The content of silicon dioxide in light-burned magnesium balls should be controlled to a certain percentage. If the silicon content exceeds the standard, the plasticity and toughness of steel will be significantly reduced. Silicon can reduce the density, thermal conductivity, and electrical conductivity of steel. Can promote the coarsening of ferrite grains and reduce the coercive force. Silicon can promote columnar crystal growth in cast steel and reduce plasticity. Silicon can reduce the welding performance of steel. Because silicon is stronger than iron in binding ability with oxygen, it is easy to generate low melting point silicate during welding, which increases the fluidity of molten slag and molten l, causing spattering and affecting welding quality. Therefore, the content of silicon must be strictly controlled in light-burned magnesium balls to avoid being brought in as raw materials during steelmaking.