Silicon Carbide Electric Heating Elements | Sic Heaters

The silicon carbide rod utilizes the latest Heating Element technology both domestically and internationally. It can withstand temperatures up to 1625 degrees Celsius, exhibiting high density and low porosity. It effectively resists the erosion of harmful gases, water vapor, and metal oxides, significantly reducing aging speed and prolonging the lifespan. This reduces the frequency of replacements and lowers production costs for users. It is suitable for demanding applications in fields such as glass, electronics, and precious metal materials.

We offer silicon carbide rods in various materials and structures, including hollow tubular, solid rods, and spiral shapes. We can design and produce according to customer requirements. Additionally, we can provide silicon carbide rods with different surface coatings to effectively block harmful gas emissions, such as water vapor, nitrogen, hydrogen, alkaline gases, and metal oxides, depending on the production environment within different furnaces.

Characteristics of Silicon Carbide Rods

1. Silicon Carbide (Sic) Heating Elements are non-metallic High-Temperature electric heating elements made from green, high-purity hexagonal silicon carbide as the main raw material. They are processed into rod shapes through embryo processing, high-temperature siliconization, and recrystallization at temperatures of up to 2200°C. The surface temperature of the rod can reach 1450°C. When the surface temperature exceeds 1500°C, the aging speed of the rod increases, making it prone to burnout. Under proper usage conditions, the silicon carbide rod can be continuously used for over 2000 hours. The lifespan of the silicon carbide rod depends not only on inherent quality differences but also on factors such as the surface load it bears (the higher the surface load, the shorter the lifespan), the atmospheric environment in which it operates, the heating method (intermittent or continuous heating), and the series-parallel connection during its usage.
2. Silicon carbide rods have a hard and brittle texture. They have a low coefficient of expansion and exhibit good resistance to rapid cooling and heating, making them resistant to deformation. They possess excellent chemical stability and are highly resistant to acids, as they do not react with strong acids.
3. The resistance value of silicon carbide rods varies with the temperature of the element because silicon carbide rods are non-linear resistive elements. From room temperature to around 900 degrees Celsius, the resistance value decreases. Above around 900 degrees Celsius, the resistance value of the silicon carbide rod increases. In other words, the resistance value of the silicon carbide rod is minimum at around 900 degrees Celsius. Generally, when we refer to the resistance value of a silicon carbide rod, it is the resistance value at that specific temperature.
4. Molten KOH, NaOH, Na2CO3, and K2CO3 decompose silicon carbide at high temperatures. Silicon carbide rods can be corroded when in contact with alkalis, alkali-earth metals, sulfates, borides, and similar substances. It is strictly prohibited to allow them to come into contact with silicon carbide rods.
5. Silicon carbide reacts with Cl2 at 600°C and reacts with water vapor at 1300-1400°C. Silicon carbide is not oxidized below 1000°C, but significant oxidation occurs at 1350°C. Between 1350°C and 1500°C, a protective SiO2 film forms and adheres to the surface of the silicon carbide rod, preventing further oxidation of SiC.
6. The resistance value of silicon carbide rods increases with usage time. The higher the content of SiO2, the larger the resistance value of the silicon carbide rod. Therefore, it is not advisable to mix new and old silicon carbide rods for use. Otherwise, there will be an imbalance in resistance values, which is highly detrimental to the temperature field and the lifespan of the silicon carbide rods.

Precautions for Using Silicon Carbide

1. Silicon carbide rods should be stored in a dry place to prevent moisture from affecting the aluminum-coated end and compromising its performance and lifespan.
2. Silicon carbide rods are hard and brittle, so special care should be taken during installation, transportation, and maintenance to avoid damage.
3. To ensure uniform load-bearing capacity and furnace temperature, it is necessary to assemble the silicon carbide rods before installation. The resistance deviation of each group of rods should not exceed 10%.
4. The wiring of silicon carbide rods should have close contact with the white aluminum head at the cold end of the rod to prevent sparking.
5. When starting the Electric Furnace and applying power, gradually increase the voltage slowly and avoid applying full load at once. Otherwise, the silicon carbide rods may be damaged due to excessive current.
6. During long-term use, if individual rods are damaged and need to be replaced, select replacement rods with resistance values based on the resistance growth. If multiple rods are damaged or there is a significant increase in resistance, replacing all the silicon carbide rods with new ones is advisable.

Silicon Carbon Rod Inspection Standards

1. The surface of the silicon carbon rod must be free from cracks and adhesive residue, with no significant color difference in appearance. The welded joints of rods with the same diameter should be smooth and have a seamless transition. The welded joints at the thicker end of the rod should be fully filled without any gaps. The surface of the aluminum-sprayed section should be flat, with a uniform and securely bonded aluminum layer.

1. Deviation in shape and dimensions

1. The maximum allowable bending radius is 0.3%.
2. The resistance value of the silicon carbon rod shall comply with the requirements stated in the production plan, with a permissible tolerance of ±20% deviation from the median resistance value.
3. If the user has special requirements, the acceptance shall be based on those requirements.
4. The ratio of resistance per unit length between the heating section and the end section, allowable deviation in surface temperature of the heating section, and any other requirements not explicitly mentioned shall follow the company's standards.

Application

Metal industry

Powder metallurgy sintering

Aluminum alloy dissolution, casting heat preservation, aging treatment

Gas carburizing hardening of automotive, aircraft and mechanical components

Carburizing, nitriding and annealing of steel

Quenching and tempering of various dies and wires

Bright treatment of die steel

Tempering and welding of machine components

Carbon and sulfur analysis

Electronics industry

Firing of ceramic capacitors

Sintering of alumina and talc

Ignition of Piezoelectric Elements

C. Firing of the substrate

Refining of ceramic resistors, varistors and thermistors

Sintering and calcining of ferrites

Annealing heat treatment of plain steel plates, iron, optical fibers, optical discs, etc.

Ceramic industry

Fusion, heat preservation and gradual cooling of glass

Surface treatment of glass

Heat Treatment of Liquid Crystals

Lens processing

Safety glass manufacturing

Firing production of ceramics and glass fibers

Firing of Quartz Raw Materials

Test of various refractory products

Chemical industry

Firing of phosphors and various pigments

combustion of catalyst

Heating of reactive gases

Dry distillation, coking, degreasing

Firing of activated carbon

Purification furnace, deodorization furnace

Others

Various high temperature experimental furnaces

Combustion of gas and kerosene appliances

local heating