Application of enamel on electric heating tube
Introduction: The enamel electric heating tube is a protective layer of enamel frit coated on the outer surface of the metal tube. In this way, due to the coating of the enamel layer, the enamel electric heating pipe can be used to directly heat some liquids that easily corrode metal materials, which can greatly extend the service life of the electric heating pipe.
The electric heating tube uses a metal tube as a shell, an alloy electric heating wire as a heating element, and an extraction rod (wire) at one end or two ends. The metal tube is filled with a magnesium oxide insulating medium to fix the heating element. Electric heating tube is a heating device commonly used in industrial production and daily life. It is suitable for heating gases, oil, water, organic chemicals, compression molds, molten salts, alkalis and low melting alloys. The electric heating pipe has the characteristics of high thermal efficiency, long service life, high impact toughness, and convenient installation. Widely used in petroleum, machinery, chemical, printing and dyeing, shipbuilding, power and other industries, it is an energy-efficient heating, and viscosity reduction equipment, replacing the traditional methods of heating oil, coal, and steam.
In general, the materials of electric heating pipes are mainly iron, 201 stainless steel, 304 stainless steel, 316 stainless steel, titanium steel and the like. Although the titanium steel pipe has excellent corrosion resistance, it is not easy for downstream users to accept it because the cost is too high.
Ordinary iron enamel is not recommended for electric heaters. Because iron pipes have pores in the process of enamel. In this way, the chloride ions in the water body will penetrate and corrode; the inner wall of the electric heating pipe is not coated with enamel, and the iron on the inner wall is easily damaged by oxidation during the heating process. Therefore, even if the ordinary iron pipe is coated with an enamel glaze protective layer, the service life cannot be significantly extended when used in harsh environments.
In summary, we still recommend the use of stainless steel enamel to protect the electric heating tube. First, the stainless steel itself has good corrosion resistance, and it is not easy to be oxidized and corroded on the inner wall of the electric heating pipe. Second, the enamel coating on the side in contact with the liquid can obviously protect and prevent corrosion. We know that 304 stainless steel is very prone to corrosion in the environment with temperature and chloride ions. With the protection of enamel coating, the service life of the electric heating pipe can be greatly extended. At the same time, stainless steel is prone to scaling. Thick scale will affect the heat conduction of the electric heating tube. In addition to causing energy loss, the heat is concentrated on the electric heating tube and does not dissipate heat. The high temperature is very easy to be oxidized and damaged; while the enamel coating is not easy to scale .
Although the stainless steel electric heating pipe has many advantages after being coated with enamel, stainless steel enamel is different from ordinary steel enamel after all. Stainless steel pipes contain high chromium and nickel components, and the surface oxide film is dense. It is far more difficult to form strong adhesion than ordinary steel pipes. This requires annealing and sanding during the pretreatment process. Only after the oxide film on the surface of the stainless steel pipe is sufficiently destroyed can the porcelain layer penetrate into the lattice structure of the steel pipe.
At the same time, the choice of enamel frit is also important. First, we must choose enamel frit with strong adhesion. The simple point is that the selected enamel itself has a strong ability to combine with steel pipes. At the same time, considering the application environment of electric heating pipes is more complicated, so you need to choose an enamel with outstanding acid and alkali resistance. Regarding the selection and specific operation of enamel frit for stainless steel electric heating tube, please contact Hunan Noli Enamel Co., Ltd.