When this phenomenon occurs on the same workpiece, there are the following reasons:

1. For pre-treatment polishing, the proportion of liquid medicine is uneven. It is necessary to blow air to make the proportion and temperature of liquid medicine uniform. If it is three acid polishing, it is also related to the method. If it is a large piece, it must be preheated first, otherwise it will affect the subsequent uneven color

2. Conductivity: when the hanging position of the hanging gear is not conductive well, the survival film structure will be different. The film layer with good conductivity is regular. When the conductivity is not very good, the film layer will be irregular, which belongs to the abnormal survival film, so it will also cause the phenomenon of different colors

3. The neutralization after oxidation is not in place or the neutralization concentration is not enough, the concentration of dye solution in dyeing is high, there is no stirring equipment, the pH is low, etc

All the above abnormalities will cause the phenomenon of different colors on the same workpiece