressed by diameter * wall thickness.

Article source: https://article-realm.com/article/Finance/29138-Methods-of-prolonging-the-service-life-of-welded-pipes.html