The choice of electric heating wire affects the electric heating elements:
The main components of electricheating elements are insulating magnesium oxide powder, electric heating wire and metal tube. The selection of electric heating wire is a crucial link. There are many kinds of electric heating wire, and its different characteristics determine its application scope. Today, I will introduce the different characteristics of the main electric heating wire used in Yancheng Feiyu electric heating pipe, so as to facilitate customers to understand it The difference of different heating wires.
1. Due to the low strength of Fe Cr Al at high temperature, the components are easy to deform under high temperature. If the wire diameter is not selected properly or the installation is improper, the components will collapse and short circuit due to high temperature deformation. Therefore, the factors must be considered in the design of components.
2. Because of the difference of chemical composition, service temperature, oxidation resistance and resistivity, the service temperature and service life of Fe Cr Al and Ni Cr alloys are determined. Al element determines the resistivity of Fe Cr Al alloy, and Ni element determines the resistivity of Ni Cr Al alloy. At high temperature, the oxide film formed on the surface of alloy components is also aging and destruction. The internal elements of its components are constantly consumed. Such as Al, Ni, etc., so as to shorten the service life. Therefore, when selecting the wire diameter, we should choose the large size wire rod or the thicker flat belt.
3. The oxidation resistance of Fe Cr Al and Ni Cr electric heating alloys is generally strong. However, due to the gas contained in the furnace, such as air, carbon atmosphere, sulfur atmosphere, hydrogen and nitrogen atmosphere, these gases have a certain effect on the components under high temperature Although all kinds of electric heating alloys have been treated with anti-oxidation treatment before leaving the factory, the components will be damaged in transportation, winding and installation to a certain extent, which will reduce the service life and prolong the service life The customer is required to carry out pre oxidation treatment before use. The method is to electrify the installed electric heating alloy elements in dry air to 100-200 degrees below the allowable service temperature of the alloy, keep the temperature for 5-10 hours, and then slowly cool down with the furnace.
4. The service temperature of the element refers to the surface temperature of the element itself in the dry air, not the temperature of the furnace or the object being heated. Generally, the surface temperature is about 100 degrees higher than the furnace temperature. Therefore, considering the above factors When the service temperature exceeds a certain limit, the oxidation capacity of the element itself will be accelerated and the heat resistance will be reduced. In particular, the iron chromium aluminum electric heating alloy element will be easy to deform, collapse, and even fracture, thus shortening the service life.
5. The corrosive atmosphere in the furnace is also related to the service temperature of the components, and the service temperature and service life of the components are often affected by the existence of the corrosive atmosphere.
6. The service temperature of the element is also related to the wire diameter of the element. Generally, the wire diameter of the component should not be less than 3mm, and the thickness of the flat strip should not be less than 2mm.