Experts talk about the phosphating process before the primer is applied

phosphating before the primer is applied, it will improve the adhesion of the paint film and the substrate metal, improve the corrosion resistance of the entire coating system, and provide inter-process protection to avoid secondary rustTherefore, the primary problem of phosphating before paint is that phosphide film must have excellent matching with primer, and phosphating film itself rust prevention is secondary, phosphating film meticulous and compact, film thinWhen the phospanding film is thick, it can have a negative effect on the comprehensiveness of the paint filmThe selection of phosphating system and process is mainly determined by: workpiece material, oil rust degree, geometry, time interval between phosphating and painting, primer variety and construction method and relevant site equipment conditionsgenerally, low-carbon steel higher carbon steel is easy to phosphating treatment, phosphating into membrane performance is betterFor rust (oxidizing skin) workpieces must go through the acid washing process, and the acid-washed workpiece will bring a lot of trouble to phosphosphating, such as the process of rusting yellowing, residual acid removal, phosphating film roughing and so onThe finishafter after acid washing is generally subject to surface adjustment before the phosphate of zinc and zinc manganesein intermittent production occasions, due to the conditions, phosphorus chemical parts must be stored for a period of time before painting, so the phosplasty film itself has a better rust resistanceIf the storage period is more than 10 days, the general should use medium temperature phosphatization, such as medium-temperature zinc system, medium-temperature zinc manganese system, medium-temperature zinc calcium system, etc., the thickness of phosphecing film should be between 2.0 to 4.5g/m2The phosphated workpiece should be dried immediately, and should not be coolandd naturally, so as not to form rust in the sandwich and weldingIf the storage period is only 3 to 5 days, can be low-temperature zinc system, light iron system phosphating, drying effect will be better than natural cold dry