Box-type resistance furnaces are also known as muffle furnaces, resistance furnaces, high-temperature furnaces, etc. They are generally categorized into low-temperature, medium-temperature, and high-temperature based on different design temperatures. Typically, medium-temperature muffle furnaces refer to equipment with a temperature range between 1000°C and 1400°C. The heating elements used in such equipment are generally silicon carbide rods.
I. Introduction to Silicon Carbide Rods
Silicon carbide rods are formed by high-temperature sintering using high-purity silicon carbide as the raw material. The operating temperature of silicon carbide rods is generally not higher than 1400°C, with a continuous service life of up to 2000 hours. As non-metallic heating elements, silicon carbide rods offer advantages such as high operating temperature, oxidation resistance, corrosion resistance, and long service life.
II. Technical Specifications of Silicon Carbide Rods
Silicon carbide rods are classified by shape into straight rods, U-shaped rods, L-shaped rods, large-end rods, etc.
The structure of a silicon carbide rod consists of a hot end and a cold end. The hot end is the heating section, while the cold end is the terminal for wiring and clamping.

III. Confirming Technical Specifications of Silicon Carbide Rods
Common parameters of silicon carbide rods include shape, hot end length, cold end length, rod diameter, resistance value, etc.
IV. Maintenance of Silicon Carbide Rods
1. Inspect the rod surface for cracks or sintering slag.
2. Measure the resistance value of each set of rods to assess their condition.
3. Check whether the wiring and clamping at the cold end are secure.
V. Replacing Silicon Carbide Rods
As silicon carbide rods age, their resistance value changes. It is generally recommended to replace all rods at once to ensure resistance matching. Avoid mixing new and old rods.
Selection principles:
1. Consistent specifications and dimensions.
2. Matched resistance values.
3. Complete replacement or substitution with old rods.
VI. Lifespan of Silicon Carbide Rods
With prolonged use, the resistance value of silicon carbide rods increases, leading to reduced heating current and lower heating efficiency. At this point, the rods need to be replaced.