Using Ferric chloride for steel id

[J.Marsillo]

this just sounds stupid but i had to ask anyway.
When etching damascus the different contents of the steel etch at different rates and give different shades of gray pretty much from black to white.
Can ferric be used to check a Mystery steels properties by using a control peice of known steel? Ie: Mild steel vs a leaf spring or saw blade? feel free to flame me but i had to ask

 

[jhiggins]

this just sounds stupid but i had to ask anyway.
When etching damascus the different contents of the steel etch at different rates and give different shades of gray pretty much from black to white.
Can ferric be used to check a Mystery steels properties by using a control peice of known steel? Ie: Mild steel vs a leaf spring or saw blade? feel free to flame me but i had to ask

We don't flame in here, bro.

As far as your question, I think there are too many variables in the FC solution concentration strength, material temperature, Ambient tempurature, and solution temp, not to mention relative cleanliness of the test piece. Other than a chromatograph test, there is no concrete method. The closest is the spark test, which will really only ballpark you anyway.

Good question, JOE! Something I haven't heard yet. :thumbup:

 

[mdoyle]

would also depend largely on the hardness of the piece or the hardened state of the piece, ie. annealed or hardened or hardened and tempered....
Matt

 

[J.Marsillo]

way too many variables thanks Higgy It's been raining so much all i do is sit in my car at work and daydream.
Matt i had no idea hardness affected etching,but now that i just typed it it makes perfect sense

 

[Daniel Koster]

Too many variables - yes. However, if you have a knife that is already heat-treated differentially and you want to figure out what steel it is...might be able to tell from an etch.

Seems there's a clear difference in the etching I've done on 5160, vs the 10xx steels. The 1095 has been a "harder" etch than the 1075/80 I've used too, though it's more difficult to discern. Also, O-1 seems to react differently as well.

Here are my notes:

W-1 or 2 = clearest quench lines
1095 = next clearest difference
1075/80 = "wider" quench line..can be fuzzy
5160 and O-1 = quench line is more blurry & wide


YMMV