The degreasing time is too long, will the strip surface be oxidized?
Galvanized steel plate in spray, generally do phosphating treatment, the parameters of free acid phosphating solution should be kept low, and high temperature, acid, zinc ions reduced excessive reaction, resulting in coarse crystallization. Reference: Fa:0.8-1.5 Ta:17-28 acid ratio of about 25, the temperature can be 35-45 degrees.
Sheet metal pretreatment, degreasing total alkalinity is recommended in 15-20, alkali spent large, must be short time processing, for a long time will make the metal crystal nucleus passivation, influence phosphating film. Sheet metal general oil should not be cleaned, especially stamping parts, etc., it is recommended to use degreasing temperature, the temperature can be 65-75 degrees.
