Analysis And Application Of Salt Bath Cleaning In Remanufacturing

Remanufacturing is one of the development directions of the mechanical industry for its advantages like good production quality, high resource utilization. Remanufactured products can totally satisfy the requirement of work and help to solve the issue of employment situation. As the base of remanufacturing, cleaning technology guarantees the quality of the remanufactured products. Salt bath cleaning has the virtue of being high-temperature, stable and versatile can be used as a new cleaning method for remanufacturing cleaning.Molten salt is used as the working medium in the salt bath cleaning for it being hot, stable, small volatile and viscosity. With the high temperature, the speed of cleaning process can be promoted. Small volatility reduces the loss of the cleaning medium. Stability prevents the metal of the parts being corroded by the molten salt. And small viscosity can take the dirt off the surface of the parts easier. After all, molten salt still has the good wetting ability which can promote the cleaning efficiency as well.Up to now, the studies of remanufacturing salt bath are still not very satisfactory. But salt bath cleaning is applied widely aboard. This paper has studied the theoretical basis of remanufacturing salt bath cleaning from studying the physical property, such as the melting point, degradation temperature, viscosity and surface tension and so on. The experiment on the carbon deposition cleaning has been conducted.DSC (Differential Scanning Calorimetry) technology was adopted to analyze the physical properties of the mixed salt of potassium nitrate and sodium nitrite. According to the curves, we have got the melting points and the degradation temperatures with different compositions of the mixed salt and the working temperature range has been decided. The heat capacity was measured by the sapphire method to study the stability of cleaning temperature.A few liquid viscosity measuring methods were summoned and introduced in this paper. Rotary oscillation method was adopted to measure the viscosity of the mixed salt of potassium nitrate and sodium nitrite, and the line chart has been drawn according to the data. The calculated viscosity of molten salt according to different emprical formulas were compared with the others. Based on the experimental results, we have fitted the data and got the emprical formulas of the mixed salt viscosity.Interfacial tension shows the infiltration and adhesion capacity between liquid and solid. Using the maximum bubble pressure method designed the experiment device and measured the surface tensions of mixed salt. Based on the experimental data have analyzed the relationship between surface tension and composition and temperature. The experiments done were meant to lower the surface tension to improve the adhesion capacity of the molten salt so as to the cleaning efficiency.Carbon deposition of the engine was chosen as the remanufacturing salt bath cleaning object, different cleaning conditions have been applied in the cleaning experiment. It proved that alkaline salt bath has the ability to accelerate the speed and improve the cleaning quality of the carbon deposition cleaning process.