In his PhD thesis engineer Rafael Gonzaga Jarquín has shown that thermal treatments are essential for the casting of iron and that, through a judicious balance of alloying elements, the mechanical properties of the material can be enhanced. The proposed system, moreover, provides energy and cost savings. The PhD was defended at the Public University of Navarre and led by Javier Fernández Carrasquilla of the Department of Mechanical Engineering, Energy and Materials.
More economic processes
In casting, once the piece is obtained as “pig” iron – i.e. directly extracted from the mould -, thermal annealing, standardising, shrinking and tempering treatments are applied, depending on the mechanical characteristics and properties required. Thus, for example, these processes vary if what is sought is ferrite, perlite, martensite or other spheroid carbon casting microstructures.
However, while it is true that the mechanical properties and characteristics of the ductile castings largely depend on the applied thermal treatments, the author also points out that additives play an important role. In concrete, the main contribution of this PhD is demonstrating that such heat treatment, very costly in financial terms, can be replaced by a suitable balance of alloying elements, and this process can achieve equal results or even better ones as regards enhanced mechanical properties.
Moreover, this thesis concludes that, “knowing that values for resilience and absorbed energy depend on the temperatures at which the test is undertaken and that there also exists a relation regarding thermal treatments, such values for resilience and absorbed energy are directly associated with the chemical composition of the said material, the effect of silicon above all”.