Papers by Keyword: Thin Slab Direct Rolling

Abstract: Thermomechanical processing is a well-defined route to achieve adequate combinations of strength/toughness for a wide range of applications. Inside this family, that based on accumulated strain in austenite followed by proper accelerated cooling strategies is probably one of the most selected. Usually this has been achieved with steels with Nb additions and other microalloying combinations. Recently, it has been observed an increase in the relevance of Ti as microalloying element. In addition to the classical approaches based on its availability to avoid grain growth, Ti provides, mainly in near-net-shape technologies, additional possibilities in relation to austenite conditioning and precipitation hardening. Multiple factors intervene simultaneously (solidification rates, Ti amount, Ti/N ratio, interaction with Nb...) leading nowadays, to important difficulties to properly predict its behavior. This manuscript focuses on some of these issues.

Abstract: The microstructural heterogeneities in steels may have different origins. The tendency in industry to decrease the total amount of reduction during hot working decreases the possibilities of applying approaches based on “thermo-mechanical homogenization”. In this situation, alternative approaches need to be evaluated to reduce the heterogeneities present in the initial microstructure and, simultaneously, to avoid the possibility of inducing additional heterogeneities during processing. This paper analyzes the relevance of several processing parameters in different cases.

Abstract: The microstructural evolution during the hot rolling of coarse grain sized austenite has been modeled taking into consideration all the microstructural mechanisms (dynamic, static and metadynamic recrystallization, strain induced precipitation) that could take place during the industrial TSDR production of a Nb microalloyed steel. Based on the results obtained from the model, processing maps have been drawn for a 0.035%Nb microalloyed steel. Optimum processing conditions to exploit all the benefits of Nb microalloying have been defined considering a final gauge thickness range between 1.5 and 12.65 mm.

Abstract: Thin slab direct rolling (TSDR) of microalloyed steels belongs to a new generation of thermomechanical treatments. TSDR shows some metallurgical peculiarities that significantly differentiate this process from the traditional route. This paper reviews some of these singularities, considering in a more detail those processing aspects which need to be optimized in order to obtain final homogeneous microstructures that bring about the strength and toughness levels required for specific applications.