1958 Volume 44 Issue 6 Pages 650-656
The authors investigated the relations between variations of chemical elements and gases in molten steel near the solid during solidification process and contents of chemical elements and gases in the same position after the solidification of the ingot (12 ton ingot), and the occurrence of various defects.
The results obtained were as follows:
i) Even in case of such molten steel as most unlikely to incur defects at the time of immediately before casting, the process concentration into the liquid phase along with the progress of solidification enhanced remarkably the possiblity of blowholes and deoxidation products to appear.
ii) Such being the circumstances, the molten steel near the solidus-liquidus border line was in such a condition that the percentage of probability for various defects to appear was rather high, and even a slight difference in the conditions of solidification was most likely to result in the occurrence of such defects in ingots.
iii) The concentration of each chemical element into the liquid phase was mostly at equal ratio to a theoretical quantity if positions in the tested ingot were fixed, and in the case of a 12 tons ingot it was regarded as 10-30% at a lower half of the ingot.
iv) It was possible to account for the negative segregation which arose in the lower part of the ingot by means of the difference in concentration which took place in case the solid phase and liquid co-existed.
