Results of industrial converter operation have been analyzed withseveral approaches, based on statistics or on the kinetics of thevarious reactions. Cogent results have also been obtained throughthe follow up of gas emissions. The kinetics models that have beendeveloped constitute a significant contribution to the implementationof new strategies for converter operation.

To meet the demand for Interstitial Free and Bake Hardening steelgrades for the automotive industry, CST has developed a productionprocess for steels with ultra low carbon (<20 ppm), and low nitrogen(<30 ppm) levels, along with a narrow range of carbon content. Thenew process also ensures a high degree of cleanliness of the CCslabs.

Hot tearing close to the solidus temperature occurs in continuouscasting of steels. Four hot tearing criteria from the literature are reviewedand assessed against laboratory tests. Based on a critical straincriterion, an accumulated strain approach is introduced and criticalvalues are determined by laboratory experiments.

New dynamic features of the descaling process are reported, referringto the continuous water jet formed by the descaling nozzle in particular.A water jet is formed by clusters of droplets moving at highvelocity. In the impact area, pressure peaks of several hundred MPa,lasting microseconds per peak are observed: this is described as the“water hammer” effect. This finding modifies most existing conceptsof descaling and the impact on current theory is discussed.

Two innovative processes have been developed in order to produceultra fine grained steel at the hot strip mill. One is based on highspeed, large reduction forging, the other on combined rolling/bendingstrain accumulation. Both processes afford drastic reductionsof the strip ferrite grain-size.

Crystallographic textures of hot rolled microalloyed steel strips fromthe thin slab direct rolling AST process is determined by EBSD. Theeffect of the thermomechanical treatment on the strip texture is analyzed,pointing out a significant through thickness gradient.

Fatigue crack propagation in a welded joint of a cablecar post hasbeen developed, based on parameters measured on real joints. Itmakes it possible to optimise the schedule for inspection of theposts.