Effect of the Parameters of the Technology Used to Make Multiphase Automotive Sheet Steels on the Degree of Assimilation of the Alloying Components

Abstract

The effect of process parameters in the production of progressive multiphase automobile steels on the assimilation of the elements used for alloying and microalloying is examined in order to develop an efficient steelmaking technology for this purpose, Data from the production and ladle treatment of 96 experimental heats of steels that are similar to these steels in chemical composition is statistically analyzed to improve these elements' assimilation by optimizing the regimes used for the addition of ferroalloys and other materials at different stages of the steels' treatment. It is established that the assimilation coefficients for Mn, Cr, Nb, V, and Si (to a lesser extent) are nearly independent of the timing and volume of the in-treatment additions of materials that contain these elements. On the other hand, the efficiency of the assimilation of Al and Ti depend to an appreciable extent on the type of material used and the treatment stage in which it is added. The results that are obtained are used to formulate a new approach to optimizing the addition of materials during the production of two-phase ferritic/martensitic steels of the HCT980X type. The adequacy of this approach was demonstrated by a trial heat that was made of this type of steel.