Thermo-mechanisch hergestelltes, mehrphasiges Kugelgraphitgusseisen

点击翻译按钮获取中文摘要

In this project, a new processing method is proposed to investigate the possibility to improve the strength and elongation of ductile iron (DI) by grain refinement of parent austenite using multipass deformation before slow cooling in the two phase ferrite+austenite region to various quenching temperatures (TQ). The aim is to obtain different ferrite to austenite ratios. The material is subsequently to be quenched from the two phase region either to room temperature, to obtain a martensite + ferrite matrix, or to austempering temperature to obtain a ferrite + ausferrite + retained austenite matrix. In one process-chain, the suggested processing method combines two processes reported to improve the excellent combination and range of mechanical properties of ductile irons namely, thermomechanical processing and production of dual matrix structure (DMS). Such a processing-method would find its application in the wide-spread field of hot strip rolling mills, using controlled rolling and cooling technologies. Application of this technology helps to manage the kinetics of various metallurgical processes, like austenite formation, recrystallization and austenite decomposition behaviours. Multiphase steels such as hot rolled dual phase steel (DP-steel), TRIPsteel and complex phase steel (CP-steel) are examples of products from such rolling mills. It is planned to transfer the preceding technology, already used for steel, to produce multi-phase flat rolled ductile-iron for the use in applications requiring high toughness, particularly for automotive industry.