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Welding Wire Machine
- Aug 13, 2017 -

               According to the production experience at home and abroad, the first pretreatment of the oxidized skin of stainless steel, then using the mixed acid cleaning containing oxidant and activator, is the most reasonable and effective method to remove the stainless steel oxide skin. The pretreatment methods used in stainless steel wire rod have alkali leaching method.Welding Wire Machine

               1. Alkali leaching method. Alkali leaching is to soak the wire rods in alkaline molten salts or solutions to change the structure of the oxidized skin. Alkali leaching is divided into molten alkali leaching and solution alkali leaching.

               1) Molten saline-alkali leaching method. Molten salt used in molten saline leaching is composed of hydroxide of alkaline metal and oxidizing agent or reductant. Molten salt has NaOH, NaNO3, Na2b7o4, NaCl, nah and so on, its principle is: a. The expansion coefficient of the oxide skin and the metal matrix is very wide, and the expansion coefficient of the metal is much larger than that of the oxidized skin, in the process of rapid quenching and cooling in molten saline-alkali leaching and alkali-leaching, the oxidized skin is burst by heat and heat expansion, and some oxides fall into alkaline mud. B. Some insoluble oxides in the oxide, as well as acidic oxides such as SiO2, $literal and TiO2, MoO3, WO3, etc. are dissolved in alkali in advance, the oxidized skin is no longer dense and intact, which creates favorable conditions for pickling. C. Soluble salts can change the structure of the oxidized skin so that the $literal of insoluble acid is converted to high valence oxide CrO3, or the oxide is reduced directly to metal. The drawback of alkali leaching is that it needs to have a base tank, increase the cost, and the temperature of the alkali trough is long and the energy consumption is large.Welding Wire Machine

               2 solution alkali leaching method. The principle of solution alkali leaching is the same as that of molten alkali leaching, but the use temperature is lower than the boiling point, and the alkali leaching time is longer. Solution has NaOH, KMnO4, Koh and so on. KMnO4 in solution is a strong oxidant, NaOH (or KOH) is to promote KMnO4 decomposition, release atomic oxygen, with the increase of NaOH content, decomposition accelerated. The KMnO4 consumption of the reaction was the largest, and the consumption of NaOH was small. The new solution is purple, the use of purple gradually fade, when the KMnO4 depletion, the intermediate product K2mno4 the solution into green. The cleaning time can be shortened obviously by the combination of solution alkali leaching and pickling. In some small production, not continuous production of manufacturers to choose this method.Welding Wire Machine