The maximum operating temperature of the electric heating alloy refers to the maximum temperature that the surface of the electric heating element is allowed to reach in dry air. When the heating element is heated in an open state, the surface temperature of the heating element is about 50~100℃ higher than the furnace temperature. When heating in a closed state, the surface temperature of the electric heating element is about 100~150℃ higher than the furnace temperature.
According to the maximum use temperature, the electric heating alloy can be divided into four grades: ultra-high temperature electric heating alloy, high temperature electric heating alloy, medium temperature electric heating alloy, and low temperature electric heating alloy.
1. Ultra-high temperature electric heating alloy
The service temperature of ultra-high temperature electric heating alloy is 1400℃. It is used to manufacture electric heating elements for heating furnaces with a working temperature of 1200~1300℃. The chemical composition of the alloy all belong to the iron-chromium-aluminum series. In order to ensure the performance of the alloy at high temperatures, this combination of gold contains high chromium and aluminum. Among them, chromium is 22%-28%, aluminum is 6%-8%, and also contains a small amount of cobalt, molybdenum, niobium, titanium and trace elements such as yttrium, lanthanum, and cerium. This combination of gold includes steel billets manufactured by powder metallurgy, processed and manufactured electric heating alloy wires, and strips.
Ultra-high temperature electric heating alloys are mainly used for electric heating elements in single crystal diffusion furnaces, powder metallurgy products sintering furnaces, ceramic calcining furnaces, and high-temperature heat treatment furnaces whose working temperature is 1200~1300℃.
The electric heating alloy grades belonging to the ultra-high temperature grade are: 0Cr26Al7.5; 0Cr27Al7Mo2, 0Cr24Al6R, 0Cr22Al6CoRe and 0Cr22Al5.8, 0Cr23Al6 refined by powder metallurgy.
2. High temperature grade electric heating alloy
The use temperature of high temperature electric heating alloy is 1300℃, mainly used for manufacturing temperature of 1100~1200℃
Electric heating elements for heating furnaces. This group of electric heating alloys also belong to the iron-chromium-aluminum series. The content of chromium and aluminum in this combination gold is slightly lower than that of super high-grade alloys. It contains 22%-25% chromium and 4%-6% aluminum. It also contains a small amount of molybdenum, niobium, cobalt, titanium and rare earth elements.
High-temperature grade electric heating alloys are mainly used to manufacture electric heating elements for heat treatment furnaces such as quenching, normalizing, annealing, and solution treatment, and electric heating elements for melting furnaces of copper, aluminum and their alloys.
The grades of high-temperature electric heating alloys are 0Cr25Al5, 0Cr21Al6Nb, 0Cr23Al6, etc.
3. Medium temperature electric heating alloy
The medium temperature grade electric heating alloy uses a temperature of 1100℃, and is mainly used to manufacture electric heating elements for heating furnaces with a working temperature of 850~950℃, such as high temperature tempering furnaces, aluminum melting furnaces and household appliances. This group of electric heating alloys has relatively good plasticity and can be processed into electric heating elements with complex shapes at room temperature. The electric heating alloy grades belonging to this category are: nickel-chromium alloy Cr30Ni70; Cr20Ni80, iron-chromium-aluminum alloy 0Cr23Al5, 0Cr20Al3, 0Cr19Al5, 0Cr21Al6, etc.
4. Low temperature grade electric heating alloy
The operating temperature of low-temperature electric heating alloy is below 950℃. It is mainly used to manufacture electric heating elements for heating furnaces whose working temperature is below 800~750℃, such as low-temperature tempering furnaces, drying furnaces and household appliances. Electrical heating alloys belonging to this category include: Cr15Ni60, Cr20Ni35, Cr20Ni25 alloys in the nickel-chromium series and 1Cr13Al4, 0Cr19Al3 in the iron-chromium-aluminum series alloys.
The above grouping of electric heating alloys is based on the temperature when used under atmospheric conditions. If the working environment medium of the heating element changes, its use temperature should be adjusted accordingly.
