Quantitative and qualitative investigation of the heterogeneous microstructures using surface hardness mapping and dilatation data

It is well known that each microstructural phase in steel has its own hardness level. Therefore, using surface hardness mapping data would be a reasonable method to characterize the present phases. Moreover, there are contractions and expansions during certain phase transformation which can be recorded during dilatation experiments. The resultant dilatation values can be employed to quantify and/or to identify the present phases. In the current work, these novel techniques are used to discriminate bainitic and martensitic microstructures after non-isothermal deformation of a boron alloyed steel. It is shown that these two methods are reliable, applicable and consistent.