Abstract
Segregation in steel ingots cause the degradation of mechanical and chemical properties. We have experimented on segregation and solidification of the large steel ingots (24-39T) and obtained the results as follows:
1. The solidification pattern in the large flat steel ingots is proportional to the square root of timeafter teeming in the first stage solidification and the square of it with the formation of sedimental crystals.
2. By scraping the liquid steel in a mold, the inverse V segregation disappears in the near surface of ingot top, but it remains in the ingot bottom. Further, the inverse V segregation lines become thin and shift to the inner parts of the ingot and the floating velocity of the rich liquid steel quickly increases.
3. The formation of the inverse V segregation is closely related with the solidification velocity and the critical solidification velocity of the formation of the inverse V segregation becomes small byscraping the liquid steel in a mold.
4. By R. E. M. addition to the liquid steel in a ladle, the inverse V segregation lines in sulfurprint become the white segregation and also the large inclusion is insignificant. Judging from these results, we could confirm the effectiveness of the method of R. E. M. addition to the liquid steel in a mold (BCCTMethod).
