Microstructural Characterization of Martensitic All-Weld Metal Samples

The development of welding consumables is permanently challenged with matching the increasing strength and toughness of thermomechanically treated or quenched and tempered steels. A martensitic microstructure offers promising prospects to guarantee such requirements in the all-weld metal as well. A thorough characterization of the microstructure is indispensable to understand its effects on the mechanical properties. This paper shall summarize how light optical microscopy and electron backscatter diffraction can be used to deepen the understanding of fully martensitic weld metal. It was found that electron backscatter diffraction offers a variety of information that light optical microscopy cannot deliver, particularly regarding the prior austenite grain structure. Grain sizes of the primary dendrites, the prior austenite grains and the martensitic structure can be measured with a combination of these techniques.