1.Elimination of stress before plating. The key of the maximum tensile strength greater than 1034Mpa, the important parts should be relieved at 200±10°C for more than 1 hour before plating, and the carburized or surface hardened parts should be relieved at 140±10°C for 5 hours. the above.
2.The cleaning agent used for cleaning should have no effect on the bonding strength of the coating and no corrosion to the substrate.
3.The acid-activated acid activation solution should be able to remove the rust products and oxide film (skin) on the surface of the part without excessive corrosion of the substrate.
4,galvanized galvanizing can use zincate galvanizing or chloride galvanizing processes, etc., should use appropriate additives to obtain the coating that meets the requirements of this standard.
5.After the light plating, light treatment should be carried out.
6.Passivation of parts requiring hydrogen removal should be carried out after dehydrogenation. Before passivation, use 1% H2SO4 or 1% hydrochloric acid for 5~15s. Passivation should be treated with colored chromate unless otherwise specified on the design drawing.
What are the main reasons for the zinc layer falling off?
The main causes of zinc layer detachment are: surface oxidation, silicon compound, cold emulsified emulsion is too dirty, NOF stage oxidation atmosphere and protective gas dew point is too high, air-fuel ratio is unreasonable, hydrogen flow rate is low, furnace aerobic infiltration, strip steel The temperature of the boiling pot is low, the pressure of the RWP section is low, the suction of the furnace door is low, the temperature of the NOF section is low, the oil is not evaporated, the aluminum content of the zinc pot is low, the speed of the unit is too fast, the reduction is insufficient, and the zinc liquid stays. The time is too short and the plating is too thick.we are provide galvanized iron wire,we can guarantee quality.