Characteristics of different materials of refractory slide gate

The refractory slide gate is the refractory part of the ladle sliding mechanism in continuous casting production. Since the refractory slide gate is repeatedly subjected to erosion, chemical erosion, and strong thermal shock by molten steel during use, in order to meet the precise flow control function, the slide must have excellent characteristics such as high-temperature resistance, high strength, good erosion resistance, good thermal shock resistance, high oxidation resistance, and low creep. Refractory slides of different materials have different advantages and disadvantages.

Advantages and disadvantages of different materials of refractory slide gate plate

High aluminum refractory slide gate

Poor corrosion resistance, serious corrosion on the sliding surface, and casting mouth. Poor thermal shock stability, easy to crack during use.

Aluminum carbon sliding gate systems

Aluminum carbon skateboards have gone through unfired aluminum carbon and fired aluminum carbon. In order to improve the corrosion resistance and thermal shock stability of unfired aluminum carbon skateboards, synthetic mullite, andalusite, and silicon carbide materials are added to the granular material, and corundum and silicon carbide are added to the matrix.

However, during the use of this material skateboard, problems such as low hot strength, severe wear of the sliding surface, and poor crack resistance gradually appeared. The disadvantages of fired aluminum carbon bricks are that the thermal shock resistance is low, it cannot be used continuously many times, the carbon is easily oxidized during use, and the corrosion resistance is low.

Aluminum zirconium carbon ladle sliding gate

Aluminum-zirconium carbon refractory slide gates are developed on the basis of fired aluminum-carbon skateboards. This material skateboard uses low-expansion Al2O3-SiO2-ZrO2 raw materials to make refractory materials with baddeleyite, mullite, corundum, dan lain-lain. as the main crystal phase and carbon bonding as the characteristic. Aluminum-carbon skateboards have quite good performance and applicability, but cracking and sliding surface wear during repeated use is the key to restricting their life.

Carbon-bonded aluminum-carbon and aluminum-zirconium carbon skateboards are currently widely used skateboard materials in domestic and foreign steel mills, but these two skateboards have poor resistance to calcium erosion when casting calcium-treated steel, and are not suitable for casting calcium-treated steel, Al/Si killed steel and other steel grades.

Magnesium carbon and spinel carbon slide gate plates

Magnesium slide plates were first used in Europe because magnesium oxide has good resistance to mechanical stress and chemical erosion, which to a certain extent meets the requirements of casting calcium-treated steel and high-oxygen steel. However, magnesium oxide slide plates have a large thermal expansion coefficient, which is prone to thermal spalling when casting steel, and there is still room for improvement in thermal shock resistance.

Spinel carbon slide plates are refractory materials that use magnesium aluminum spinel as the main crystal phase and are characterized by a composite combination of ceramic and carbon. The thermal expansion coefficient and elastic modulus of magnesium aluminum spinel materials are smaller than those of magnesium oxide, and the thermal shock resistance is stronger than that of magnesium oxide. However, spinel materials react slowly with calcium in steel to produce low-melting products, which affects their service life.

Zirconia slide gate plates

The hot-pressed zirconia slide plate has the characteristics of high-temperature strength, low apparent porosity, small pore diameter, dan lain-lain., and has good resistance to molten steel corrosion when used on the tundish. Zirconia material has good high-temperature performance, but due to its cost and other reasons, the industry generally uses zirconia rings embedded around the casting holes of aluminum-carbon slide plates to make composite slide plates.