What is the approximate temperature when the heating wire is working?

The exact name of the heating wire should be called the resistance wire. It is an alloy made of iron mixed with nickel, chromium, tungsten and other metals. It will generate heat due to resistance when it is energized. The resistance wire basically does not change below 200 degrees Celsius, but it will appear white due to the evaporation of water on the surface. At 200-400 degrees Celsius, the resistance wire will start to turn blue. At 400-700 degrees Celsius, the resistance wire will be slightly black due to surface oxidation, and gradually glow red. At 700-1400 degrees Celsius, the resistance wire will start to glow strongly, and the color will gradually change from dark red to orange and white. Above 1400 degrees, most resistance wires will melt or even burn and evaporate. If it is a tungsten alloy, it can reach about 3000 degrees in the absence of air. At this time, it will emit a hot orange-white light. Above 3000 degrees, only special alloys can be used. Generally no one uses them to make resistance wires.