Processing and thermal treatment of oxide inclusion containing carbon steels

Controlling the composition, size and microstructure of oxide inclusions, whose presence is practically unavoidable in steels, is a major goal within the steelmaking industry. It is well known that the amount and type of non-metallic inclusions have a direct influence on the physical and mechanical properties of steel properties like strength, fatigue, ductile-brittle fracture, welding, machinability and corrosion resistance to name a few. Generally, after deoxidation there are myriad numbers of small oxides in the steel acting as local oxygen-rich carrier phases. To understand the influence of such inclusions on the final properties of steel, it is fundamental to assess their local mechanical properties, as well as those of their inclusion/matrix interfaces. To such end, the first step is to obtain reproducible microstructures containing oxide inclusions of defined compositions.

In this semester project, the student will investigate different routes for adding carbon into pure iron, aiming for near-eutectoid steel compositions in lab-scale samples. Then, further addition of a single deoxidizing element (i.e. silicon) will follow to obtain oxide inclusions of specific stoichiometry (i.e. silica) upon reaction with dissolved oxygen in the matrix. Several melting techniques and heat treatments will be explored to obtain uniform and reproducible inclusion-containin near-eutectoid steel microstructures. Specimens will be prepared by standard metallographic techniques for microstructural and compositional characterization, including optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS).

Responsible supervisors: David Hernández Escobar and Sándor Lipcsei
Contact: [email protected] and [email protected]