3<sup>rd</sup> Generation AHSS by Thin Slab Technology

Abstract

Modern steel making and hot rolling processes like CSP® thin slab technology require precise data on casting and rolling behavior of the produced steel grades. Up today only few data is available for the latest generations of advanced high strength steel (AHSS) grades. AHSS have developed by 3 generations [1, 2]. 1st Generation AHSS as dual phase (DP), complex phase (CP), martensitic (MS) and transformation induced plasticity (TRIP) steel grades are currently applied in automotive industry. 2nd and 3rd Generation AHSS typically have elevated Mn-content as well as Al and Si content. High Mn-content of up to 30% seriously affects casting and forming properties of 2nd Generation AHSS. In particular, the large solidification range of more than 100 K prevents commercial production of these steel grades by continuous casting [3]. 3rd Generation AHSS with reduced Mn-content up to about 12% are currently under development [1-4]. Investigations have been carried out to assess the CSP® thin slab process for the production of such grades. To this purpose solidification and hot forming properties of different alloys having Mn-content up to 10% have been examined by thermodynamic calculations and laboratory testing by hot forming dilatometry. The achieved flow curves match figures achieved on a hot rolling mill.