Hot-rolled high-strength steels with leaner alloying concepts

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Steel remains the dominant engineering material with a world production of more than a billion tones annually to be used in a wide range of applications, e.g. ¾ of all manufactured goods contain steel. Thus, the development of new steel products continues to play an important role in economy and society. Further, new processing routes are being developed to reduce energy consumption and green house gas emissions from steel making. An important technological development in this regard was the introduction of the direct strip production complex (DSPC) for hot rolled steels which is employed by Algoma Steel, the sponsor of this project. A number of technological advances have been made to enable the production of most high strength steel grades in the DSPC. Further modernization of steel design and steel production facilities are critical for steel companies like Algoma to remain competitive. In particular, accelerated cooling has become a key technology to produce thermo-mechanically controlled processed (TMCP) steels with reduced alloying content but the improved mechanical properties required for demanding applications. Using well-designed processing paths rather than alloying additions is an attractive approach to manufacture advanced high-performance steels. The austenite-ferrite transformation takes place during cooling on the runout table and the design of appropriate cooling strategies is critical to obtain fine-grained and/or multi-phase transformation products required in state-of-the-art TMCP steels. Further, coiling of the hot band must be conducted to maximize the precipitation strengthening potential of microalloying elements, e.g. Nb, Ti. Through process modelling for the DSPC is a critical tool for Algoma to optimize the design of robust processing strategies for leaner steel chemistries. This project seeks to develop a DSCP process model for selected steel chemistries using the microstructure engineering approach, i.e. to link the operational process parameters of the DSPC to the hot strip properties by accurately modelling the microstructure evolution. The new model will be validated with industrial data. The project offers training opportunities for four graduate students.