What are the casting methods of steel ingots (casting process of smelting steel ingots)

1, ordinary ingot method The method of pouring molten steel into ingot mould in the atmosphere to make it solidify slowly is called ordinary ingot method. It is divided into up-bet method and bet method. Large ingot casting method is widely used. Thyssen-Henrik Metallurgical Company of Germany successfully cast a steel ingot weighing 435t by betting method.

2. The upward spraying method is easy to cause surface blowholes due to molten steel splashing. Compared with casting method, the surface of ingot is uneven. In order to prevent the secondary oxidation of molten steel during casting, emotional gas protection is adopted. Vacuum pouring method is a method of pouring molten steel in ladle into ingot mould placed in vacuum chamber through tundish, which is called vacuum pouring method. The degassing equipment is the same as the above trickle removal method.

3. This method is widely used to produce large steel ingots to remove hydrogen. Compared with the normal ingot casting method, it not only avoids the secondary oxidation of molten steel, but also reduces the non-metallic inclusions in molten steel.

4. At the same time, the carbon-oxygen reaction in high vacuum can be used to control the vacuum carbon deoxidation, which is especially important for the ingot casting of large steel ingots with low silicon NiCr-M6, NiCrMoV and other steels or ultra-pure steel. It not only reduces the content of steel and improves the purity of steel, but also significantly improves the segregation of ingot and greatly improves the internal quality of ingot. The geometric shape and size of ingot mold directly affect the crystallization process and quality of ingot. The geometry and size of the ingot mould depend on the number of bottom angles, the taper of the ingot and the ratio of height to diameter.

5. The edges and corners of large steel ingot are 8. 16.24, 32 edges. The shuttle angle of multi-edge spindle is blunt, with less segregation, and the angular deviation bridge is dispersed because of many edges. Increasing the number of edges and corners means increasing the number of ingot curved surfaces, so that it can have greater buffering and landing during solidification, thus giving the trend of crack formation. Therefore, 24-sided or 32-sided ingots are often used. As for ordinary steel ingots, each factory determines them according to the situation of classic bodies. China No.1 Heavy Machinery Group Co., Ltd. has 8 edges for ingots below 85t, and 24 edges for large ingots above 85t.

6. People realize through production practice that scientifically and reasonably determining the taper and height-diameter ratio of steel ingot can make inclusions float up easily and gas escape easily; It can fully realize the orderly solidification of ingot from bottom to top, which is beneficial to feeding and reducing the density of powder thinning and dancing center; Stress can be reduced and cracks on the surface of the ingot can be prevented. The size of the riser is determined scientifically and reasonably. M Buddha fills the shrinkage cavity of the spindle and concentrates the most serious shrinkage cavity and air hole in the riser, thus ensuring the quality of the spindle. The shape and geometric size of billet determined before are the result of continuous improvement with the deepening of the above understanding on the basis of a large number of production practices. In recent 20 years, due to the development of solidification theory and computer technology, it has been gradually applied to the research of large steel ingots. Using the simulation study of temperature field calculation, there have been many successful examples abroad to predict the internal porosity of ingot.