【Weekly Topic】1.11~1.17 Differences between pickling and passivation of carbon steel and stainless steel (automatically +5 points for replies; +3-10 points for financial analysis...)
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This post was last edited by lzy4225925 on 2016-1-23 09:39. This week’s topic is: Can carbon steel be pickled and passivated? If possible, what is the difference between acid washing and passivation for carbon steel and stainless steel?
Answer: I don’t think it will work. Under normal circumstances, we use sandblasting; if acid cleaning is used, will a reaction occur?
The pickling formula for carbon steel is completely different from that for stainless steel, and a corrosion inhibitor must be added. 【We have encountered scaling in the cooling water circulation pipelines; the online pickling method was used for treatment, and a corrosion inhibitor needed to be added. 】
Can carbon steel be pickled and passivated? If possible, what is the difference between acid washing and passivation for carbon steel and stainless steel? Carbon steel can be pickled; it can be cleaned by soaking before installation or through online cyclic cleaning. The pickling formula for carbon steel is completely different from that for stainless steel, and a corrosion inhibitor must be added.
Carbon steel can be pickled, and a corrosion inhibitor must be added to the pickling solution. Water + corrosion inhibitor + acid. Stainless steel is resistant to corrosion because it can form a passivation film, and pickling is done to facilitate the formation of this passivation film during use. The corrosion resistance of carbon steel does not rely on a passivation film; pickling is used for surface pre-treatment, such as in painting and powder coating, as well as on equipment with high surface quality requirements, the casings and bases of machine tools and industrial machines, distribution boxes, and household and consumer electronics.
Can carbon steel be pickled and passivated? If possible, what is the difference between acid washing and passivation for carbon steel and stainless steel? Stainless steel is resistant to corrosion because it can form a passivation film, and pickling is done to facilitate the formation of this passivation film during use. The corrosion resistance of carbon steel does not depend on a passivation film; pickling is pointless for carbon steel, and its susceptibility to acid corrosion is very low. Pickling may cause varying degrees of corrosion in carbon steel.
Pickling is used to dissolve the surface oils, slag, stains, and incomplete oxide layers that form on the surface of carbon steel or stainless steel. Passivation involves using a passivating solution to treat carbon steel and stainless steel, thereby forming a dense oxide layer. Carbon steel dissolves in dilute acids such as dilute sulfuric acid, dilute hydrochloric acid, and dilute nitric acid, but it can form a dense oxide layer in concentrated nitric acid and concentrated sulfuric acid, which prevents further corrosion. Taking advantage of this property, carbon steel is subjected to pickling and passivation treatment, and the pH value of the passivation solution is strictly controlled. The main component of the passivation film is iron oxide. Chromium is added to stainless steel, which facilitates the formation of a passivation film in a passivation solution; the main component of this passivation film is chromium oxide
Carbon steel can be pickled; it can be cleaned by soaking before installation or through online cyclic cleaning. The formula for pickling carbon steel is completely different from that of stainless steel, and a corrosion inhibitor must be added
Carbon steel can be pickled, and a corrosion inhibitor must be added to the pickling solution.
Carbon steel can be pickled, mainly for surface treatment of thin sheets. Since thin plates deform during sandblasting, pickling and phosphating are used as the pretreatment process.