Mechanical galvanizing 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 of rotating barrel plating loading, make the parts inside the barrel medium collide with each other, achieve mechanical industry to transfer to form coating: coating level structure for particle spherical zinc powder by mechanical force transmission collision deformation, become flat, saucer-shaped superposition of lamellar zinc particles to condensation for the coating, the coating structure with metal zinc, the basic physical characteristics, the function of the coating effect is to provide basic parts of iron rust protection requirements of the anodic protection coating.The process characteristics are: it does not cause hydrogen embrittlement damage to the industrial parts of high-strength steel and the heavy anti-corrosion coating (25-110um) for small rolled parts has the competitive advantage of industrial application.
1, the main mechanical galvanizing technique process of
1, 1 before the main mechanical galvanizing process parts processing, oil removal, rust removal (can offline processing) - water - flash replacement copper plating a wash of mechanical galvanizing sedimentary transition - mechanical galvanizing bottom - water poured out separation of a hot water wash, polishing a parts (or parts surface chromium passivation as required, relevant protective layer) - with dry and drying - check acceptance.
1.2 pretreatment, oil removal and rust removal of partsOf common parts, according to surface treatment of the conventional method, but the high strength steel substrate for parts of rust removal, in addition to scale, especially pay attention to, because we can not longer using strongly acidic chemical materials containing hydrogen ion to parts, leather surface rust removal and deoxidization, this kind of treatment will have a certain influence on permeability of hydrogen on steel base parts, so the mechanical method should be adopted to solve: such as sand blasting, vibration finishing and shot blasting process, etc.
1.3 flash copper platingThe replacement copper layer has no thickness requirement, but it should completely cover the substrate surface of the part. Its function is to improve the bonding strength of the coating layer, facilitate the uniformity of the coating surface, and prevent the infiltration of hydrogen to the substrate generated by the process. 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 is dew 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 of 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 of wisdom in copper plating process technical requirements, and China national mechanical industry bureau promulgated on January 1, 2000 implementation of the "iron and steel parts mechanical galvanizing, machinery industry standard" (IB/T8928-1999) for replacement of mechanical zinc plating copper layer does not make the rules, to this: according to the requirements of both sides of supply and demand to determine.