The metal skeleton degreasing method includes lye degreasing, solvent degreasing (dipping, washing, steam) and ultrasonic degreasing.
The lye degreasing removes the oil on the surface of the metal by infiltration, dispersion, emulsification, and saponification of the oil by the lye.
It is also a common method to impregnate or clean metal parts with a solvent and dissolve the oil by solvent. The commonly used solvents are 120# gasoline, ethyl acetate, benzene, toluene, alcohol, tetrachloroethylene, trichloroethane. , acetone, etc.
When the working surface grease is seriously polluted. Once the impregnation does not meet the degreasing requirements, it must be sub-impregnated or cleaned. Even if it is double-impregnated or cleaned, it is sometimes difficult to achieve the desired effect. To achieve the desired degreasing effect, steam degreasing is recommended.
When the solvent vapor contacts the surface of the metal member, since the temperature of the metal surface is lower than the boiling point of the solvent, the vapor condenses, and the condensed solvent is dropped from the metal surface to the evaporation zone, and at the same time, the surface grease is dissolved and brought out of the metal surface, thereby Achieve a better degreasing effect. Suitable solvents and indicators are as follows: tetrachloroethylene, trichloroethane, trichloroethylene. The process control of steam degreasing mainly has the following points: the metal parts can not be immersed in the solvent, nor can it be higher than the condensation zone, the metal parts can not touch each other; when the temperature of the metal parts reaches the boiling point of the solvent, the degreasing process should be finished; the pH of the solvent is maintained. It should be updated at 7.0~7.5; when the solvent contains 25% oil.