Etching 304L

[Hercules28]

What etchant would you use for 304L. Grain boundaries.

Non electrolytic are preffered.

 

[Goahead]

You can find what you need in an article titled
A Guide to Etching Specialty Alloys for Microstructural Evaluation
at

http://www.cartech.com/techarticles.aspx?id=1450

http://www.welding-advisers.com/

 

[EdStainless]

electrolytic oxalic acid is still the best.
If you don't want to mess with a power supply just use a battery.

You can try two things, a more concentrated oxalic acid may be good enough. Or a dilute HCl, however this may mess the rest of the micro up too much for you.
I'll check my list when I get back to the office.

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Plymouth Tube

 

[metengr]

http://www.asmfoundation.org/static...oken=d6f805c6d0c69f9910efde59b58b106ebd12cc5f

 

[Hercules28]

Just so you know,

I tried Marbles and it work great.
37% HCL and 7 gr CuSO4.

Swab for 5-10sec. Rinse with water.

Thanks for your suggestions. I will try the oxalic.

 

[metengr]

Mighty agressive etch for 304L. Marbles reagent is used for high end nickel-base alloys. I'll stick with 10% oxalic acid, thank you.

 

[EdStainless]

A number of the more aggressive etches will give good grain boundary definition in 304. But they also tend to produce a huge number of etch related artifacts that may be easily misinterpreted as defects.

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Plymouth Tube

 

[Guest102023]

Oxalic is crude but effective, and very easy to use. Concentration is saturated, about 10%.

Sodium or potassium hydroxide also works well, at concentrations from 10 to 40%. Just beware of the impressive heat of solution that is generated when you mix it with water.

Radio Shack sells a variable voltage charger that is good enough for much electrolytic etching work. Also you don't need lab grade water - I have always used distilled water at the grocery store.