Abstract
Based on extensive utilization of traditional improvement techniques of slabbing yield and several newly-developed improvement ones, a record-breaking yield of 96.8% has been achieved for capped steel ingots in Nagoya Works, Nippon Steel Corp.
The new techniques are as follows:
1) Determination of optimum ingot profile to maximize yield such as cross-section dimensions, ingot top-corner profile and top capped figure.
2) Introduction of special rolling precesses of ingot such as one-way rolling and reverse one-way rolling.
3) Development of defect free capped steel ingot making method with bottom pouring technique and defect minimization rolling method.
4) Development of multi-step well type bottom plate to minimize slab crop.
It has been actually proved that these new techniques give a great yield improvement and the cost for adequately compensated by the effects.
