A NEW grade of silicon carbide heating element has been launched by furnace heating specialist Kanthal AB.
Called Kanthal Globar SD, the new element has high mechanical strength, a lower rate of reaction with the process atmosphere, longer life potential, and has been designed for maximum performance in the widest range of high temperature applications.
Combining the best features of the existing Kanthal Hot Rod, Silit ED and Globar LL products, Globar SD is a more versatile, high quality element offering repeatable and reliable performance.
Globar SD elements are extruded from a controlled blend of high purity, alpha silicon carbide grain, which is then recrystallised at over 2500ºC to form a strong, self-bonded structure, with uniform heating charactistics.
Manufactured in a one-piece or three-piece construction, depending on the application, and in a range of sizes, Globar SD elements can be supplied as straight rods or as multi-leg elements.
Special glazes and coatings are available for added protection in aggressive furnace atmospheres.
Porosity and average grain size are the two main features that determine the life and performance of recrystallised silicon carbide heating elements.
The Globar SD elements are less porous than other Kanthal elements and have a relatively large grain size. These features reduce the total surface area of silicon carbide that is exposed to the furnace atmosphere, and this reduces the rate of resistance increase over time.
The rate of resistance increase is the most convenient measure of element performance since it determines the theoretical life that can be achieved.
Globar SD elements have demonstrated high performance in laboratory tests and rates of resistance increase are much lower than those of Kanthal's existing range of recrystallised elements.
This extensive laboratory testing programme has been supplemented by field trials. Over 2,000 Globar SD elements have been installed in furnaces throughout Europe, Africa and Asia and have performed well in a variety of applications.
Globar SD elements are available in a range of sizes and resistance values designed directly to replace all types of silicon carbide element.