1. Common media for pickling of seamless steel pipes (smls)
Sulfuric acid, nitric acid, phosphoric acid, hydrofluoric acid. Be sure to add a pickling corrosion inhibitor during pickling to prevent acid corrosion of metals.
2. Pickling process of seamless steel pipe
There are mainly dipping pickling method, spray pickling method and acid paste rust removal method. Generally, the dipping and pickling method is used, and the spray method can be used in mass production. Steel parts are generally pickled in 10% to 20% (volume) sulfuric acid solution at a temperature of 40°C. When the iron content in the solution exceeds 80g/L and the ferrous sulfate exceeds 215g/L, the pickling solution should be replaced.
Under normal temperature, pickling steel with 20% to 80% (volume) hydrochloric acid solution is not easy to cause excessive corrosion and hydrogen embrittlement. Since the acid has a great corrosion effect on the metal, it is necessary to add a corrosion inhibitor. After cleaning, the metal surface becomes silver-white, and the surface is passivated to improve the corrosion resistance of stainless steel. In order to eliminate the adsorption on the surface of the diatomite carrier and reduce the tailing of chromatographic peaks, the carrier needs to be acid washed or alkali washed before use.
Pickling is to soak the carrier with 6mol/L hydrochloric acid for 2h or concentrated hydrochloric acid for 30min, filter, wash with water until neutral, and dry. Pickling can remove impurities such as iron, aluminum, calcium, and magnesium on the surface, but cannot remove silanol groups. Acid-washed supports are suitable for the analysis of acidic samples.
3. Pickling effect of seamless steel pipe
Degrease and rust the surface of the precision seamless steel pipe
in order to prepare for the next process. In the production process, the pickling process is to remove the surface oxide scale, and then after lubricating treatment (carbon steel-phosphorus saponification, stainless steel-tallow lime, copper-aluminum tube-oiling), using the old process-copper plating), and then Carry out drawing and deep processing. If the steel pipe is not pickled, there may be oxides and oil stains on the surface, and the phosphating liquid nuclear energy cannot remove them, and the phosphating quality will be reduced.