Arcelor recently awarded Danieli an order for substantial revamping of three twin-strand slab casters (CC21, CC22 and CC23) in operation at its Dunkerque facility in France.

Plans for the project call for one caster to be revamped per year in order to minimize the impact on plant productivity. The object of the strategic project is to improve plant performances in terms of both quality and productivity, and to reduce maintenance cost associated with the old designs.

To improve slab quality, particularly internal quality, two of the casters (CC21 and CC23) will be converted from curved to vertical-curved design. The product mix for these two casters will be mainly focused on ultra low carbon grades for automotive applications.

The casters’ containment length will also be increased in order to increase the casting speed. Top feeding dummy bar practice will be introduced, and a fully automatic robot-type segment manipulator will be added for segment replacement; these upgrades will help to achieve a fully segmented design and reduce caster production down times. An advanced low maintenance design will be utilized to help increase caster reliability.

CC22 will be revamped following the same guidelines but keeping a curved design, being its product mix focused on higher alloyed grades.

The first machine to be renewed will be CC23, a 1972 vintage, 12.2-meter radius Demag curved caster. CC23 will be converted into a fully-segmented vertical-curved caster with a vertical length exceeding 2.2 meters, multipoint bending and unbending design and an 8.2 meter main radius.

Danieli’s scope of work mainly includes provision of a Danieli patented INMO mould with integrated hydraulic oscillator (including dedicated automation package and hydraulic unit), as well as "Optimum" segments, specifically designed for the future application of Dynamic Soft Reduction process. Danieli will also provide bananas and segment supporting structures; top feeding dummy bar system; segment manipulator; and relevant maintenance stands. Optimized strand support will be facilitated by Peripheral Drill Rolls (PDR) with multiple span, which will provide proper small roll diameter and pitch.

This project will be implemented in an extremely short period during a blast furnace shutdown scheduled during summer 2007. The project follows similar projects at Posco, South Korea, and ThyssenKrupp Stahl, Germany. It is the third major Danieli order involving slab casters in Arcelor plants, following a new twin-strand slab caster for Sidmar, Belgium, which has been in operation since 2002, and a caster revamp for Acesita, Brazil, at the end of the 1990s.