etchant, CRES, welds
etchant, CRES, welds
(OP)
1) The best etchant formula to reveal the weld penetration of 304 stainless steel ?
2) After etching, will the HAZ show up too which confuses the reading for penetration ?
3) The underlining etching mechanics?
thanks.
2) After etching, will the HAZ show up too which confuses the reading for penetration ?
3) The underlining etching mechanics?
thanks.





RE: etchant, CRES, welds
2. Weld metal/fusion zone should be distinct from HAZ after etching.
3. Different mechanisms are present for different etchants. Anodic dissolution of grain boundaries, sulfide film formation, and others are present.
RE: etchant, CRES, welds
(2)The HAZ will exhibit some networking of carbides along grain boundaries.
(3) read here https://www.cartech.com/news.aspx?id=578 or http://vacaero.com/information-resources/metallogr...
RE: etchant, CRES, welds
Best regards - Al
RE: etchant, CRES, welds
A light electrolytic etch in 10% oxalic acid will work well, don't over etch.
Most etchants rely on differential attack rates for various phases/orientation/compositions.
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P.E. Metallurgy, Plymouth Tube