Companhia Siderúrgica de Tubarão (CST) has continually been carrying out process improvements in order to increase and maintain the slab production to 5 Mt/year. The technology that makes it possible to start the continuous casting using a tundish at cold temperature is one of the developments that will help CST to meet that goal. This paper describes the implementation of the cold tundish at CST, using the approach already adopted at other plants of the Arcelor Group. Through the implementation of the cold tundish process it was possible to reduce not only the time for setting-up the continuous casting machine, but also the gas consumption and the noise at the casting platform, thus improving the operators environment.

The wish to increase the production capacity of the Dunkirk plant has led the steel shop to modify the refractories in order to respond better to these new conditions. The first target is to produce 6.7 Mt of hot metal per year on the three blast furnaces of Dunkirk, and the second, after the relining of blast furnace No. 3 planned in 2004, to produce 6.9 Mt of hot metal, in order to cast more slabs (6.7 Mt of steel). One of the main challenges is to increase the capacity of the steel ladles from 240 to 270 t and, at the same time, to improve reliability. For all these reasons, work for the design of new ladles is really complex and different trials are on the way on wall structure, monolithic bottoms, lip ring, and repairs.

The innovative technological solutions by VAI (VOEST-ALPINE Industrieanlagenbau, Austria), which are presented, allow to obtain substantially improved results for profile and flatness of hot rolled strip. These solutions concern, on the one hand, the design of rolling stands and rolls and, on the other hand, highly modern numerical models for the control of the important parameters.

The efficiency of automatic flatness control systems in tandem cold mills is mainly based on the accuracy of the prediction models and on the selection of optimum control concepts. BFI, together with EKO Stahl, has recently developed and partly applied advanced flatness control strategies (providing online-adaptation of actuator action to thickness profile information and in-gap process condition towards a fully integrated flatness control of all stands) that are superior to conventional techniques and lead to significant improvements in strip flatness. The present article aims to demonstrate the principles, advantages and results of this work.

At the interface between the hot strip mill and the cold plant, the pickling plant is becoming a key point in the production line. The development of new grades and the constant evolution of the order book (warm coiling, direct production of thin gauge strips), most often have productivity and surface quality stakes. All our pickling know-how (kinetics and reactor) has been integrated into a pickling simulation model that makes it possible to assess the potential productivity gains.

Though it is usually neglected, and in spite of its detrimental effects, the expulsion phenomenon is very commonly observed in spot welding practice. Here, it is better emphasized through an experimental study, which brings to light the importance of the expulsion diameter. But some work has still to be done in order to better understand this phenomenon, its triggering mechanisms and its consequences.

Due to their outstanding properties, high strength steels (HSS) are ever more required by the automotive industry. Indeed, high strength steels make it possible to reduce the overall weight of the vehicles. However, manufacturing of industrial parts may be hindered by the higher hardenability of these steels. The laser weldability of different HSS joints and the beneficial effects of on-line pre- and post-heat treatments on the mechanical properties of the welds are presented.

The heavy steel plates (100 - 300 mm) require a good geometric stability during the manufacturing operations by end users. This stability depends on the residual stress state inherited from the manufacturing process. This residual stress state is assessed by an ultrasonic testing method : the acoustical birefringence. The first tests carried out on representative heavy plates allowed to define the most suitable measurement configurations and to identify the residual stress states that could generate shape defects. Then, this method was applied to industrial heavy plates with success.