Visualization method of austenite phase in duplex steel and duplex steel slab for structure observation

摘要

The present invention provides a method for visualizing an austenite phase in a duplex steel that can identify the austenite phase in the duplex steel on a nanoscale. According to the method of the present invention, a) a surface of a multiphase steel slab is electropolished in an electrolyte solution containing a corrosive acid and an organic solvent, and a natural oxide layer is formed on the surface of the multiphase steel slab. And b) after the completion of the electropolishing, the multiphase steel slab is continuously immersed in the electrolyte solution, and selectively on only the region of the natural oxide layer that covers the austenite phase. A step of forming a corrosion product layer; and c) subjecting the surface of the multiphase billet to a scanning electron microscope to obtain a contrast between the corrosion product layer and the remaining surface, thereby changing the austenite phase. Visualizing as the darkest area. [Selection] Figure 1