Abstract
This paper deals with the production of large steel ingots for wire rod and bar. Lately steelmakers attempt to produce larger ingot for productivity, but in this case it is most important to reduce the segregation.
The qualitative problems caused by the segregation are well known as follows;
(1) Fluctuation of mechanical properties.
(2) The troubles at the secondary processing such as the fracture during drawing and cold heading.
(3) The fluctuation of machinability, etc.
The segregation in 3t, 5t, 7t and 10t killed ingots was investigated and the effect of ingot size on the segregation is considerably made clear.
As the representative procedure to reduce the segregation, the optimization of head volume and top discard ratio, the ingot-case designing and the holding time after the pouring are considered.
