Thermography for microstructure control during additive manufacturing of duplex stainless steel

Duplex stainless steels are used by maritime, nuclear, offshore oil and gas, and process industries due to their combination of strength, toughness and corrosion resistance. However, during additive manufacturing, duplex materials are prone to formation of brittle microstructural constituents. This study has applied thermography during the additive process to document thermal history for different sections of a simple geometry. The materials investigated in this study are duplex and super duplex stainless steels. The time spent in different temperature intervals in certain positions were determined and correlated to the achieved microstructures. Part-oriented thermal imaging can provide in-process quality assurance for microstructural development.