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This paper presents the results of the work carried out by the Department for Metal Working Processes at NUST for production technology of: high-strength automotive flat stock from bi-phase ferrite martensite steels (BPHFMS) on a broad-strip hot-rolling mill by staged laminar cooling on a runoff table, as well as K52–56 strength grade cold- and corrosion-resistant tubular strip bar. The metal’s ferrite grains rolled on the broad-strip mill are ground by combining the controlled rolling (CR) of strips with their rapid cooling (RCL). Thermal kinetic diagrams (TKDs) were created to show modeling sheet cooling, as well as to predict the resulting structure type depending on the metal cooling rate.

The goal is to produce hot-rolled dual-phase steel of strength class DP 450–600 at OAO Novolipetskii Metallurgicheskii Kombinat (NLMK). The steel’s final structure and properties is greatly affected by single-stage strip cooling on the output roller conveyer of the 2000 continuous broad-strip mill. The influence of the hot-rolling parameters on the structure and mechanical properties of the hot-rolled SPRC440R steel from which cold-rolled dual-phase steel is produced at OAO NLMK is studied in the laboratory. The temperatures and rates for accelerated cooling on the output roller conveyer of the 2000 continuous broad-strip mill at OAO NLMK are calculated by means of a mathematical model. The laboratory data and simulation results are used in developing trial conditions for industrial rolling. Recommendations are made regarding the production of hot-rolled dual-phase steel corresponding to strength class DP 450–600.

The step-by-step development in the production of HDT580X hot-rolled dual-phase steel (according to the EN 10338 standard) by means of the 2000 broad-strip hot-rolling mill at OAO Novolipetskii Metallurgicheskii Kombinat is considered. The analysis is based on theoretical and experimental results regarding topics such as the influence of alloying elements and the cooling parameters on structural and phase transformations in dual-phase steel for the auto industry. Physical modeling of the deformational parameters and the rolling and cooling temperatures and speeds on the broad-strip mill also proves helpful. Rolling and cooling rates are proposed for the 140 FGA semicontinuous hot-rolling mill.