Photos for you to keep---for good.
Very low carbon steel sheet for forming. 2 mm thick.
Photos without Pearlite (arrowed) are taken from near-surface.
Last photo, dark field. white arrow: grainboundary; yellow arrow:
carbide film.
Austenitic Manganese Steel. Cast.
Shown in the photos are: interdendritic carbide particles and
"coring" (漸層) of the dendritic arms.
This as-cast specimen was not successfully solution annealed. It stayed
at 1020 C in a salt bath for too short a time (20 min) and then quenched in water.