INFLUENCES OF PREHEATING TEMPERATURE ON CERAMIC-LINED PIPES BY GRAVITATIONAL-THERMIT SHS METHOD

The ceramic-lined pipes had been produced by gravitational-thermit SHS method. The influences of preheating temperature on SHS reaction and quality of ceramic surface had been investigated. It was found that preheating powder and pipes benefited the SHS reaction and the quality of ceramic lined pipes. When preheating temperatur was too low, the ceramic surface was knotty and had a lot of pores, and the machnical properties of ceramic lined pipes were poor. When the preheating temperature was too high, the SHS reaction velocity was slow for the breakdown of CrO₃ additive. Meanwhile, the unncessary melted iron and ceramic solidified in the pipes in stead of flowing out. The quality of ceramic lined pipes was the best when the powder heaed at 120℃ for 4h.