The metallurgical characteristics of RH vacuum circulation treatment are the circulation degassing of molten steel under vacuum. The RH device works under high temperature and vacuum conditions. The middle and lower linings of the vacuum tank and the castables are subjected to the splashing and scouring of molten steel and the circulation, and the damage is relatively serious. The lining and inner wall of the immersion tube are subjected to the scouring of high-speed airflow and molten steel, and the outer wall is eroded by slag and the effects of rapid cooling and heating, which are prone to thermal spalling, and mechanical damage will also be caused during slag cleaning. The working conditions of RH refractory materials are very harsh.
The refractory bricks materials for the lining of RH vacuum treatment furnaces must have the following characteristics
① Good volume stability under vacuum conditions;
② Sufficient high temperature strength, high-speed scouring of high-temperature molten steel
③ Excellent slag erosion resistance;
④ Good thermal shock stability against rapid cooling and heating;
⑤ High thermal shock resistance and high corrosion resistance during oxygen blowing treatment.
What refractory bricks are used for RH vacuum treatment lining?
① Directly bonded magnesia-chrome bricks are made of high-purity magnesia sand and high-quality chrome ore as raw materials, with reasonable particle size ratio, formed under high pressure and fired at high temperature. Magnesia-chrome bricks are directly bonded between periclase and periclase, periclase and spinel in the brick aggregate. Refractory castables Directly bonded magnesia-chrome bricks have good volume stability at high temperatures, good slag resistance, high high-temperature strength, and low sensitivity to thermal shock.
② Pre-synthesized direct-bonded magnesia-chrome refractory bricks are easy to sinter, reduce firing temperature, and improve high-temperature mechanical properties of bricks. The production method of pre-synthesized magnesia-chrome sand as fine powder is used to make bricks. The raw materials of this brick are pre-synthesized, then formed under high pressure and fired at high temperature. The finished product is inspected by ultrasonic non-destructive flaw detector. Wear-resistant castables This brick has good thermal shock resistance and strong slag corrosion resistance.
