Abstract

The effects of boron and titanium microalloying on scale‐layer formation and structure on AISI 304 austenitic stainless steel are studied. The research is focused on a steel slab’s oxide scale formation in a reheat furnace prior to hot rolling. The studied boron microalloying amounts are 7, 35, and 55 ppm and the studied titanium microalloying amounts are <100 and 400 ppm. In‐depth temperature and atmosphere tests span from 1100 to 1300 °C for an O₂‐containing atmosphere and 1100 to 1250 °C in an H₂O‐containing atmosphere, both using 25 °C increments. Research shows that microalloying 55 ppm B reduces scale growth at above 1175 °C in an H₂O atmosphere, all microalloying elements show significant scale growth reduction at 1175 °C in an O₂ atmosphere, microalloying 35 and 55 ppm B increases scale growth amounts at above 1225 °C in an O₂ atmosphere, while microalloying 400 ppm Ti reduced it. The inhibiting effect on scale growth that results from boron microalloying is tied to silicon oxide infiltration of the steel substrate.