Talking about the decarburization form of the wrong carbon material in molten steel

Carbonaceous materials play a crucial role in carbon composite refractory materials, particularly in resisting slag erosion and thermal shock. However, decarburization of these materials at high temperatures is unavoidable. In addition to oxidation, there are two main mechanisms of decarburization: dissolution and reaction-based decarburization, both influenced by the interaction with molten steel.

When carbon components in the material come into direct contact with molten steel, they can dissolve into it. At the same time, oxidative reactions at high temperatures may occur between the carbon in the material—such as graphite, ceramic fibers, or carbon black—and the molten steel. These reactions can lead to the formation of a carbonized layer that has good wettability with the molten steel, promoting its penetration into the material. As a result, the molten steel dissolves carbon and forms a decarburized layer on the surface of the material.

The second form of decarburization is reaction-based decarburization. This occurs when molten steel and its inclusions penetrate deeply into the material, allowing carbon to react with oxides present in the steel. This reaction leads to the formation of a decarburized layer, further weakening the structural integrity of the material.

The purity of the carbonaceous raw materials also significantly affects the material's resistance to erosion. For instance, if graphite is used as the primary carbon source, impurities such as ash containing flame retardants like Al₂O₃ may interact with calcium oxide or magnesium oxide, leading to oxidative instability. This can cause the formation of a monoclinic phase, resulting in volume expansion and structural degradation. Therefore, using high-purity graphite as a feedstock helps minimize the negative effects of such impurities, improving the stability of the material under oxidative conditions.

In summary, understanding the mechanisms of decarburization and selecting appropriate high-purity carbon sources are essential for enhancing the performance and durability of carbon composite refractory materials in high-temperature environments.