Etchant for Revealing Prior Austenite Grain in Alloy Steel / Ätzmittel für die Entwicklung des Primäraustenitkorns in legierten Stählen

A new approach to etching low‐carbon microalloyed steels to reveal prior austenite grain boundaries and the dual‐phase microstructure

“…Multiple studies have shown that prior‐austenite grain boundaries in quenched steels can be revealed using picric acid solutions plus wetting agents. 7 , 8 , 9 , 10 This is because during austenitisation and tempering, phosphorus and other trace solute atoms segregate to the grain boundaries. 11 , 12 Wetting agents or surface‐active agents (surfactants) are added to etchants to improve grain boundary delineation in steels acting on the etching speed or selectivity modification.…”