Hope things are going great across the board for you all! Getting into some metallographic, we do this quite often at my work. Today however were running into an issue getting a 301 Cres. Stainless to etch. We have a standard 70% Nitric- 30% Methanol, it is an electrolytic solution and even though the acid corrodes one current is induced, its only wearing down the metal, not staining it. It will turn its clack nasty color like it is etching but after rinse its gone. We trying running the hydrochloric and nitric together and got nothing.
Does anyone have a tried and true method for etching chromium and nickel steels?
Look @ this... Go to page 9 of 13 in the .pdf below and look for Kalling's or Marbles Reagent for the chemical composition of these electrolyte solutions:
You should find the answer to your question on page 9 of 13in the first listed .pdf... The book gives you a sort of reference for the subject. enjoy the read!
Ok so we ran with a certain set up, I think the problem is that it is a resistance seam weld on near foil thin sheet. The difference in grain etching is so low heat that its hard to find contrast. Hmmmm