tube furnace

Our products cover muffle furnace,tube furnace,vacuum furnace,atmosphere furnace,CVD system,dental furnace

How to choose the heating element of the box muffle furnace

The box-type muffle furnace is a cyclic operation type, which is used for heating in laboratories, industrial and mining enterprises, scientific research units for element analysis and determination and general small steel parts quenching, annealing, tempering and other heat treatment. The heating element is an important part of the box muffle furnace. How to choose the heating element? The editor summarizes as follows:.
box furnace
  1. Silicon carbide rods, which are distributed around or around the hearth of the box muffle furnace

  The carbon rod is a rod-shaped non-metal high temperature electric heating element that is made of green silicon carbide material as the main raw material, and is made by light processing, high temperature silicification, and crystallization. Compared with metal electric heating elements, this element has the advantages of high operating temperature, oxidation resistance, corrosion resistance, long life, micro deformation, and convenient installation and maintenance. The silicon carbide rod has a large specific resistance. When heated in the air, the surface temperature of the heating part can reach 1450℃; from room temperature to 800℃, it is a negative value, and above 800℃ is a positive characteristic curve. Silicon carbide has good chemical stability, acid has no effect on it, but alkali and alkaline earth metal oxides have corrosive effect on it under certain temperature conditions. At high temperatures, water vapor, hydrogen, halogen, sulfur, etc. can also oxidize and corrode it.

In order for the furnace temperature and the rod to bear the load uniformly, resistance must be matched before installation to keep the resistance consistent ±10%; during the long-term use of the box muffle furnace, when individual rods are damaged due to other reasons and need to be replaced, it should be based on the increase in resistance at the time In case, choose a rod with a suitable compensation resistance value, and do not replace it with a new rod. If the rods are damaged more or the resistance increases too much, they can be replaced with new rods when the required furnace temperature cannot be reached. Re-measure the resistance value of the replaced rod and match it to the low temperature zone.

  2. Silicon molybdenum rods, which are distributed around the hearth of the box muffle furnace

  The silicon molybdenum rod heating element is a resistance heating element based on molybdenum silicide. The sintered molybdenum silicide product is heated to a high temperature in an oxidizing atmosphere, and a dense quartz glass film is formed on its surface, which can keep the product from being oxidized. Therefore, silicon molybdenum rod components have unique high temperature oxidation resistance. The maximum operating temperature is 1750℃ in an oxidizing atmosphere. The resistance of the silicon molybdenum rod element does not change with the length of time of use (the resistance increases with the increase of temperature), that is, it does not age, so the new and old elements can be mixed. The mechanical system of silicon molybdenum rod components is the same as other ceramic products. It is a brittle material that is easy to break at room temperature, but it can be avoided with proper use and reasonable installation.

  The heating elements commonly used in box muffle furnaces are silicon carbide rods and silicon molybdenum rods. Which heating element to choose can be selected according to the actual situation!

Please Leave A Message