Contributions of metallurgical research to the improvement of quality

Objective. Research and development must be included as a continuous improvement process among the measures for promoting quality. increased process reliability, changes in process and plant engineering, new measurement and monitoring techniques, and the introduction of new process lines are R&D's contributions towards the betterment of quality. Current examples from the "ladle metallurgy-continuous casting" steelmaking chain serve to demonstrate the necessity for research effort and expenditure. Summary. Increased process reliability is achievable through process-related optimisation in ladle metallurgy, e.g. optimised stirring strategies for alloying and for soft-bubbling to improve cleanness, and through knowledge of the transition phenomena in sequence casting. The possible effects of casting disturbances on quality have to be known. Changes to the metallurgical process engineering in the tundish and mould can improve the steel cleanness. In the secondary cooling zone, a cooling strategy adapted to the high-temperature properties of the steel avoids surface cracking. New measuring techniques to determine the flow characteristics and inclusion content of melts permit direct operator intervention in the process to avoid impairment of quality. An outstanding example, where highest quality demands are involved, of a plant engineering change influencing quality improvement is the conversion of curved-mould casters to vertical-bending casters for continuous slab casting. A new process line also with a great potential for further quality improvements is emerging in the twin-roller casting of stainless steel strips.