The Study On The Spray And Heat Solidification Process Of Metal Pipe Non-Stick Coating

The heat exchanger is an indispensable component in the industrial production and daily life. However, the heat exchanger generally works in a terrible environment,which makes the heat exchanger facing a serious problem of corrosion, and this will greatly reduce the service life of the heat exchanger. Thus, many researchers are focus on improving the corrosion resistance of heat exchanger. Among the various methods of preventing the corrosion of heat exchanger, the use of non-stick coating has the advantages of low cost, nonpollution, easy operation. However, most of the coatings are used in low temperature of 200 ℃, the non-stick coating that used in high temperatureis relatively less. In recent years, there have been several non-stick coatings which can be used for more than 300 ℃ on the market, but there is no systematic research on the heating and spraying process of the coating. In this paper,the influence factors and the effect of NQ non-stick coating(self-developed) in spraying process were studied, and the specific research contents are as follows:1. Study on the influence of the roughness of metal plate, spray times and cooling method of coating on the properties of NQ coating.Some experimental parameters, such as roughness of metal plate, spray times and cooling method of coating, which had nothing to do with the metal structure were studied to determine the best experimental conditions. The results show that the roughness of 0.6 μm, 2 times spraying and the air cooling method will obtain a more dense non-stick coating under the premise of saving time.2. The design and construction of the integral spray solidification device.At present, there are several problems in non-stick coatings spray during studying the properties of non-stick coating. In order to solve these problems, a cylindrical furnace which can be moved by rail is designed and constructed, and the heating performance of the furnace is tested. The results show that temperature is uniformly distributed in radial direction of the metal tube, but the temperature difference is large in axial direction, and the maximum temperature difference is 34℃.In addition, the spraying and curing of the coating are also studied by the device.The results show that the coating performance can not meet the performance requirements, unless it is to further extend the heat preservation time of the fin tube to make the coating fully cured.3. Research on continuous heating and spraying system of metal pipe.A continuous heating and spraying system for metal pipe was designed by optimizing and improving the integrated non-stick coating spray and solidification device. The temperature uniformity of this continuous heating and spraying system was tested. The results show that, the temperature change of the metal tube is stable when the movement speed of the metal tube is low. When the velocity is greater than6cm/min, the temperature curves begin to fluctuate. And the greater the moving speed is, the greater the temperature fluctuation is. In addition, the moving frequency of metal tube has little influence on the temperature change when the furnace temperature and metal tube moving speed is unchanged. The different temperature control parameters for different metal tube movement speed were determined by the research on control parameters of the continuous heating and spraying system of metal pipe.4. Study on continuous spraying and solidification of metal pipe.The influence of the metal tube rotation, firing craft of the coating and the connectivity between the furnaces on the coating firing and coating properties were studied. The results show that if keeping the rotation of metal tube when heating and solidification, the coating will obtain better properties under the same process conditions. Separation of heating furnace also helps to improve the properties of coating. In addition, only increase the moving speed of metal tube appropriately can shorten the firing time of coating and not affect performance of metal tube. When the moving speed of metal tube is 4 cm/min, the firing time can be shortened from 60 minutes to 45 minutes.