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Hot galvanizing process

- Jun 12, 2018 -

Hot galvanizing process

Mechanical galvanized iron is a kind of electric galvanized, hot galvanized iron, dacromet process different anticorrosion coating, its technological characteristics is: room temperature operation, form does not belong to the electrochemical deposition, is a component plating loading, the rotation of the drum, the drum the media parts collide with each other, to form the coating can realize industrial machinery transmission; Coating level structure for particle spherical zinc powder by mechanical force transmission collision deformation, become flat, dished lamellar zinc particles, superposition to condense for coating, the coating structure with metal zinc basic physical characteristics, the function of the coating, is to provide basic parts of iron rust protection requirements of the anodic protection coating. The process characteristics are as follows: for high-strength steel industry, heavy corrosion coatings (25-110um) of heavy anti-corrosion coatings (25-110um) of small rollable plating parts do not cause hydrogen embrittlement hazard and replace hot dip.

1. Main process of mechanical galvanizing1.1 main process flow of mechanical galvanized ironParts before processing, oil removal, rust removal (can offline processing) - washing a flash replacement copper plating - washing a mechanical galvanizing sedimentary transition underlying a mechanical galvanizing monohydrate polishing a parts poured out separation - hot water washing (or zero according to the requirement, the chromium passivation, relevant protective layer on the surface of the) - dry drying and inspection acceptance.1.2 pre-treatment, oil removal and rust removal of partsFor ordinary parts, the conventional surface treatment method can be adopted, but for high-strength steel matrix parts, the rust removal and oxidation removal leather,Especially pay attention to, because we can not longer using strongly acidic chemical materials containing hydrogen ions was carried out on the workpiece surface, rust and oxygen skin, this kind of treatment will have a certain influence on permeability of hydrogen on steel base parts, therefore, mechanical method should be adoptedUnscrambled light, Cin.CO1.3 flash plating replacement copperReplacement copper layer thickness requirements, but to completely cover parts surface of substrate, its role is: improve the bonding strength, is conducive to the uniformity of coating surface condition, stop the process to produce hydrogen infiltration of matrix. Another role found, because the copper layer has good conductivity, mechanical zinc plating thickness same galvanized parts with zinc impregnation parts salt fog box comparing experiment examination, reach 11 cycles in salt spray test, found that due to salt fog water flushing, edges and corners of the bulk seepage zinc parts appear red rust, and mechanical galvanizing edges while already see, matrix, but the batch six pieces of all does not produce red rust: this is due to the small displacement copper layer resistance, electric conductive open, ensure the normal state of electrochemical cathode, iron matrix so that the replacement of mechanical zinc plating copper layer structure, electrochemical anti-corrosion ability is especially important. About internal displacement plating process, mechanical galvanized common technical standards in the United States, the specified ASTM - B695-91, has the flash replacement copper plating process technical requirements: and China national mechanical industry bureau issued and implemented on January 1, 2000 "steel mechanical galvanized parts, machinery industry standards