Matters needing attention during the galvanizing process of stamping parts
1. Incomplete pretreatment
There is an oxide film on the surface of the workpiece, which affects the normal deposition of zinc.
2. Poor conductivity
The current is consumed on the conductor, and the current distributed to the surface of the workpiece is too small.
3. The workpiece has a high carbon content
High carbon steel and cast iron parts will reduce the hydrogen evolution potential, accelerate hydrogen evolution on the surface of the workpiece, and reduce the current efficiency.
4. The workpiece is tied too tightly
During galvanizing, the parts are partially shielded, resulting in a too thin coating.
5. Low bath temperature
When the bath temperature is low, the current density and deposition rate of the coating will decrease accordingly.
6. The sodium hydroxide content in the bath is too high
When the sodium hydroxide content is high, the current efficiency will decrease accordingly.
7. The additive content in the bath is low
The low additive content will affect the dispersion ability and the coating will be too thin.
8. The area of the electroplated part is underestimated, and the current density distributed during electroplating is too small.
9. If the workpiece is not properly suspended, the distance between the workpiece and the zinc anode is too large, and the position should be adjusted.
10. The workpiece is corroded
When the hydrogen evolution potential decreases, the current efficiency of accelerating hydrogen evolution on the workpiece surface decreases, affecting the zinc deposition rate. An appropriate amount of corrosion inhibitor should be added to the pickling solution. If the local oxide scale is too thick, it should be removed mechanically first, and more inspections should be done during pickling.
11. Anode passivation
The reduction in effective area affects the normal distribution of current.
12. Low sodium hydroxide content
If the sodium hydroxide content is low, the current density is not high, and the anode is passivated.
