In the rolling process of seamless steel pipes, especially precision seamless steel pipes, the pickling process is very important to remove the oxide scale and rust on the surface. How is pickling performed?
The method of using acid solution to remove oxide scale and rust on the surface of steel is called pickling. Iron oxides such as scale and rust (Fe3O4, Fe2O3, FeO, etc.) react chemically with the acid solution to form salts that are dissolved in the acid solution and removed. Acids for pickling include sulfuric acid, hydrochloric acid, phosphoric acid, nitric acid and mixed acids.
In order to eliminate the adsorption on the surface of the diatomaceous earth carrier and reduce the tailing of the chromatographic peak, the carrier needs to be acid washed or alkali washed before use. Pickling is to soak the carrier with 6mol/L hydrochloric acid for 2 hours or heat and soak with concentrated hydrochloric acid for 30 minutes, filter, wash with water to neutrality, and dry. Pickling can remove iron, aluminum, calcium, magnesium and other impurities on the surface, but cannot remove silanol groups. The pickling carrier is suitable for the analysis of acidic samples.
Degreasing and derusting the surface of precision seamless steel pipes to prepare for the next process. In the production process, the pickling process is to remove the surface oxide scale, and then go through lubrication treatment (carbon steel-phosphorous saponification, stainless steel-butter lime, copper aluminum pipe-oiling), using the old process-copper plating), and then For drawing and deep processing. If the steel pipe is not pickled, there may be oxides and oil stains on the surface, and the nuclear energy of the phosphating solution cannot remove them, and the quality of phosphating will be reduced.
Tips: ASTM A106 seamless pressure pipe (also known as ASME SA106 pipe) is commonly used in the construction of oil and gas refineries, power plants, petrochemical plants, boilers, and ships where the piping must transport fluids and gases that exhibit higher temperatures and pressure levels.