Modifying the Microstructure and Mechanical Properties of a Microalloyed Steel developed for use in the Automotive Industry

The aim of the present work is to analyse the microstructural changes caused by distinct heat treatments and their relationships with the mechanical properties of a recently developed microalloyed steel with 0.08%C-1,5%Mn. This steel, designated as B550, is being considered as a promising alternative to replace the low carbon steel in some wheel`s components for the automotive industry. Various multiphase microstructures with different amounts of ferrite, martensite, bainite and retained austenite were obtained by means of heat treatments conducted at distinct temperatures. Tensile tests allowed evaluating the mechanical properties of the various material conditions. The experimental results showed that water quench from 800°C results in a better combination of mechanical properties of strength, hardenability and ductility.