Iron-chromium-aluminum and nickel-chromium electrothermal alloys generally have strong oxidation resistance, but because the furnace contains various gases, such as air, carbon atmosphere, sulfur atmosphere, hydrogen, nitrogen atmosphere, etc. All have a certain impact. Although all kinds of electrothermal alloys have been subjected to anti-oxidation treatment before leaving the factory, they will cause damage to the components to a certain extent in the links of transportation, winding, and installation, which will reduce the service life. In order to prolong the service life , the customer is required to carry out pre-oxidation treatment before use. The method is to heat the installed electric heating alloy element in dry air to 100-200 degrees below the maximum allowable temperature of the alloy, keep it warm for 5-10 hours, and then Allow the oven to cool slowly.