WKTaylor
Well-known member
- Sep 24, 2001
- 4,110
Please advise...
This report just came to my attention…
EASA SIB No 2018-04R1: Environmentally Assisted Cracking in certain Aluminum Alloys
This report states that EASA experience and testing of 7037, 7040, 7055, 7085, 7099, 7140 and 7449 have revealed 'SCC-like' cracking within these alloys caused by hydrogen embrittlement along grain boundaries. NOTE: I hate it when a technical document refers solely to an aluminum alloy designation number... and omits '-Txxx' temper and 'form' and specifications.
As a long-time user of 7XXX-T7XXX alloys where ST threshold of 25-KSIsqrt was considered 'SCC resistant'... along comes this related phenomena? Is 'EAC caused by hydrogen embrittlement' [EAC-HE] a fancy term for 'classic' SCC...? or is EAC-HE a subset of SCC...? or is EAC-HC an obscure similar [kissing-cousin?] phenomena that I have been unaware of... since it would normally merge with SCC during SCC testing?
PS: I have deliberately edited out the word alumininum… in favor of aluminum.
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]
This report just came to my attention…
EASA SIB No 2018-04R1: Environmentally Assisted Cracking in certain Aluminum Alloys
This report states that EASA experience and testing of 7037, 7040, 7055, 7085, 7099, 7140 and 7449 have revealed 'SCC-like' cracking within these alloys caused by hydrogen embrittlement along grain boundaries. NOTE: I hate it when a technical document refers solely to an aluminum alloy designation number... and omits '-Txxx' temper and 'form' and specifications.
As a long-time user of 7XXX-T7XXX alloys where ST threshold of 25-KSIsqrt was considered 'SCC resistant'... along comes this related phenomena? Is 'EAC caused by hydrogen embrittlement' [EAC-HE] a fancy term for 'classic' SCC...? or is EAC-HE a subset of SCC...? or is EAC-HC an obscure similar [kissing-cousin?] phenomena that I have been unaware of... since it would normally merge with SCC during SCC testing?
PS: I have deliberately edited out the word alumininum… in favor of aluminum.
Regards, Wil Taylor
o Trust - But Verify!
o We believe to be true what we prefer to be true. [Unknown]
o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]
o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]