Etchants for 440C Stainless 1

[Chamblin]

I am looking for a etchant that will show the retained austinite in 440C stainless steel. Would anyone know a reliable one?

 

[bruv]

ASTM E407, Standard test method for microetching metals and alloys should have something you can use.

If you cannot get hold of a copy I will have a look and see what I can find.

Bruv

 

[metrat]

The most common etchant for 440C is Vilella's reagent (nitric-hydrochloric). A note of caution regarding visually evaluating retained austenite, unless the levels are fairly high 15+%, it maybe difficult to see and evaluate. Typically, retained austenite is tested by x ray diffraction, in order to accurately determine the volume present. Hope this helps.