Solid Metal Induced Embrittlement

[KaiserSauzee]

I am seeking a clarification regarding galvanised steel and the effects of SMIE.
According to ASTM A193 - Paraphrase - Galvanised Bolting should not be used when operating above half the melting point of zinc.
Can anyone provide guidance or a reference to a standard that mentions SMIE in steel sheets / plates?
Previous threads have discussed SMIE however something is still not clear to me.
It is unclear if the clause in A193 would apply generally to all galvanised items or if there is some particular issue with SMIE when combined with e.g. the bolt thread.

 

[cloa]

I think you mean liquid metal induced embrittlement. The zinc would have significant vapour at half its melting point. Also the problem of galvanisation especially at high temperatures is one of contamination-embrittlement of welds

 

[TVP]

KS,

The susceptibility of a steel to LMIE or SMIE (there is a formal distinction) is a function of the microstructure, with higher strength/hardness being more susceptible. This is why threaded fasteners such as those specified by ASTM A 193 clearly identify this as a concern. A good reference on the subject is the article "Embrittlement of Steels" that appears in ASM HANDBOOK Volume 1 Properties and Selection: Irons, Steels, and High-Performance Alloys. You can obtain this article as a download from ASM using the following link:

http://asmcommunity.asminternational.org/portal/site/

http://www/AsmStore/ProductDetails/?vgnextoid=51b74ef322e18110VgnVCM100000701e010aRCRD

 

[KaiserSauzee]

TVP,
Thanks for your input. I got a hold of the ASM handbook and it is certainly the best source of information on the subject I could find.

Just to add to the discussion - through my research on this topic I came across some documented cases of Cadmium plated bolts and aluminium compressed air cylinders failing through SMIE. As far as I can see, there have been no documented cases of in service Galvanised bolts / structures failing through SMIE.
If anyone has experience (or evidence) contrary to this then please let me know. I would be very interested to hear from you.