Research Of Large Ingot Slab For Heavy Plate And Relative Technology In Baosteel

As the product constitution of Baosteel is renovated, the blooms of Baosteel is no longer supplied for rolling thin sheets, but for rolling heavy plates such as die steel, ship plate and so forth. Although heavy plates are the high-additional-value products of Baosteel, they are still produced using an old type of ingot BF28 that was introduced from Japan in 1980's. This type of ingot is composed of small top/large bottom, due to which it is easy to form central porosity, solute segregation and double shrinkages in the ingot. Therefore, the quality of the ingot is degraded, and the competitive power of the heavy plate is weakened.According to the existing technical and equipped conditions of Baosteel, a new type of ingot BV30 with large top/small bottom has been developed. The solidification process of the new ingot and the heating and cooling process of the ingot mould were computer simulated using a finite difference method. Site examination and subsequent analyses indicated that the new ingot has a reasonable configuration. Consequently, there is no secondary shrinkage to occur, and the solute segregation and central porosity are significantly depressed (especially the level of carbon segregation is reduced by 70%). Meanwhile the ultrasonic test quality is greatly improved. The new ingot can be used as the current bloom, and can also meet the requirement of the coming 5000-mm wide-heavy-plate rolling mill.