Abstract
We have tried to apply a pressureless sintered silicon carbide radiant tube to heat treatment in a metal furnace using a high temperature over 1250K. The tube was a 2-meter single-end type radiant tube, where both outer and inner tubes were cantilevered at each flange without any other support. In this study we researched fundamental mechanical and thermal characteristics when using silicon carbide for a radiant tube. Bending strength does not decrease in temperatures less than 1580K, which is about the maximum temperature for a burner head made of metal. The safety factor calculated from the Weibll probability of failure is sufficient for use. We found no problem on either oxidation or thermal shock resistance tests through burning. On a simulation of the radiant-tube furnace, the stress that occurred because of the difference between the temperatures of the upper and lower surfaces was found to be not large enough to cause fractures; this, because of high thermal conductivities. Pressureless sintered silicon carbide radiant tubes have been in use in such industrial furnaces as carburizing furnaces for more than 10 years. The long life of radiant tubes contributes to a low running cost for customers, and has zero emissions. We recognize the practical use for pressureless sintered silicon carbide radiant tubes.
