Some aspects in the production of microalloyed steels

Continuous casting has been a primary process innovation in the steel industry from the 60's to the 80's of the last century. This technology led to dramatic improvements in the productivity of the steelmaking process and in the quality of products. However, for keeping steel materials competitive and cost effective, an all-embracing approach of the steel making process is required. The whole manufacturing path from hot metal and/or melting through refining to casting through to the rolling and finishing has to be put under integrated control. In regard to continuous casting, two examples of this trend are: improvements in tundish design and metallurgy, optimized submerged nozzles and high performance mold level control. The neverending search for clean steel has shifted from the caster itself to ladle metallurgy. In the same way, the search for a defect-free surface is not simply focused on continuous casting technology, but also takes steel making into account. With structural steel grades changing alloy design from plain medium carbon-manganese to cracksensitive low carbon micro-alloyed HSLA modern steel, continuous caster design and technology stayed abreast of changes. However, it remains the foremost responsibility of steel plant operations and operation's maintenance to keep the equipment in excellent condition to produce defect free quality slabs. (AU) OBS. © TMS