Galvanized seamless steel pipes, as the name implies, refers to the product after the surface coating of seamless steel pipes. Galvanized seamless steel pipes have the advantages of strong corrosion resistance, long service life, high temperature resistance, etc., and have been widely used in construction, machinery, automobile, aerospace and other fields.
Production process of galvanized seamless steel pipes
The first is the selection and pretreatment of raw materials. The raw material for producing galvanized seamless steel pipes is seamless steel pipes, and corrosive media such as sodium hydroxide and hydrochloric acid as well as stabilizers and other substances are also required. After entering the production workshop, the raw materials need to be pickled to remove oil and rust on the surface, making the surface smoother to facilitate subsequent processing.
Next is soaking in hydrochloric acid solution. Soak the cleaned seamless steel pipe in hydrochloric acid solution to remove residual rust and other impurities on the surface, reduce the depletion of the passivation film, and thus increase the adhesion and quality of the coating.
Next is alkaline washing. Put the steel pipe into sodium hydroxide solution, so that the metal salt and iron hydroxide products and iron hydroxide dissolution will gradually appear on its surface. These metal precipitates and iron hydroxide substances will reduce the depletion of the passivation film, and then wash to get a clean surface.
Then comes electroplating. The cleaned seamless steel pipe is immersed in an electrolytic tank, stabilized, and indirectly contacted with the zinc plate of the other pole. Under the action of direct current, zinc metal is deposited on the surface of the seamless steel pipe through electrochemical processes such as anodizing and electrolytic deposition to form a uniform and dense zinc layer.
Finally, inspection and packaging. After a series of process treatments, the galvanized seamless steel pipe needs to undergo multiple inspections to ensure its quality; packaging work must also be carefully implemented to prevent damage during long-distance transportation.
How to distinguish the authenticity of galvanized seamless pipes?
(1) Anything that is planed or ground off will leave traces, some of which are very obvious;
(2) Hot-dip galvanized seamless steel pipes are all fixed in length of 6 meters, 9 meters or 12 meters. There are very few genuine hot-dip galvanized seamless steel pipes in fixed lengths, because the factory will add a lot of price to the fixed length;
(3) The manufacturers of this kind of pipes are afraid of taking responsibility, so their quality certificates are all fluid pipes and they dare not say they are seamless steel pipes;
4) Check whether the wall thickness is uniform. Since seamless steel pipes are made of round steel hot-rolled and perforated, the wall thickness of seamless steel pipes will generally have deviations (with the continuous improvement of technology, the wall thickness deviation of seamless steel pipes is getting smaller and smaller, but there are still some). Although the welded pipe has undergone welding rib treatment or heat expansion and other procedures, its wall thickness is very uniform because its raw material is strip steel.
Read more: Production Process of Hot-dip Galvanized Seamless Steel Pipe
